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, 54 insertions, 0 deletions

diff --git a/Documentation/admin-guide/device-mapper/delay.rst b/Documentation/admin-guide/device-mapper/delay.rst
new file mode 100644
index 000000000..a1e673c0e
--- /dev/null
+++ b/Documentation/admin-guide/device-mapper/delay.rst
@@ -0,0 +1,54 @@
+========
+dm-delay
+========
+
+Device-Mapper's "delay" target delays reads and/or writes
+and/or flushes and optionally maps them to different devices.
+
+Arguments::
+
+    <device> <offset> <delay> [<write_device> <write_offset> <write_delay>
+			       [<flush_device> <flush_offset> <flush_delay>]]
+
+Table line has to either have 3, 6 or 9 arguments:
+
+3: apply offset and delay to read, write and flush operations on device
+
+6: apply offset and delay to device, also apply write_offset and write_delay
+   to write and flush operations on optionally different write_device with
+   optionally different sector offset
+
+9: same as 6 arguments plus define flush_offset and flush_delay explicitly
+   on/with optionally different flush_device/flush_offset.
+
+Offsets are specified in sectors.
+
+Delays are specified in milliseconds.
+
+
+Example scripts
+===============
+
+::
+	#!/bin/sh
+	#
+	# Create mapped device named "delayed" delaying read, write and flush operations for 500ms.
+	#
+	dmsetup create delayed --table  "0 `blockdev --getsz $1` delay $1 0 500"
+
+::
+	#!/bin/sh
+	#
+	# Create mapped device delaying write and flush operations for 400ms and
+	# splitting reads to device $1 but writes and flushes to different device $2
+	# to different offsets of 2048 and 4096 sectors respectively.
+	#
+	dmsetup create delayed --table "0 `blockdev --getsz $1` delay $1 2048 0 $2 4096 400"
+
+::
+	#!/bin/sh
+	#
+	# Create mapped device delaying reads for 50ms, writes for 100ms and flushes for 333ms
+	# onto the same backing device at offset 0 sectors.
+	#
+	dmsetup create delayed --table "0 `blockdev --getsz $1` delay $1 0 50 $2 0 100 $1 0 333"