Re: [PATCH v1 07/10] iio:adc:at91-sama5d2: Support backup mode

[Romain Izard <romain.izard.pro@gmail.com>]

2017-09-08 18:03 GMT+02:00 Nicolas Ferre <nicolas.ferre@microchip.com>:
> On 08/09/2017 at 17:36, Romain Izard wrote:
>> Support the backup mode for platform suspend, by restoring the hardware
>> registers on resume.
>>
>> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
>
> Romain,
>
> Thanks for your series: definitively some of your patches need to be
> integrated (I've merged some of them in our current linux-4.9-at91 branch.
> However, It seems that some of your additions have already been
> submitted and/or accepted by maintainers.
> For instance an equivalent of this one seems already in Linus' tree:
> 500a2eefd6b16ba141a8fb777ea6962d2eb65e3b ("iio: adc: at91-sama5d2_adc:
> add support for suspend/resume functionality").
>
> Please tell us if it fits what your observed on this driver (or others).
>
> Regards,
>
>> ---
>>  drivers/iio/adc/at91-sama5d2_adc.c | 71 ++++++++++++++++++++++++++++++++------
>>  1 file changed, 61 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
>> index e10dca3ed74b..f9718c863363 100644
>> --- a/drivers/iio/adc/at91-sama5d2_adc.c
>> +++ b/drivers/iio/adc/at91-sama5d2_adc.c
>> @@ -200,6 +200,7 @@ struct at91_adc_state {
>>       u32                             conversion_value;
>>       struct at91_adc_soc_info        soc_info;
>>       wait_queue_head_t               wq_data_available;
>> +     unsigned int                    current_rate;
>>       /*
>>        * lock to prevent concurrent 'single conversion' requests through
>>        * sysfs.
>> @@ -269,6 +270,8 @@ static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
>>       mr |= AT91_SAMA5D2_MR_PRESCAL(prescal);
>>       at91_adc_writel(st, AT91_SAMA5D2_MR, mr);
>>
>> +     st->current_rate = freq;
>> +
>>       dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
>>               freq, startup, prescal);
>>  }
>> @@ -375,7 +378,9 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev,
>>           val > st->soc_info.max_sample_rate)
>>               return -EINVAL;
>>
>> +     mutex_lock(&st->lock);
>>       at91_adc_setup_samp_freq(st, val);
>> +     mutex_unlock(&st->lock);
>>
>>       return 0;
>>  }
>> @@ -386,6 +391,21 @@ static const struct iio_info at91_adc_info = {
>>       .driver_module = THIS_MODULE,
>>  };
>>
>> +static void at91_adc_init_hw(struct at91_adc_state *st, unsigned int freq)
>> +{
>> +     at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
>> +     at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
>> +     /*
>> +      * Transfer field must be set to 2 according to the datasheet and
>> +      * allows different analog settings for each channel.
>> +      */
>> +     at91_adc_writel(st, AT91_SAMA5D2_MR,
>> +                     AT91_SAMA5D2_MR_TRANSFER(2) | AT91_SAMA5D2_MR_ANACH);
>> +
>> +     at91_adc_setup_samp_freq(st, freq);
>> +
>> +}
>> +
>>  static int at91_adc_probe(struct platform_device *pdev)
>>  {
>>       struct iio_dev *indio_dev;
>> @@ -482,16 +502,7 @@ static int at91_adc_probe(struct platform_device *pdev)
>>               goto vref_disable;
>>       }
>>
>> -     at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
>> -     at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
>> -     /*
>> -      * Transfer field must be set to 2 according to the datasheet and
>> -      * allows different analog settings for each channel.
>> -      */
>> -     at91_adc_writel(st, AT91_SAMA5D2_MR,
>> -                     AT91_SAMA5D2_MR_TRANSFER(2) | AT91_SAMA5D2_MR_ANACH);
>> -
>> -     at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);
>> +     at91_adc_init_hw(st, st->soc_info.min_sample_rate);
>>
>>       ret = clk_prepare_enable(st->per_clk);
>>       if (ret)
>> @@ -541,12 +552,52 @@ static const struct of_device_id at91_adc_dt_match[] = {
>>  };
>>  MODULE_DEVICE_TABLE(of, at91_adc_dt_match);
>>
>> +#ifdef CONFIG_PM_SLEEP
>> +static int at91_adc_suspend(struct device *dev)
>> +{
>> +     struct platform_device *pdev = to_platform_device(dev);
>> +     struct iio_dev *indio_dev = platform_get_drvdata(pdev);
>> +     struct at91_adc_state *st = iio_priv(indio_dev);
>> +
>> +     clk_disable_unprepare(st->per_clk);
>> +
>> +     regulator_disable(st->vref);
>> +     regulator_disable(st->reg);
>> +
>> +     return 0;
>> +}
>> +
>> +static int at91_adc_resume(struct device *dev)
>> +{
>> +     struct platform_device *pdev = to_platform_device(dev);
>> +     struct iio_dev *indio_dev = platform_get_drvdata(pdev);
>> +     struct at91_adc_state *st = iio_priv(indio_dev);
>> +     int err;
>> +
>> +     err = regulator_enable(st->reg);
>> +     if (err)
>> +             return err;
>> +
>> +     err = regulator_enable(st->vref);
>> +     if (err)
>> +             return err;
>> +
>> +     at91_adc_init_hw(st, st->current_rate);
>> +
>> +     err = clk_prepare_enable(st->per_clk);
>> +     return err;
>> +}
>> +#endif
>> +
>> +static SIMPLE_DEV_PM_OPS(at91_adc_pm_ops, at91_adc_suspend, at91_adc_resume);
>> +
>>  static struct platform_driver at91_adc_driver = {
>>       .probe = at91_adc_probe,
>>       .remove = at91_adc_remove,
>>       .driver = {
>>               .name = "at91-sama5d2_adc",
>>               .of_match_table = at91_adc_dt_match,
>> +             .pm = &at91_adc_pm_ops,
>>       },
>>  };
>>  module_platform_driver(at91_adc_driver)
>>

Please ignore this patch. The existing merged patch is better.

Best regards,
-- 
Romain Izard