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, 94 insertions, 0 deletions

diff --git a/Documentation/input/devices/appletouch.rst b/Documentation/input/devices/appletouch.rst
new file mode 100644
index 000000000..c94470e66
--- /dev/null
+++ b/Documentation/input/devices/appletouch.rst
@@ -0,0 +1,94 @@
+.. include:: <isonum.txt>
+
+----------------------------------
+Apple Touchpad Driver (appletouch)
+----------------------------------
+
+:Copyright: |copy| 2005 Stelian Pop <stelian@popies.net>
+
+appletouch is a Linux kernel driver for the USB touchpad found on post
+February 2005 and October 2005 Apple Aluminium Powerbooks.
+
+This driver is derived from Johannes Berg's appletrackpad driver [#f1]_,
+but it has been improved in some areas:
+
+	* appletouch is a full kernel driver, no userspace program is necessary
+	* appletouch can be interfaced with the synaptics X11 driver, in order
+	  to have touchpad acceleration, scrolling, etc.
+
+Credits go to Johannes Berg for reverse-engineering the touchpad protocol,
+Frank Arnold for further improvements, and Alex Harper for some additional
+information about the inner workings of the touchpad sensors. Michael
+Hanselmann added support for the October 2005 models.
+
+Usage
+-----
+
+In order to use the touchpad in the basic mode, compile the driver and load
+the module. A new input device will be detected and you will be able to read
+the mouse data from /dev/input/mice (using gpm, or X11).
+
+In X11, you can configure the touchpad to use the synaptics X11 driver, which
+will give additional functionalities, like acceleration, scrolling, 2 finger
+tap for middle button mouse emulation, 3 finger tap for right button mouse
+emulation, etc. In order to do this, make sure you're using a recent version of
+the synaptics driver (tested with 0.14.2, available from [#f2]_), and configure
+a new input device in your X11 configuration file (take a look below for an
+example). For additional configuration, see the synaptics driver documentation::
+
+	Section "InputDevice"
+		Identifier      "Synaptics Touchpad"
+		Driver          "synaptics"
+		Option          "SendCoreEvents"        "true"
+		Option          "Device"                "/dev/input/mice"
+		Option          "Protocol"              "auto-dev"
+		Option		"LeftEdge"		"0"
+		Option		"RightEdge"		"850"
+		Option		"TopEdge"		"0"
+		Option		"BottomEdge"		"645"
+		Option		"MinSpeed"		"0.4"
+		Option		"MaxSpeed"		"1"
+		Option		"AccelFactor"		"0.02"
+		Option		"FingerLow"		"0"
+		Option		"FingerHigh"		"30"
+		Option		"MaxTapMove"		"20"
+		Option		"MaxTapTime"		"100"
+		Option		"HorizScrollDelta"	"0"
+		Option		"VertScrollDelta"	"30"
+		Option		"SHMConfig"		"on"
+	EndSection
+
+	Section "ServerLayout"
+		...
+		InputDevice	"Mouse"
+		InputDevice	"Synaptics Touchpad"
+	...
+	EndSection
+
+Fuzz problems
+-------------
+
+The touchpad sensors are very sensitive to heat, and will generate a lot of
+noise when the temperature changes. This is especially true when you power-on
+the laptop for the first time.
+
+The appletouch driver tries to handle this noise and auto adapt itself, but it
+is not perfect. If finger movements are not recognized anymore, try reloading
+the driver.
+
+You can activate debugging using the 'debug' module parameter. A value of 0
+deactivates any debugging, 1 activates tracing of invalid samples, 2 activates
+full tracing (each sample is being traced)::
+
+	modprobe appletouch debug=1
+
+or::
+
+	echo "1" > /sys/module/appletouch/parameters/debug
+
+
+.. Links:
+
+.. [#f1] http://johannes.sipsolutions.net/PowerBook/touchpad/
+
+.. [#f2] `<http://web.archive.org/web/*/http://web.telia.com/~u89404340/touchpad/index.html>`_