[PATCH 03/15] iio: adc: axp288_adc: do not use internal iio_dev lock

[Jonathan Cameron]

On Tue, 20 Sep 2022 13:28:09 +0200
Nuno Sá <nuno.sa at analog.com> wrote:

> The iio_device lock is only meant for internal use. Hence define a
> device local lock to protect against concurrent accesses.
> 
> Signed-off-by: Nuno Sá <nuno.sa at analog.com>
Looks good. Not sure how we missed cleaning this one up earlier
given how simple it is!  Anyhow, given Andy's feedback I'll wait for v2
to pick this up.

> ---
>  drivers/iio/adc/axp288_adc.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/adc/axp288_adc.c b/drivers/iio/adc/axp288_adc.c
> index 580361bd9849..3bbb96156739 100644
> --- a/drivers/iio/adc/axp288_adc.c
> +++ b/drivers/iio/adc/axp288_adc.c
> @@ -9,6 +9,7 @@
>  
>  #include <linux/dmi.h>
>  #include <linux/module.h>
> +#include <linux/mutex.h>
>  #include <linux/kernel.h>
>  #include <linux/device.h>
>  #include <linux/regmap.h>
> @@ -50,6 +51,8 @@ enum axp288_adc_id {
>  struct axp288_adc_info {
>  	int irq;
>  	struct regmap *regmap;
> +	/* lock to protect against multiple access to the device */
> +	struct mutex lock;
>  	bool ts_enabled;
>  };
>  
> @@ -161,7 +164,7 @@ static int axp288_adc_read_raw(struct iio_dev *indio_dev,
>  	int ret;
>  	struct axp288_adc_info *info = iio_priv(indio_dev);
>  
> -	mutex_lock(&indio_dev->mlock);
> +	mutex_lock(&info->lock);
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
>  		if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON_ONDEMAND,
> @@ -178,7 +181,7 @@ static int axp288_adc_read_raw(struct iio_dev *indio_dev,
>  	default:
>  		ret = -EINVAL;
>  	}
> -	mutex_unlock(&indio_dev->mlock);
> +	mutex_unlock(&info->lock);
>  
>  	return ret;
>  }
> @@ -264,6 +267,7 @@ static int axp288_adc_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	info = iio_priv(indio_dev);
> +	mutex_init(&info->lock);
>  	info->irq = platform_get_irq(pdev, 0);
>  	if (info->irq < 0)
>  		return info->irq;