On Wed, 27 Sep 2017, Aastha Gupta 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 driver private lock.
>
> Also, as there are state changes in the ad7192_ write_raw function, a lock
> is added to prevent the concurrent state changes.
Why was it not needed before?
julia
>
> Signed-off-by: Aastha Gupta <aastha.gupta4104@xxxxxxxxx>
> ---
> changes in v4:
> - added comment for mutex
> - improved commit message
> drivers/staging/iio/adc/ad7192.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
> index d11c6de..c1343ec 100644
> --- a/drivers/staging/iio/adc/ad7192.c
> +++ b/drivers/staging/iio/adc/ad7192.c
> @@ -162,6 +162,7 @@ struct ad7192_state {
> u32 scale_avail[8][2];
> u8 gpocon;
> u8 devid;
> + struct mutex lock; /* protect sensor state */
>
> struct ad_sigma_delta sd;
> };
> @@ -463,10 +464,10 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
> case IIO_CHAN_INFO_SCALE:
> switch (chan->type) {
> case IIO_VOLTAGE:
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> *val = st->scale_avail[AD7192_CONF_GAIN(st->conf)][0];
> *val2 = st->scale_avail[AD7192_CONF_GAIN(st->conf)][1];
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
> return IIO_VAL_INT_PLUS_NANO;
> case IIO_TEMP:
> *val = 0;
> @@ -510,6 +511,7 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
> switch (mask) {
> case IIO_CHAN_INFO_SCALE:
> ret = -EINVAL;
> + mutex_lock(&st->lock);
> for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
> if (val2 == st->scale_avail[i][1]) {
> ret = 0;
> @@ -523,6 +525,7 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
> ad7192_calibrate_all(st);
> break;
> }
> + mutex_unlock(&st->lock);
> break;
> case IIO_CHAN_INFO_SAMP_FREQ:
> if (!val) {
> @@ -634,6 +637,8 @@ static int ad7192_probe(struct spi_device *spi)
>
> st = iio_priv(indio_dev);
>
> + mutex_init(&st->lock);
> +
> st->avdd = devm_regulator_get(&spi->dev, "avdd");
> if (IS_ERR(st->avdd))
> return PTR_ERR(st->avdd);
> --
> 2.7.4
>
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