Merge tag 'gpio-updates-for-v6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio updates from Bartosz Golaszewski:
 "There's one new driver, lots of various updates to existing ones, some
  refactoring support for new models and misc tweaks and fixes.

  The biggest new feature in GPIO core is adding support for managed,
  enable-counted sharing of GPIO pins, something that - until now - was
  only hacked around with the GPIOD_FLAGS_BIT_NONEXCLUSIVE request flag
  which basically allowed drivers to "fight it out" for the descriptor
  and provided no synchronization. It was enabled on Qualcomm platforms
  (and thus is enabled on arm64 defconfig) and I plan on removing
  GPIOD_FLAGS_BIT_NONEXCLUSIVE once all drivers using it are switched to
  the new mechanism.

  GPIO core:
   - add proper support for shared GPIOs that's aiming to replace the
     current sharing mechanism (which provides no synchronization ot
     enable counting) and enable it for Qualcomm platforms
   - improve the software node GPIO lookup by using the fwnode
     representation instead of the software node's name which was prone
     to bugs (GPIO controllers don't have to use the software node's
     name as their kernel label)
   - remove the last user of legacy-of-mm-gpiochip.h and drop the header
   - move closer to removing the legacy gpio_request_one() routine
   - rename some symbols for consistency
   - shrink GPIO printk() helpers by reusing existing code
   - remove some redundant kernel messages
   - use min() instead of min_t() in GPIO ACPI code
   - use system_percpu_wq instead of system_wq in GPIO character device
     code

  New drivers:
   - add a driver for the QIXIS FPGA GPIO controller

  Driver improvements:
   - use modernized variants of power management macros across a wide
     array of drivers in order to avoid having to use the __maybe_unused
     attribute
   - convert gpio-elkhartlake and reset-gpio to using the auxiliary bus
     instead of the platform bus as they are not really described in
     firmware
   - use lock guards and update symbol prefixes in gpio-mmio
   - support the bryx radio interface kit in gpio-mpsse + refactor the
     driver
   - use software nodes for configuring the reset-gpio driver, including
     setting up the reference to the shared "reset" pin
   - check and propagate the return value of gpiod_set_value() to
     user-space in gpio-virtuser (this was previously not possible as
     this function returned void)
   - extend the gpio-regmap helper with more features (bypass cache for
     aliased inputs, force writes for aliased data registers, add a new
     configuration parameter)
   - remove unneeded includes from gpio-aspeed and gpio-latch
   - add support for Tegra410 to gpio-tegra186
   - replace PCI-specific PM with generic device-level PM in gpio-bt8xx
   - use dynamic GPIO range allocation in gpio-loongson-64bit
   - improve handling of level-triggered interrupts in gpio-pca953x
   - add suspend/resume support to gpio-fxl6408
   - add support for more models to gpio-menz127
   - optimize gpio-mvebu interrupt handling by avoiding unnecessary
     calls to mvebu_gpio_irq_handler()
   - make locking more consistent in gpio-grgpio

  Device-tree bindings:
   - document new NXP and Microchip models

  Documentation:
   - add a comprehensive compatibility and feature list for
     gpio-pca953x, which is a great addition as it's probably the most
     commonly used GPIO expander driver
   - kernel-doc tweaks

  Late fixes:
   - use BYTE_CTRL_MODE for 2K2000/3000 models in gpio-loongson"

* tag 'gpio-updates-for-v6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (80 commits)
  gpio: loongson: Switch 2K2000/3000 GPIO to BYTE_CTRL_MODE
  gpio: regmap: fix kernel-doc notation
  gpio: shared: fix a deadlock
  gpio: shared-proxy: set suppress_bind_attrs
  gpio: shared: ignore GPIO hogs when traversing the device tree
  gpio: shared: ignore special __symbols__ node when traversing device tree
  gpio: shared: handle the reset-gpios corner case
  gpio: zynq: Use modern PM macros
  gpio: xilinx: Use modern PM macros
  gpio: xgene: Use modern PM macros
  gpio: uniphier: Use modern PM macros
  gpio: tqmx86: Use modern PM macros
  gpio: pch: Use modern PM macros
  gpio: omap: Use modern PM macros
  gpio: msc313: Use modern PM macros
  gpio: mlxbf2: Use modern PM macros
  gpio: ml-ioh: Use modern PM macros
  gpio: pl061: Use modern PM macros
  gpio: htc-egpio: Use modern PM macros
  gpio: brcmstb: Use modern PM macros
  ...

