[PATCH v2] iio: adc: mt6360: Handle error in cleanup path correctly

[Haotian Zhang <vulab@iscas.ac.cn>]

The return value of a regmap_raw_write() and regmap_update_bits()
in the cleanup path was being ignored.

Fix this by checking the return value and warn on error.

Fixes: 1f4877218f7e ("iio: adc: mt6360: Add ADC driver for MT6360")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>

---
Changes in v2:
 - Do not propagate cleanup path errors.
 - Log a warning on failure instead of overwriting the return value, as
   suggested by the maintainer.
 - Also check the return value of regmap_update_bits() for consistency.
---
 drivers/iio/adc/mt6360-adc.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c
index 69b3569c90e5..9ee7247aacbe 100644
--- a/drivers/iio/adc/mt6360-adc.c
+++ b/drivers/iio/adc/mt6360-adc.c
@@ -70,6 +70,7 @@ static int mt6360_adc_read_channel(struct mt6360_adc_data *mad, int channel, int
 	ktime_t predict_end_t, timeout;
 	unsigned int pre_wait_time;
 	int ret;
+	int cleanup_ret;
 
 	mutex_lock(&mad->adc_lock);
 
@@ -130,11 +131,16 @@ static int mt6360_adc_read_channel(struct mt6360_adc_data *mad, int channel, int
 out_adc_conv:
 	/* Only keep ADC enable */
 	adc_enable = cpu_to_be16(MT6360_ADCEN_MASK);
-	regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, &adc_enable, sizeof(adc_enable));
+	cleanup_ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG,
+				&adc_enable, sizeof(adc_enable));
+	if (cleanup_ret)
+		dev_warn(mad->dev, "Failed to reset ADC config: %d\n", cleanup_ret);
 	mad->last_off_timestamps[channel] = ktime_get();
 	/* Config prefer channel to NO_PREFER */
-	regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
+	cleanup_ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
 			   MT6360_NO_PREFER << MT6360_PREFERCH_SHFT);
+	if (cleanup_ret)
+		dev_warn(mad->dev, "Failed to reset prefer channel: %d\n", cleanup_ret);
 out_adc_lock:
 	mutex_unlock(&mad->adc_lock);
 
-- 
2.50.1.windows.1