Re: [PATCH v1 1/2] i2c: qcom-cci: Select pinctrl states during runtime PM

[Loic Poulain]

On Thu, Oct 22, 2026 at 9:14 AM Saikiran <bjsaikiran@xxxxxxxxx> wrote:
>
> The CCI runtime PM callbacks only gate the controller clocks, leaving the
> bus pins in their default state while the controller is suspended. On the
> Lenovo Yoga Slim 7x, this can back-power the camera sensor through SDA and
> SCL after its supplies have been disabled, contributing to brownouts on
> subsequent power cycles.
>
> Select the sleep pinctrl state before disabling the clocks so that the
> configured pull-downs can take effect. Restore the default state before
> enabling the clocks on resume, and return to the sleep state if enabling
> the clocks fails.
>
> Tested-on: Lenovo Yoga Slim 7x (Snapdragon X Elite)
> Signed-off-by: Saikiran <bjsaikiran@xxxxxxxxx>
> ---
>  drivers/i2c/busses/i2c-qcom-cci.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-qcom-cci.c b/drivers/i2c/busses/i2c-qcom-cci.c
> index 873e901a23d7..fba5f664eeaa 100644
> --- a/drivers/i2c/busses/i2c-qcom-cci.c
> +++ b/drivers/i2c/busses/i2c-qcom-cci.c
> @@ -10,6 +10,7 @@
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
> +#include <linux/pinctrl/consumer.h>
>  #include <linux/pm_runtime.h>
>
>  #define CCI_HW_VERSION                         0x0
> @@ -474,6 +475,11 @@ static void cci_disable_clocks(struct cci *cci)
>  static int __maybe_unused cci_suspend_runtime(struct device *dev)
>  {
>         struct cci *cci = dev_get_drvdata(dev);
> +       int ret;
> +
> +       ret = pinctrl_pm_select_sleep_state(dev);
> +       if (ret)
> +               return ret;

You should perform the do/undo symmetrically in suspend/resume, so it
would probably be better to move the pinctrl handling to the end of
the suspend function after clock disabling.

>
>         cci_disable_clocks(cci);
>         return 0;
> @@ -484,10 +490,16 @@ static int __maybe_unused cci_resume_runtime(struct device *dev)
>         struct cci *cci = dev_get_drvdata(dev);
>         int ret;
>
> -       ret = cci_enable_clocks(cci);
> +       ret = pinctrl_pm_select_default_state(dev);
>         if (ret)
>                 return ret;
>
> +       ret = cci_enable_clocks(cci);
> +       if (ret) {
> +               pinctrl_pm_select_sleep_state(dev);
> +               return ret;
> +       }
> +
>         cci_init(cci);
>         return 0;
>  }
> --
> 2.56.0
>