Re: [PATCH 3/5 v3] iio: exynos_adc: reduce timeout and use wait_for_completion_timeout

Jonathan Cameron
2014-04-30T20:43:18Z

On 30/04/14 10:26, Naveen Krishna Chatradhi wrote:
> ADC module on Exynos5 SoCs runs at 600KSPS. At this conversion rate,
> waiting for 1000 msecs is wasteful (incase of h/w failure).
>
> Hence, reduce the time out to 100msecs and use
> wait_for_completion_timeout() instead of
> wait_for_completion_interruptible_timeout()
>
> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
> Reviewed-by: Doug Anderson <dianders@chromium.org>
Applied to the togreg branch of iio.git

Thanks
> ---
> Changes since v2:
> None
> Changes since v1:
> None
> v0:
> This change is a part of the patch reviewd at https://lkml.org/lkml/2013/11/5/92
>
> drivers/iio/adc/exynos_adc.c | 18 +++++++++++-------
> 1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
> index ff98c5d..939aaf7 100644
> --- a/drivers/iio/adc/exynos_adc.c
> +++ b/drivers/iio/adc/exynos_adc.c
> @@ -82,7 +82,7 @@ enum adc_version {
> #define ADC_CON_EN_START (1u << 0)
> #define ADC_DATX_MASK 0xFFF
>
> -#define EXYNOS_ADC_TIMEOUT (msecs_to_jiffies(1000))
> +#define EXYNOS_ADC_TIMEOUT (msecs_to_jiffies(100))
>
> struct exynos_adc {
> void __iomem *regs;
> @@ -121,6 +121,7 @@ static int exynos_read_raw(struct iio_dev *indio_dev,
> struct exynos_adc *info = iio_priv(indio_dev);
> unsigned long timeout;
> u32 con1, con2;
> + int ret;
>
> if (mask != IIO_CHAN_INFO_RAW)
> return -EINVAL;
> @@ -145,16 +146,19 @@ static int exynos_read_raw(struct iio_dev *indio_dev,
> ADC_V1_CON(info->regs));
> }
>
> - timeout = wait_for_completion_interruptible_timeout
> + timeout = wait_for_completion_timeout
> (&info->completion, EXYNOS_ADC_TIMEOUT);
> - *val = info->value;
> + if (timeout == 0) {
> + ret = -ETIMEDOUT;
> + } else {
> + *val = info->value;
> + *val2 = 0;
> + ret = IIO_VAL_INT;
> + }
>
> mutex_unlock(&indio_dev->mlock);
>
> - if (timeout == 0)
> - return -ETIMEDOUT;
> -
> - return IIO_VAL_INT;
> + return ret;
> }
>
> static irqreturn_t exynos_adc_isr(int irq, void *dev_id)
>