[PATCH 02/10] leds: st1202: validate pattern input before stopping the sequence

[Manuel Fombuena]

Input validation for pattern duration is performed inside the write
loop, after the pattern sequence has already been stopped. If
validation fails mid-loop the chip is left with the sequence stopped
and partially written pattern data, with no recovery.

Move all input validation before the mutex and before any hardware
interaction, so an invalid input leaves the chip state unchanged.

Signed-off-by: Manuel Fombuena <fombuena@xxxxxxxxxxx>
Assisted-by: Claude:claude-sonnet-4-6
---
 drivers/leds/leds-st1202.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/leds/leds-st1202.c b/drivers/leds/leds-st1202.c
index 28e3f1e2314c..5f4238181057 100644
--- a/drivers/leds/leds-st1202.c
+++ b/drivers/leds/leds-st1202.c
@@ -228,6 +228,12 @@ static int st1202_led_pattern_set(struct led_classdev *ldev,
 	if (len > ST1202_MAX_PATTERNS)
 		return -EINVAL;
 
+	for (int patt = 0; patt < len; patt++) {
+		if (pattern[patt].delta_t < ST1202_MILLIS_PATTERN_DUR_MIN ||
+				pattern[patt].delta_t > ST1202_MILLIS_PATTERN_DUR_MAX)
+			return -EINVAL;
+	}
+
 	guard(mutex)(&chip->lock);
 
 	ret = st1202_write_reg(chip, ST1202_CONFIG_REG, ST1202_CONFIG_REG_SHFT);
@@ -235,10 +241,6 @@ static int st1202_led_pattern_set(struct led_classdev *ldev,
 		return ret;
 
 	for (int patt = 0; patt < len; patt++) {
-		if (pattern[patt].delta_t < ST1202_MILLIS_PATTERN_DUR_MIN ||
-				pattern[patt].delta_t > ST1202_MILLIS_PATTERN_DUR_MAX)
-			return -EINVAL;
-
 		ret = st1202_pwm_pattern_write(chip, led->led_num, patt, pattern[patt].brightness);
 		if (ret != 0)
 			return ret;
-- 
2.54.0