diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2025-12-04 11:04:38 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-12-04 11:04:38 -0800 |
| commit | 77956cf36494cc5e5649b187f552b90fb14d0674 (patch) | |
| tree | 7c50b686423464b627b81b1360696bdc0ed872a1 | |
| parent | 04265849c856ace113e75ae88069b8665bd4dcbe (diff) | |
| parent | fae00ea9f00367771003ace78f29549dead58fc7 (diff) | |
Merge tag 'pwm/for-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux
Pull pwm updates from Uwe Kleine-König:
"In addition to the usual mix of core cleanups, driver changes, minor
fixes and device tree updates the highlight this cycle is Rust support
for the core and a first Rust driver both provided by Michal
Wilczynski.
Michal wrote about these changes on
https://mwilczynski.dev/posts/bringing-rust-to-the-pwm-subsystem/
which is a nice read"
* tag 'pwm/for-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux: (22 commits)
pwm: rzg2l-gpt: Allow checking period_tick cache value only if sibling channel is enabled
pwm: bcm2835: Make sure the channel is enabled after pwm_request()
pwm: mediatek: Make use of struct_size macro
pwm: mediatek: Remove unneeded semicolon
pwm: airoha: Add support for EN7581 SoC
pwm: mediatek: Convert to waveform API
pwm: max7360: Clean MAX7360 code
pwm: Drop unused function pwm_apply_args()
pwm: Use %u to printf unsigned int pwm_chip::npwm and pwm_chip::id
pwm: Simplify printf to emit chip->npwm in $debugfs/pwm
pwm: th1520: Use module_pwm_platform_driver! macro
pwm: th1520: Fix clippy warning for redundant struct field init
pwm: Fix Rust formatting
dt-bindings: pwm: thead: Add T-HEAD TH1520 PWM controller
pwm: Add Rust driver for T-HEAD TH1520 SoC
rust: pwm: Fix broken intra-doc link
rust: pwm: Drop wrapping of PWM polarity and state
rust: pwm: Add module_pwm_platform_driver! macro
rust: pwm: Add complete abstraction layer
rust: pwm: Add Kconfig and basic data structures
...
| -rw-r--r-- | Documentation/devicetree/bindings/pwm/thead,th1520-pwm.yaml | 48 | ||||
| -rw-r--r-- | MAINTAINERS | 10 | ||||
| -rw-r--r-- | drivers/pwm/Kconfig | 33 | ||||
| -rw-r--r-- | drivers/pwm/Makefile | 2 | ||||
| -rw-r--r-- | drivers/pwm/core.c | 8 | ||||
| -rw-r--r-- | drivers/pwm/pwm-airoha.c | 622 | ||||
| -rw-r--r-- | drivers/pwm/pwm-bcm2835.c | 28 | ||||
| -rw-r--r-- | drivers/pwm/pwm-max7360.c | 2 | ||||
| -rw-r--r-- | drivers/pwm/pwm-mediatek.c | 285 | ||||
| -rw-r--r-- | drivers/pwm/pwm-rzg2l-gpt.c | 15 | ||||
| -rw-r--r-- | drivers/pwm/pwm_th1520.rs | 387 | ||||
| -rw-r--r-- | include/linux/pwm.h | 39 | ||||
| -rw-r--r-- | rust/bindings/bindings_helper.h | 1 | ||||
| -rw-r--r-- | rust/helpers/helpers.c | 1 | ||||
| -rw-r--r-- | rust/helpers/pwm.c | 20 | ||||
| -rw-r--r-- | rust/kernel/lib.rs | 2 | ||||
| -rw-r--r-- | rust/kernel/pwm.rs | 735 | ||||
| -rw-r--r-- | rust/macros/module.rs | 8 |
18 files changed, 2071 insertions, 175 deletions
diff --git a/Documentation/devicetree/bindings/pwm/thead,th1520-pwm.yaml b/Documentation/devicetree/bindings/pwm/thead,th1520-pwm.yaml new file mode 100644 index 000000000000..855aec59ac53 --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/thead,th1520-pwm.yaml @@ -0,0 +1,48 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/pwm/thead,th1520-pwm.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: T-HEAD TH1520 PWM controller + +maintainers: + - Michal Wilczynski <m.wilczynski@samsung.com> + +allOf: + - $ref: pwm.yaml# + +properties: + compatible: + const: thead,th1520-pwm + + reg: + maxItems: 1 + + clocks: + items: + - description: SoC PWM clock + + "#pwm-cells": + const: 3 + +required: + - compatible + - reg + - clocks + +unevaluatedProperties: false + +examples: + - | + #include <dt-bindings/clock/thead,th1520-clk-ap.h> + soc { + #address-cells = <2>; + #size-cells = <2>; + pwm@ffec01c000 { + compatible = "thead,th1520-pwm"; + reg = <0xff 0xec01c000 0x0 0x4000>; + clocks = <&clk CLK_PWM>; + #pwm-cells = <3>; + }; + }; diff --git a/MAINTAINERS b/MAINTAINERS index f5b643ae8e90..5501d0ae7c70 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20871,6 +20871,14 @@ F: include/linux/pwm.h F: include/linux/pwm_backlight.h K: pwm_(config|apply_might_sleep|apply_atomic|ops) +PWM SUBSYSTEM BINDINGS [RUST] +M: Michal Wilczynski <m.wilczynski@samsung.com> +L: linux-pwm@vger.kernel.org +L: rust-for-linux@vger.kernel.org +S: Maintained +F: rust/helpers/pwm.c +F: rust/kernel/pwm.rs + PXA GPIO DRIVER M: Robert Jarzmik <robert.jarzmik@free.fr> L: linux-gpio@vger.kernel.org @@ -22293,6 +22301,7 @@ F: Documentation/devicetree/bindings/firmware/thead,th1520-aon.yaml F: Documentation/devicetree/bindings/mailbox/thead,th1520-mbox.yaml F: Documentation/devicetree/bindings/net/thead,th1520-gmac.yaml F: Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml +F: Documentation/devicetree/bindings/pwm/thead,th1520-pwm.yaml F: Documentation/devicetree/bindings/reset/thead,th1520-reset.yaml F: arch/riscv/boot/dts/thead/ F: drivers/clk/thead/clk-th1520-ap.c @@ -22303,6 +22312,7 @@ F: drivers/pinctrl/pinctrl-th1520.c F: drivers/pmdomain/thead/ F: drivers/power/reset/th1520-aon-reboot.c F: drivers/power/sequencing/pwrseq-thead-gpu.c +F: drivers/pwm/pwm_th1520.rs F: drivers/reset/reset-th1520.c F: include/dt-bindings/clock/thead,th1520-clk-ap.h F: include/dt-bindings/power/thead,th1520-power.h diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index c2fd3f4b62d9..bf2d101f67a1 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -63,6 +63,16 @@ config PWM_ADP5585 This option enables support for the PWM function found in the Analog Devices ADP5585. +config PWM_AIROHA + tristate "Airoha PWM support" + depends on ARCH_AIROHA || COMPILE_TEST + select REGMAP_MMIO + help + Generic PWM framework driver for Airoha SoC. + + To compile this driver as a module, choose M here: the module + will be called pwm-airoha. + config PWM_APPLE tristate "Apple SoC PWM support" depends on ARCH_APPLE || COMPILE_TEST @@ -748,6 +758,17 @@ config PWM_TEGRA To compile this driver as a module, choose M here: the module will be called pwm-tegra. +config PWM_TH1520 + tristate "TH1520 PWM support" + depends on RUST + select RUST_PWM_ABSTRACTIONS + help + This option enables the driver for the PWM controller found on the + T-HEAD TH1520 SoC. + + To compile this driver as a module, choose M here; the module + will be called pwm-th1520. If you are unsure, say N. + config PWM_TIECAP tristate "ECAP PWM support" depends on ARCH_OMAP2PLUS || ARCH_DAVINCI_DA8XX || ARCH_KEYSTONE || ARCH_K3 || COMPILE_TEST @@ -819,4 +840,16 @@ config PWM_XILINX To compile this driver as a module, choose M here: the module will be called pwm-xilinx. + config RUST_PWM_ABSTRACTIONS + bool + depends on RUST + help + This option enables the safe Rust abstraction layer for the PWM + subsystem. It provides idiomatic wrappers and traits necessary for + writing PWM controller drivers in Rust. + + The abstractions handle resource management (like memory and reference + counting) and provide safe interfaces to the underlying C core, + allowing driver logic to be written in safe Rust. + endif diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index dfa8b4966ee1..0dc0d2b69025 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -2,6 +2,7 @@ obj-$(CONFIG_PWM) += core.o obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o obj-$(CONFIG_PWM_ADP5585) += pwm-adp5585.o +obj-$(CONFIG_PWM_AIROHA) += pwm-airoha.o obj-$(CONFIG_PWM_APPLE) += pwm-apple.o obj-$(CONFIG_PWM_ARGON_FAN_HAT) += pwm-argon-fan-hat.o obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o @@ -68,6 +69,7 @@ obj-$(CONFIG_PWM_STMPE) += pwm-stmpe.o obj-$(CONFIG_PWM_SUN4I) += pwm-sun4i.o obj-$(CONFIG_PWM_SUNPLUS) += pwm-sunplus.o obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o +obj-$(CONFIG_PWM_TH1520) += pwm_th1520.o obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o obj-$(CONFIG_PWM_TWL) += pwm-twl.o diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index ea2ccf42e814..cd06229db394 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -1608,12 +1608,13 @@ void pwmchip_put(struct pwm_chip *chip) } EXPORT_SYMBOL_GPL(pwmchip_put); -static void pwmchip_release(struct device *pwmchip_dev) +void pwmchip_release(struct device *pwmchip_dev) { struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); kfree(chip); } +EXPORT_SYMBOL_GPL(pwmchip_release); struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv) { @@ -2696,11 +2697,10 @@ static int pwm_seq_show(struct seq_file *s, void *v) { struct pwm_chip *chip = v; - seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n", + seq_printf(s, "%s%u: %s/%s, npwm: %u\n", (char *)s->private, chip->id, pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus", - dev_name(pwmchip_parent(chip)), chip->npwm, - (chip->npwm != 1) ? "s" : ""); + dev_name(pwmchip_parent(chip)), chip->npwm); pwm_dbg_show(chip, s); diff --git a/drivers/pwm/pwm-airoha.c b/drivers/pwm/pwm-airoha.c new file mode 100644 index 000000000000..7236e31d2f17 --- /dev/null +++ b/drivers/pwm/pwm-airoha.c @@ -0,0 +1,622 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2022 Markus Gothe <markus.gothe@genexis.eu> + * Copyright 2025 Christian Marangi <ansuelsmth@gmail.com> + * + * Limitations: + * - Only 8 concurrent waveform generators are available for 8 combinations of + * duty_cycle and period. Waveform generators are shared between 16 GPIO + * pins and 17 SIPO GPIO pins. + * - Supports only normal polarity. + * - On configuration the currently running period is completed. + * - Minimum supported period is 4 ms + * - Maximum supported period is 1s + */ + +#include <linux/array_size.h> +#include <linux/bitfield.h> +#include <linux/bitmap.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/math64.