Re: [PATCH] iio: stmpe-adc: Fix wait_for_completion_timeout return value check

Miaoqian Lin
2022-04-11T14:05:03Z

On 2022/4/11 20:05, Philippe Schenker wrote:
> On Mon, 2022-04-11 at 10:30 +0000, Miaoqian Lin wrote:
>> 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
> Hello and thanks for your fix. Any specific reason you didn't apply this
> also in function stmpe_read_temp?

Hi，sorry I just missed that. I will send v2 to fix this.

>> Fixes: e813dde6f833 ("iio: stmpe-adc: Use
>> wait_for_completion_timeout")
>> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
>> ---
>>  drivers/iio/adc/stmpe-adc.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c
>> index d2d405388499..d475d1c17bfc 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);