[PATCH v2 07/10] leds: st1202: fix spurious pattern sequence start in setup

[Manuel Fombuena]

st1202_setup() writes PATS and PATSR to the Configuration register as
its final step, which starts the hardware pattern sequencer during
device probe before any patterns have been programmed. This causes the
device to run a sequence with whatever values happen to be in the
pattern registers at the time.

This write also has a second unintended effect: it overwrites the
Configuration register without the SHFT bit, silently undoing the
phase-shift write made earlier in the same function. As a result the
phase-shift feature is never actually enabled after probe, despite the
explicit write intended to enable it.

Both problems are caused by the same write. Remove it. The device
reset at the start of setup restores all registers to their power-on
defaults, leaving PATS and PATSR cleared. The Configuration register
correctly retains its earlier SHFT-only value.

Fixes: 259230378c65 ("leds: Add LED1202 I2C driver")
Signed-off-by: Manuel Fombuena <fombuena@xxxxxxxxxxx>
Assisted-by: Claude:claude-sonnet-4-6
---
 drivers/leds/leds-st1202.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/leds/leds-st1202.c b/drivers/leds/leds-st1202.c
index 933c50c317c1..9150b92ccbac 100644
--- a/drivers/leds/leds-st1202.c
+++ b/drivers/leds/leds-st1202.c
@@ -341,11 +341,6 @@ static int st1202_setup(struct st1202_chip *chip)
 	if (ret < 0)
 		return ret;
 
-	ret = st1202_write_reg(chip, ST1202_CONFIG_REG,
-				ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR);
-	if (ret < 0)
-		return ret;
-
 	return 0;
 }
 
-- 
2.54.0