[PATCH 08/10] leds: st1202: fix brightness having no effect while pattern mode is active

[Manuel Fombuena]

Once a hardware pattern is running (PATS=1), writing to the brightness
sysfs attribute only updates the ILED register. The visible output is
ILED x Pattern_PWM/4095, so the change has little effect and the LED
never returns to steady static operation as the user expects.

Set CONFIG_REG to SHFT (static mode) before writing ILED so that a
direct brightness write always produces a steady output at the
requested level.

This also enables basic LED operation without the pattern trigger: with
the trigger set to none, the brightness sysfs attribute fully controls
the LED as a simple on/off device. Previously there was no working path
for this, as brightness writes had no visible effect unless a hardware
pattern had first been programmed.

This is safe because software patterns already run with PATS=0 (making
the write a no-op in that path), and the hardware pattern engine does
not call brightness_set during autonomous pattern execution.

Note that CONFIG_REG is chip-wide, so this clears the pattern mode for
all channels on the device.

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 | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/leds/leds-st1202.c b/drivers/leds/leds-st1202.c
index 9150b92ccbac..bca2d9a80b63 100644
--- a/drivers/leds/leds-st1202.c
+++ b/drivers/leds/leds-st1202.c
@@ -136,6 +136,7 @@ static void st1202_brightness_set(struct led_classdev *led_cdev,
 
 	guard(mutex)(&chip->lock);
 
+	st1202_write_reg(chip, ST1202_CONFIG_REG, ST1202_CONFIG_REG_SHFT);
 	st1202_write_reg(chip, ST1202_ILED_REG0 + led->led_num, value);
 }
 
-- 
2.54.0