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authorJon Hunter <jonathanh@nvidia.com>2016-06-29 10:17:52 +0100
committerThierry Reding <treding@nvidia.com>2016-06-30 11:01:13 +0200
commit98b00488459e9d27d8e42b6d241f309f26ffde07 (patch)
tree9d395e7670fed514074e81afc5368d974826b764 /Documentation/devicetree/bindings
parent1a695a905c18548062509178b98bc91e67510864 (diff)
dt-bindings: i2c: Add support for 'i2c-bus' subnode
The I2C driver core for boards using device-tree assumes any subnode of an I2C adapter in the device-tree blob is an I2C slave device. Although this makes complete sense, some I2C adapters may have subnodes which are not I2C slaves but subnodes presenting other features. For example some Tegra devices have an I2C interface which may share its pins with other devices. In order to share these pins using the pinctrl framework, it is necessary to add subnodes to the I2C device node that represent these pins. To allow I2C adapters to have non-I2C specific subnodes in device-tree that are not parsed by the I2C driver core, add support for an optional 'i2c-bus' subnode where I2C slaves can be placed. If the 'i2c-bus' subnode is present then all I2C slaves must be placed under this subnode. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Acked-by: Thierry Reding <treding@nvidia.com> Acked-by: Rob Herring <robh@kernel.org> Acked-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'Documentation/devicetree/bindings')
-rw-r--r--Documentation/devicetree/bindings/i2c/i2c.txt8
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
index c8d977ed847f..a07452854118 100644
--- a/Documentation/devicetree/bindings/i2c/i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c.txt
@@ -32,6 +32,14 @@ wants to support one of the below features, it should adapt the bindings below.
- clock-frequency
frequency of bus clock in Hz.
+- i2c-bus
+ For I2C adapters that have child nodes that are a mixture of both I2C
+ devices and non-I2C devices, the 'i2c-bus' subnode can be used for
+ populating I2C devices. If the 'i2c-bus' subnode is present, only
+ subnodes of this will be considered as I2C slaves. The properties,
+ '#address-cells' and '#size-cells' must be defined under this subnode
+ if present.
+
- i2c-scl-falling-time-ns
Number of nanoseconds the SCL signal takes to fall; t(f) in the I2C
specification.