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, 52 insertions, 0 deletions

diff --git a/Documentation/admin-guide/sysctl/debug.rst b/Documentation/admin-guide/sysctl/debug.rst
new file mode 100644
index 000000000..506bd5e48
--- /dev/null
+++ b/Documentation/admin-guide/sysctl/debug.rst
@@ -0,0 +1,52 @@
+================
+/proc/sys/debug/
+================
+
+These files show up in ``/proc/sys/debug/``, depending on the
+kernel configuration:
+
+.. contents:: :local:
+
+exception-trace
+===============
+
+This flag controls whether the kernel prints information about unhandled
+signals (like segmentation faults) to the kernel log (``dmesg``).
+
+- ``0``: Unhandled signals are not traced.
+- ``1``: Information about unhandled signals is printed.
+
+The default value is ``1`` on most architectures (like x86, MIPS, RISC-V),
+but it is ``0`` on **arm64**.
+
+The actual information printed and the context provided varies
+significantly depending on the CPU architecture. For example:
+
+- On **x86**, it typically prints the instruction pointer (IP), error
+  code, and address that caused a page fault.
+- On **PowerPC**, it may print the next instruction pointer (NIP),
+  link register (LR), and other relevant registers.
+
+When enabled, this feature is often rate-limited to prevent the kernel
+log from being flooded during a crash loop.
+
+kprobes-optimization
+====================
+
+This flag enables or disables the optimization of Kprobes on certain
+architectures (like x86).
+
+- ``0``: Kprobes optimization is turned off.
+- ``1``: Kprobes optimization is turned on (default).
+
+For more details on Kprobes and its optimization, please refer to
+Documentation/trace/kprobes.rst.
+
+Copyright (c) 2026, Shubham Chakraborty <chakrabortyshubham66@gmail.com>
+
+For general info and legal blurb, please look in
+Documentation/admin-guide/sysctl/index.rst.
+
+.. See scripts/check-sysctl-docs to keep this up to date:
+.. scripts/check-sysctl-docs -vtable="debug" \
+..         $(git grep -l register_sysctl_)