On Thu 03 Feb 08:46 PST 2022, Vladimir Zapolskiy wrote:
> Quite regularly I2C bus lines on QCOM CCI controller require an external
> pull-up to a regulator powered line, to be able to define all such
> cases an additional vbus-supply property of a bus subnode is wanted.
>
> Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@xxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/i2c/i2c-qcom-cci.txt | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-qcom-cci.txt b/Documentation/devicetree/bindings/i2c/i2c-qcom-cci.txt
> index 924ad8c03464..9f5b321748f1 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-qcom-cci.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-qcom-cci.txt
> @@ -60,6 +60,11 @@ PROPERTIES:
> Definition: Desired I2C bus clock frequency in Hz, defaults to 100
> kHz if omitted.
>
> +- vbus-supply:
I don't think "vbus" is an appropriate name for his. Perhaps "vddio" or
something like that would be better.
But there's a bigger question here, this is not a supply for the
i2c master, it's simply a supply for pulling up the bus. So it's not
entirely correct to specify it as a supply for the CCI node (which is
also the reason why the name isn't obvious).
Typically we don't don't mention the bus-supply because it happens to be
pulled up either by io-supply for the block, or by some always-on
regulator in the system.
Looping in Linus and Mark in hope they have seen this need elsewhere.
Regards,
Bjorn
> + Usage: optional
> + Value type: phandle
> + Definition: Regulator that provides power to SCL/SDA lines
> +
> Example:
>
> cci@a0c000 {
> --
> 2.33.0
>
