From: Manuel Fombuena <fombuena@outlook.com>
To: lee@kernel.org, pavel@kernel.org,
vicentiu.galanopulo@remote-tech.co.uk,
linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v6 4/9] leds: st1202: set all pattern PWM slots to full after clearing pattern
Date: Thu, 2 Jul 2026 18:38:45 +0100 [thread overview]
Message-ID: <GV1PR08MB849765352C4031BD2D800207C5F52@GV1PR08MB8497.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <GV1PR08MB84972A16ED557BFB96D63F57C5F52@GV1PR08MB8497.eurprd08.prod.outlook.com>
pattern_clear() zeros all PWM registers then restores only Pattern0 to
full duty cycle. Patterns 1-7 are left at zero.
The LED1202 has a single global sequencer shared across all channels. If
another channel starts the sequencer after this one has been cleared, the
cleared channel cycles through its PWM steps — full brightness on step 0,
dark for steps 1-7 — producing an unintended blink.
Set all 8 PWM slots to ST1202_PATTERN_PWM_FULL and unify into a single
loop from 0, ensuring the channel outputs steady ILED regardless of which
sequencer step is active.
Signed-off-by: Manuel Fombuena <fombuena@outlook.com>
Assisted-by: Claude:claude-sonnet-4-6
---
drivers/leds/leds-st1202.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/leds/leds-st1202.c b/drivers/leds/leds-st1202.c
index b4adade49898..3203b3768ec5 100644
--- a/drivers/leds/leds-st1202.c
+++ b/drivers/leds/leds-st1202.c
@@ -35,6 +35,7 @@
#define ST1202_MILLIS_PATTERN_DUR_MIN 22
#define ST1202_PATTERN_DUR 0x16
#define ST1202_PATTERN_PWM 0x1E
+#define ST1202_PATTERN_PWM_FULL 0x0FFF
#define ST1202_PATTERN_REP 0x15
struct st1202_led {
@@ -205,7 +206,7 @@ static int st1202_led_pattern_clear(struct led_classdev *ldev)
return ret;
for (int patt = 0; patt < ST1202_MAX_PATTERNS; patt++) {
- ret = st1202_pwm_pattern_write(chip, led->led_num, patt, LED_OFF);
+ ret = st1202_pwm_pattern_write(chip, led->led_num, patt, ST1202_PATTERN_PWM_FULL);
if (ret != 0)
return ret;
--
2.55.0
next prev parent reply other threads:[~2026-07-02 17:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-02 17:33 [PATCH v6 0/9] leds: st1202: fix multiple bugs in pattern engine and brightness handling Manuel Fombuena
2026-07-02 17:36 ` [PATCH v6 1/9] leds: st1202: stop pattern sequence before reprogramming Manuel Fombuena
2026-07-02 17:37 ` [PATCH v6 2/9] leds: st1202: validate pattern input before stopping the sequence Manuel Fombuena
2026-07-02 17:37 ` [PATCH v6 3/9] leds: st1202: fix pattern duration prescaler and pattern_clear skip marker Manuel Fombuena
2026-07-02 17:38 ` Manuel Fombuena [this message]
2026-07-02 17:39 ` [PATCH v6 5/9] leds: st1202: fix spurious pattern sequence start in setup Manuel Fombuena
2026-07-02 17:41 ` [PATCH v6 6/9] leds: st1202: fix brightness having no effect while pattern mode is active Manuel Fombuena
2026-07-02 17:42 ` [PATCH v6 7/9] leds: st1202: disable channel when brightness is set to zero Manuel Fombuena
2026-07-02 17:43 ` [PATCH v6 8/9] leds: st1202: validate LED reg property against channel count Manuel Fombuena
2026-07-02 17:44 ` [PATCH v6 9/9] leds: st1202: correct and extend hw_pattern documentation Manuel Fombuena
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