Re: [PATCH v3 2/2] staging: iio: ade7753: Replace mlock with driver private lock

From: Jonathan Cameron
Date: Wed Mar 22 2017 - 16:26:25 EST


On 21/03/17 18:03, simran singhal wrote:
> The IIO subsystem is redefining iio_dev->mlock to be used by
> the IIO core only for protecting device operating mode changes.
> ie. Changes between INDIO_DIRECT_MODE, INDIO_BUFFER_* modes.
>
> In this driver, mlock was being used to protect hardware state
> changes. Replace it with a lock in the devices global data.
>
> Signed-off-by: simran singhal <singhalsimran0@xxxxxxxxx>
Mutex is not initialized...
> ---
> drivers/staging/iio/meter/ade7753.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
> index b71fbd3..9674e05 100644
> --- a/drivers/staging/iio/meter/ade7753.c
> +++ b/drivers/staging/iio/meter/ade7753.c
> @@ -80,11 +80,13 @@
> * @us: actual spi_device
> * @tx: transmit buffer
> * @rx: receive buffer
> + * @lock: protect sensor state
> * @buf_lock: mutex to protect tx and rx
> **/
> struct ade7753_state {
> struct spi_device *us;
> struct mutex buf_lock;
> + struct mutex lock; /* protect sensor state */
> u8 tx[ADE7753_MAX_TX] ____cacheline_aligned;
> u8 rx[ADE7753_MAX_RX];
> };
> @@ -484,7 +486,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
> if (!val)
> return -EINVAL;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
>
> t = 27900 / val;
> if (t > 0)
> @@ -505,7 +507,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
> ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
>
> out:
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
>
> return ret ? ret : len;
> }
>