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authorSimon Glass <sjg@chromium.org>2015-01-26 20:29:37 -0700
committerSimon Glass <sjg@chromium.org>2015-01-29 17:10:01 -0700
commit7132b9fd68a1c76bf557d56dd62756a6607cf761 (patch)
tree01e328c5353ed266cf7b6e22efb7540116f13d64 /doc
parent189d80166b31db55b99190be3164c8d3348b57fc (diff)
dm: i2c: dts: Support an offset-len device tree property
Since U-Boot can support different offset lengths (0-4 bytes), add a device tree property to specify this. This avoids hard-coding it in the driver. Signed-off-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'doc')
-rw-r--r--doc/device-tree-bindings/i2c/i2c.txt28
1 files changed, 28 insertions, 0 deletions
diff --git a/doc/device-tree-bindings/i2c/i2c.txt b/doc/device-tree-bindings/i2c/i2c.txt
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+++ b/doc/device-tree-bindings/i2c/i2c.txt
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+U-Boot I2C
+----------
+
+U-Boot's I2C model has the concept of an offset within a chip (I2C target
+device). The offset can be up to 4 bytes long, but is normally 1 byte,
+meaning that offsets from 0 to 255 are supported by the chip. This often
+corresponds to register numbers.
+
+Apart from the controller-specific I2C bindings, U-Boot supports a special
+property which allows the chip offset length to be selected.
+
+Optional properties:
+- u-boot,i2c-offset-len - length of chip offset in bytes. If omitted the
+ default value of 1 is used.
+
+
+Example
+-------
+
+i2c4: i2c@12ca0000 {
+ cros-ec@1e {
+ reg = <0x1e>;
+ compatible = "google,cros-ec";
+ i2c-max-frequency = <100000>;
+ u-boot,i2c-offset-len = <0>;
+ ec-interrupt = <&gpx1 6 GPIO_ACTIVE_LOW>;
+ };
+};