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/regmap.h> +#include <linux/types.h> + +#define AIROHA_PWM_REG_SGPIO_LED_DATA 0x0024 +#define AIROHA_PWM_SGPIO_LED_DATA_SHIFT_FLAG BIT(31) +#define AIROHA_PWM_SGPIO_LED_DATA_DATA GENMASK(16, 0) + +#define AIROHA_PWM_REG_SGPIO_CLK_DIVR 0x0028 +#define AIROHA_PWM_SGPIO_CLK_DIVR GENMASK(1, 0) +#define AIROHA_PWM_SGPIO_CLK_DIVR_32 FIELD_PREP_CONST(AIROHA_PWM_SGPIO_CLK_DIVR, 3) +#define AIROHA_PWM_SGPIO_CLK_DIVR_16 FIELD_PREP_CONST(AIROHA_PWM_SGPIO_CLK_DIVR, 2) +#define AIROHA_PWM_SGPIO_CLK_DIVR_8 FIELD_PREP_CONST(AIROHA_PWM_SGPIO_CLK_DIVR, 1) +#define AIROHA_PWM_SGPIO_CLK_DIVR_4 FIELD_PREP_CONST(AIROHA_PWM_SGPIO_CLK_DIVR, 0) + +#define AIROHA_PWM_REG_SGPIO_CLK_DLY 0x002c + +#define AIROHA_PWM_REG_SIPO_FLASH_MODE_CFG 0x0030 +#define AIROHA_PWM_SERIAL_GPIO_FLASH_MODE BIT(1) +#define AIROHA_PWM_SERIAL_GPIO_MODE_74HC164 BIT(0) + +#define AIROHA_PWM_REG_GPIO_FLASH_PRD_SET(_n) (0x003c + (4 * (_n))) +#define AIROHA_PWM_REG_GPIO_FLASH_PRD_SHIFT(_n) (16 * (_n)) +#define AIROHA_PWM_GPIO_FLASH_PRD_LOW GENMASK(15, 8) +#define AIROHA_PWM_GPIO_FLASH_PRD_HIGH GENMASK(7, 0) + +#define AIROHA_PWM_REG_GPIO_FLASH_MAP(_n) (0x004c + (4 * (_n))) +#define AIROHA_PWM_REG_GPIO_FLASH_MAP_SHIFT(_n) (4 * (_n)) +#define AIROHA_PWM_GPIO_FLASH_EN BIT(3) +#define AIROHA_PWM_GPIO_FLASH_SET_ID GENMASK(2, 0) + +/* Register map is equal to GPIO flash map */ +#define AIROHA_PWM_REG_SIPO_FLASH_MAP(_n) (0x0054 + (4 * (_n))) + +#define AIROHA_PWM_REG_CYCLE_CFG_VALUE(_n) (0x0098 + (4 * (_n))) +#define AIROHA_PWM_REG_CYCLE_CFG_SHIFT(_n) (8 * (_n)) +#define AIROHA_PWM_WAVE_GEN_CYCLE GENMASK(7, 0) + +/* GPIO/SIPO flash map handles 8 pins in one register */ +#define AIROHA_PWM_PINS_PER_FLASH_MAP 8 +/* Cycle(Period) registers handles 4 generators in one 32-bit register */ +#define AIROHA_PWM_BUCKET_PER_CYCLE_CFG 4 +/* Flash(Duty) producer handles 2 generators in one 32-bit register */ +#define AIROHA_PWM_BUCKET_PER_FLASH_PROD 2 + +#define AIROHA_PWM_NUM_BUCKETS 8 +/* + * The first 16 GPIO pins, GPIO0-GPIO15, are mapped into 16 PWM channels, 0-15. + * The SIPO GPIO pins are 17 pins which are mapped into 17 PWM channels, 16-32. + * However, we've only got 8 concurrent waveform generators and can therefore + * only use up to 8 different combinations of duty cycle and period at a time. + */ +#define AIROHA_PWM_NUM_GPIO 16 +#define AIROHA_PWM_NUM_SIPO 17 +#define AIROHA_PWM_MAX_CHANNELS (AIROHA_PWM_NUM_GPIO + AIROHA_PWM_NUM_SIPO) + +struct airoha_pwm_bucket { + /* Concurrent access protected by PWM core */ + int used; + u32 period_ticks; + u32 duty_ticks; +}; + +struct airoha_pwm { + struct regmap *regmap; + + DECLARE_BITMAP(initialized, AIROHA_PWM_MAX_CHANNELS); + + struct airoha_pwm_bucket buckets[AIROHA_PWM_NUM_BUCKETS]; + + /* Cache bucket used by each pwm channel */ + u8 channel_bucket[AIROHA_PWM_MAX_CHANNELS]; +}; + +/* The PWM hardware supports periods between 4 ms and 1 s */ +#define AIROHA_PWM_PERIOD_TICK_NS (4 * NSEC_PER_MSEC) +#define AIROHA_PWM_PERIOD_MAX_NS (1 * NSEC_PER_SEC) +/* It is represented internally as 1/250 s between 1 and 250. Unit is ticks. */ +#define AIROHA_PWM_PERIOD_MIN 1 +#define AIROHA_PWM_PERIOD_MAX 250 +/* Duty cycle is relative with 255 corresponding to 100% */ +#define AIROHA_PWM_DUTY_FULL 255 + +static void airoha_pwm_get_flash_map_addr_and_shift(unsigned int hwpwm, + u32 *addr, u32 *shift) +{ + unsigned int offset, hwpwm_bit; + + if (hwpwm >= AIROHA_PWM_NUM_GPIO) { + unsigned int sipohwpwm = hwpwm - AIROHA_PWM_NUM_GPIO; + + offset = sipohwpwm / AIROHA_PWM_PINS_PER_FLASH_MAP; + hwpwm_bit = sipohwpwm % AIROHA_PWM_PINS_PER_FLASH_MAP; + + /* One FLASH_MAP register handles 8 pins */ + *shift = AIROHA_PWM_REG_GPIO_FLASH_MAP_SHIFT(hwpwm_bit); + *addr = AIROHA_PWM_REG_SIPO_FLASH_MAP(offset); + } else { + offset = hwpwm / AIROHA_PWM_PINS_PER_FLASH_MAP; + hwpwm_bit = hwpwm % AIROHA_PWM_PINS_PER_FLASH_MAP; + + /* One FLASH_MAP register handles 8 pins */ + *shift = AIROHA_PWM_REG_GPIO_FLASH_MAP_SHIFT(hwpwm_bit); + *addr = AIROHA_PWM_REG_GPIO_FLASH_MAP(offset); + } +} + +static u32 airoha_pwm_get_period_ticks_from_ns(u32 period_ns) +{ + return period_ns / AIROHA_PWM_PERIOD_TICK_NS; +} + +static u32 airoha_pwm_get_duty_ticks_from_ns(u32 period_ns, u32 duty_ns) +{ + return mul_u64_u32_div(duty_ns, AIROHA_PWM_DUTY_FULL, period_ns); +} + +static u32 airoha_pwm_get_period_ns_from_ticks(u32 period_tick) +{ + return period_tick * AIROHA_PWM_PERIOD_TICK_NS; +} + +static u32 airoha_pwm_get_duty_ns_from_ticks(u32 period_tick, u32 duty_tick) +{ + u32 period_ns = period_tick * AIROHA_PWM_PERIOD_TICK_NS; + + /* + * Overflow can't occur in multiplication as duty_tick is just 8 bit + * and period_ns is clamped to AIROHA_PWM_PERIOD_MAX_NS and fit in a + * u64. + */ + return DIV_U64_ROUND_UP(duty_tick * period_ns, AIROHA_PWM_DUTY_FULL); +} + +static int airoha_pwm_get_bucket(struct airoha_pwm *pc, int bucket, + u64 *period_ns, u64 *duty_ns) +{ + struct regmap *map = pc->regmap; + u32 period_tick, duty_tick; + unsigned int offset; + u32 shift, val; + int ret; + + offset = bucket / AIROHA_PWM_BUCKET_PER_CYCLE_CFG; + shift = bucket % AIROHA_PWM_BUCKET_PER_CYCLE_CFG; + shift = AIROHA_PWM_REG_CYCLE_CFG_SHIFT(shift); + + ret = regmap_read(map, AIROHA_PWM_REG_CYCLE_CFG_VALUE(offset), &val); + if (ret) + return ret; + + period_tick = FIELD_GET(AIROHA_PWM_WAVE_GEN_CYCLE, val >> shift); + *period_ns = airoha_pwm_get_period_ns_from_ticks(period_tick); + + offset = bucket / AIROHA_PWM_BUCKET_PER_FLASH_PROD; + shift = bucket % AIROHA_PWM_BUCKET_PER_FLASH_PROD; + shift = AIROHA_PWM_REG_GPIO_FLASH_PRD_SHIFT(shift); + + ret = regmap_read(map, AIROHA_PWM_REG_GPIO_FLASH_PRD_SET(offset), + &val); + if (ret) + return ret; + + duty_tick = FIELD_GET(AIROHA_PWM_GPIO_FLASH_PRD_HIGH, val >> shift); + *duty_ns = airoha_pwm_get_duty_ns_from_ticks(period_tick, duty_tick); + + return 0; +} + +static int airoha_pwm_get_generator(struct airoha_pwm *pc, u32 duty_ticks, + u32 period_ticks) +{ + int best = -ENOENT, unused = -ENOENT; + u32 duty_ns, best_duty_ns = 0; + u32 best_period_ticks = 0; + unsigned int i; + + duty_ns = airoha_pwm_get_duty_ns_from_ticks(period_ticks, duty_ticks); + + for (i = 0; i < ARRAY_SIZE(pc->buckets); i++) { + struct airoha_pwm_bucket *bucket = &pc->buckets[i]; + u32 bucket_period_ticks = bucket->period_ticks; + u32 bucket_duty_ticks = bucket->duty_ticks; + + /* If found, save an unused bucket to return it later */ + if (!bucket->used) { + unused = i; + continue; + } + + /* We found a matching bucket, exit early */ + if (duty_ticks == bucket_duty_ticks && + period_ticks == bucket_period_ticks) + return i; + + /* + * Unlike duty cycle zero, which can be handled by + * disabling PWM, a generator is needed for full duty + * cycle but it can be reused regardless of period + */ + if (duty_ticks == AIROHA_PWM_DUTY_FULL && + bucket_duty_ticks == AIROHA_PWM_DUTY_FULL) + return i; + + /* + * With an unused bucket available, skip searching for + * a bucket to recycle (closer to the requested period/duty) + */ + if (unused >= 0) + continue; + + /* Ignore bucket with invalid period */ + if (bucket_period_ticks > period_ticks) + continue; + + /* + * Search for a bucket closer to the requested period + * that has the maximal possible period that isn't bigger + * than the requested period. For that period pick the maximal + * duty cycle that isn't bigger than the requested duty_cycle. + */ + if (bucket_period_ticks >= best_period_ticks) { + u32 bucket_duty_ns = airoha_pwm_get_duty_ns_from_ticks(bucket_period_ticks, + bucket_duty_ticks); + + /* Skip bucket that goes over the requested duty */ + if (bucket_duty_ns > duty_ns) + continue; + + if (bucket_duty_ns > best_duty_ns) { + best_period_ticks = bucket_period_ticks; + best_duty_ns = bucket_duty_ns; + best = i; + } + } + } + + /* Return an unused bucket or the best one found (if ever) */ + return unused >= 0 ? unused : best; +} + +static void airoha_pwm_release_bucket_config(struct airoha_pwm *pc, + unsigned int hwpwm) +{ + int bucket; + + /* Nothing to clear, PWM channel never used */ + if (!test_bit(hwpwm, pc->initialized)) + return; + + bucket = pc->channel_bucket[hwpwm]; + pc->buckets[bucket].used--; +} + +static int airoha_pwm_apply_bucket_config(struct airoha_pwm *pc, unsigned int bucket, + u32 duty_ticks, u32 period_ticks) +{ + u32 mask, shift, val; + u32 offset; + int ret; + + offset = bucket / AIROHA_PWM_BUCKET_PER_CYCLE_CFG; + shift = bucket % AIROHA_PWM_BUCKET_PER_CYCLE_CFG; + shift = AIROHA_PWM_REG_CYCLE_CFG_SHIFT(shift); + + /* Configure frequency divisor */ + mask = AIROHA_PWM_WAVE_GEN_CYCLE << shift; + val = FIELD_PREP(AIROHA_PWM_WAVE_GEN_CYCLE, period_ticks) << shift; + ret = regmap_update_bits(pc->regmap, AIROHA_PWM_REG_CYCLE_CFG_VALUE(offset), + mask, val); + if (ret) + return ret; + + offset = bucket / AIROHA_PWM_BUCKET_PER_FLASH_PROD; + shift = bucket % AIROHA_PWM_BUCKET_PER_FLASH_PROD; + shift = AIROHA_PWM_REG_GPIO_FLASH_PRD_SHIFT(shift); + + /* Configure duty cycle */ + mask = AIROHA_PWM_GPIO_FLASH_PRD_HIGH << shift; + val = FIELD_PREP(AIROHA_PWM_GPIO_FLASH_PRD_HIGH, duty_ticks) << shift; + ret = regmap_update_bits(pc->regmap, AIROHA_PWM_REG_GPIO_FLASH_PRD_SET(offset), + mask, val); + if (ret) + return ret; + + mask = AIROHA_PWM_GPIO_FLASH_PRD_LOW << shift; + val = FIELD_PREP(AIROHA_PWM_GPIO_FLASH_PRD_LOW, + AIROHA_PWM_DUTY_FULL - duty_ticks) << shift; + return regmap_update_bits(pc->regmap, AIROHA_PWM_REG_GPIO_FLASH_PRD_SET(offset), + mask, val); +} + +static int airoha_pwm_consume_generator(struct airoha_pwm *pc, + u32 duty_ticks, u32 period_ticks, + unsigned int hwpwm) +{ + bool config_bucket = false; + int bucket, ret; + + /* + * Search for a bucket that already satisfies duty and period + * or an unused one. + * If not found, -ENOENT is returned. + */ + bucket = airoha_pwm_get_generator(pc, duty_ticks, period_ticks); + if (bucket < 0) + return bucket; + + /* Release previous used bucket (if any) */ + airoha_pwm_release_bucket_config(pc, hwpwm); + + if (!pc->buckets[bucket].used) + config_bucket = true; + pc->buckets[bucket].used++; + + if (config_bucket) { + pc->buckets[bucket].period_ticks = period_ticks; + pc->buckets[bucket].duty_ticks = duty_ticks; + ret = airoha_pwm_apply_bucket_config(pc, bucket, + duty_ticks, + period_ticks); + if (ret) { + pc->buckets[bucket].used--; + return ret; + } + } + + return bucket; +} + +static int airoha_pwm_sipo_init(struct airoha_pwm *pc) +{ + u32 val; + int ret; + + ret = regmap_clear_bits(pc->regmap, AIROHA_PWM_REG_SIPO_FLASH_MODE_CFG, + AIROHA_PWM_SERIAL_GPIO_MODE_74HC164); + if (ret) + return ret; + + /* Configure shift register chip clock timings, use 32x divisor */ + ret = regmap_write(pc->regmap, AIROHA_PWM_REG_SGPIO_CLK_DIVR, + AIROHA_PWM_SGPIO_CLK_DIVR_32); + if (ret) + return ret; + + /* + * Configure the shift register chip clock delay. This needs + * to be configured based on the chip characteristics when the SoC + * apply the shift register configuration. + * This doesn't affect actual PWM operation and is only specific to + * the shift register chip. + * + * For 74HC164 we set it to 0. + * + * For reference, the actual delay applied is the internal clock + * feed to the SGPIO chip + 1. + * + * From documentation is specified that clock delay should not be + * greater than (AIROHA_PWM_REG_SGPIO_CLK_DIVR / 2) - 1. + */ + ret = regmap_write(pc->regmap, AIROHA_PWM_REG_SGPIO_CLK_DLY, 0); + if (ret) + return ret; + + /* + * It is necessary to explicitly shift out all zeros after muxing + * to initialize the shift register before enabling PWM + * mode because in PWM mode SIPO will not start shifting until + * it needs to output a non-zero value (bit 31 of led_data + * indicates shifting in progress and it must return to zero + * before led_data can be written or PWM mode can be set). + */ + ret = regmap_read_poll_timeout(pc->regmap, AIROHA_PWM_REG_SGPIO_LED_DATA, val, + !