Commit 1555790c authored Oct 12, 2022 by Nuno Sá Committed by Jonathan Cameron Nov 23, 2022

iio: health: max30100: do not use internal iio_dev lock



The pattern used in this device does not quite fit in the
iio_device_claim_direct_mode() typical usage. In this case,
iio_buffer_enabled() was being used not to prevent the raw
access but to allow it. Hence, let's make use of the new
iio_device_claim_buffer_mode() API to make sure we stay in
buffered mode during the complete read.

Note that we are shadowing the error code returned by
iio_device_claim_buffer_mode() so that we keep the original one
(-EAGAIN). The reason is that some userspace stack might already be
relying on this particular code so that we are not taking chances and
leave it alone.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20221012151620.1725215-3-nuno.sa@analog.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

parent 0a856542

drivers/iio/health/max30100.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -387,18 +387,21 @@ static int max30100_read_raw(struct iio_dev *indio_dev,
		* Temperature reading can only be acquired while engine
		* is running
		*/
		mutex_lock(&indio_dev->mlock);

		if (!iio_buffer_enabled(indio_dev))
		if (iio_device_claim_buffer_mode(indio_dev)) {
		/*
		* Replacing -EBUSY or other error code
		* returned by iio_device_claim_buffer_mode()
		* because user space may rely on the current
		* one.
		*/
		ret = -EAGAIN;
		else {
		} else {
		ret = max30100_get_temp(data, val);
		if (!ret)
		ret = IIO_VAL_INT;

		iio_device_release_buffer_mode(indio_dev);
		}

		mutex_unlock(&indio_dev->mlock);
		break;
		case IIO_CHAN_INFO_SCALE:
		val = 1; / 0.0625 */