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, 124 insertions, 0 deletions

diff --git a/Documentation/admin-guide/btmrvl.rst b/Documentation/admin-guide/btmrvl.rst
new file mode 100644
index 000000000..ec57740ea
--- /dev/null
+++ b/Documentation/admin-guide/btmrvl.rst
@@ -0,0 +1,124 @@
+=============
+btmrvl driver
+=============
+
+All commands are used via debugfs interface.
+
+Set/get driver configurations
+=============================
+
+Path:	/debug/btmrvl/config/
+
+gpiogap=[n], hscfgcmd
+	These commands are used to configure the host sleep parameters::
+	bit 8:0  -- Gap
+	bit 16:8 -- GPIO
+
+	where GPIO is the pin number of GPIO used to wake up the host.
+	It could be any valid GPIO pin# (e.g. 0-7) or 0xff (SDIO interface
+	wakeup will be used instead).
+
+	where Gap is the gap in milli seconds between wakeup signal and
+	wakeup event, or 0xff for special host sleep setting.
+
+	Usage::
+
+		# Use SDIO interface to wake up the host and set GAP to 0x80:
+		echo 0xff80 > /debug/btmrvl/config/gpiogap
+		echo 1 > /debug/btmrvl/config/hscfgcmd
+
+		# Use GPIO pin #3 to wake up the host and set GAP to 0xff:
+		echo 0x03ff >  /debug/btmrvl/config/gpiogap
+		echo 1 > /debug/btmrvl/config/hscfgcmd
+
+psmode=[n], pscmd
+	These commands are used to enable/disable auto sleep mode
+
+	where the option is::
+
+			1 	-- Enable auto sleep mode
+			0 	-- Disable auto sleep mode
+
+	Usage::
+
+		# Enable auto sleep mode
+		echo 1 > /debug/btmrvl/config/psmode
+		echo 1 > /debug/btmrvl/config/pscmd
+
+		# Disable auto sleep mode
+		echo 0 > /debug/btmrvl/config/psmode
+		echo 1 > /debug/btmrvl/config/pscmd
+
+
+hsmode=[n], hscmd
+	These commands are used to enable host sleep or wake up firmware
+
+	where the option is::
+
+			1	-- Enable host sleep
+			0	-- Wake up firmware
+
+	Usage::
+
+		# Enable host sleep
+		echo 1 > /debug/btmrvl/config/hsmode
+		echo 1 > /debug/btmrvl/config/hscmd
+
+		# Wake up firmware
+		echo 0 > /debug/btmrvl/config/hsmode
+		echo 1 > /debug/btmrvl/config/hscmd
+
+
+Get driver status
+=================
+
+Path:	/debug/btmrvl/status/
+
+Usage::
+
+	cat /debug/btmrvl/status/<args>
+
+where the args are:
+
+curpsmode
+	This command displays current auto sleep status.
+
+psstate
+	This command display the power save state.
+
+hsstate
+	This command display the host sleep state.
+
+txdnldrdy
+	This command displays the value of Tx download ready flag.
+
+Issuing a raw hci command
+=========================
+
+Use hcitool to issue raw hci command, refer to hcitool manual
+
+Usage::
+
+	Hcitool cmd <ogf> <ocf> [Parameters]
+
+Interface Control Command::
+
+	hcitool cmd 0x3f 0x5b 0xf5 0x01 0x00    --Enable All interface
+	hcitool cmd 0x3f 0x5b 0xf5 0x01 0x01    --Enable Wlan interface
+	hcitool cmd 0x3f 0x5b 0xf5 0x01 0x02    --Enable BT interface
+	hcitool cmd 0x3f 0x5b 0xf5 0x00 0x00    --Disable All interface
+	hcitool cmd 0x3f 0x5b 0xf5 0x00 0x01    --Disable Wlan interface
+	hcitool cmd 0x3f 0x5b 0xf5 0x00 0x02    --Disable BT interface
+
+SD8688 firmware
+===============
+
+Images:
+
+- /lib/firmware/sd8688_helper.bin
+- /lib/firmware/sd8688.bin
+
+
+The images can be downloaded from:
+
+git.infradead.org/users/dwmw2/linux-firmware.git/libertas/