1 files changed, 217 insertions, 12 deletions

diff --git a/drivers/gpio/gpio-mpsse.c b/drivers/gpio/gpio-mpsse.c
index 9f42bb30b4ec..ace652ba4df1 100644
--- a/drivers/gpio/gpio-mpsse.c
+++ b/drivers/gpio/gpio-mpsse.c
@@ -10,6 +10,7 @@
 #include <linux/cleanup.h>
 #include <linux/gpio/driver.h>
 #include <linux/mutex.h>
+#include <linux/spinlock.h>
 #include <linux/usb.h>
 
 struct mpsse_priv {
@@ -17,8 +18,10 @@ struct mpsse_priv {
 	struct usb_device *udev;     /* USB device encompassing all MPSSEs */
 	struct usb_interface *intf;  /* USB interface for this MPSSE */
 	u8 intf_id;                  /* USB interface number for this MPSSE */
-	struct work_struct irq_work; /* polling work thread */
+	struct list_head workers;    /* polling work threads */
 	struct mutex irq_mutex;	     /* lock over irq_data */
+	struct mutex irq_race;	     /* race for polling worker teardown */
+	raw_spinlock_t irq_spin;     /* protects worker list */
 	atomic_t irq_type[16];	     /* pin -> edge detection type */
 	atomic_t irq_enabled;
 	int id;
@@ -26,6 +29,9 @@ struct mpsse_priv {
 	u8 gpio_outputs[2];	     /* Output states for GPIOs [L, H] */
 	u8 gpio_dir[2];		     /* Directions for GPIOs [L, H] */
 
+	unsigned long dir_in;        /* Bitmask of valid input pins  */
+	unsigned long dir_out;       /* Bitmask of valid output pins */
+
 	u8 *bulk_in_buf;	     /* Extra recv buffer to grab status bytes */
 
 	struct usb_endpoint_descriptor *bulk_in;
@@ -34,6 +40,14 @@ struct mpsse_priv {
 	struct mutex io_mutex;	    /* sync I/O with disconnect */
 };
 
+struct mpsse_worker {
+	struct mpsse_priv  *priv;
+	struct work_struct  work;
+	atomic_t       cancelled;
+	struct list_head    list;   /* linked list */
+	struct list_head destroy;   /* teardown linked list */
+};
+
 struct bulk_desc {
 	bool tx;	            /* direction of bulk transfer */
 	u8 *data;                   /* input (tx) or output (rx) */
@@ -43,8 +57,27 @@ struct bulk_desc {
 	int timeout;
 };
 
+#define MPSSE_NGPIO 16
+
+struct mpsse_quirk {
+	const char   *names[MPSSE_NGPIO]; /* Pin names, if applicable     */
+	unsigned long dir_in;             /* Bitmask of valid input pins  */
+	unsigned long dir_out;            /* Bitmask of valid output pins */
+};
+
+static struct mpsse_quirk bryx_brik_quirk = {
+	.names = {
+		[3] = "Push to Talk",
+		[5] = "Channel Activity",
+	},
+	.dir_out = BIT(3),	/* Push to Talk     */
+	.dir_in  = BIT(5),	/* Channel Activity */
+};
+
 static const struct usb_device_id gpio_mpsse_table[] = {
 	{ USB_DEVICE(0x0c52, 0xa064) },   /* SeaLevel Systems, Inc. */
+	{ USB_DEVICE(0x0403, 0x6988),     /* FTDI, assigned to Bryx */
+	  .driver_info = (kernel_ulong_t)&bryx_brik_quirk},
 	{ }                               /* Terminating entry */
 };
 
@@ -160,6 +193,32 @@ static int gpio_mpsse_get_bank(struct mpsse_priv *priv, u8 bank)
 	return buf;
 }
 