(val & AIROHA_PWM_SGPIO_LED_DATA_SHIFT_FLAG), + 10, 200 * USEC_PER_MSEC); + if (ret) + return ret; + + ret = regmap_clear_bits(pc->regmap, AIROHA_PWM_REG_SGPIO_LED_DATA, + AIROHA_PWM_SGPIO_LED_DATA_DATA); + if (ret) + return ret; + ret = regmap_read_poll_timeout(pc->regmap, AIROHA_PWM_REG_SGPIO_LED_DATA, val, + !(val & AIROHA_PWM_SGPIO_LED_DATA_SHIFT_FLAG), + 10, 200 * USEC_PER_MSEC); + if (ret) + return ret; + + /* Set SIPO in PWM mode */ + return regmap_set_bits(pc->regmap, AIROHA_PWM_REG_SIPO_FLASH_MODE_CFG, + AIROHA_PWM_SERIAL_GPIO_FLASH_MODE); +} + +static int airoha_pwm_config_flash_map(struct airoha_pwm *pc, + unsigned int hwpwm, int index) +{ + unsigned int addr; + u32 shift; + int ret; + + airoha_pwm_get_flash_map_addr_and_shift(hwpwm, &addr, &shift); + + /* negative index means disable PWM channel */ + if (index < 0) { + /* + * If we need to disable the PWM, we just put low the + * GPIO. No need to setup buckets. + */ + return regmap_clear_bits(pc->regmap, addr, + AIROHA_PWM_GPIO_FLASH_EN << shift); + } + + ret = regmap_update_bits(pc->regmap, addr, + AIROHA_PWM_GPIO_FLASH_SET_ID << shift, + FIELD_PREP(AIROHA_PWM_GPIO_FLASH_SET_ID, index) << shift); + if (ret) + return ret; + + return regmap_set_bits(pc->regmap, addr, AIROHA_PWM_GPIO_FLASH_EN << shift); +} + +static int airoha_pwm_config(struct airoha_pwm *pc, struct pwm_device *pwm, + u32 period_ticks, u32 duty_ticks) +{ + unsigned int hwpwm = pwm->hwpwm; + int bucket, ret; + + bucket = airoha_pwm_consume_generator(pc, duty_ticks, period_ticks, + hwpwm); + if (bucket < 0) + return bucket; + + ret = airoha_pwm_config_flash_map(pc, hwpwm, bucket); + if (ret) { + pc->buckets[bucket].used--; + return ret; + } + + __set_bit(hwpwm, pc->initialized); + pc->channel_bucket[hwpwm] = bucket; + + /* + * SIPO are special GPIO attached to a shift register chip. The handling + * of this chip is internal to the SoC that takes care of applying the + * values based on the flash map. To apply a new flash map, it's needed + * to trigger a refresh on the shift register chip. + * If a SIPO is getting configuring , always reinit the shift register + * chip to make sure the correct flash map is applied. + * Skip reconfiguring the shift register if the related hwpwm + * is disabled (as it doesn't need to be mapped). + */ + if (hwpwm >= AIROHA_PWM_NUM_GPIO) { + ret = airoha_pwm_sipo_init(pc); + if (ret) { + airoha_pwm_release_bucket_config(pc, hwpwm); + return ret; + } + } + + return 0; +} + +static void airoha_pwm_disable(struct airoha_pwm *pc, struct pwm_device *pwm) +{ + /* Disable PWM and release the bucket */ + airoha_pwm_config_flash_map(pc, pwm->hwpwm, -1); + airoha_pwm_release_bucket_config(pc, pwm->hwpwm); + + __clear_bit(pwm->hwpwm, pc->initialized); + + /* If no SIPO is used, disable the shift register chip */ + if (!bitmap_read(pc->initialized, + AIROHA_PWM_NUM_GPIO, AIROHA_PWM_NUM_SIPO)) + regmap_clear_bits(pc->regmap, AIROHA_PWM_REG_SIPO_FLASH_MODE_CFG, + AIROHA_PWM_SERIAL_GPIO_FLASH_MODE); +} + +static int airoha_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + struct airoha_pwm *pc = pwmchip_get_drvdata(chip); + u32 period_ticks, duty_ticks; + u32 period_ns, duty_ns; + + if (!state->enabled) { + airoha_pwm_disable(pc, pwm); + return 0; + } + + /* Only normal polarity is supported */ + if (state->polarity == PWM_POLARITY_INVERSED) + return -EINVAL; + + /* Exit early if period is less than minimum supported */ + if (state->period < AIROHA_PWM_PERIOD_TICK_NS) + return -EINVAL; + + /* Clamp period to MAX supported value */ + if (state->period > AIROHA_PWM_PERIOD_MAX_NS) + period_ns = AIROHA_PWM_PERIOD_MAX_NS; + else + period_ns = state->period; + + /* Validate duty to configured period */ + if (state->duty_cycle > period_ns) + duty_ns = period_ns; + else + duty_ns = state->duty_cycle; + + /* Convert period ns to ticks */ + period_ticks = airoha_pwm_get_period_ticks_from_ns(period_ns); + /* Convert period ticks to ns again for cosistent duty tick calculation */ + period_ns = airoha_pwm_get_period_ns_from_ticks(period_ticks); + duty_ticks = airoha_pwm_get_duty_ticks_from_ns(period_ns, duty_ns); + + return airoha_pwm_config(pc, pwm, period_ticks, duty_ticks); +} + +static int airoha_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct airoha_pwm *pc = pwmchip_get_drvdata(chip); + int ret, hwpwm = pwm->hwpwm; + u32 addr, shift, val; + u8 bucket; + + airoha_pwm_get_flash_map_addr_and_shift(hwpwm, &addr, &shift); + + ret = regmap_read(pc->regmap, addr, &val); + if (ret) + return ret; + + state->enabled = FIELD_GET(AIROHA_PWM_GPIO_FLASH_EN, val >> shift); + if (!state->enabled) + return 0; + + state->polarity = PWM_POLARITY_NORMAL; + + bucket = FIELD_GET(AIROHA_PWM_GPIO_FLASH_SET_ID, val >> shift); + return airoha_pwm_get_bucket(pc, bucket, &state->period, + &state->duty_cycle); +} + +static const struct pwm_ops airoha_pwm_ops = { + .apply = airoha_pwm_apply, + .get_state = airoha_pwm_get_state, +}; + +static int airoha_pwm_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct airoha_pwm *pc; + struct pwm_chip *chip; + int ret; + + chip = devm_pwmchip_alloc(dev, AIROHA_PWM_MAX_CHANNELS, sizeof(*pc)); + if (IS_ERR(chip)) + return PTR_ERR(chip); + + chip->ops = &airoha_pwm_ops; + pc = pwmchip_get_drvdata(chip); + + pc->regmap = device_node_to_regmap(dev_of_node(dev->parent)); + if (IS_ERR(pc->regmap)) + return dev_err_probe(dev, PTR_ERR(pc->regmap), "Failed to get PWM regmap\n"); + + ret = devm_pwmchip_add(dev, chip); + if (ret) + return dev_err_probe(dev, ret, "Failed to add PWM chip\n"); + + return 0; +} + +static const struct of_device_id airoha_pwm_of_match[] = { + { .compatible = "airoha,en7581-pwm" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, airoha_pwm_of_match); + +static struct platform_driver airoha_pwm_driver = { + .driver = { + .name = "pwm-airoha", + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + .of_match_table = airoha_pwm_of_match, + }, + .probe = airoha_pwm_probe, +}; +module_platform_driver(airoha_pwm_driver); + +MODULE_AUTHOR("Lorenzo Bianconi <lorenzo@kernel.org>"); +MODULE_AUTHOR("Markus Gothe <markus.gothe@genexis.eu>"); +MODULE_AUTHOR("Benjamin Larsson <benjamin.larsson@genexis.eu>"); +MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>"); +MODULE_DESCRIPTION("Airoha EN7581 PWM driver"); +MODULE_LICENSE("GPL"); diff --git a/drivers/pwm/pwm-bcm2835.c b/drivers/pwm/pwm-bcm2835.c index 578e95e0296c..532903da521f 100644 --- a/drivers/pwm/pwm-bcm2835.c +++ b/drivers/pwm/pwm-bcm2835.c @@ -34,29 +34,6 @@ static inline struct bcm2835_pwm *to_bcm2835_pwm(struct pwm_chip *chip) return pwmchip_get_drvdata(chip); } -static int bcm2835_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) -{ - struct bcm2835_pwm *pc = to_bcm2835_pwm(chip); - u32 value; - - value = readl(pc->base + PWM_CONTROL); - value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm)); - value |= (PWM_MODE << PWM_CONTROL_SHIFT(pwm->hwpwm)); - writel(value, pc->base + PWM_CONTROL); - - return 0; -} - -static void bcm2835_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) -{ - struct bcm2835_pwm *pc = to_bcm2835_pwm(chip); - u32 value; - - value = readl(pc->base + PWM_CONTROL); - value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm)); - writel(value, pc->base + PWM_CONTROL); -} - static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { @@ -102,6 +79,9 @@ static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, /* set polarity */ val = readl(pc->base + PWM_CONTROL); + val &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm)); + val |= PWM_MODE << PWM_CONTROL_SHIFT(pwm->hwpwm); + if (state->polarity == PWM_POLARITY_NORMAL) val &= ~(PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm)); else @@ -119,8 +99,6 @@ static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, } static const struct pwm_ops bcm2835_pwm_ops = { - .request = bcm2835_pwm_request, - .free = bcm2835_pwm_free, .apply = bcm2835_pwm_apply, }; diff --git a/drivers/pwm/pwm-max7360.c b/drivers/pwm/pwm-max7360.c index ebf93a7aee5b..16261958ce7f 100644 --- a/drivers/pwm/pwm-max7360.c +++ b/drivers/pwm/pwm-max7360.c @@ -75,7 +75,7 @@ static int max7360_pwm_round_waveform_tohw(struct pwm_chip *chip, duty_steps = MAX7360_PWM_MAX - 1; } - wfhw->duty_steps = min(MAX7360_PWM_MAX, duty_steps); + wfhw->duty_steps = duty_steps; wfhw->enabled = !!wf->period_length_ns; if (wf->period_length_ns && wf->period_length_ns < MAX7360_PWM_PERIOD_NS) diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c index 4291072a13a7..9d206303404a 100644 --- a/drivers/pwm/pwm-mediatek.c +++ b/drivers/pwm/pwm-mediatek.c @@ -135,50 +135,51 @@ static inline u32 pwm_mediatek_readl(struct pwm_mediatek_chip *chip, num * chip->soc->chanreg_width + offset); } -static void pwm_mediatek_enable(struct pwm_chip *chip, struct pwm_device *pwm) -{ - struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip); - u32 value; - - value = readl(pc->regs); - value |= BIT(pwm->hwpwm); - writel(value, pc->regs); -} - -static void pwm_mediatek_disable(struct pwm_chip *chip, struct pwm_device *pwm) -{ - struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip); - u32 value; - - value = readl(pc->regs); - value &= ~BIT(pwm->hwpwm); - writel(value, pc->regs); -} +struct pwm_mediatek_waveform { + u32 enable; + u32 con; + u32 