On Fri, Jun 17, 2016 at 01:03:43PM +0100, Jon Hunter wrote: > On Tegra124, Tegra132 and Tegra210 devices the pads used by the Display > Port Auxiliary (DPAUX) channel are multiplexed such that they can also > be used by one of the internal i2c controllers. Note that this is > different from i2c-over-AUX supported by the DPAUX controller. The > register that configures these pads is part of the DPAUX controllers > register set and so a pinctrl driver is being added for the DPAUX device > to share these pads. Add the device-tree binding documentation for the > DPAUX pad controller. There are a couple more "i2c" vs. "I2C" in the above. Please use the latter consistently. Also the subject line should be something different. drm is a linuxism and hence shouldn't be used anywhere near DT bindings. > Please note that although the "off" function for the DPAUX pads is not > technically a pin-mux setting but more of a pin-conf setting it is > simpler to expose these as a function so that the user can simply select > either "aux", "i2c" or "off" as the current function/mode. > > Update the main DPAUX binding documentation to reference the DPAUX pad > controller binding document and add the 'i2c-bus' subnode. The 'i2c-bus' > subnode is used for populating I2C slaves for the DPAUX device so that > the I2C driver core does not attempt to add the DPAUX pad controller > nodes as I2C slaves. > > Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx> > --- > .../display/tegra/nvidia,tegra20-host1x.txt | 4 ++ > .../pinctrl/nvidia,tegra124-dpaux-padctl.txt | 60 ++++++++++++++++++++++ > 2 files changed, 64 insertions(+) > create mode 100644 Documentation/devicetree/bindings/pinctrl/nvidia,tegra124-dpaux-padctl.txt > > diff --git a/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt b/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt > index 361a472eac4b..6759554b7b8f 100644 > --- a/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt > +++ b/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt > @@ -242,6 +242,10 @@ of the following host1x client modules: > - reset-names: Must include the following entries: > - dpaux > - vdd-supply: phandle of a supply that powers the DisplayPort link > + - i2c-bus: Subnode where I2C slave devices should be listed. Should we perhaps say at this point that the subnode should always be added, oven if empty? Otherwise we'll still run into a conflict with the pinmux nodes. > + > + See ../pinctrl/nvidia,tegra124-dpaux-padctl.txt for information > + regarding the DPAUX pad controller bindings. > > Example: > > diff --git a/Documentation/devicetree/bindings/pinctrl/nvidia,tegra124-dpaux-padctl.txt b/Documentation/devicetree/bindings/pinctrl/nvidia,tegra124-dpaux-padctl.txt > new file mode 100644 > index 000000000000..3be0ced01680 > --- /dev/null > +++ b/Documentation/devicetree/bindings/pinctrl/nvidia,tegra124-dpaux-padctl.txt > @@ -0,0 +1,60 @@ > +Device tree binding for NVIDIA Tegra DPAUX pad controller > +======================================================== > + > +The Tegra Display Port Auxiliary (DPAUX) pad controller manages two pins > +which can be assigned to either the DPAUX channel or to an I2C > +controller. > + > +This document defines the device-specific binding for the DPAUX pad > +controller. Refer to pinctrl-bindings.txt in this directory for generic > +information about pin controller device tree bindings. Please refer to > +the binding document ../display/tegra/nvidia,tegra20-host1x.txt for more > +details on the DPAUX binding. > + > +Pin muxing: > +----------- > + > +Child nodes contain the pinmux configurations following the conventions > +from the pinctrl-bindings.txt document. > + > +Since only three configurations are possible, only three child nodes are > +needed to describe the pin mux'ing options for the DPAUX pads. > +Furthermore, given that the pad functions are only applicable to a > +single set of pads, the child nodes do not need to describe the pads the > +functions are being applied to. > + > +Required properties: > +- groups: Must be "dpaux-io" Above you say that we don't need to describe the pads, but then the groups property does describe the pads. Why? Thierry
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