On 20/07/16 05:25, Alison Schofield wrote:
> Replace the code that guarantees the device stays in direct mode
> with iio_device_claim_direct_mode() which does same.
>
> Signed-off-by: Alison Schofield <amsfield22@xxxxxxxxx>
> Cc: Daniel Baluta <daniel.baluta@xxxxxxxxx>
> ---
> Peter: I was not clear if we want to keep the data->mutex lock
> in addition to claiming direct mode. I see that lock assuring
> exclusivity amongst a few other tasks in the driver. Let me
> know if this needs both locks. Thanks!
>
I'd go with keeping it. Makes it change obviously correct,
rather than requiring a careful analysis of the driver..
Using that lock to protect entry into buffered mode would
probably never have worked so I think we definitely need
both locks to be taken here.
Jonathan
>
> drivers/iio/accel/bma180.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/accel/bma180.c b/drivers/iio/accel/bma180.c
> index e3f88ba..ce5a476 100644
> --- a/drivers/iio/accel/bma180.c
> +++ b/drivers/iio/accel/bma180.c
> @@ -469,13 +469,12 @@ static int bma180_read_raw(struct iio_dev *indio_dev,
>
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> - mutex_lock(&data->mutex);
> - if (iio_buffer_enabled(indio_dev)) {
> - mutex_unlock(&data->mutex);
> - return -EBUSY;
> - }
> + ret = iio_device_claim_direct_mode(indio_dev);
> + if (ret)
> + return ret;
> +
> ret = bma180_get_data_reg(data, chan->scan_index);
> - mutex_unlock(&data->mutex);
> + iio_device_release_direct_mode(indio_dev);
> if (ret < 0)
> return ret;
> *val = sign_extend32(ret >> chan->scan_type.shift,
>
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