Re: [PATCH v3] iio: exynos_adc: use wait_for_completion_timeout instead of interruptible

[Naveen Krishna Ch <naveenkrishna.ch@gmail.com>]

On 11 October 2013 20:00, Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 10/11/2013 10:23 AM, Naveen Krishna Chatradhi wrote:
>> This patch does the following
>> 1. use wait_for_completion_timeout instead of
>>    wait_for_completion_interruptible_timeout
>> 2. Reset software if a timeout happens.
>> 3. Also reduce the timeout to 100milli secs
>
> It is always good to have a description of why a chance should be done in
> the commit message. It is obvious what the patch does by just looking at the
> changed lines, it is not that obvious though why those lines had to be changed.
>
>>
>> Note: submitted for review at https://patchwork.kernel.org/patch/2279591/
>>
>> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
>> Cc: Doug Anderson <dianders@chromium.org>
>> Cc: Lars-Peter Clausen <lars@metafoo.de>
>> ---
>> Changes since v1:
>> As per discussion at
>> http://marc.info/?l=linux-kernel&m=136517637228869&w=3
>>
>> This patch does the following
>> 1. use wait_for_completion_timeout instead of
>>    wait_for_completion_interruptible_timeout
>> 2. Reset software if a timeout happens.
>> 3. Also reduce the timeout to 100milli secs
>>
>> Changes since v2:
>> None.
>> Rebased and reposting.
>>
>> ---
>>  drivers/iio/adc/exynos_adc.c |   66 +++++++++++++++++++++++-------------------
>>  1 file changed, 36 insertions(+), 30 deletions(-)
>>
>> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
>> index d25b262..f18ed7e 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;
>> @@ -112,6 +112,30 @@ static inline unsigned int exynos_adc_get_version(struct platform_device *pdev)
>>       return (unsigned int)match->data;
>>  }
>>
>> +static void exynos_adc_hw_init(struct exynos_adc *info)
>> +{
>> +     u32 con1, con2;
>> +
>> +     if (info->version == ADC_V2) {
>> +             con1 = ADC_V2_CON1_SOFT_RESET;
>> +             writel(con1, ADC_V2_CON1(info->regs));
>> +
>> +             con2 = ADC_V2_CON2_OSEL | ADC_V2_CON2_ESEL |
>> +                     ADC_V2_CON2_HIGHF | ADC_V2_CON2_C_TIME(0);
>> +             writel(con2, ADC_V2_CON2(info->regs));
>> +
>> +             /* Enable interrupts */
>> +             writel(1, ADC_V2_INT_EN(info->regs));
>> +     } else {
>> +             /* set default prescaler values and Enable prescaler */
>> +             con1 =  ADC_V1_CON_PRSCLV(49) | ADC_V1_CON_PRSCEN;
>> +
>> +             /* Enable 12-bit ADC resolution */
>> +             con1 |= ADC_V1_CON_RES;
>> +             writel(con1, ADC_V1_CON(info->regs));
>> +     }
>> +}
>> +
>>  static int exynos_read_raw(struct iio_dev *indio_dev,
>>                               struct iio_chan_spec const *chan,
>>                               int *val,
>> @@ -121,6 +145,7 @@ 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 +170,21 @@ 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);
>
> Nitpick: It would be nice to put the &info->completion on the same line as
> the wait_for_completion...
I received a comment from Grant regarding the same.
I'm away from work this weekend. Will submit the code once i get back,
>
>> +     if (timeout == 0) {
>> +             dev_warn(&indio_dev->dev, "Conversion timed out reseting\n");
>> +             exynos_adc_hw_init(info);
>> +             ret = -ETIMEDOUT;
>> +     } else {
>> +             *val = info->value;
>> +             ret = IIO_VAL_INT;
>> +     }
>>       *val = info->value;
>
> This line above should probably be removed.
Yes this is unnecessary. Will remove this.
>
>>
>>       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)
>> @@ -226,30 +256,6 @@ static int exynos_adc_remove_devices(struct device *dev, void *c)
>>       return 0;
>>  }
>>
>> -static void exynos_adc_hw_init(struct exynos_adc *info)
>> -{
>> -     u32 con1, con2;
>> -
>> -     if (info->version == ADC_V2) {
>> -             con1 = ADC_V2_CON1_SOFT_RESET;
>> -             writel(con1, ADC_V2_CON1(info->regs));
>> -
>> -             con2 = ADC_V2_CON2_OSEL | ADC_V2_CON2_ESEL |
>> -                     ADC_V2_CON2_HIGHF | ADC_V2_CON2_C_TIME(0);
>> -             writel(con2, ADC_V2_CON2(info->regs));
>> -
>> -             /* Enable interrupts */
>> -             writel(1, ADC_V2_INT_EN(info->regs));
>> -     } else {
>> -             /* set default prescaler values and Enable prescaler */
>> -             con1 =  ADC_V1_CON_PRSCLV(49) | ADC_V1_CON_PRSCEN;
>> -
>> -             /* Enable 12-bit ADC resolution */
>> -             con1 |= ADC_V1_CON_RES;
>> -             writel(con1, ADC_V1_CON(info->regs));
>> -     }
>> -}
>> -
>>  static int exynos_adc_probe(struct platform_device *pdev)
>>  {
>>       struct exynos_adc *info = NULL;
>>
>
Thanks for the review.



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