Re: [PATCH 3/4] arm64: dts: qcom: qcm6490-fairphone-fp5: Enable CCI pull-up

Konrad Dybcio
2025-10-02T12:45:55Z

On 10/2/25 12:15 PM, Griffin Kroah-Hartman wrote:
> Enable vreg_l6p which is used as a pull-up for the CCI busses, to make
> sure I2C communication works as expected.
>
> Signed-off-by: Griffin Kroah-Hartman <griffin.kroah@fairphone.com>
> ---

Makes me wonder if we should maybe extend the CCI definition
(or maybe the common i2c-bus binding?) to accept an external
pull-up supply, as this is a common problem.. (+Bryan, Wolfram)

We could then shut down the regulator when cameras are not
in use, preserving some trace amounts of power.

Or maybe L6P is already used as a pull-up supply for more things
onboard and should be always-on either way? Could you please
check that, Griffin?

Konrad

> arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
> index e115b6a52b299ef663ccfb614785f8f89091f39d..2dd2c452592aa6b0ac826f19eb9cb1a8b90cee47 100644
> --- a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
> +++ b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
> @@ -749,6 +749,8 @@ vreg_l6p: ldo6 {
> regulator-name = "vreg_l6p";
> regulator-min-microvolt = <1700000>;
> regulator-max-microvolt = <1904000>;
> + /* Pull-up for CCI I2C busses */
> + regulator-always-on;
> };
>
> vreg_l7p: ldo7 {
>