Merge branch '2021-10-19-assorted-changes'

- Assorted minor fixes and a new GPIO driver

2 files changed, 57 insertions, 0 deletions

diff --git a/doc/build/gcc.rst b/doc/build/gcc.rst
index 0cdc307d57b..6c4b4ad7a05 100644
--- a/doc/build/gcc.rst
+++ b/doc/build/gcc.rst
@@ -120,6 +120,27 @@ Further important build parameters are
 * O=<dir> - generate all output files in directory <dir>, including .config
 * V=1 - verbose build
 
+Devicetree compiler
+~~~~~~~~~~~~~~~~~~~
+
+Boards that use `CONFIG_OF_CONTROL` (i.e. almost all of them) need the
+devicetree compiler (dtc). Those with `CONFIG_PYLIBFDT` need pylibfdt, a Python
+library for accessing devicetree data. Suitable versions of these are included
+in the U-Boot tree in `scripts/dtc` and built automatically as needed.
+
+To use the system versions of these, use the DTC parameter, for example
+
+.. code-block:: bash
+
+    DTC=/usr/bin/dtc make
+
+In this case, dtc and pylibfdt are not built. The build checks that the version
+of dtc is new enough. It also makes sure that pylibfdt is present, if needed
+(see `scripts_dtc` in the Makefile).
+
+Note that the :doc:`tools` are always built with the included version of libfdt
+so it is not possible to build U-Boot tools with a system libfdt, at present.
+
 Other build targets
 ~~~~~~~~~~~~~~~~~~~
 
diff --git a/doc/device-tree-bindings/gpio/gpio-max7320.txt b/doc/device-tree-bindings/gpio/gpio-max7320.txt
new file mode 100644
index 00000000000..87b703bb69f
--- /dev/null
+++ b/doc/device-tree-bindings/gpio/gpio-max7320.txt
@@ -0,0 +1,36 @@
+* MAX7320 I/O expanders
+
+The original maxim 7320 i/o expander offers 8 bit push/pull outputs.
+There exists some clones which offers 16 bit.
+
+Required Properties:
+
+  - compatible: should be one of the following.
+    - "maxim,max7320"
+
+  - reg: I2C slave address.
+
+  - gpio-controller: Marks the device node as a gpio controller.
+  - #gpio-cells: Should be 2. The first cell is the GPIO number and the second
+    cell specifies GPIO flags, as defined in <dt-bindings/gpio/gpio.h>. Only the
+    GPIO_ACTIVE_HIGH and GPIO_ACTIVE_LOW flags are supported.
+
+Optional Properties:
+
+   - ngpios: tell the driver how many gpios the device offers.
+     if the property is omitted, 8bit (original maxim) is assumed.
+
+Please refer to gpio.txt in this directory for details of the common GPIO
+bindings used by client devices.
+
+Example: MAX7320 I/O expander node
+
+	ledgpio: max7320@5d {
+		status = "okay";
+		compatible = "maxim,max7320";
+		reg = <0x5d>;
+		#gpio-cells = <2>;
+		gpio-controller;
+		ngpios = <16>;
+	};
+