diff options
author | David Daney <david.daney@cavium.com> | 2012-04-13 01:14:23 +0400 |
---|---|---|
committer | Wolfram Sang <w.sang@pengutronix.de> | 2012-05-12 16:28:16 +0400 |
commit | bc45449b1444611d68466ae7f45f235420d79019 (patch) | |
tree | 89be285b67ffb6d11a5db26cc34fbe7f3f621aaf /Documentation/devicetree/bindings/i2c | |
parent | 5a3ecd5f9877b963a581ca5d4495a1a24dafc88c (diff) | |
download | linux-bc45449b1444611d68466ae7f45f235420d79019.tar.xz |
i2c/of: Automatically populate i2c mux busses from device tree data.
For 'normal' i2c bus drivers, we can call of_i2c_register_devices()
and have the device tree framework automatically populate the bus with
the devices specified in the device tree.
This patch adds a common code to the i2c mux framework to have the mux
sub-busses be populated by the of_i2c_register_devices() too. If the
mux device has an of_node, we populate the sub-bus' of_node so that
the subsequent call to of_i2c_register_devices() will find the
corresponding devices.
It seemed better to put this logic in i2c_add_mux_adapter() rather
than the individual mux drivers, as they will all probably want to do
the same thing.
Signed-off-by: David Daney <david.daney@cavium.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
[wsa: removed superfluous ret-variable and fixed a typo in a comment]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Diffstat (limited to 'Documentation/devicetree/bindings/i2c')
-rw-r--r-- | Documentation/devicetree/bindings/i2c/mux.txt | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/mux.txt b/Documentation/devicetree/bindings/i2c/mux.txt new file mode 100644 index 000000000000..af84cce5cd7b --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/mux.txt @@ -0,0 +1,60 @@ +Common i2c bus multiplexer/switch properties. + +An i2c bus multiplexer/switch will have several child busses that are +numbered uniquely in a device dependent manner. The nodes for an i2c bus +multiplexer/switch will have one child node for each child +bus. + +Required properties: +- #address-cells = <1>; +- #size-cells = <0>; + +Required properties for child nodes: +- #address-cells = <1>; +- #size-cells = <0>; +- reg : The sub-bus number. + +Optional properties for child nodes: +- Other properties specific to the multiplexer/switch hardware. +- Child nodes conforming to i2c bus binding + + +Example : + + /* + An NXP pca9548 8 channel I2C multiplexer at address 0x70 + with two NXP pca8574 GPIO expanders attached, one each to + ports 3 and 4. + */ + + mux@70 { + compatible = "nxp,pca9548"; + reg = <0x70>; + #address-cells = <1>; + #size-cells = <0>; + + i2c@3 { + #address-cells = <1>; + #size-cells = <0>; + reg = <3>; + + gpio1: gpio@38 { + compatible = "nxp,pca8574"; + reg = <0x38>; + #gpio-cells = <2>; + gpio-controller; + }; + }; + i2c@4 { + #address-cells = <1>; + #size-cells = <0>; + reg = <4>; + + gpio2: gpio@38 { + compatible = "nxp,pca8574"; + reg = <0x38>; + #gpio-cells = <2>; + gpio-controller; + }; + }; + }; |