Re: [PATCH v2] iio: light: ltr501: claim direct mode during select raw reads

From: Jonathan Cameron
Date: Sun Oct 16 2016 - 09:25:10 EST


On 16/10/16 06:00, Alison Schofield wrote:
> Driver was checking for direct mode but not locking it. Use
> claim/release helper functions to guarantee the device stays
> in direct mode during required raw read cases.
>
> Signed-off-by: Alison Schofield <amsfield22@xxxxxxxxx>
Very nice.

Applied to the togreg branch fo iio.git and pushed out as testing.
Peter, if you have any comments on this, there is still plenty of
time as I won't send a pull request until at lest next weekend.

Jonathan
> ---
> Changes in v2:
> Reworked IIO_CHAN_INFO_RAW case so claim and release are
> executed at same level in the switch statements. (rather
> than claims on top level and releases nested in cases)
>
> drivers/iio/light/ltr501.c | 30 ++++++++++++++++++++----------
> 1 file changed, 20 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index 3afc53a..d577477 100644
> --- a/drivers/iio/light/ltr501.c
> +++ b/drivers/iio/light/ltr501.c
> @@ -631,14 +631,16 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
>
> switch (mask) {
> case IIO_CHAN_INFO_PROCESSED:
> - if (iio_buffer_enabled(indio_dev))
> - return -EBUSY;
> -
> switch (chan->type) {
> case IIO_LIGHT:
> + ret = iio_device_claim_direct_mode(indio_dev);
> + if (ret)
> + return ret;
> +
> mutex_lock(&data->lock_als);
> ret = ltr501_read_als(data, buf);
> mutex_unlock(&data->lock_als);
> + iio_device_release_direct_mode(indio_dev);
> if (ret < 0)
> return ret;
> *val = ltr501_calculate_lux(le16_to_cpu(buf[1]),
> @@ -648,8 +650,9 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
> return -EINVAL;
> }
> case IIO_CHAN_INFO_RAW:
> - if (iio_buffer_enabled(indio_dev))
> - return -EBUSY;
> + ret = iio_device_claim_direct_mode(indio_dev);
> + if (ret)
> + return ret;
>
> switch (chan->type) {
> case IIO_INTENSITY:
> @@ -657,21 +660,28 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
> ret = ltr501_read_als(data, buf);
> mutex_unlock(&data->lock_als);
> if (ret < 0)
> - return ret;
> + break;
> *val = le16_to_cpu(chan->address == LTR501_ALS_DATA1 ?
> buf[0] : buf[1]);
> - return IIO_VAL_INT;
> + ret = IIO_VAL_INT;
> + break;
> case IIO_PROXIMITY:
> mutex_lock(&data->lock_ps);
> ret = ltr501_read_ps(data);
> mutex_unlock(&data->lock_ps);
> if (ret < 0)
> - return ret;
> + break;
> *val = ret & LTR501_PS_DATA_MASK;
> - return IIO_VAL_INT;
> + ret = IIO_VAL_INT;
> + break;
> default:
> - return -EINVAL;
> + ret = -EINVAL;
> + break;
> }
> +
> + iio_device_release_direct_mode(indio_dev);
> + return ret;
> +
> case IIO_CHAN_INFO_SCALE:
> switch (chan->type) {
> case IIO_INTENSITY:
>