On 03/12/2017 02:32 PM, 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.
>
> Fix some coding style issues related to white space also.
>
> Signed-off-by: simran singhal <singhalsimr...@gmail.com>
> ---
> drivers/staging/iio/meter/ade7753.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/iio/meter/ade7753.c
> b/drivers/staging/iio/meter/ade7753.c
> index dfd8b71..ca99d82 100644
> --- a/drivers/staging/iio/meter/ade7753.c
> +++ b/drivers/staging/iio/meter/ade7753.c
> @@ -81,12 +81,14 @@
> * @tx: transmit buffer
> * @rx: receive buffer
> * @buf_lock: mutex to protect tx and rx
> + * @lock: protect sensor state
It might make sense to reuse the existing lock which currently protects the
read/write functions. You can do this by introducing a variant of
ade7753_spi_{read,write}_reg_16() that does not take a lock and use these to
implement the read-modify-write cycle in a protected section.
Looking through the driver there seem to be other places as well that do
read-modify-write that should be protected by a lock, but currently are not.
This might be a good task.
> **/
> struct ade7753_state {
> - struct spi_device *us;
> - struct mutex buf_lock;
> - u8 tx[ADE7753_MAX_TX]
> ____cacheline_aligned;
> - u8 rx[ADE7753_MAX_RX];
> + 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];
> };
>
> static int ade7753_spi_write_reg_8(struct device *dev,
> @@ -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;
> }
>
