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authorLinus Torvalds <torvalds@linux-foundation.org>2012-06-05 10:55:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-06-05 10:55:31 -0700
commit690efa08e268a36df170bee79df93a9649c3f217 (patch)
tree16fa1ccd5cefd3db92201908ca2a1051f86799db /Documentation
parent5698e9180cb70020bbf8b613174afe6308f902b0 (diff)
parentae58d1e406986f31d1e88b32f5ac601506c196d8 (diff)
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Merge branch 'i2c-embedded/for-current' of git://git.pengutronix.de/git/wsa/linux
Pull embedded i2c update from Wolfram Sang: "This only contains one new driver which had multiple dependencies (pinctrl, i2c-mux-rework, new devm_* functions), so I decided to wait for rc1. Plus, it had to wait a little for the ack of a devicetree maintainer since the bindings were not trivial enough for me to pass through. So, given that, I hope there is still something like the "new driver rule", so we could have the driver in 3.5 and people can start using it. That would make merging support for some boards easier for 3.6 since the dependency on this driver is gone then." * 'i2c-embedded/for-current' of git://git.pengutronix.de/git/wsa/linux: i2c: Add generic I2C multiplexer using pinctrl API
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+Pinctrl-based I2C Bus Mux
+
+This binding describes an I2C bus multiplexer that uses pin multiplexing to
+route the I2C signals, and represents the pin multiplexing configuration
+using the pinctrl device tree bindings.
+
+ +-----+ +-----+
+ | dev | | dev |
+ +------------------------+ +-----+ +-----+
+ | SoC | | |
+ | /----|------+--------+
+ | +---+ +------+ | child bus A, on first set of pins
+ | |I2C|---|Pinmux| |
+ | +---+ +------+ | child bus B, on second set of pins
+ | \----|------+--------+--------+
+ | | | | |
+ +------------------------+ +-----+ +-----+ +-----+
+ | dev | | dev | | dev |
+ +-----+ +-----+ +-----+
+
+Required properties:
+- compatible: i2c-mux-pinctrl
+- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
+ port is connected to.
+
+Also required are:
+
+* Standard pinctrl properties that specify the pin mux state for each child
+ bus. See ../pinctrl/pinctrl-bindings.txt.
+
+* Standard I2C mux properties. See mux.txt in this directory.
+
+* I2C child bus nodes. See mux.txt in this directory.
+
+For each named state defined in the pinctrl-names property, an I2C child bus
+will be created. I2C child bus numbers are assigned based on the index into
+the pinctrl-names property.
+
+The only exception is that no bus will be created for a state named "idle". If
+such a state is defined, it must be the last entry in pinctrl-names. For
+example:
+
+ pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1
+ pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last)
+ pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last)
+
+Whenever an access is made to a device on a child bus, the relevant pinctrl
+state will be programmed into hardware.
+
+If an idle state is defined, whenever an access is not being made to a device
+on a child bus, the idle pinctrl state will be programmed into hardware.
+
+If an idle state is not defined, the most recently used pinctrl state will be
+left programmed into hardware whenever no access is being made of a device on
+a child bus.
+
+Example:
+
+ i2cmux {
+ compatible = "i2c-mux-pinctrl";
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ i2c-parent = <&i2c1>;
+
+ pinctrl-names = "ddc", "pta", "idle";
+ pinctrl-0 = <&state_i2cmux_ddc>;
+ pinctrl-1 = <&state_i2cmux_pta>;
+ pinctrl-2 = <&state_i2cmux_idle>;
+
+ i2c@0 {
+ reg = <0>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ eeprom {
+ compatible = "eeprom";
+ reg = <0x50>;
+ };
+ };
+
+ i2c@1 {
+ reg = <1>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ eeprom {
+ compatible = "eeprom";
+ reg = <0x50>;
+ };
+ };
+ };
+