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

Nicolas Ferre
2017-09-08T16:02:32Z

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)
>

--
Nicolas Ferre