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leds: st1202: Fix brightness having no effect while pattern mode is active

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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.

The LED1202 has a single global sequencer shared across all channels.
Stopping it in brightness_set() to force static mode would halt running
patterns on all other active LEDs.

Instead, set all 8 PWM slots for the channel to ST1202_PATTERN_PWM_FULL
before writing ILED. With every step at full duty cycle, the output is
ILED x FULL / 4095 = ILED regardless of the sequencer state, without
disturbing other channels.

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.

Fixes: 259230378c ("leds: Add LED1202 I2C driver")
Signed-off-by: Manuel Fombuena <fombuena@outlook.com>
Assisted-by: Claude:claude-sonnet-4-6
Link: https://patch.msgid.link/GV1PR08MB8497570FD162D0D42A9864E3C5F52@GV1PR08MB8497.eurprd08.prod.outlook.com
Signed-off-by: Lee Jones <lee@kernel.org>
This commit is contained in:
Manuel Fombuena
2026-07-09 10:52:08 +01:00
committed by Lee Jones
parent dcc31246aa
commit 7cbe470366
1 changed files with 2 additions and 0 deletions
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drivers/leds/leds-st1202.c
+2
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@@ -136,6 +136,8 @@ static void st1202_brightness_set(struct led_classdev *led_cdev,
guard(mutex)(&chip->lock);
for (int patt = 0; patt < ST1202_MAX_PATTERNS; patt++)
st1202_pwm_pattern_write(chip, led->led_num, patt, ST1202_PATTERN_PWM_FULL);
st1202_write_reg(chip, ST1202_ILED_REG0 + led->led_num, value);
}