On 17/06/16 17:45, Thierry Reding wrote: > * PGP Signed by an unknown key > > On Fri, Jun 17, 2016 at 05:30:54PM +0100, Mark Rutland wrote: >> 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. > > Good catch. Yes, I think the i2c-bus subnode would be the right place > for #address-cells and #size-cells. Yes, indeed. Thanks. Will fix. Cheers Jon -- nvpublic -- 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
