[RFC PATCH] drm/msm: lookup the ICC paths in both mdp5/dpu and mdss devices

[Stephen Boyd]

Quoting Dmitry Baryshkov (2022-08-05 04:56:30)
> diff --git a/drivers/gpu/drm/msm/msm_io_utils.c b/drivers/gpu/drm/msm/msm_io_utils.c
> index 7b504617833a..d02cd29ce829 100644
> --- a/drivers/gpu/drm/msm/msm_io_utils.c
> +++ b/drivers/gpu/drm/msm/msm_io_utils.c
> @@ -124,3 +126,23 @@ void msm_hrtimer_work_init(struct msm_hrtimer_work *work,
>         work->worker = worker;
>         kthread_init_work(&work->work, fn);
>  }
> +
> +struct icc_path *msm_icc_get(struct device *dev, const char *name)
> +{
> +       struct device *mdss_dev = dev->parent;
> +       struct icc_path *path;
> +
> +       path = of_icc_get(dev, name);
> +       if (path)
> +               return path;
> +
> +       /*
> +        * If there are no interconnects attached to the corresponding device
> +        * node, of_icc_get() will return NULL.
> +        *
> +        * If the MDP5/DPU device node doesn't have interconnects, lookup the
> +        * path in the parent (MDSS) device.
> +        */
> +       return of_icc_get(mdss_dev, name);

Perhaps this would be better served by having another icc_get() API that
looks in the device and also the parent? Or maybe there should be
interconnect-ranges (similar to clock-ranges) so that interconnects can
be mapped to child nodes in DT.