On 2016-06-28 10:21, Jon Hunter wrote: > > On 27/06/16 13:04, Peter Rosin wrote: >> On 2016-06-23 17:59, 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> >>> Acked-by: Thierry Reding <treding@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..71bea55d4c1b 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. 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. >> >> Hmmm, those #-properties are listed above, under "Required properties", which >> is no longer 100% true. Maybe rephrase to >> >> slaves. The required properties '#address-cells' and '#size-cells' >> must be defined under this subnode instead, if this subnode is present. >> >> to make the rules (even) clearer? > > I see what you are saying but I wonder if the following is better ... > > slaves. The required properties '#address-cells' and '#size-cells' > must be defined under this subnode if present and not the parent node. Naaw, I don't like that either, I associate the last "and not" with the "if present" part and not the intended "under this subnode". Then I go WTF when I fail to parse. Maybe just add an example instead... Or just forget me ever saying anything. Sorry for making a fuss over this. Cheers, Peter -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
