Merge tag 'i2c-updates-for-2025-10-rc2' of https://source.denx.de/u-boot/custodians/u-boot-i2c

i2c updates for v2025.10-rc2

bugfixes:

- rcar_iic: do not use unitialised variable
  from Andrew

- fix coverity issue in cmd/i2c.c
  from Heiko

new driver:

late, but hopefully okay for rc2, as already picked up when
merge window was open, but there was a problem in common code,
which is now fixed

- new i3c driver support from Dinesh

1 files changed, 146 insertions, 0 deletions

diff --git a/doc/usage/cmd/i3c.rst b/doc/usage/cmd/i3c.rst
new file mode 100644
index 00000000000..922fa3ea37c
--- /dev/null
+++ b/doc/usage/cmd/i3c.rst
@@ -0,0 +1,146 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. index::
+   single: i3c (command)
+
+i3c command
+===========
+
+Synopsis
+--------
+
+::
+
+    i3c <host_controller>
+    i3c current
+    i3c list
+    i3c device_list
+    i3c write <mem_addr> <length> <device_number>
+    i3c read <mem_addr> <length> <device_number>
+
+Description
+-----------
+
+The ``i3c`` command is used to probe the i3c host controller and perform
+read and write operations on the connected i3c devices.
+
+i3c current
+------------
+
+Display the currently selected i3c host controller.
+
+i3c list
+---------
+
+List all the i3c hosts defined in the device-tree.
+
+i3c device_list
+----------------
+
+List all the i3c devices' device number, static address, dynamic address,
+PID, BCR, DCR, Max Write Speed, and Max Read Speed of the probed i3c host
+controller.
+
+i3c write
+----------
+
+Perform a write operation from memory to the connected i3c device. The data
+is read from a specified memory address and written to the selected i3c
+device, which is identified by its device number.
+
+You need to provide the memory address (``mem_addr``), the length of data
+to be written (``length``), and the device number (``device_number``). The
+data in memory will be transferred to the device in the specified order.
+
+i3c read
+---------
+
+Perform a read operation from the connected i3c device to memory. The data
+is read from the selected i3c device and stored at the specified memory
+address. You need to provide the memory address (``mem_addr``), the length
+of data to be read (``length``), and the device number (``device_number``).
+
+The device will send the requested data, which is then written to the memory
+location you specified. This operation allows you to retrieve information
+from the device and use it in your application. The data is read in the
+order specified and can be multiple bytes.
+
+host_controller
+    The name of the i3c host controller defined in the device-tree.
+
+length
+    The size of the data to be read or written.
+
+device_number
+    The device number in the driver model of the device connected to the i3c
+    host controller.
+
+mem_addr
+    The start address in memory from which to read or write the data.
+
+Examples
+--------
+
+Probe the ``i3c0`` controller::
+
+    => i3c i3c0
+
+Display the current i3c host controller::
+
+    => i3c current
+
+Check the device number and PID of the connected devices::
+
+    => i3c device_list
+
+Perform write operations on the connected i3c device (device 0) from memory::
+
+    => i3c write 0x1000 4 0
+
+    This command reads 4 bytes of data from memory starting at address
+    ``0x1000`` and writes them to device 0, which is identified by its device
+    number in the driver model. Example data from memory could look like this:
+
+    ```
+    Data at 0x1000: 0xAA 0xBB 0xCC 0xDD
+    ```
+
+    The bytes `0xAA`, `0xBB`, `0xCC`, and `0xDD` will be written to device 0.
+
+Perform a read operation from device 0 to memory (multiple bytes)::
+
+    => i3c read 0x1000 4 0
+
+    This command reads 4 bytes of data from device 0 and writes them to
+    memory starting at address ``0x1000``.
+
+    Example output after reading 4 bytes from device 0:
+
+    ```
+    i3c Read:
+    00000000  AA BB CC DD
+    ```
+
+    The bytes `0xAA`, `0xBB`, `0xCC`, and `0xDD` are read from device 0
+    and written to memory at address `0x1000`.
+
+Configuration
+-------------
+
+The ``i3c`` command is only available if CONFIG_CMD_I3C=y.
+
+Return value
+------------
+
+If the command succeeds, the return value ``$?`` is set to 0. If an error
+occurs, the return value ``$?`` is set to 1.
+
+Note
+----
+
+When specifying the data to be written to the i3c device (for example, with
+the ``i3c write`` command), the data can be provided in either uppercase
+or lowercase hexadecimal format. Both are valid and will be processed
+correctly. Similarly, when reading data with ``i3c read``, the data will be
+retrieved in the specified length and can include multiple bytes, all
+formatted in the same way.
\ No newline at end of file