wait_for_completion_timeout() returns unsigned long not long. it returns 0 if timed out, and positive if completed. The check for <= 0 is ambiguous and should be == 0 here indicating timeout which is the only error case Fixes: e813dde6f833 ("iio: stmpe-adc: Use wait_for_completion_timeout") Signed-off-by: Miaoqian Lin <linmq006@xxxxxxxxx> --- changes in v2: - Fix same issue in stmpe_read_temp. --- changes in v3: - update the patch subject. --- drivers/iio/adc/stmpe-adc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c index d2d405388499..83e0ac4467ca 100644 --- a/drivers/iio/adc/stmpe-adc.c +++ b/drivers/iio/adc/stmpe-adc.c @@ -61,7 +61,7 @@ struct stmpe_adc { static int stmpe_read_voltage(struct stmpe_adc *info, struct iio_chan_spec const *chan, int *val) { - long ret; + unsigned long ret; mutex_lock(&info->lock); @@ -79,7 +79,7 @@ static int stmpe_read_voltage(struct stmpe_adc *info, ret = wait_for_completion_timeout(&info->completion, STMPE_ADC_TIMEOUT); - if (ret <= 0) { + if (ret == 0) { stmpe_reg_write(info->stmpe, STMPE_REG_ADC_INT_STA, STMPE_ADC_CH(info->channel)); mutex_unlock(&info->lock); @@ -96,7 +96,7 @@ static int stmpe_read_voltage(struct stmpe_adc *info, static int stmpe_read_temp(struct stmpe_adc *info, struct iio_chan_spec const *chan, int *val) { - long ret; + unsigned long ret; mutex_lock(&info->lock); @@ -114,7 +114,7 @@ static int stmpe_read_temp(struct stmpe_adc *info, ret = wait_for_completion_timeout(&info->completion, STMPE_ADC_TIMEOUT); - if (ret <= 0) { + if (ret == 0) { mutex_unlock(&info->lock); return -ETIMEDOUT; } -- 2.17.1