Re: [PATCH 21/29] iio: adc: at91-sama5d2: Move claim of direct mode up a level and use guard()

[Claudiu Beznea <claudiu.beznea@tuxon.dev>]

On 17.02.2025 16:16, Jonathan Cameron wrote:
> From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> Move iio_device_claim_direct_mode() up one layer in the call stack,
> and use guard() for scope based unlocking to simplify error handling
> by allowing direct returns.
> 
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Cc: Claudiu Beznea <claudiu.beznea@tuxon.dev>

Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>

> ---
>  drivers/iio/adc/at91-sama5d2_adc.c | 42 +++++++++++++++---------------
>  1 file changed, 21 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
> index 8e5aaf15a921..70d3dbb39b25 100644
> --- a/drivers/iio/adc/at91-sama5d2_adc.c
> +++ b/drivers/iio/adc/at91-sama5d2_adc.c
> @@ -9,6 +9,7 @@
>   */
>  
>  #include <linux/bitops.h>
> +#include <linux/cleanup.h>
>  #include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/dma-mapping.h>
> @@ -1814,19 +1815,10 @@ static int at91_adc_read_info_locked(struct iio_dev *indio_dev,
>  				     struct iio_chan_spec const *chan, int *val)
>  {
>  	struct at91_adc_state *st = iio_priv(indio_dev);
> -	int ret;
> -
> -	ret = iio_device_claim_direct_mode(indio_dev);
> -	if (ret)
> -		return ret;
> -
> -	mutex_lock(&st->lock);
> -	ret = at91_adc_read_info_raw(indio_dev, chan, val);
> -	mutex_unlock(&st->lock);
>  
> -	iio_device_release_direct_mode(indio_dev);
> +	guard(mutex)(&st->lock);
>  
> -	return ret;
> +	return at91_adc_read_info_raw(indio_dev, chan, val);
>  }
>  
>  static void at91_adc_temp_sensor_configure(struct at91_adc_state *st,
> @@ -1871,14 +1863,11 @@ static int at91_adc_read_temp(struct iio_dev *indio_dev,
>  	u32 tmp;
>  	int ret, vbg, vtemp;
>  
> -	ret = iio_device_claim_direct_mode(indio_dev);
> -	if (ret)
> -		return ret;
> -	mutex_lock(&st->lock);
> +	guard(mutex)(&st->lock);
>  
>  	ret = pm_runtime_resume_and_get(st->dev);
>  	if (ret < 0)
> -		goto unlock;
> +		return ret;
>  
>  	at91_adc_temp_sensor_configure(st, true);
>  
> @@ -1900,9 +1889,6 @@ static int at91_adc_read_temp(struct iio_dev *indio_dev,
>  	at91_adc_temp_sensor_configure(st, false);
>  	pm_runtime_mark_last_busy(st->dev);
>  	pm_runtime_put_autosuspend(st->dev);
> -unlock:
> -	mutex_unlock(&st->lock);
> -	iio_device_release_direct_mode(indio_dev);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -1924,10 +1910,17 @@ static int at91_adc_read_raw(struct iio_dev *indio_dev,
>  			     int *val, int *val2, long mask)
>  {
>  	struct at91_adc_state *st = iio_priv(indio_dev);
> +	int ret;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
> -		return at91_adc_read_info_locked(indio_dev, chan, val);
> +		ret = iio_device_claim_direct_mode(indio_dev);
> +		if (ret)
> +			return ret;
> +
> +		ret = at91_adc_read_info_locked(indio_dev, chan, val);
> +		iio_device_release_direct_mode(indio_dev);
> +		return ret;
>  
>  	case IIO_CHAN_INFO_SCALE:
>  		*val = st->vref_uv / 1000;
> @@ -1939,7 +1932,14 @@ static int at91_adc_read_raw(struct iio_dev *indio_dev,
>  	case IIO_CHAN_INFO_PROCESSED:
>  		if (chan->type != IIO_TEMP)
>  			return -EINVAL;
> -		return at91_adc_read_temp(indio_dev, chan, val);
> +		ret = iio_device_claim_direct_mode(indio_dev);
> +		if (ret)
> +			return ret;
> +
> +		ret = at91_adc_read_temp(indio_dev, chan, val);
> +		iio_device_release_direct_mode(indio_dev);
> +
> +		return ret;
>  
>  	case IIO_CHAN_INFO_SAMP_FREQ:
>  		*val = at91_adc_get_sample_freq(st);