diff options
| author | Andrei Lalaev <andrei.lalaev@anton-paar.com> | 2025-08-20 10:47:12 +0200 |
|---|---|---|
| committer | Lee Jones <lee@kernel.org> | 2025-09-02 13:26:25 +0100 |
| commit | d6058316d16ee0d1861c0550051b2492efb54b79 (patch) | |
| tree | 4b6843725c9418040a777c10e44d326d45bce859 | |
| parent | 19c5010e8ae23faf7b98fd738ff9970bb9066b78 (diff) | |
leds: leds-lp55xx: Use correct address for memory programming
Memory programming doesn't work for devices without page support.
For example, LP5562 has 3 engines but doesn't support pages,
the start address is changed depending on engine number.
According to datasheet [1], the PROG MEM register addresses for each
engine are as follows:
Engine 1: 0x10
Engine 2: 0x30
Engine 3: 0x50
However, the current implementation incorrectly calculates the address
of PROG MEM register using the engine index starting from 1:
prog_mem_base = 0x10
LP55xx_BYTES_PER_PAGE = 0x20
Engine 1: 0x10 + 0x20 * 1 = 0x30
Engine 2: 0x10 + 0x20 * 2 = 0x50
Engine 3: 0x10 + 0x20 * 3 = 0x70
This results in writing to the wrong engine memory, causing pattern
programming to fail.
To correct it, the engine index should be decreased:
Engine 1: 0x10 + 0x20 * 0 = 0x10
Engine 2: 0x10 + 0x20 * 1 = 0x30
Engine 3: 0x10 + 0x20 * 2 = 0x50
1 - https://www.ti.com/lit/ds/symlink/lp5562.pdf
Fixes: 31379a57cf2f ("leds: leds-lp55xx: Generalize update_program_memory function")
Signed-off-by: Andrei Lalaev <andrei.lalaev@anton-paar.com>
Link: https://lore.kernel.org/r/20250820-lp5562-prog-mem-address-v1-1-8569647fa71d@anton-paar.com
Signed-off-by: Lee Jones <lee@kernel.org>
| -rw-r--r-- | drivers/leds/leds-lp55xx-common.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c index e71456a56ab8..fd447eb7eb15 100644 --- a/drivers/leds/leds-lp55xx-common.c +++ b/drivers/leds/leds-lp55xx-common.c @@ -212,7 +212,7 @@ int lp55xx_update_program_memory(struct lp55xx_chip *chip, * For LED chip that support page, PAGE is already set in load_engine. */ if (!cfg->pages_per_engine) - start_addr += LP55xx_BYTES_PER_PAGE * idx; + start_addr += LP55xx_BYTES_PER_PAGE * (idx - 1); for (page = 0; page < program_length / LP55xx_BYTES_PER_PAGE; page++) { /* Write to the next page each 32 bytes (if supported) */ |