width; + u32 thres; +}; -static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm, - u64 duty_ns, u64 period_ns) +static int pwm_mediatek_round_waveform_tohw(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_waveform *wf, void *_wfhw) { + struct pwm_mediatek_waveform *wfhw = _wfhw; struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip); u32 clkdiv, enable; - u32 reg_width = PWMDWIDTH, reg_thres = PWMTHRES; u64 cnt_period, cnt_duty; unsigned long clk_rate; - int ret; + int ret = 0; - ret = pwm_mediatek_clk_enable(pc, pwm->hwpwm); - if (ret < 0) - return ret; + if (wf->period_length_ns == 0) { + *wfhw = (typeof(*wfhw)){ + .enable = 0, + }; - clk_rate = pc->clk_pwms[pwm->hwpwm].rate; + return 0; + } + + if (!pc->clk_pwms[pwm->hwpwm].rate) { + struct clk *clk = pc->clk_pwms[pwm->hwpwm].clk; + + ret = clk_prepare_enable(clk); + if (ret) + return ret; - /* Make sure we use the bus clock and not the 26MHz clock */ - if (pc->soc->pwm_ck_26m_sel_reg) - writel(0, pc->regs + pc->soc->pwm_ck_26m_sel_reg); + pc->clk_pwms[pwm->hwpwm].rate = clk_get_rate(clk); - cnt_period = mul_u64_u64_div_u64(period_ns, clk_rate, NSEC_PER_SEC); + clk_disable_unprepare(clk); + } + + clk_rate = pc->clk_pwms[pwm->hwpwm].rate; + if (clk_rate == 0 || clk_rate > 1000000000) + return -EINVAL; + + cnt_period = mul_u64_u64_div_u64(wf->period_length_ns, clk_rate, NSEC_PER_SEC); if (cnt_period == 0) { - ret = -ERANGE; - goto out; + cnt_period = 1; + ret = 1; } if (cnt_period > FIELD_MAX(PWMDWIDTH_PERIOD) + 1) { @@ -193,7 +194,7 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm, clkdiv = 0; } - cnt_duty = mul_u64_u64_div_u64(duty_ns, clk_rate, NSEC_PER_SEC) >> clkdiv; + cnt_duty = mul_u64_u64_div_u64(wf->duty_length_ns, clk_rate, NSEC_PER_SEC) >> clkdiv; if (cnt_duty > cnt_period) cnt_duty = cnt_period; @@ -206,121 +207,187 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm, cnt_period -= 1; - dev_dbg(&chip->dev, "pwm#%u: %lld/%lld @%lu -> CON: %x, PERIOD: %llx, DUTY: %llx\n", - pwm->hwpwm, duty_ns, period_ns, clk_rate, clkdiv, cnt_period, cnt_duty); + dev_dbg(&chip->dev, "pwm#%u: %lld/%lld @%lu -> ENABLE: %x, CON: %x, PERIOD: %llx, DUTY: %llx\n", + pwm->hwpwm, wf->duty_length_ns, wf->period_length_ns, clk_rate, + enable, clkdiv, cnt_period, cnt_duty); - if (pc->soc->pwm45_fixup && pwm->hwpwm > 2) { - /* - * PWM[4,5] has distinct offset for PWMDWIDTH and PWMTHRES - * from the other PWMs on MT7623. - */ - reg_width = PWM45DWIDTH_FIXUP; - reg_thres = PWM45THRES_FIXUP; - } + *wfhw = (typeof(*wfhw)){ + .enable = enable, + .con = clkdiv, + .width = cnt_period, + .thres = cnt_duty, + }; - pwm_mediatek_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv); - pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, cnt_period); + return ret; +} - if (enable) { - pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, cnt_duty); - pwm_mediatek_enable(chip, pwm); +static int pwm_mediatek_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm, + const void *_wfhw, struct pwm_waveform *wf) +{ + const struct pwm_mediatek_waveform *wfhw = _wfhw; + struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip); + u32 clkdiv, cnt_period, cnt_duty; + unsigned long clk_rate; + + /* + * When _wfhw was populated, the clock was on, so .rate is + * already set appropriately. + */ + clk_rate = pc->clk_pwms[pwm->hwpwm].rate; + + if (wfhw->enable) { + clkdiv = FIELD_GET(PWMCON_CLKDIV, wfhw->con); + cnt_period = FIELD_GET(PWMDWIDTH_PERIOD, wfhw->width); + cnt_duty = FIELD_GET(PWMTHRES_DUTY, wfhw->thres); + + /* + * cnt_period is a 13 bit value, NSEC_PER_SEC is 30 bits wide + * and clkdiv is less than 8, so the multiplication doesn't + * overflow an u64. + */ + *wf = (typeof(*wf)){ + .period_length_ns = + DIV_ROUND_UP_ULL((u64)(cnt_period + 1) * NSEC_PER_SEC << clkdiv, clk_rate), + .duty_length_ns = + DIV_ROUND_UP_ULL((u64)(cnt_duty + 1) * NSEC_PER_SEC << clkdiv, clk_rate), + }; } else { - pwm_mediatek_disable(chip, pwm); + clkdiv = 0; + cnt_period = 0; + cnt_duty = 0; + + /* + * .enable = 0 is also used for too small duty_cycle values, so + * report the HW as being enabled to communicate the minimal + * period. + */ + *wf = (typeof(*wf)){ + .period_length_ns = + DIV_ROUND_UP_ULL(NSEC_PER_SEC, clk_rate), + .duty_length_ns = 0, + }; } -out: - pwm_mediatek_clk_disable(pc, pwm->hwpwm); + dev_dbg(&chip->dev, "pwm#%u: ENABLE: %x, CLKDIV: %x, PERIOD: %x, DUTY: %x @%lu -> %lld/%lld\n", + pwm->hwpwm, wfhw->enable, clkdiv, cnt_period, cnt_duty, clk_rate, + wf->duty_length_ns, wf->period_length_ns); - return ret; + return 0; } -static int pwm_mediatek_apply(struct pwm_chip *chip, struct pwm_device *pwm, - const struct pwm_state *state) +static int pwm_mediatek_read_waveform(struct pwm_chip *chip, + struct pwm_device *pwm, void *_wfhw) { + struct pwm_mediatek_waveform *wfhw = _wfhw; struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip); - int err; + u32 enable, clkdiv, cnt_period, cnt_duty; + u32 reg_width = PWMDWIDTH, reg_thres = PWMTHRES; + int ret; - if (state->polarity != PWM_POLARITY_NORMAL) - return -EINVAL; + ret = pwm_mediatek_clk_enable(pc, pwm->hwpwm); + if (ret < 0) + return ret; - if (!state->enabled) { - if (pwm->state.enabled) { - pwm_mediatek_disable(chip, pwm); - pwm_mediatek_clk_disable(pc, pwm->hwpwm); + enable = readl(pc->regs) & BIT(pwm->hwpwm); + + if (enable) { + if (pc->soc->pwm45_fixup && pwm->hwpwm > 2) { + /* + * PWM[4,5] has distinct offset for PWMDWIDTH and PWMTHRES + * from the other PWMs on MT7623. + */ + reg_width = PWM45DWIDTH_FIXUP; + reg_thres = PWM45THRES_FIXUP; } - return 0; - } + clkdiv = FIELD_GET(PWMCON_CLKDIV, pwm_mediatek_readl(pc, pwm->hwpwm, PWMCON)); + cnt_period = FIELD_GET(PWMDWIDTH_PERIOD, pwm_mediatek_readl(pc, pwm->hwpwm, reg_width)); + cnt_duty = FIELD_GET(PWMTHRES_DUTY, pwm_mediatek_readl(pc, pwm->hwpwm, reg_thres)); - err = pwm_mediatek_config(chip, pwm, state->duty_cycle, state->period); - if (err) - return err; + *wfhw = (typeof(*wfhw)){ + .enable = enable, + .con = BIT(15) | clkdiv, + .width = cnt_period, + .thres = cnt_duty, + }; + } else { + *wfhw = (typeof(*wfhw)){ + .enable = 0, + }; + } - if (!pwm->state.enabled) - err = pwm_mediatek_clk_enable(pc, pwm->hwpwm); + pwm_mediatek_clk_disable(pc, pwm->hwpwm); - return err; + return ret; } -static int pwm_mediatek_get_state(struct pwm_chip *chip, struct pwm_device *pwm, - struct pwm_state *state) +static int pwm_mediatek_write_waveform(struct pwm_chip *chip, + struct pwm_device *pwm, const void *_wfhw) { + const struct pwm_mediatek_waveform *wfhw = _wfhw; struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip); + u32 ctrl; int ret; - u32 enable; - u32 reg_width = PWMDWIDTH, reg_thres = PWMTHRES; - - if (pc->soc->pwm45_fixup && pwm->hwpwm > 2) { - /* - * PWM[4,5] has distinct offset for PWMDWIDTH and PWMTHRES - * from the other PWMs on MT7623. - */ - reg_width = PWM45DWIDTH_FIXUP; - reg_thres = PWM45THRES_FIXUP; - } ret = pwm_mediatek_clk_enable(pc, pwm->hwpwm); if (ret < 0) return ret; - enable = readl(pc->regs); - if (enable & BIT(pwm->hwpwm)) { - u32 clkdiv, cnt_period, cnt_duty; - unsigned long clk_rate; + ctrl = readl(pc->regs); - clk_rate = pc->clk_pwms[pwm->hwpwm].rate; + if (wfhw->enable) { + u32 reg_width = PWMDWIDTH, reg_thres = PWMTHRES; - state->enabled = true; - state->polarity = PWM_POLARITY_NORMAL; + if (pc->soc->pwm45_fixup && pwm->hwpwm > 2) { + /* + * PWM[4,5] has distinct offset for PWMDWIDTH and PWMTHRES + * from the other PWMs on MT7623. + */ + reg_width = PWM45DWIDTH_FIXUP; + reg_thres = PWM45THRES_FIXUP; + } - clkdiv = FIELD_GET(PWMCON_CLKDIV, - pwm_mediatek_readl(pc, pwm->hwpwm, PWMCON)); - cnt_period = FIELD_GET(PWMDWIDTH_PERIOD, - pwm_mediatek_readl(pc, pwm->hwpwm, reg_width)); - cnt_duty = FIELD_GET(PWMTHRES_DUTY, - pwm_mediatek_readl(pc, pwm->hwpwm, reg_thres)); + if (!(ctrl & BIT(pwm->hwpwm))) { + /* + * The clks are already on, just increasing the usage + * counter doesn't fail. + */ + ret = pwm_mediatek_clk_enable(pc, pwm->hwpwm); + if (unlikely(ret < 0)) + goto out; + + ctrl |= BIT(pwm->hwpwm); + writel(ctrl, pc->regs); + } - /* - * cnt_period is a 13 bit value, NSEC_PER_SEC is 30 bits wide - * and clkdiv is less than 8, so the multiplication doesn't - * overflow an u64. - */ - state->period = - DIV_ROUND_UP_ULL((u64)cnt_period * NSEC_PER_SEC << clkdiv, clk_rate); - state->duty_cycle = - DIV_ROUND_UP_ULL((u64)cnt_duty * NSEC_PER_SEC << clkdiv, clk_rate); + /* Make sure we use the bus clock and not the 26MHz clock */ + if (pc->soc->pwm_ck_26m_sel_reg) + writel(0, pc->regs + pc->soc->pwm_ck_26m_sel_reg); + + pwm_mediatek_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | wfhw->con); + pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, wfhw->width); + pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, wfhw->thres); } else { - state->enabled = false; + if (ctrl & BIT(pwm->hwpwm)) { + ctrl &= ~BIT(pwm->hwpwm); + writel(ctrl, pc->regs); + + pwm_mediatek_clk_disable(pc, pwm->hwpwm); + } } +out: pwm_mediatek_clk_disable(pc, pwm->hwpwm); return ret; } static const struct pwm_ops pwm_mediatek_ops = { - .apply = pwm_mediatek_apply, - .get_state = pwm_mediatek_get_state, + .sizeof_wfhw = sizeof(struct pwm_mediatek_waveform), + .round_waveform_tohw = pwm_mediatek_round_waveform_tohw, + .round_waveform_fromhw = pwm_mediatek_round_waveform_fromhw, + .read_waveform = pwm_mediatek_read_waveform, + .write_waveform = pwm_mediatek_write_waveform, }; static int pwm_mediatek_init_used_clks(struct pwm_mediatek_chip *pc) @@ -377,7 +444,7 @@ static int pwm_mediatek_probe(struct platform_device *pdev) soc = of_device_get_match_data(&pdev->dev); chip = devm_pwmchip_alloc(&pdev->dev, soc->num_pwms, - sizeof(*pc) + soc->num_pwms * sizeof(*pc->clk_pwms)); + struct_size(pc, clk_pwms, soc->num_pwms)); if (IS_ERR(chip)) return PTR_ERR(chip); pc = to_pwm_mediatek_chip(chip); diff --git a/drivers/pwm/pwm-rzg2l-gpt.c b/drivers/pwm/pwm-rzg2l-gpt.c index 360c8bf3b190..4856af080e8e 100644 --- a/drivers/pwm/pwm-rzg2l-gpt.c +++ b/drivers/pwm/pwm-rzg2l-gpt.c @@ -96,6 +96,11 @@ static inline unsigned int rzg2l_gpt_subchannel(unsigned int hwpwm) return hwpwm & 0x1; } +static inline unsigned int rzg2l_gpt_sibling(unsigned int hwpwm) +{ + return hwpwm ^ 0x1; +} + static void rzg2l_gpt_write(struct rzg2l_gpt_chip *rzg2l_gpt, u32 reg, u32 data) { writel(data, rzg2l_gpt->mmio + reg); @@ -271,10 +276,14 @@ static int rzg2l_gpt_config(struct pwm_chip *chip, struct pwm_device *pwm, * in use with different settings. */ if (rzg2l_gpt->channel_request_count[ch] > 1) { - if (period_ticks < rzg2l_gpt->period_ticks[ch]) - return -EBUSY; - else + u8 sibling_ch = rzg2l_gpt_sibling(pwm->hwpwm); + + if (rzg2l_gpt_is_ch_enabled(rzg2l_gpt, sibling_ch)) { + if (period_ticks < rzg2l_gpt->period_ticks[ch]) + return -EBUSY; + period_ticks = rzg2l_gpt->period_ticks[ch]; + } } prescale = rzg2l_gpt_calculate_prescale(rzg2l_gpt, period_ticks); diff --git a/drivers/pwm/pwm_th1520.rs b/drivers/pwm/pwm_th1520.rs new file mode 100644 index 000000000000..955c359b07fb --- /dev/null +++ b/drivers/pwm/pwm_th1520.rs @@ -0,0 +1,387 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2025 Samsung Electronics Co., Ltd. +// Author: Michal Wilczynski <m.wilczynski@samsung.com> + +//! Rust T-HEAD TH1520 PWM driver +//! +//! Limitations: +//! - The period and duty cycle are controlled by 32-bit hardware registers, +//! limiting the maximum resolution. +//! - The driver supports continuous output mode only; one-shot mode is not +//! implemented. +//! - The controller hardware provides up to 6 PWM channels. +//! - Reconfiguration is glitch free - new period and duty cycle values are +//! latched and take effect at the start of the next period. +//! - Polarity is handled via a simple hardware inversion bit; arbitrary +//! duty cycle offsets are not supported. +//! - Disabling a channel is achieved by configuring its duty cycle to zero to +//! produce a static low output. Clearing the `start` does not reliably +//! force the static inactive level defined by the `INACTOUT` bit. Hence +//! this method is not used in this driver. +//! + +use core::ops::Deref; +use kernel::{ + c_str, + clk::Clk, + device::{Bound, Core, Device}, + devres, + io::mem::IoMem, + of, platform, + prelude::*, + pwm, time, +}; + +const TH1520_MAX_PWM_NUM: u32 = 6; + +// Register offsets +const fn th1520_pwm_chn_base(n: u32) -> usize { + (n * 0x20) as usize +} + +const fn th1520_pwm_ctrl(n: u32) -> usize { + th1520_pwm_chn_base(n) +} + +const fn th1520_pwm_per(n: u32) -> usize { + th1520_pwm_chn_base(n) + 0x08 +} + +const fn th1520_pwm_fp(n: u32) -> usize { + th1520_pwm_chn_base(n) + 0x0c +} + +// Control register bits +const TH1520_PWM_START: u32 = 1 << 0; +const TH1520_PWM_CFG_UPDATE: u32 = 1 << 2; +const TH1520_PWM_CONTINUOUS_MODE: u32 = 1 << 5; +const TH1520_PWM_FPOUT: u32 = 1 << 8; + +const TH1520_PWM_REG_SIZE: usize = 0xB0; + +fn ns_to_cycles(ns: u64, rate_hz: u64) -> u64 { + const NSEC_PER_SEC_U64: u64 = time::NSEC_PER_SEC as u64; + + (match ns.checked_mul(rate_hz) { + Some(product) => product, + None => u64::MAX, + }) / NSEC_PER_SEC_U64 +} + +fn cycles_to_ns(cycles: u64, rate_hz: u64) -> u64 { + const NSEC_PER_SEC_U64: u64 = time::NSEC_PER_SEC as u64; + + // TODO: Replace with a kernel helper like `mul_u64_u64_div_u64_roundup` + // once available in Rust. + let numerator = cycles + .saturating_mul(NSEC_PER_SEC_U64) + .saturating_add(rate_hz - 1); + + numerator / rate_hz +} + +/// Hardware-specific waveform representation for TH1520. +#[derive(Copy, Clone, Debug, Default)] +struct Th1520WfHw { + period_cycles: u32, + duty_cycles: u32, + ctrl_val: u32, + enabled: bool, +} + +/// The driver's private data struct. It holds all necessary devres managed resources. +#[pin_data(PinnedDrop)] +struct Th1520PwmDriverData { + #[pin] + iomem: devres::Devres<IoMem<TH1520_PWM_REG_SIZE>>, + clk: Clk, +} + +// This `unsafe` implementation is a temporary necessity because the underlying `kernel::clk::Clk` +// type does not yet expose `Send` and `Sync` implementations. This block should be removed +// as soon as the clock abstraction provides these guarantees directly. +// TODO: Remove those unsafe impl's when Clk will support them itself. + +// SAFETY: The `devres` framework requires the driver's private data to be `Send` and `Sync`. +// We can guarantee this because the PWM core synchronizes all callbacks, preventing concurrent +// access to the contained `iomem` and `clk` resources. +unsafe impl Send for Th1520PwmDriverData {} + +// SAFETY: The same reasoning applies as for `Send`. The PWM core's synchronization +// guarantees that it is safe for multiple threads to have shared access (`&self`) +// to the driver data during callbacks. +unsafe impl Sync for Th1520PwmDriverData {} + +impl pwm::PwmOps for Th1520PwmDriverData { + type WfHw = Th1520WfHw; + + fn round_waveform_tohw( + chip: &pwm::Chip<Self>, + _pwm: &pwm::Device, + wf: &pwm::Waveform, + ) -> Result<pwm::RoundedWaveform<Self::WfHw>> { + let data = chip.drvdata(); + let mut status = 0; + + if wf.period_length_ns == 0 { + dev_dbg!(chip.device(), "Requested period is 0, disabling PWM.\n"); + + return Ok(pwm::RoundedWaveform { + status: 0, + hardware_waveform: Th1520WfHw { + enabled: false, + ..Default::default() + }, + }); + } + + let rate_hz = data.clk.rate().as_hz() as u64; + + let mut period_cycles = ns_to_cycles(wf.period_length_ns, rate_hz).min(u64::from(u32::MAX)); + + if period_cycles == 0 { + dev_dbg!( + chip.device(), + "Requested period {} ns is too small for clock rate {} Hz, rounding up.\n", + wf.period_length_ns, + rate_hz + ); + + period_cycles = 1; + status = 1; + } + + let mut duty_cycles = ns_to_cycles(wf.duty_length_ns, rate_hz).min(u64::from(u32::MAX)); + + let mut ctrl_val = TH1520_PWM_CONTINUOUS_MODE; + + let is_inversed = wf.duty_length_ns > 0 + && wf.duty_offset_ns > 0 + && wf.duty_offset_ns >= wf.period_length_ns.saturating_sub(wf.duty_length_ns); + if is_inversed { + duty_cycles = period_cycles - duty_cycles; + } else { + ctrl_val |= TH1520_PWM_FPOUT; + } + + let wfhw = Th1520WfHw { + // The cast is safe because the value was clamped with `.min(u64::from(u32::MAX))`. + period_cycles: period_cycles as u32, + duty_cycles: duty_cycles as u32, + ctrl_val, + enabled: true, + }; + + dev_dbg!( + chip.device(), + "Requested: {}/{} ns [+{} ns] -> HW: {}/{} cycles, ctrl 0x{:x}, rate {} Hz\n", + wf.duty_length_ns, + wf.period_length_ns, + wf.duty_offset_ns, + wfhw.duty_cycles, + wfhw.period_cycles, + wfhw.ctrl_val, + rate_hz + ); + + Ok(pwm::RoundedWaveform { + status, + hardware_waveform: wfhw, + }) + } + + fn round_waveform_fromhw( + chip: &pwm::Chip<Self>, + _pwm: &pwm::Device, + wfhw: &Self::WfHw, + wf: &mut pwm::Waveform, + ) -> Result { + let data = chip.drvdata(); + let rate_hz = data.clk.rate().as_hz() as u64; + + if wfhw.period_cycles == 0 { + dev_dbg!( + chip.device(), + "HW state has zero period, reporting as disabled.\n" + ); + *wf = pwm::Waveform::default(); + return Ok(()); + } + + wf.period_length_ns = cycles_to_ns(u64::from(wfhw.period_cycles), rate_hz); + + let duty_cycles = u64::from(wfhw.duty_cycles); + + if (wfhw.ctrl_val & TH1520_PWM_FPOUT) != 0 { + wf.duty_length_ns = cycles_to_ns(duty_cycles, rate_hz); + wf.duty_offset_ns = 0; + } else { + let period_cycles = u64::from(wfhw.period_cycles); + let original_duty_cycles = period_cycles.saturating_sub(duty_cycles); + + // For an inverted signal, `duty_length_ns` is the high time (period - low_time). + wf.duty_length_ns = cycles_to_ns(original_duty_cycles, rate_hz); + // The offset is the initial low time, which is what the hardware register provides. + wf.duty_offset_ns = cycles_to_ns(duty_cycles, rate_hz); + } + + Ok(()) + } + + fn read_waveform( + chip: &pwm::Chip<Self>, + pwm: &pwm::Device, + parent_dev: &Device<Bound>, + ) -> Result<Self::WfHw> { + let data = chip.drvdata(); + let hwpwm = pwm.hwpwm(); + let iomem_accessor = data.iomem.access(parent_dev)?; + let iomap = iomem_accessor.deref(); + + let ctrl = iomap.try_read32(th1520_pwm_ctrl(hwpwm))?; + let period_cycles = iomap.try_read32(th1520_pwm_per(hwpwm))?; + let duty_cycles = iomap.try_read32(th1520_pwm_fp(hwpwm))?; + + let wfhw = Th1520WfHw { + period_cycles, + duty_cycles, + ctrl_val: ctrl, + enabled: duty_cycles != 0, + }; + + dev_dbg!( + chip.device(), + "PWM-{}: read_waveform: Read hw state - period: {}, duty: {}, ctrl: 0x{:x}, enabled: {}", + hwpwm, + wfhw.period_cycles, + wfhw.duty_cycles, + wfhw.ctrl_val, + wfhw.enabled + ); + + Ok(wfhw) + } + + fn write_waveform( + chip: &pwm::Chip<Self>, + pwm: &pwm::Device, + wfhw: &Self::WfHw, + parent_dev: &Device<Bound>, + ) -> Result { + let data = chip.drvdata(); + let hwpwm = pwm.hwpwm(); + let iomem_accessor = data.iomem.access(parent_dev)?; + let iomap = iomem_accessor.deref(); + let duty_cycles = iomap.try_read32(th1520_pwm_fp(hwpwm))?; + let was_enabled = duty_cycles != 0; + + if !wfhw.enabled { + dev_dbg!(chip.device(), "PWM-{}: Disabling channel.\n", hwpwm); + if was_enabled { + iomap.try_write32(wfhw.ctrl_val, th1520_pwm_ctrl(hwpwm))?; + iomap.try_write32(0, th1520_pwm_fp(hwpwm))?; + iomap.try_write32( + wfhw.ctrl_val | TH1520_PWM_CFG_UPDATE, + th1520_pwm_ctrl(hwpwm), + )?; + } + return Ok(()); + } + + iomap.try_write32(wfhw.ctrl_val, th1520_pwm_ctrl(hwpwm))?; + iomap.try_write32(wfhw.period_cycles, th1520_pwm_per(hwpwm))?; + iomap.try_write32(wfhw.duty_cycles, th1520_pwm_fp(hwpwm))?; + iomap.try_write32( + wfhw.ctrl_val | TH1520_PWM_CFG_UPDATE, + th1520_pwm_ctrl(hwpwm), + )?; + + // The `TH1520_PWM_START` bit must be written in a separate, final transaction, and + // only when enabling the channel from a disabled state. + if !was_enabled { + iomap.try_write32(wfhw.ctrl_val | TH1520_PWM_START, th1520_pwm_ctrl(hwpwm))?; + } + + dev_dbg!( + chip.device(), + "PWM-{}: Wrote {}/{} cycles", + hwpwm, + wfhw.duty_cycles, + wfhw.period_cycles, + ); + + Ok(()) + } +} + +#[pinned_drop] +impl PinnedDrop for Th1520PwmDriverData { + fn drop(self: Pin<&mut Self>) { + self.clk.disable_unprepare(); + } +} + +struct Th1520PwmPlatformDriver; + +kernel::of_device_table!( + OF_TABLE, + MODULE_OF_TABLE, + <Th1520PwmPlatformDriver as platform::Driver>::IdInfo, + [(of::DeviceId::new(c_str!("thead,th1520-pwm")), ())] +); + +impl platform::Driver for Th1520PwmPlatformDriver { + type IdInfo = (); + const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE); + + fn probe( + pdev: &platform::Device<Core>, + _id_info: Option<&Self::IdInfo>, + ) -> Result<Pin<KBox<Self>>> { + let dev = pdev.as_ref(); + let request = pdev.io_request_by_index(0).ok_or(ENODEV)?; + + let clk = Clk::get(dev, None)?; + + clk.prepare_enable()?; + + // TODO: Get exclusive ownership of the clock to prevent rate changes. + // The Rust equivalent of `clk_rate_exclusive_get()` is not yet available. + // This should be updated once it is implemented. + let rate_hz = clk.rate().as_hz(); + if rate_hz == 0 { + dev_err!