+static int mpsse_ensure_supported(struct gpio_chip *chip,
+				  unsigned long mask, int direction)
+{
+	unsigned long supported, unsupported;
+	char *type = "input";
+	struct mpsse_priv *priv = gpiochip_get_data(chip);
+
+	supported = priv->dir_in;
+	if (direction == GPIO_LINE_DIRECTION_OUT) {
+		supported = priv->dir_out;
+		type = "output";
+	}
+
+	/* An invalid bit was in the provided mask */
+	unsupported = mask & ~supported;
+	if (unsupported) {
+		dev_err(&priv->udev->dev,
+			"mpsse: GPIO %lu doesn't support %s\n",
+			find_first_bit(&unsupported, sizeof(unsupported) * 8),
+			type);
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
 static int gpio_mpsse_set_multiple(struct gpio_chip *chip, unsigned long *mask,
 				   unsigned long *bits)
 {
@@ -167,6 +226,10 @@ static int gpio_mpsse_set_multiple(struct gpio_chip *chip, unsigned long *mask,
 	int ret;
 	struct mpsse_priv *priv = gpiochip_get_data(chip);
 
+	ret = mpsse_ensure_supported(chip, *mask, GPIO_LINE_DIRECTION_OUT);
+	if (ret)
+		return ret;
+
 	guard(mutex)(&priv->io_mutex);
 	for_each_set_clump8(i, bank_mask, mask, chip->ngpio) {
 		bank = i / 8;
@@ -194,6 +257,10 @@ static int gpio_mpsse_get_multiple(struct gpio_chip *chip, unsigned long *mask,
 	int ret;
 	struct mpsse_priv *priv = gpiochip_get_data(chip);
 
+	ret = mpsse_ensure_supported(chip, *mask, GPIO_LINE_DIRECTION_IN);
+	if (ret)
+		return ret;
+
 	guard(mutex)(&priv->io_mutex);
 	for_each_set_clump8(i, bank_mask, mask, chip->ngpio) {
 		bank = i / 8;
@@ -242,10 +309,15 @@ static int gpio_mpsse_gpio_set(struct gpio_chip *chip, unsigned int offset,
 static int gpio_mpsse_direction_output(struct gpio_chip *chip,
 				       unsigned int offset, int value)
 {
+	int ret;
 	struct mpsse_priv *priv = gpiochip_get_data(chip);
 	int bank = (offset & 8) >> 3;
 	int bank_offset = offset & 7;
 
+	ret = mpsse_ensure_supported(chip, BIT(offset), GPIO_LINE_DIRECTION_OUT);
+	if (ret)
+		return ret;
+
 	scoped_guard(mutex, &priv->io_mutex)
 		priv->gpio_dir[bank] |= BIT(bank_offset);
 
@@ -255,15 +327,19 @@ static int gpio_mpsse_direction_output(struct gpio_chip *chip,
 static int gpio_mpsse_direction_input(struct gpio_chip *chip,
 				      unsigned int offset)
 {
+	int ret;
 	struct mpsse_priv *priv = gpiochip_get_data(chip);
 	int bank = (offset & 8) >> 3;
 	int bank_offset = offset & 7;
 
+	ret = mpsse_ensure_supported(chip, BIT(offset), GPIO_LINE_DIRECTION_IN);
+	if (ret)
+		return ret;
+
 	guard(mutex)(&priv->io_mutex);
 	priv->gpio_dir[bank] &= ~BIT(bank_offset);
-	gpio_mpsse_set_bank(priv, bank);
 
-	return 0;
+	return gpio_mpsse_set_bank(priv, bank);
 }
 
 static int gpio_mpsse_get_direction(struct gpio_chip *chip,
@@ -284,18 +360,62 @@ static int gpio_mpsse_get_direction(struct gpio_chip *chip,
 	return ret;
 }
 
