6.17-stable review patch. If anyone has any objections, please let me know.
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From: Andrei Lalaev andrei.lalaev@anton-paar.com
[ Upstream commit d6058316d16ee0d1861c0550051b2492efb54b79 ]
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... Signed-off-by: Lee Jones lee@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/leds/leds-lp55xx-common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c index e71456a56ab8d..fd447eb7eb15e 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) */