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, 116 insertions, 0 deletions

diff --git a/Documentation/scsi/leapraid.rst b/Documentation/scsi/leapraid.rst
new file mode 100644
index 000000000..d36ff627d
--- /dev/null
+++ b/Documentation/scsi/leapraid.rst
@@ -0,0 +1,116 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+LeapRAID Driver for Linux
+=========================
+
+Introduction
+============
+
+LeapRAID is a storage RAID controller driver developed by LeapIO Tech Inc. The
+controller targets enterprise storage, cloud infrastructure, high performance
+computing (HPC), and AI workloads.
+
+It provides high-performance storage virtualization over PCI Express Gen4
+and supports both SAS and SATA HDDs and SSDs. It offers both Host Bus Adapter
+and RAID modes to meet diverse deployment requirements.
+
+Supported devices
+=================
+
+- LeapHBA-8200C
+
+Features
+========
+
+- PCIe Gen4 x8 host interface
+- Support for SAS and SATA devices
+- RAID levels: 0, 1, 10, 5, 50, 6, 60
+- Advanced error handling and end-to-end data integrity
+
+LeapRAID specific host attributes
+=================================
+
+::
+
+   /sys/class/scsi_host/host*/fw_queue_depth
+   /sys/class/scsi_host/host*/host_sas_address
+   /sys/class/scsi_host/host*/board_name
+
+The host "fw_queue_depth" read-only attribute shows the firmware queue
+depth of the host.
+
+The host "host_sas_address" read-only attribute shows the SAS address
+of the host.
+
+The host "board_name" read-only attribute shows the board name reported
+by manufacturing page 0.
+
+LeapRAID specific disk attributes
+=================================
+
+::
+
+   /sys/block/<disk>/device/sas_device_handle
+   /sys/block/<disk>/device/sas_ncq_prio_supported
+   /sys/block/<disk>/device/sas_ncq_prio_enable
+
+The read-only attribute "sas_device_handle" represents the disk's device
+handle, which is a unique identifier maintained by the firmware.
+
+The read-only attribute "sas_ncq_prio_supported" reports whether a SATA
+device supports NCQ command priority.
+
+The attribute "sas_ncq_prio_enable" controls NCQ command priority. A value
+of 0 disables NCQ priority handling for RT-priority I/O. Writing 1 enables
+NCQ priority handling when the device reports support for the feature through
+VPD page 0x89. Writes to unsupported devices fail with an error.
+
+LeapRAID module parameters
+==========================
+
+The following module parameters can be configured at driver load time to
+control driver behavior and tuning options.
+
+1. open_pcie_trace
+------------------
+
+This parameter controls whether PCIe transaction tracing is enabled in the
+driver. When set to 1, PCIe trace collection is enabled by default, allowing
+detailed tracing of PCIe operations for debugging and performance analysis.
+Setting it to 0 disables the trace functionality to reduce overhead in
+production environments.
+
+2. enable_mp
+------------
+
+This parameter enables or disables multipath support for target devices.
+When set to 1, multipath functionality is enabled (default), allowing
+multiple paths to be established. Setting it to 0 disables multipath
+handling.
+
+3. max_msix_vectors
+-------------------
+
+This parameter sets the upper limit on the number of MSI-X interrupt
+vectors that the driver will request during initialization. The default
+value of -1 allows the driver to use all available vectors as provided
+by the device. Setting a positive integer restricts the number of vectors.
+
+4. poll_queues
+--------------
+
+This parameter specifies the number of I/O queues to be used when operating
+in io_uring poll mode. The default value is 0.
+
+File Location
+=============
+
+The driver source is located at:
+
+``drivers/scsi/leapraid/``
+
+.. note::
+
+   This document is intended for kernel developers and system
+   integrators who need to build, test, and deploy the LeapRAID driver.