(dev, "Clock rate is zero\n"); + return Err(EINVAL); + } + + if rate_hz > time::NSEC_PER_SEC as usize { + dev_err!( + dev, + "Clock rate {} Hz is too high, not supported.\n", + rate_hz + ); + return Err(EINVAL); + } + + let chip = pwm::Chip::new( + dev, + TH1520_MAX_PWM_NUM, + try_pin_init!(Th1520PwmDriverData { + iomem <- request.iomap_sized::<TH1520_PWM_REG_SIZE>(), + clk <- clk, + }), + )?; + + pwm::Registration::register(dev, chip)?; + + Ok(KBox::new(Th1520PwmPlatformDriver, GFP_KERNEL)?.into()) + } +} + +kernel::module_pwm_platform_driver! { + type: Th1520PwmPlatformDriver, + name: "pwm-th1520", + authors: ["Michal Wilczynski <m.wilczynski@samsung.com>"], + description: "T-HEAD TH1520 PWM driver", + license: "GPL v2", +} diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 549ac4aaad59..b11ae91723f8 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -488,6 +488,12 @@ int __pwmchip_add(struct pwm_chip *chip, struct module *owner); #define pwmchip_add(chip) __pwmchip_add(chip, THIS_MODULE) void pwmchip_remove(struct pwm_chip *chip); +/* + * For FFI wrapper use only: + * The Rust PWM abstraction needs this to properly free the pwm_chip. + */ +void pwmchip_release(struct device *dev); + int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner); #define devm_pwmchip_add(dev, chip) __devm_pwmchip_add(dev, chip, THIS_MODULE) @@ -611,39 +617,6 @@ devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, } #endif -static inline void pwm_apply_args(struct pwm_device *pwm) -{ - struct pwm_state state = { }; - - /* - * PWM users calling pwm_apply_args() expect to have a fresh config - * where the polarity and period are set according to pwm_args info. - * The problem is, polarity can only be changed when the PWM is - * disabled. - * - * PWM drivers supporting hardware readout may declare the PWM device - * as enabled, and prevent polarity setting, which changes from the - * existing behavior, where all PWM devices are declared as disabled - * at startup (even if they are actually enabled), thus authorizing - * polarity setting. - * - * To fulfill this requirement, we apply a new state which disables - * the PWM device and set the reference period and polarity config. - * - * Note that PWM users requiring a smooth handover between the - * bootloader and the kernel (like critical regulators controlled by - * PWM devices) will have to switch to the atomic API and avoid calling - * pwm_apply_args(). - */ - - state.enabled = false; - state.polarity = pwm->args.polarity; - state.period = pwm->args.period; - state.usage_power = false; - - pwm_apply_might_sleep(pwm, &state); -} - struct pwm_lookup { struct list_head list; const char *provider; diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 2e43c66635a2..70b11fc6338c 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -72,6 +72,7 @@ #include <linux/pm_opp.h> #include <linux/poll.h> #include <linux/property.h> +#include <linux/pwm.h> #include <linux/random.h> #include <linux/refcount.h> #include <linux/regulator/consumer.h> diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 551da6c9b506..014f20df9148 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -43,6 +43,7 @@ #include "poll.c" #include "processor.c" #include "property.c" +#include "pwm.c" #include "rbtree.c" #include "rcu.c" #include "refcount.c" diff --git a/rust/helpers/pwm.c b/rust/helpers/pwm.c new file mode 100644 index 000000000000..d75c58886368 --- /dev/null +++ b/rust/helpers/pwm.c @@ -0,0 +1,20 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2025 Samsung Electronics Co., Ltd. +// Author: Michal Wilczynski <m.wilczynski@samsung.com> + +#include <linux/pwm.h> + +struct device *rust_helper_pwmchip_parent(const struct pwm_chip *chip) +{ + return pwmchip_parent(chip); +} + +void *rust_helper_pwmchip_get_drvdata(struct pwm_chip *chip) +{ + return pwmchip_get_drvdata(chip); +} + +void rust_helper_pwmchip_set_drvdata(struct pwm_chip *chip, void *data) +{ + pwmchip_set_drvdata(chip, data); +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index de39dae9ce34..a4eee75cf07a 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -125,6 +125,8 @@ pub mod prelude; pub mod print; pub mod processor; pub mod ptr; +#[cfg(CONFIG_RUST_PWM_ABSTRACTIONS)] +pub mod pwm; pub mod rbtree; pub mod regulator; pub mod revocable; diff --git a/rust/kernel/pwm.rs b/rust/kernel/pwm.rs new file mode 100644 index 000000000000..cb00f8a8765c --- /dev/null +++ b/rust/kernel/pwm.rs @@ -0,0 +1,735 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2025 Samsung Electronics Co., Ltd. +// Author: Michal Wilczynski <m.wilczynski@samsung.com> + +//! PWM subsystem abstractions. +//! +//! C header: [`include/linux/pwm.h`](srctree/include/linux/pwm.h). + +use crate::{ + bindings, + container_of, + device::{self, Bound}, + devres, + error::{self, to_result}, + prelude::*, + types::{ARef, AlwaysRefCounted, Opaque}, // +}; +use core::{marker::PhantomData, ptr::NonNull}; + +/// Represents a PWM waveform configuration. +/// Mirrors struct [`struct pwm_waveform`](srctree/include/linux/pwm.h). +#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)] +pub struct Waveform { + /// Total duration of one complete PWM cycle, in nanoseconds. + pub period_length_ns: u64, + + /// Duty-cycle active time, in nanoseconds. + /// + /// For a typical normal polarity configuration (active-high) this is the + /// high time of the signal. + pub duty_length_ns: u64, + + /// Duty-cycle start offset, in nanoseconds. + /// + /// Delay from the beginning of the period to the first active edge. + /// In most simple PWM setups this is `0`, so the duty cycle starts + /// immediately at each period’s start. + pub duty_offset_ns: u64, +} + +impl From<bindings::pwm_waveform> for Waveform { + fn from(wf: bindings::pwm_waveform) -> Self { + Waveform { + period_length_ns: wf.period_length_ns, + duty_length_ns: wf.duty_length_ns, + duty_offset_ns: wf.duty_offset_ns, + } + } +} + +impl From<Waveform> for bindings::pwm_waveform { + fn from(wf: Waveform) -> Self { + bindings::pwm_waveform { + period_length_ns: wf.period_length_ns, + duty_length_ns: wf.duty_length_ns, + duty_offset_ns: wf.duty_offset_ns, + } + } +} + +/// Describes the outcome of a `round_waveform` operation. +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +pub enum RoundingOutcome { + /// The requested waveform was achievable exactly or by rounding values down. + ExactOrRoundedDown, + + /// The requested waveform could only be achieved by rounding up. + RoundedUp, +} + +/// Wrapper for a PWM device [`struct pwm_device`](srctree/include/linux/pwm.h). +#[repr(transparent)] +pub struct Device(Opaque<bindings::pwm_device>); + +impl Device { + /// Creates a reference to a [`Device`] from a valid C pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the + /// returned [`Device`] reference. + pub(crate) unsafe fn from_raw<'a>(ptr: *mut bindings::pwm_device) -> &'a Self { + // SAFETY: The safety requirements guarantee the validity of the dereference, while the + // `Device` type being transparent makes the cast ok. + unsafe { &*ptr.cast::<Self>() } + } + + /// Returns a raw pointer to the underlying `pwm_device`. + fn as_raw(&self) -> *mut bindings::pwm_device { + self.0.get() + } + + /// Gets the hardware PWM index for this device within its chip. + pub fn hwpwm(&self) -> u32 { + // SAFETY: `self.as_raw()` provides a valid pointer for `self`'s lifetime. + unsafe { (*self.as_raw()).hwpwm } + } + + /// Gets a reference to the parent `Chip` that this device belongs to. + pub fn chip<T: PwmOps>(&self) -> &Chip<T> { + // SAFETY: `self.as_raw()` provides a valid pointer. (*self.as_raw()).chip + // is assumed to be a valid pointer to `pwm_chip` managed by the kernel. + // Chip::from_raw's safety conditions must be met. + unsafe { Chip::<T>::from_raw((*self.as_raw()).chip) } + } + + /// Gets the label for this PWM device, if any. + pub fn label(&self) -> Option<&CStr> { + // SAFETY: self.as_raw() provides a valid pointer. + let label_ptr = unsafe { (*self.as_raw()).label }; + if label_ptr.is_null() { + return None; + } + + // SAFETY: label_ptr is non-null and points to a C string + // managed by the kernel, valid for the lifetime of the PWM device. + Some(unsafe { CStr::from_char_ptr(label_ptr) }) + } + + /// Sets the PWM waveform configuration and enables the PWM signal. + pub fn set_waveform(&self, wf: &Waveform, exact: bool) -> Result { + let c_wf = bindings::pwm_waveform::from(*wf); + + // SAFETY: `self.as_raw()` provides a valid `*mut pwm_device` pointer. + // `&c_wf` is a valid pointer to a `pwm_waveform` struct. The C function + // handles all necessary internal locking. + let ret = unsafe { bindings::pwm_set_waveform_might_sleep(self.as_raw(), &c_wf, exact) }; + to_result(ret) + } + + /// Queries the hardware for the configuration it would apply for a given + /// request. + pub fn round_waveform(&self, wf: &mut Waveform) -> Result<RoundingOutcome> { + let mut c_wf = bindings::pwm_waveform::from(*wf); + + // SAFETY: `self.as_raw()` provides a valid `*mut pwm_device` pointer. + // `&mut c_wf` is a valid pointer to a mutable `pwm_waveform` struct that + // the C function will update. + let ret = unsafe { bindings::pwm_round_waveform_might_sleep(self.as_raw(), &mut c_wf) }; + + to_result(ret)?; + + *wf = Waveform::from(c_wf); + + if ret == 1 { + Ok(RoundingOutcome::RoundedUp) + } else { + Ok(RoundingOutcome::ExactOrRoundedDown) + } + } + + /// Reads the current waveform configuration directly from the hardware. + pub fn get_waveform(&self) -> Result<Waveform> { + let mut c_wf = bindings::pwm_waveform::default(); + + // SAFETY: `self.as_raw()` is a valid pointer. We provide a valid pointer + // to a stack-allocated `pwm_waveform` struct for the kernel to fill. + let ret = unsafe { bindings::pwm_get_waveform_might_sleep(self.as_raw(), &mut c_wf) }; + + to_result(ret)?; + + Ok(Waveform::from(c_wf)) + } +} + +/// The result of a `round_waveform_tohw` operation. +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +pub struct