-static void gpio_mpsse_poll(struct work_struct *work)
+/*
+ * Stops all workers except `my_worker`.
+ * Safe to call only when `irq_race` is held.
+ */
+static void gpio_mpsse_stop_all_except(struct mpsse_priv *priv,
+				       struct mpsse_worker *my_worker)
+{
+	struct mpsse_worker *worker, *worker_tmp;
+	struct list_head destructors = LIST_HEAD_INIT(destructors);
+
+	scoped_guard(raw_spinlock_irqsave, &priv->irq_spin) {
+		list_for_each_entry_safe(worker, worker_tmp,
+					 &priv->workers, list) {
+			/* Don't stop ourselves */
+			if (worker == my_worker)
+				continue;
+
+			list_del(&worker->list);
+
+			/* Give worker a chance to terminate itself */
+			atomic_set(&worker->cancelled, 1);
+			/* Keep track of stuff to cancel */
+			INIT_LIST_HEAD(&worker->destroy);
+			list_add(&worker->destroy, &destructors);
+		}
+	}
+
+	list_for_each_entry_safe(worker, worker_tmp,
+				 &destructors, destroy) {
+		list_del(&worker->destroy);
+		cancel_work_sync(&worker->work);
+		kfree(worker);
+	}
+}
+
+static void gpio_mpsse_poll(struct work_struct *my_work)
 {
 	unsigned long pin_mask, pin_states, flags;
 	int irq_enabled, offset, err, value, fire_irq,
 		irq, old_value[16], irq_type[16];
-	struct mpsse_priv *priv = container_of(work, struct mpsse_priv,
-					       irq_work);
+	struct mpsse_worker *my_worker = container_of(my_work, struct mpsse_worker, work);
+	struct mpsse_priv *priv = my_worker->priv;
 
 	for (offset = 0; offset < priv->gpio.ngpio; ++offset)
 		old_value[offset] = -1;
 
-	while ((irq_enabled = atomic_read(&priv->irq_enabled))) {
+	/*
+	 * We only want one worker. Workers race to acquire irq_race and tear
+	 * down all other workers. This is a cond guard so that we don't deadlock
+	 * trying to cancel a worker.
+	 */
+	scoped_cond_guard(mutex_try, return, &priv->irq_race)
+		gpio_mpsse_stop_all_except(priv, my_worker);
+
+	while ((irq_enabled = atomic_read(&priv->irq_enabled)) &&
+	       !atomic_read(&my_worker->cancelled)) {
 		usleep_range(MPSSE_POLL_INTERVAL, MPSSE_POLL_INTERVAL + 1000);
 		/* Cleanup will trigger at the end of the loop */
 		guard(mutex)(&priv->irq_mutex);
@@ -370,21 +490,45 @@ static int gpio_mpsse_set_irq_type(struct irq_data *irqd, unsigned int type)
 
 static void gpio_mpsse_irq_disable(struct irq_data *irqd)
 {
+	struct mpsse_worker *worker;
 	struct mpsse_priv *priv = irq_data_get_irq_chip_data(irqd);
 
 	atomic_and(~BIT(irqd->hwirq), &priv->irq_enabled);
 	gpiochip_disable_irq(&priv->gpio, irqd->hwirq);
+
+	/*
+	 * Can't actually do teardown in IRQ context (it blocks).
+	 * As a result, these workers will stick around until irq is reenabled
+	 * or device gets disconnected
+	 */
+	scoped_guard(raw_spinlock_irqsave, &priv->irq_spin)
+		list_for_each_entry(worker, &priv->workers, list)
+			atomic_set(&worker->cancelled, 1);
 }
 
 static void gpio_mpsse_irq_enable(struct irq_data *irqd)
 {
+	struct mpsse_worker *worker;
 	struct mpsse_priv *priv = irq_data_get_irq_chip_data(irqd);
 
 	gpiochip_enable_irq(&priv->gpio, irqd->hwirq);
 	/* If no-one else was using the IRQ, enable it */
 	if (!atomic_fetch_or(BIT(irqd->hwirq), &priv->irq_enabled)) {
-		INIT_WORK(&priv->irq_work, gpio_mpsse_poll);
-		schedule_work(&priv->irq_work);
+		/*
+		 * Can't be devm because it uses a non-raw spinlock (illegal in
+		 * this context, where a raw spinlock is held by our caller)
+		 */
+		worker = kzalloc(sizeof(*worker), GFP_NOWAIT);
+		if (!worker)
+			return;
+
+		worker->priv = priv;
+		INIT_LIST_HEAD(&worker->list);
+		INIT_WORK(&worker->work, gpio_mpsse_poll);
+		schedule_work(&worker->work);
+
+		scoped_guard(raw_spinlock_irqsave, &priv->irq_spin)
+			list_add(&worker->list, &priv->workers);
 	}
 }
 
@@ -404,18 +548,49 @@ static void gpio_mpsse_ida_remove(void *data)
 	ida_free(&gpio_mpsse_ida, priv->id);
 }
 
