[PATCH v2 RESEND] iio: accel: adxl345: update period cache after successful write

[Wenqiang Zhao via B4 Relay <devnull+berringtoni36.gmail.com@kernel.org>]

From: Wenqiang Zhao <berringtoni36@gmail.com>

The ADXL345 event-period read path returns st->inact_time_ms. The setters
for inactivity, free-fall and the ODR-derived default currently update
this cache before writing TIME_INACT or TIME_FF. If the regmap write
fails, the sysfs write reports an error but a subsequent read returns
the requested period even though it was not programmed.

Update the cached period only after the corresponding regmap write
succeeds.

Fixes: 8a1536cc4a1c ("iio: accel: adxl345: add inactivity feature")
Fixes: f6f22950d925 ("iio: accel: adxl345: extend inactivity time for less than 1s")
Assisted-by: LLM
Signed-off-by: Wenqiang Zhao <berringtoni36@gmail.com>
---
Resend: unchanged code; submitted via b4 web submission to avoid delivery-time wrapping.

v2:
- Keep Fixes: tags on a single line (Nuno)
- Use a Latin-script name in From: and Signed-off-by: (Nuno)
- Drop the long validation notes; build-tested only, not tested on hardware

The missing serialization between concurrent sysfs callers that Nuno
pointed out is a separate issue and will be addressed in a follow-up
patch.

 drivers/iio/accel/adxl345_core.c | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 6c9080d..cd58304 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -391,30 +391,47 @@ static int adxl345_set_default_time(struct adxl345_state *st)
 	odr = FIELD_GET(ADXL345_BW_RATE_MSK, regval);
 	val = clamp(max_boundary - adxl345_odr_tbl[odr][0],
 		    min_boundary, max_boundary);
-	st->inact_time_ms = MILLI * val;
 
 	/* Inactivity time in s */
-	return regmap_write(st->regmap, ADXL345_REG_TIME_INACT, val);
+	ret = regmap_write(st->regmap, ADXL345_REG_TIME_INACT, val);
+	if (ret)
+		return ret;
+
+	st->inact_time_ms = MILLI * val;
+
+	return 0;
 }
 
 static int adxl345_set_inactivity_time(struct adxl345_state *st, u32 val_int)
 {
+	int ret;
+
+	ret = regmap_write(st->regmap, ADXL345_REG_TIME_INACT, val_int);
+	if (ret)
+		return ret;
+
 	st->inact_time_ms = MILLI * val_int;
 
-	return regmap_write(st->regmap, ADXL345_REG_TIME_INACT, val_int);
+	return 0;
 }
 
 static int adxl345_set_freefall_time(struct adxl345_state *st, u32 val_fract)
 {
+	int ret;
+
 	/*
 	 * Datasheet max. value is 255 * 5000 us = 1.275000 seconds.
 	 *
 	 * Recommended values between 100ms and 350ms (0x14 to 0x46)
 	 */
+	ret = regmap_write(st->regmap, ADXL345_REG_TIME_FF,
+			   DIV_ROUND_CLOSEST(val_fract, 5));
+	if (ret)
+		return ret;
+
 	st->inact_time_ms = DIV_ROUND_UP(val_fract, MILLI);
 
-	return regmap_write(st->regmap, ADXL345_REG_TIME_FF,
-			    DIV_ROUND_CLOSEST(val_fract, 5));
+	return 0;
 }
 
 /**

base-commit: 9ee8306121495d2a25aa5d1bfd519f2748786b83
-- 
2.50.1 (Apple Git-155)