RoundedWaveform<WfHw> { + /// A status code, 0 for success or 1 if values were rounded up. + pub status: c_int, + /// The driver-specific hardware representation of the waveform. + pub hardware_waveform: WfHw, +} + +/// Trait defining the operations for a PWM driver. +pub trait PwmOps: 'static + Sized { + /// The driver-specific hardware representation of a waveform. + /// + /// This type must be [`Copy`], [`Default`], and fit within `PWM_WFHWSIZE`. + type WfHw: Copy + Default; + + /// Optional hook for when a PWM device is requested. + fn request(_chip: &Chip<Self>, _pwm: &Device, _parent_dev: &device::Device<Bound>) -> Result { + Ok(()) + } + + /// Optional hook for capturing a PWM signal. + fn capture( + _chip: &Chip<Self>, + _pwm: &Device, + _result: &mut bindings::pwm_capture, + _timeout: usize, + _parent_dev: &device::Device<Bound>, + ) -> Result { + Err(ENOTSUPP) + } + + /// Convert a generic waveform to the hardware-specific representation. + /// This is typically a pure calculation and does not perform I/O. + fn round_waveform_tohw( + _chip: &Chip<Self>, + _pwm: &Device, + _wf: &Waveform, + ) -> Result<RoundedWaveform<Self::WfHw>> { + Err(ENOTSUPP) + } + + /// Convert a hardware-specific representation back to a generic waveform. + /// This is typically a pure calculation and does not perform I/O. + fn round_waveform_fromhw( + _chip: &Chip<Self>, + _pwm: &Device, + _wfhw: &Self::WfHw, + _wf: &mut Waveform, + ) -> Result { + Err(ENOTSUPP) + } + + /// Read the current hardware configuration into the hardware-specific representation. + fn read_waveform( + _chip: &Chip<Self>, + _pwm: &Device, + _parent_dev: &device::Device<Bound>, + ) -> Result<Self::WfHw> { + Err(ENOTSUPP) + } + + /// Write a hardware-specific waveform configuration to the hardware. + fn write_waveform( + _chip: &Chip<Self>, + _pwm: &Device, + _wfhw: &Self::WfHw, + _parent_dev: &device::Device<Bound>, + ) -> Result { + Err(ENOTSUPP) + } +} + +/// Bridges Rust `PwmOps` to the C `pwm_ops` vtable. +struct Adapter<T: PwmOps> { + _p: PhantomData<T>, +} + +impl<T: PwmOps> Adapter<T> { + const VTABLE: PwmOpsVTable = create_pwm_ops::<T>(); + + /// # Safety + /// + /// `wfhw_ptr` must be valid for writes of `size_of::<T::WfHw>()` bytes. + unsafe fn serialize_wfhw(wfhw: &T::WfHw, wfhw_ptr: *mut c_void) -> Result { + let size = core::mem::size_of::<T::WfHw>(); + + build_assert!(size <= bindings::PWM_WFHWSIZE as usize); + + // SAFETY: The caller ensures `wfhw_ptr` is valid for `size` bytes. + unsafe { + core::ptr::copy_nonoverlapping( + core::ptr::from_ref::<T::WfHw>(wfhw).cast::<u8>(), + wfhw_ptr.cast::<u8>(), + size, + ); + } + + Ok(()) + } + + /// # Safety + /// + /// `wfhw_ptr` must be valid for reads of `size_of::<T::WfHw>()` bytes. + unsafe fn deserialize_wfhw(wfhw_ptr: *const c_void) -> Result<T::WfHw> { + let size = core::mem::size_of::<T::WfHw>(); + + build_assert!(size <= bindings::PWM_WFHWSIZE as usize); + + let mut wfhw = T::WfHw::default(); + // SAFETY: The caller ensures `wfhw_ptr` is valid for `size` bytes. + unsafe { + core::ptr::copy_nonoverlapping( + wfhw_ptr.cast::<u8>(), + core::ptr::from_mut::<T::WfHw>(&mut wfhw).cast::<u8>(), + size, + ); + } + + Ok(wfhw) + } + + /// # Safety + /// + /// `dev` must be a valid pointer to a `bindings::device` embedded within a + /// `bindings::pwm_chip`. This function is called by the device core when the + /// last reference to the device is dropped. + unsafe extern "C" fn release_callback(dev: *mut bindings::device) { + // SAFETY: The function's contract guarantees that `dev` points to a `device` + // field embedded within a valid `pwm_chip`. `container_of!` can therefore + // safely calculate the address of the containing struct. + let c_chip_ptr = unsafe { container_of!(dev, bindings::pwm_chip, dev) }; + + // SAFETY: `c_chip_ptr` is a valid pointer to a `pwm_chip` as established + // above. Calling this FFI function is safe. + let drvdata_ptr = unsafe { bindings::pwmchip_get_drvdata(c_chip_ptr) }; + + // SAFETY: The driver data was initialized in `new`. We run its destructor here. + unsafe { core::ptr::drop_in_place(drvdata_ptr.cast::<T>()) }; + + // Now, call the original release function to free the `pwm_chip` itself. + // SAFETY: `dev` is the valid pointer passed into this callback, which is + // the expected argument for `pwmchip_release`. + unsafe { + bindings::pwmchip_release(dev); + } + } + + /// # Safety + /// + /// Pointers from C must be valid. + unsafe extern "C" fn request_callback( + chip_ptr: *mut bindings::pwm_chip, + pwm_ptr: *mut bindings::pwm_device, + ) -> c_int { + // SAFETY: PWM core guarentees `chip_ptr` and `pwm_ptr` are valid pointers. + let (chip, pwm) = unsafe { (Chip::<T>::from_raw(chip_ptr), Device::from_raw(pwm_ptr)) }; + + // SAFETY: The PWM core guarantees the parent device exists and is bound during callbacks. + let bound_parent = unsafe { chip.bound_parent_device() }; + match T::request(chip, pwm, bound_parent) { + Ok(()) => 0, + Err(e) => e.to_errno(), + } + } + + /// # Safety + /// + /// Pointers from C must be valid. + unsafe extern "C" fn capture_callback( + chip_ptr: *mut bindings::pwm_chip, + pwm_ptr: *mut bindings::pwm_device, + res: *mut bindings::pwm_capture, + timeout: usize, + ) -> c_int { + // SAFETY: Relies on the function's contract that `chip_ptr` and `pwm_ptr` are valid + // pointers. + let (chip, pwm, result) = unsafe { + ( + Chip::<T>::from_raw(chip_ptr), + Device::from_raw(pwm_ptr), + &mut *res, + ) + }; + + // SAFETY: The PWM core guarantees the parent device exists and is bound during callbacks. + let bound_parent = unsafe { chip.bound_parent_device() }; + match T::capture(chip, pwm, result, timeout, bound_parent) { + Ok(()) => 0, + Err(e) => e.to_errno(), + } + } + + /// # Safety + /// + /// Pointers from C must be valid. + unsafe extern "C" fn round_waveform_tohw_callback( + chip_ptr: *mut bindings::pwm_chip, + pwm_ptr: *mut bindings::pwm_device, + wf_ptr: *const bindings::pwm_waveform, + wfhw_ptr: *mut c_void, + ) -> c_int { + // SAFETY: Relies on the function's contract that `chip_ptr` and `pwm_ptr` are valid + // pointers. + let (chip, pwm, wf) = unsafe { + ( + Chip::<T>::from_raw(chip_ptr), + Device::from_raw(pwm_ptr), + Waveform::from(*wf_ptr), + ) + }; + match T::round_waveform_tohw(chip, pwm, &wf) { + Ok(rounded) => { + // SAFETY: `wfhw_ptr` is valid per this function's safety contract. + if unsafe { Self::serialize_wfhw(&rounded.hardware_waveform, wfhw_ptr) }.is_err() { + return EINVAL.to_errno(); + } + rounded.status + } + Err(e) => e.to_errno(), + } + } + + /// # Safety + /// + /// Pointers from C must be valid. + unsafe extern "C" fn round_waveform_fromhw_callback( + chip_ptr: *mut bindings::pwm_chip, + pwm_ptr: *mut bindings::pwm_device, + wfhw_ptr: *const c_void, + wf_ptr: *mut bindings::pwm_waveform, + ) -> c_int { + // SAFETY: Relies on the function's contract that `chip_ptr` and `pwm_ptr` are valid + // pointers. + let (chip, pwm) = unsafe { (Chip::<T>::from_raw(chip_ptr), Device::from_raw(pwm_ptr)) }; + // SAFETY: `deserialize_wfhw`'s safety contract is met by this function's contract. + let wfhw = match unsafe { Self::deserialize_wfhw(wfhw_ptr) } { + Ok(v) => v, + Err(e) => return e.to_errno(), + }; + + let mut rust_wf = Waveform::default(); + match T::round_waveform_fromhw(chip, pwm, &wfhw, &mut rust_wf) { + Ok(()) => { + // SAFETY: `wf_ptr` is guaranteed valid by the C caller. + unsafe { + *wf_ptr = rust_wf.into(); + }; + 0 + } + Err(e) => e.to_errno(), + } + } + + /// # Safety + /// + /// Pointers from C must be valid. + unsafe extern "C" fn read_waveform_callback( + chip_ptr: *mut bindings::pwm_chip, + pwm_ptr: *mut bindings::pwm_device, + wfhw_ptr: *mut c_void, + ) -> c_int { + // SAFETY: Relies on the function's contract that `chip_ptr` and `pwm_ptr` are valid + // pointers. + let (chip, pwm) = unsafe { (Chip::<T>::from_raw(chip_ptr), Device::from_raw(pwm_ptr)) }; + + // SAFETY: The PWM core guarantees the parent device exists and is bound during callbacks. + let bound_parent = unsafe { chip.bound_parent_device() }; + match T::read_waveform(chip, pwm, bound_parent) { + // SAFETY: `wfhw_ptr` is valid per this function's safety contract. + Ok(wfhw) => match unsafe { Self::serialize_wfhw(&wfhw, wfhw_ptr) } { + Ok(()) => 0, + Err(e) => e.to_errno(), + }, + Err(e) => e.to_errno(), + } + } + + /// # Safety + /// + /// Pointers from C must be valid. + unsafe extern "C" fn write_waveform_callback( + chip_ptr: *mut bindings::pwm_chip, + pwm_ptr: *mut bindings::pwm_device, + wfhw_ptr: *const c_void, + ) -> c_int { + // SAFETY: Relies on the function's contract that `chip_ptr` and `pwm_ptr` are valid + // pointers. + let (chip, pwm) = unsafe { (Chip::<T>::from_raw(chip_ptr), Device::from_raw(pwm_ptr)) }; + + // SAFETY: The PWM core guarantees the parent device exists and is bound during callbacks. + let bound_parent = unsafe { chip.bound_parent_device() }; + + // SAFETY: `wfhw_ptr` is valid per this function's safety contract. + let wfhw = match unsafe { Self::deserialize_wfhw(wfhw_ptr) } { + Ok(v) => v, + Err(e) => return e.to_errno(), + }; + match T::write_waveform(chip, pwm, &wfhw, bound_parent) { + Ok(()) => 0, + Err(e) => e.to_errno(), + } + } +} + +/// VTable structure wrapper for PWM operations. +/// Mirrors [`struct pwm_ops`](srctree/include/linux/pwm.h). +#[repr(transparent)] +pub struct PwmOpsVTable(bindings::pwm_ops); + +// SAFETY: PwmOpsVTable is Send. The vtable contains only function pointers +// and a size, which are simple data types that can be safely moved across +// threads. The thread-safety of calling these functions is handled by the +// kernel's locking mechanisms. +unsafe impl Send for PwmOpsVTable {} + +// SAFETY: PwmOpsVTable is Sync. The vtable is immutable after it is created, +// so it can be safely referenced and accessed concurrently by multiple threads +// e.g. to read the function pointers. +unsafe impl Sync for PwmOpsVTable {} + +impl PwmOpsVTable { + /// Returns a raw pointer to the underlying `pwm_ops` struct. + pub(crate) fn as_raw(&self) -> *const bindings::pwm_ops { + &self.0 + } +} + +/// Creates a PWM operations vtable for a type `T` that implements `PwmOps`. +/// +/// This is used to bridge Rust trait implementations to the C `struct pwm_ops` +/// expected by the kernel. +pub const fn create_pwm_ops<T: PwmOps>() -> PwmOpsVTable { + // SAFETY: `core::mem::zeroed()` is unsafe. For `pwm_ops`, all fields are + // `Option<extern "C" fn(...)