Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 74 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
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+Register-based I2C Bus Mux
+
+This binding describes an I2C bus multiplexer that uses a single register
+to route the I2C signals.
+
+Required properties:
+- compatible: i2c-mux-reg
+- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
+  port is connected to.
+* Standard I2C mux properties. See i2c-mux.txt in this directory.
+* I2C child bus nodes. See i2c-mux.txt in this directory.
+
+Optional properties:
+- reg: this pair of <offset size> specifies the register to control the mux.
+  The <offset size> depends on its parent node. It can be any memory-mapped
+  address. The size must be either 1, 2, or 4 bytes. If reg is omitted, the
+  resource of this device will be used.
+- little-endian: The existence indicates the register is in little endian.
+- big-endian: The existence indicates the register is in big endian.
+  If both little-endian and big-endian are omitted, the endianness of the
+  CPU will be used.
+- write-only: The existence indicates the register is write-only.
+- idle-state: value to set the muxer to when idle. When no value is
+  given, it defaults to the last value used.
+
+Whenever an access is made to a device on a child bus, the value set
+in the relevant node's reg property will be output to the register.
+
+If an idle state is defined, using the idle-state (optional) property,
+whenever an access is not being made to a device on a child bus, the
+register will be set according to the idle value.
+
+If an idle state is not defined, the most recently used value will be
+left programmed into the register.
+
+Example of a mux on PCIe card, the host is a powerpc SoC (big endian):
+
+	i2c-mux {
+		/* the <offset size> depends on the address translation
+		 * of the parent device. If omitted, device resource
+		 * will be used instead. The size is to determine
+		 * whether iowrite32, iowrite16, or iowrite8 will be used.
+		 */
+		reg = <0x6028 0x4>;
+		little-endian;		/* little endian register on PCIe */
+		compatible = "i2c-mux-reg";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		i2c-parent = <&i2c1>;
+		i2c@0 {
+			reg = <0>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			si5338: clock-generator@70 {
+				compatible = "silabs,si5338";
+				reg = <0x70>;
+				/* other stuff */
+			};
+		};
+
+		i2c@1 {
+			/* data is written using iowrite32 */
+			reg = <1>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			si5338: clock-generator@70 {
+				compatible = "silabs,si5338";
+				reg = <0x70>;
+				/* other stuff */
+			};
+		};
+	};