On Fri, Jun 17, 2016 at 01:03:41PM +0100, Jon Hunter wrote: > The I2C driver core for boards using device-tree assumes any subnode of > an I2C adapter in the device-tree blob as being a 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 and to share these pins subnodes for > representing these pins so they have be shared via the pinctrl framework > are needed. > > To allow I2C adapters to have non-I2C specific subnodes in device-tree > that are not parsed by the I2C driver core by adding support for a > '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@xxxxxxxxxx> > --- > Documentation/devicetree/bindings/i2c/i2c.txt | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt > index f31b2ad1552b..ed56b08c7e6e 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 (such as a pin controller), the 'i2c-bus' > + subnode can be used for populating I2C devices to prevent the I2C core > + from attempting to add any non-i2c nodes as I2C devices. If 'i2c-bus' > + subnode is present then all I2C slaves must be added under this > + subnode. The general idea seems sound. It would be good if we could remove the mention of the I2C core, something like: - i2c-bus For I2C adapters that have child nodes that are a mixture of both I2C devices and non-I2C devices (such as a pin controller), the 'i2c-bus' subnode can be used for populating I2C devices. If an 'i2c-bus' subnode is present, only subnodes of this will be considered as I2C slaves. How are #address-cells and #size-cells handled in this case? I assume that they should live under the i2c-bus subnode, which should be called out. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
