linux-kernel - Re: [PATCH v2 2/2] iio: at91-sama5d2_adc: adjust iio_triggered_buffer

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Date:   Thu, 23 Apr 2020 10:56:54 +0000
From:   <Eugen.Hristev@...rochip.com>
To:     <Ludovic.Desroches@...rochip.com>, <alexandru.ardelean@...log.com>
CC:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <jic23@...nel.org>
Subject: Re: [PATCH v2 2/2] iio: at91-sama5d2_adc: adjust
 iio_triggered_buffer_{predisable,postenable} positions

On 19.04.2020 13:04, ludovic.desroches@...rochip.com wrote:
> On Wed, Mar 04, 2020 at 10:42:19AM +0200, Alexandru Ardelean wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> The iio_triggered_buffer_{predisable,postenable} functions attach/detach
>> poll functions.
>>
>> In most cases the iio_triggered_buffer_postenable() should be called first
>> to attach the poll function, and then the driver can init the data to be
>> triggered.
>> In this case it's the other way around: the DMA code should be initialized
>> before the attaching the poll function and the reverse should be done when
>> un-initializing.
>>
>> To make things easier when removing the iio_triggered_buffer_postenable() &
>> iio_triggered_buffer_predisable() functions from the IIO core API, the DMA
>> code has been moved into preenable() for init, and postdisable() for
>> uninit.
>>
>> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
> 
> Reviewed-by: Ludovic Desroches <ludovic.desroches@...rochip.com>

Reviewed-by: Eugen Hristev <eugen.hristev@...rochip.com>

Hi Jonathan,

Please don't forget my other 2 patches on this driver, they've been 
patiently waiting for this merge window

Thanks!

> 
>> ---
>>   drivers/iio/adc/at91-sama5d2_adc.c | 32 ++++++++++++++++++++----------
>>   1 file changed, 22 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
>> index f2a74c47c768..2e01073d401d 100644
>> --- a/drivers/iio/adc/at91-sama5d2_adc.c
>> +++ b/drivers/iio/adc/at91-sama5d2_adc.c
>> @@ -882,7 +882,7 @@ static bool at91_adc_current_chan_is_touch(struct iio_dev *indio_dev)
>>                                 AT91_SAMA5D2_MAX_CHAN_IDX + 1);
>>   }
>>
>> -static int at91_adc_buffer_postenable(struct iio_dev *indio_dev)
>> +static int at91_adc_buffer_preenable(struct iio_dev *indio_dev)
>>   {
>>          int ret;
>>          struct at91_adc_state *st = iio_priv(indio_dev);
>> @@ -902,13 +902,20 @@ static int at91_adc_buffer_postenable(struct iio_dev *indio_dev)
>>                  return ret;
>>          }
>>
>> +       return 0;
>> +}
>> +
>> +static int at91_adc_buffer_postenable(struct iio_dev *indio_dev)
>> +{
>> +       if (at91_adc_current_chan_is_touch(indio_dev))
>> +               return 0;
>> +
>>          return iio_triggered_buffer_postenable(indio_dev);
>>   }
>>
>> -static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
>> +static int at91_adc_buffer_postdisable(struct iio_dev *indio_dev)
>>   {
>>          struct at91_adc_state *st = iio_priv(indio_dev);
>> -       int ret;
>>          u8 bit;
>>
>>          /* check if we are disabling triggered buffer or the touchscreen */
>> @@ -919,13 +926,8 @@ static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
>>          if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
>>                  return -EINVAL;
>>
>> -       /* continue with the triggered buffer */
>> -       ret = iio_triggered_buffer_predisable(indio_dev);
>> -       if (ret < 0)
>> -               dev_err(&indio_dev->dev, "buffer predisable failed\n");
>> -
>>          if (!st->dma_st.dma_chan)
>> -               return ret;
>> +               return 0;
>>
>>          /* if we are using DMA we must clear registers and end DMA */
>>          dmaengine_terminate_sync(st->dma_st.dma_chan);
>> @@ -952,10 +954,20 @@ static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
>>
>>          /* read overflow register to clear possible overflow status */
>>          at91_adc_readl(st, AT91_SAMA5D2_OVER);
>> -       return ret;
>> +       return 0;
>> +}
>> +
>> +static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
>> +{
>> +       if (at91_adc_current_chan_is_touch(indio_dev))
>> +               return 0;
>> +
>> +       return iio_triggered_buffer_predisable(indio_dev);
>>   }
>>
>>   static const struct iio_buffer_setup_ops at91_buffer_setup_ops = {
>> +       .preenable = &at91_adc_buffer_preenable,
>> +       .postdisable = &at91_adc_buffer_postdisable,
>>          .postenable = &at91_adc_buffer_postenable,
>>          .predisable = &at91_adc_buffer_predisable,
>>   };
>> --
>> 2.20.1
>>