linux-kernel - Re: [PATCH] iio: gyro: adxrs290: use hook for devm resource unwinding

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Message-ID: <CAHp75VeMJruyOCskBGZtyeR-p3sh7hLk2QH32LULAo7wSX3KUA@mail.gmail.com>
Date:   Thu, 10 Sep 2020 16:51:26 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Nishant Malpani <nish.malpani25@...il.com>
Cc:     Jonathan Cameron <jic23@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-iio <linux-iio@...r.kernel.org>
Subject: Re: [PATCH] iio: gyro: adxrs290: use hook for devm resource unwinding

On Thu, Sep 10, 2020 at 3:27 PM Nishant Malpani
<nish.malpani25@...il.com> wrote:
>
> Make use of devm_add_action_or_reset() hook to switch device into STANDBY
> mode during standard resource unwinding. The patch includes a helper
> function, in the form of adxrs290_set_mode(), to realise driving the
> device into STANDBY mode.

Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>

> Signed-off-by: Nishant Malpani <nish.malpani25@...il.com>
> ---
>  drivers/iio/gyro/adxrs290.c | 61 +++++++++++++++++++++++++++++++++++--
>  1 file changed, 58 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/gyro/adxrs290.c b/drivers/iio/gyro/adxrs290.c
> index ff989536d2fb..2864eb443957 100644
> --- a/drivers/iio/gyro/adxrs290.c
> +++ b/drivers/iio/gyro/adxrs290.c
> @@ -192,15 +192,70 @@ static int adxrs290_set_filter_freq(struct iio_dev *indio_dev,
>         return adxrs290_spi_write_reg(st->spi, ADXRS290_REG_FILTER, val);
>  }
>
> +static int adxrs290_set_mode(struct iio_dev *indio_dev, enum adxrs290_mode mode)
> +{
> +       struct adxrs290_state *st = iio_priv(indio_dev);
> +       int val, ret;
> +
> +       if (st->mode == mode)
> +               return 0;
> +
> +       mutex_lock(&st->lock);
> +
> +       ret = spi_w8r8(st->spi, ADXRS290_READ_REG(ADXRS290_REG_POWER_CTL));
> +       if (ret < 0)
> +               goto out_unlock;
> +
> +       val = ret;
> +
> +       switch (mode) {
> +       case ADXRS290_MODE_STANDBY:
> +               val &= ~ADXRS290_MEASUREMENT;
> +               break;
> +       case ADXRS290_MODE_MEASUREMENT:
> +               val |= ADXRS290_MEASUREMENT;
> +               break;
> +       default:
> +               ret = -EINVAL;
> +               goto out_unlock;
> +       }
> +
> +       ret = adxrs290_spi_write_reg(st->spi, ADXRS290_REG_POWER_CTL, val);
> +       if (ret < 0) {
> +               dev_err(&st->spi->dev, "unable to set mode: %d\n", ret);
> +               goto out_unlock;
> +       }
> +
> +       /* update cached mode */
> +       st->mode = mode;
> +
> +out_unlock:
> +       mutex_unlock(&st->lock);
> +       return ret;
> +}
> +
> +static void adxrs290_chip_off_action(void *data)
> +{
> +       struct iio_dev *indio_dev = data;
> +
> +       adxrs290_set_mode(indio_dev, ADXRS290_MODE_STANDBY);
> +}
> +
>  static int adxrs290_initial_setup(struct iio_dev *indio_dev)
>  {
>         struct adxrs290_state *st = iio_priv(indio_dev);
> +       struct spi_device *spi = st->spi;
> +       int ret;
> +
> +       ret = adxrs290_spi_write_reg(spi, ADXRS290_REG_POWER_CTL,
> +                                    ADXRS290_MEASUREMENT | ADXRS290_TSM);
> +       if (ret < 0)
> +               return ret;
>
>         st->mode = ADXRS290_MODE_MEASUREMENT;
>
> -       return adxrs290_spi_write_reg(st->spi,
> -                                     ADXRS290_REG_POWER_CTL,
> -                                     ADXRS290_MEASUREMENT | ADXRS290_TSM);
> +       return devm_add_action_or_reset(&spi->dev, adxrs290_chip_off_action,
> +                                       indio_dev);
>  }
>
>  static int adxrs290_read_raw(struct iio_dev *indio_dev,
> --
> 2.20.1
>


-- 
With Best Regards,
Andy Shevchenko