>` or data, so a zeroed pattern (None/0) is valid initially. + let mut ops: bindings::pwm_ops = unsafe { core::mem::zeroed() }; + + ops.request = Some(Adapter::<T>::request_callback); + ops.capture = Some(Adapter::<T>::capture_callback); + + ops.round_waveform_tohw = Some(Adapter::<T>::round_waveform_tohw_callback); + ops.round_waveform_fromhw = Some(Adapter::<T>::round_waveform_fromhw_callback); + ops.read_waveform = Some(Adapter::<T>::read_waveform_callback); + ops.write_waveform = Some(Adapter::<T>::write_waveform_callback); + ops.sizeof_wfhw = core::mem::size_of::<T::WfHw>(); + + PwmOpsVTable(ops) +} + +/// Wrapper for a PWM chip/controller ([`struct pwm_chip`](srctree/include/linux/pwm.h)). +#[repr(transparent)] +pub struct Chip<T: PwmOps>(Opaque<bindings::pwm_chip>, PhantomData<T>); + +impl<T: PwmOps> Chip<T> { + /// Creates a reference to a [`Chip`] from a valid pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the + /// returned [`Chip`] reference. + pub(crate) unsafe fn from_raw<'a>(ptr: *mut bindings::pwm_chip) -> &'a Self { + // SAFETY: The safety requirements guarantee the validity of the dereference, while the + // `Chip` type being transparent makes the cast ok. + unsafe { &*ptr.cast::<Self>() } + } + + /// Returns a raw pointer to the underlying `pwm_chip`. + pub(crate) fn as_raw(&self) -> *mut bindings::pwm_chip { + self.0.get() + } + + /// Gets the number of PWM channels (hardware PWMs) on this chip. + pub fn num_channels(&self) -> u32 { + // SAFETY: `self.as_raw()` provides a valid pointer for `self`'s lifetime. + unsafe { (*self.as_raw()).npwm } + } + + /// Returns `true` if the chip supports atomic operations for configuration. + pub fn is_atomic(&self) -> bool { + // SAFETY: `self.as_raw()` provides a valid pointer for `self`'s lifetime. + unsafe { (*self.as_raw()).atomic } + } + + /// Returns a reference to the embedded `struct device` abstraction. + pub fn device(&self) -> &device::Device { + // SAFETY: + // - `self.as_raw()` provides a valid pointer to `bindings::pwm_chip`. + // - The `dev` field is an instance of `bindings::device` embedded + // within `pwm_chip`. + // - Taking a pointer to this embedded field is valid. + // - `device::Device` is `#[repr(transparent)]`. + // - The lifetime of the returned reference is tied to `self`. + unsafe { device::Device::from_raw(&raw mut (*self.as_raw()).dev) } + } + + /// Gets the typed driver specific data associated with this chip's embedded device. + pub fn drvdata(&self) -> &T { + // SAFETY: `pwmchip_get_drvdata` returns the pointer to the private data area, + // which we know holds our `T`. The pointer is valid for the lifetime of `self`. + unsafe { &*bindings::pwmchip_get_drvdata(self.as_raw()).cast::<T>() } + } + + /// Returns a reference to the parent device of this PWM chip's device. + /// + /// # Safety + /// + /// The caller must guarantee that the parent device exists and is bound. + /// This is guaranteed by the PWM core during `PwmOps` callbacks. + unsafe fn bound_parent_device(&self) -> &device::Device<Bound> { + // SAFETY: Per the function's safety contract, the parent device exists. + let parent = unsafe { self.device().parent().unwrap_unchecked() }; + + // SAFETY: Per the function's safety contract, the parent device is bound. + // This is guaranteed by the PWM core during `PwmOps` callbacks. + unsafe { parent.as_bound() } + } + + /// Allocates and wraps a PWM chip using `bindings::pwmchip_alloc`. + /// + /// Returns an [`ARef<Chip>`] managing the chip's lifetime via refcounting + /// on its embedded `struct device`. + pub fn new( + parent_dev: &device::Device, + num_channels: u32, + data: impl pin_init::PinInit<T, Error>, + ) -> Result<ARef<Self>> { + let sizeof_priv = core::mem::size_of::<T>(); + // SAFETY: `pwmchip_alloc` allocates memory for the C struct and our private data. + let c_chip_ptr_raw = + unsafe { bindings::pwmchip_alloc(parent_dev.as_raw(), num_channels, sizeof_priv) }; + + let c_chip_ptr: *mut bindings::pwm_chip = error::from_err_ptr(c_chip_ptr_raw)?; + + // SAFETY: The `drvdata` pointer is the start of the private area, which is where + // we will construct our `T` object. + let drvdata_ptr = unsafe { bindings::pwmchip_get_drvdata(c_chip_ptr) }; + + // SAFETY: We construct the `T` object in-place in the allocated private memory. + unsafe { data.__pinned_init(drvdata_ptr.cast())? }; + + // SAFETY: `c_chip_ptr` points to a valid chip. + unsafe { + (*c_chip_ptr).dev.release = Some(Adapter::<T>::release_callback); + } + + // SAFETY: `c_chip_ptr` points to a valid chip. + // The `Adapter`'s `VTABLE` has a 'static lifetime, so the pointer + // returned by `as_raw()` is always valid. + unsafe { + (*c_chip_ptr).ops = Adapter::<T>::VTABLE.as_raw(); + } + + // Cast the `*mut bindings::pwm_chip` to `*mut Chip`. This is valid because + // `Chip` is `repr(transparent)` over `Opaque<bindings::pwm_chip>`, and + // `Opaque<T>` is `repr(transparent)` over `T`. + let chip_ptr_as_self = c_chip_ptr.cast::<Self>(); + + // SAFETY: `chip_ptr_as_self` points to a valid `Chip` (layout-compatible with + // `bindings::pwm_chip`) whose embedded device has refcount 1. + // `ARef::from_raw` takes this pointer and manages it via `AlwaysRefCounted`. + Ok(unsafe { ARef::from_raw(NonNull::new_unchecked(chip_ptr_as_self)) }) + } +} + +// SAFETY: Implements refcounting for `Chip` using the embedded `struct device`. +unsafe impl<T: PwmOps> AlwaysRefCounted for Chip<T> { + #[inline] + fn inc_ref(&self) { + // SAFETY: `self.0.get()` points to a valid `pwm_chip` because `self` exists. + // The embedded `dev` is valid. `get_device` increments its refcount. + unsafe { + bindings::get_device(&raw mut (*self.0.get()).dev); + } + } + + #[inline] + unsafe fn dec_ref(obj: NonNull<Chip<T>>) { + let c_chip_ptr = obj.cast::<bindings::pwm_chip>().as_ptr(); + + // SAFETY: `obj` is a valid pointer to a `Chip` (and thus `bindings::pwm_chip`) + // with a non-zero refcount. `put_device` handles decrement and final release. + unsafe { + bindings::put_device(&raw mut (*c_chip_ptr).dev); + } + } +} + +// SAFETY: `Chip` is a wrapper around `*mut bindings::pwm_chip`. The underlying C +// structure's state is managed and synchronized by the kernel's device model +// and PWM core locking mechanisms. Therefore, it is safe to move the `Chip` +// wrapper (and the pointer it contains) across threads. +unsafe impl<T: PwmOps + Send> Send for Chip<T> {} + +// SAFETY: It is safe for multiple threads to have shared access (`&Chip`) because +// the `Chip` data is immutable from the Rust side without holding the appropriate +// kernel locks, which the C core is responsible for. Any interior mutability is +// handled and synchronized by the C kernel code. +unsafe impl<T: PwmOps + Sync> Sync for Chip<T> {} + +/// A resource guard that ensures `pwmchip_remove` is called on drop. +/// +/// This struct is intended to be managed by the `devres` framework by transferring its ownership +/// via [`devres::register`]. This ties the lifetime of the PWM chip registration +/// to the lifetime of the underlying device. +pub struct Registration<T: PwmOps> { + chip: ARef<Chip<T>>, +} + +impl<T: 'static + PwmOps + Send + Sync> Registration<T> { + /// Registers a PWM chip with the PWM subsystem. + /// + /// Transfers its ownership to the `devres` framework, which ties its lifetime + /// to the parent device. + /// On unbind of the parent device, the `devres` entry will be dropped, automatically + /// calling `pwmchip_remove`. This function should be called from the driver's `probe`. + pub fn register(dev: &device::Device<Bound>, chip: ARef<Chip<T>>) -> Result { + let chip_parent = chip.device().parent().ok_or(EINVAL)?; + if dev.as_raw() != chip_parent.as_raw() { + return Err(EINVAL); + } + + let c_chip_ptr = chip.as_raw(); + + // SAFETY: `c_chip_ptr` points to a valid chip with its ops initialized. + // `__pwmchip_add` is the C function to register the chip with the PWM core. + unsafe { + to_result(bindings::__pwmchip_add(c_chip_ptr, core::ptr::null_mut()))?; + } + + let registration = Registration { chip }; + + devres::register(dev, registration, GFP_KERNEL) + } +} + +impl<T: PwmOps> Drop for Registration<T> { + fn drop(&mut self) { + let chip_raw = self.chip.as_raw(); + + // SAFETY: `chip_raw` points to a chip that was successfully registered. + // `bindings::pwmchip_remove` is the correct C function to unregister it. + // This `drop` implementation is called automatically by `devres` on driver unbind. + unsafe { + bindings::pwmchip_remove(chip_raw); + } + } +} + +/// Declares a kernel module that exposes a single PWM driver. +/// +/// # Examples +/// +///```ignore +/// kernel::module_pwm_platform_driver! { +/// type: MyDriver, +/// name: "Module name", +/// authors: ["Author name"], +/// description: "Description", +/// license: "GPL v2", +/// } +///``` +#[macro_export] +macro_rules! module_pwm_platform_driver { + ($($user_args:tt)*) => { + $crate::module_platform_driver! { + $($user_args)* + imports_ns: ["PWM"], + } + }; +} diff --git a/rust/macros/module.rs b/rust/macros/module.rs index 8cef6cc958b5..49131ff3e097 100644 --- a/rust/macros/module.rs +++ b/rust/macros/module.rs @@ -98,6 +98,7 @@ struct ModuleInfo { description: Option<String>, alias: Option<Vec<String>>, firmware: Option<Vec<String>>, + imports_ns: Option<Vec<String>>, } impl ModuleInfo { @@ -112,6 +113,7 @@ impl ModuleInfo { "license", "alias", "firmware", + "imports_ns", ]; const REQUIRED_KEYS: &[&str] = &["type", "name", "license"]; let mut seen_keys = Vec::new(); @@ -137,6 +139,7 @@ impl ModuleInfo { "license" => info.license = expect_string_ascii(it), "alias" => info.alias = Some(expect_string_array(it)), "firmware" => info.firmware = Some(expect_string_array(it)), + "imports_ns" => info.imports_ns = Some(expect_string_array(it)), _ => panic!("Unknown key \"{key}\". Valid keys are: {EXPECTED_KEYS:?}."), } @@ -195,6 +198,11 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { modinfo.emit("firmware", &fw); } } + if let Some(imports) = info.imports_ns { + for ns in imports { + modinfo.emit("import_ns", &ns); + } + } // Built-in modules also export the `file` modinfo string. let file = |