Re: [PATCH] iio: dac: ad5686: Replace indio_dev->mlock with own device lock

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 14 May 2020 12:19:38 +0300
Sergiu Cuciurean <sergiu.cuciurean@analog.com> wrote:

> As part of the general cleanup of indio_dev->mlock, this change replaces
> it with a local lock on the device's state structure.
> 
> Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Applied,

Thanks,

Jonathan

> ---
>  drivers/iio/dac/ad5686.c | 10 ++++++----
>  drivers/iio/dac/ad5686.h |  2 ++
>  2 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c
> index e06b29c565b9..8dd67da0a7da 100644
> --- a/drivers/iio/dac/ad5686.c
> +++ b/drivers/iio/dac/ad5686.c
> @@ -127,9 +127,9 @@ static int ad5686_read_raw(struct iio_dev *indio_dev,
>  
>  	switch (m) {
>  	case IIO_CHAN_INFO_RAW:
> -		mutex_lock(&indio_dev->mlock);
> +		mutex_lock(&st->lock);
>  		ret = st->read(st, chan->address);
> -		mutex_unlock(&indio_dev->mlock);
> +		mutex_unlock(&st->lock);
>  		if (ret < 0)
>  			return ret;
>  		*val = (ret >> chan->scan_type.shift) &
> @@ -157,12 +157,12 @@ static int ad5686_write_raw(struct iio_dev *indio_dev,
>  		if (val > (1 << chan->scan_type.realbits) || val < 0)
>  			return -EINVAL;
>  
> -		mutex_lock(&indio_dev->mlock);
> +		mutex_lock(&st->lock);
>  		ret = st->write(st,
>  				AD5686_CMD_WRITE_INPUT_N_UPDATE_N,
>  				chan->address,
>  				val << chan->scan_type.shift);
> -		mutex_unlock(&indio_dev->mlock);
> +		mutex_unlock(&st->lock);
>  		break;
>  	default:
>  		ret = -EINVAL;
> @@ -468,6 +468,8 @@ int ad5686_probe(struct device *dev,
>  	indio_dev->channels = st->chip_info->channels;
>  	indio_dev->num_channels = st->chip_info->num_channels;
>  
> +	mutex_init(&st->lock);
> +
>  	switch (st->chip_info->regmap_type) {
>  	case AD5310_REGMAP:
>  		cmd = AD5686_CMD_CONTROL_REG;
> diff --git a/drivers/iio/dac/ad5686.h b/drivers/iio/dac/ad5686.h
> index 70a779939ddb..52009b5eef88 100644
> --- a/drivers/iio/dac/ad5686.h
> +++ b/drivers/iio/dac/ad5686.h
> @@ -117,6 +117,7 @@ struct ad5686_chip_info {
>   * @pwr_down_mask:	power down mask
>   * @pwr_down_mode:	current power down mode
>   * @use_internal_vref:	set to true if the internal reference voltage is used
> + * @lock		lock to protect the data buffer during regmap ops
>   * @data:		spi transfer buffers
>   */
>  
> @@ -130,6 +131,7 @@ struct ad5686_state {
>  	ad5686_write_func		write;
>  	ad5686_read_func		read;
>  	bool				use_internal_vref;
> +	struct mutex			lock;
>  
>  	/*
>  	 * DMA (thus cache coherency maintenance) requires the