On Fri, 9 Nov 2018 11:25:31 +0800
Baolin Wang <baolin.wang@xxxxxxxxxx> wrote:
> From: Freeman Liu <freeman.liu@xxxxxxxxxx>
>
> Sometimes the ADC controller met some problems, and it will not complete
> the data conversion, that will can not wake up the read process any more
> to block users. So we should add one maximum conversion time to avoid
> this issue.
>
> Signed-off-by: Freeman Liu <freeman.liu@xxxxxxxxxx>
> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
Hi.
Patch looks good, but sounds like this is a fix so could I have a fixes
tag and a patch title that makes that clear?
I think we will want this one back ported to stable by the sound of it.
If it is just a theoretical issue then perhaps we don't need to bother.
Thanks,
Jonathan
> ---
> drivers/iio/adc/sc27xx_adc.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/adc/sc27xx_adc.c b/drivers/iio/adc/sc27xx_adc.c
> index 7940b23..f7f7a189 100644
> --- a/drivers/iio/adc/sc27xx_adc.c
> +++ b/drivers/iio/adc/sc27xx_adc.c
> @@ -52,6 +52,9 @@
> /* Timeout (ms) for the trylock of hardware spinlocks */
> #define SC27XX_ADC_HWLOCK_TIMEOUT 5000
>
> +/* Timeout (ms) for ADC data conversion according to ADC datasheet */
> +#define SC27XX_ADC_RDY_TIMEOUT 100
> +
> /* Maximum ADC channel number */
> #define SC27XX_ADC_CHANNEL_MAX 32
>
> @@ -223,7 +226,14 @@ static int sc27xx_adc_read(struct sc27xx_adc_data *data, int channel,
> if (ret)
> goto disable_adc;
>
> - wait_for_completion(&data->completion);
> + ret = wait_for_completion_timeout(&data->completion,
> + msecs_to_jiffies(SC27XX_ADC_RDY_TIMEOUT));
> + if (!ret) {
> + dev_err(data->dev, "read ADC data timeout\n");
> + ret = -ETIMEDOUT;
> + } else {
> + ret = 0;
> + }
>
> disable_adc:
> regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