+static int mpsse_init_valid_mask(struct gpio_chip *chip,
+				 unsigned long *valid_mask,
+				 unsigned int ngpios)
+{
+	struct mpsse_priv *priv = gpiochip_get_data(chip);
+
+	if (WARN_ON(priv == NULL))
+		return -ENODEV;
+
+	*valid_mask = priv->dir_in | priv->dir_out;
+
+	return 0;
+}
+
+static void mpsse_irq_init_valid_mask(struct gpio_chip *chip,
+				      unsigned long *valid_mask,
+				      unsigned int ngpios)
+{
+	struct mpsse_priv *priv = gpiochip_get_data(chip);
+
+	if (WARN_ON(priv == NULL))
+		return;
+
+	/* Can only use IRQ on input capable pins */
+	*valid_mask = priv->dir_in;
+}
+
 static int gpio_mpsse_probe(struct usb_interface *interface,
 			    const struct usb_device_id *id)
 {
 	struct mpsse_priv *priv;
 	struct device *dev;
+	char *serial;
 	int err;
+	struct mpsse_quirk *quirk = (void *)id->driver_info;
 
 	dev = &interface->dev;
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
+	INIT_LIST_HEAD(&priv->workers);
+
 	priv->udev = usb_get_dev(interface_to_usbdev(interface));
 	priv->intf = interface;
 	priv->intf_id = interface->cur_altsetting->desc.bInterfaceNumber;
@@ -436,9 +611,21 @@ static int gpio_mpsse_probe(struct usb_interface *interface,
 	if (err)
 		return err;
 
+	err = devm_mutex_init(dev, &priv->irq_race);
+	if (err)
+		return err;
+
+	raw_spin_lock_init(&priv->irq_spin);
+
+	serial = priv->udev->serial;
+	if (!serial)
+		serial = "NONE";
+
 	priv->gpio.label = devm_kasprintf(dev, GFP_KERNEL,
-					  "gpio-mpsse.%d.%d",
-					  priv->id, priv->intf_id);
+					  "MPSSE%04x:%04x.%d.%d.%s",
+					  id->idVendor, id->idProduct,
+					  priv->intf_id, priv->id,
+					  serial);
 	if (!priv->gpio.label)
 		return -ENOMEM;
 
@@ -452,10 +639,20 @@ static int gpio_mpsse_probe(struct usb_interface *interface,
 	priv->gpio.get_multiple = gpio_mpsse_get_multiple;
 	priv->gpio.set_multiple = gpio_mpsse_set_multiple;
 	priv->gpio.base = -1;
-	priv->gpio.ngpio = 16;
+	priv->gpio.ngpio = MPSSE_NGPIO;
 	priv->gpio.offset = priv->intf_id * priv->gpio.ngpio;
 	priv->gpio.can_sleep = 1;
 
+	if (quirk) {
+		priv->dir_out = quirk->dir_out;
+		priv->dir_in = quirk->dir_in;
+		priv->gpio.names = quirk->names;
+		priv->gpio.init_valid_mask = mpsse_init_valid_mask;
+	} else {
+		priv->dir_in = U16_MAX;
+		priv->dir_out = U16_MAX;
+	}
+
 	err = usb_find_common_endpoints(interface->cur_altsetting,
 					&priv->bulk_in, &priv->bulk_out,
 					NULL, NULL);
@@ -494,6 +691,7 @@ static int gpio_mpsse_probe(struct usb_interface *interface,
 	priv->gpio.irq.parents = NULL;
 	priv->gpio.irq.default_type = IRQ_TYPE_NONE;
 	priv->gpio.irq.handler = handle_simple_irq;
+	priv->gpio.irq.init_valid_mask = mpsse_irq_init_valid_mask;
 
 	err = devm_gpiochip_add_data(dev, &priv->gpio, priv);
 	if (err)
@@ -506,6 +704,13 @@ static void gpio_mpsse_disconnect(struct usb_interface *intf)
 {
 	struct mpsse_priv *priv = usb_get_intfdata(intf);
 
+	/*
+	 * Lock prevents double-free of worker from here and the teardown
+	 * step at the beginning of gpio_mpsse_poll
+	 */
+	scoped_guard(mutex, &priv->irq_race)
+		gpio_mpsse_stop_all_except(priv, NULL);
+
 	priv->intf = NULL;
 	usb_set_intfdata(intf, NULL);
 	usb_put_dev(priv->udev);