iio: proximity: vl53l0x-i2c: claim direct mode for raw readsgrafted

vl53l0x_read_raw() starts a single-shot ranging measurement and reads
back the result. Once the triggered buffer is enabled the sensor runs in
continuous mode and its data-ready interrupt is routed to the trigger,
so a concurrent in_distance_raw read disturbs the streaming setup and
never gets its completion, returning -ETIMEDOUT.

The original submission claimed direct mode here, but it was dropped
during review because the driver had no buffer support at the time [1].
Continuous (buffered) mode was later added without restoring the
claim [2], reintroducing the conflict.

Reject direct reads while buffered capture is active by claiming direct
mode around the measurement, as the vl53l1x sibling already does.

Fixes: 762186c6e7b1 ("iio: proximity: vl53l0x-i2c: Added continuous mode support")
Link: https://lore.kernel.org/linux-iio/20180911160300.GA9212@himanshu-Vostro-3559/ [1]
Link: https://lore.kernel.org/linux-iio/20240909101508.263085-3-abhashkumarjha123@gmail.com/ [2]
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/Documentation/gpu/panfrost.rst b/Documentation/gpu/panfrost.rst
new file mode 100644
index 000000000..51ba375fd
--- /dev/null
+++ b/Documentation/gpu/panfrost.rst
@@ -0,0 +1,49 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+=========================
+ drm/Panfrost Mali Driver
+=========================
+
+.. _panfrost-usage-stats:
+
+Panfrost DRM client usage stats implementation
+==============================================
+
+The drm/Panfrost driver implements the DRM client usage stats specification as
+documented in :ref:`drm-client-usage-stats`.
+
+Example of the output showing the implemented key value pairs and entirety of
+the currently possible format options:
+
+::
+      pos:    0
+      flags:  02400002
+      mnt_id: 27
+      ino:    531
+      drm-driver:     panfrost
+      drm-client-id:  14
+      drm-engine-fragment:    1846584880 ns
+      drm-cycles-fragment:    1424359409
+      drm-maxfreq-fragment:   799999987 Hz
+      drm-curfreq-fragment:   799999987 Hz
+      drm-engine-vertex-tiler:        71932239 ns
+      drm-cycles-vertex-tiler:        52617357
+      drm-maxfreq-vertex-tiler:       799999987 Hz
+      drm-curfreq-vertex-tiler:       799999987 Hz
+      drm-total-memory:       290 MiB
+      drm-shared-memory:      0 MiB
+      drm-active-memory:      226 MiB
+      drm-resident-memory:    36496 KiB
+      drm-purgeable-memory:   128 KiB
+
+Possible `drm-engine-` key names are: `fragment`, and  `vertex-tiler`.
+`drm-curfreq-` values convey the current operating frequency for that engine.
+
+Users must bear in mind that engine and cycle sampling are disabled by default,
+because of power saving concerns. `fdinfo` users and benchmark applications which
+query the fdinfo file must make sure to toggle the job profiling status of the
+driver by writing into the appropriate sysfs node::
+
+    echo <N> > /sys/bus/platform/drivers/panfrost/[a-f0-9]*.gpu/profiling
+
+Where `N` is either `0` or `1`, depending on the desired enablement status.