Re: [RFC v2 2/4] dt-bindings: i2c: mux: demux-pinctrl: add bindings

From: Jan Lübbe
Date: Thu Jan 07 2016 - 11:56:48 EST


Hi Wolfram,

On Mi, 2016-01-06 at 14:51 +0100, Wolfram Sang wrote:
[...]
> +Required properties:
> +- compatible: "i2c-demux-pinctrl"
> +- i2c-parent: List of phandles of I2C masters available for selection. The first
> + one will be used as default.
> +- i2c-bus-name: The name of this bus. Also needed as pinctrl-name for the I2C
> + parents.
[...]
> + i2chdmi: i2c@8 {
> + compatible = "i2c-demux-pinctrl";
> + i2c-parent = <&gpioi2c>, <&iic2>, <&i2c2>;
> + i2c-bus-name = "i2c-hdmi";
> + #address-cells = <1>;
> + #size-cells = <0>;
[...]
> + gpioi2c: i2c@9 {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + compatible = "i2c-gpio";
[...]
> +&i2c2 {
> + pinctrl-0 = <&i2c2_pins>;
> + pinctrl-names = "i2c-hdmi";
> +
> + clock-frequency = <100000>;
> +};
[...]
> +&iic2 {
> + pinctrl-0 = <&iic2_pins>;
> + pinctrl-names = "i2c-hdmi";
> +
> + clock-frequency = <100000>;
> +};
[...]

It seems that the demux-pinctrl driver reconfigures the pinctrl settings
for the parent devices. I would have expected to have alternative
pinctrl state on the demux node support switching the same external pins
between the different controllers. Wouldn't it be possible to have
pinctrl conflicts between &i2c2_pins and &iic2_pins otherwise?

Regards,
Jan
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