Re: [PATCH v2 2/4] drm/panfrost: Drop redundant optional clock checks in runtime PM

[Adrián Larumbe <adrian.larumbe@collabora.com>]

Hi Biju,

On 20.03.2026 16:41, Biju wrote:
> From: Biju Das <biju.das.jz@bp.renesas.com>
>
> The clk_enable() and clk_disable() APIs already handle NULL clock pointers
> gracefully — clk_enable() returns 0 and clk_disable() returns immediately
> when passed a NULL or optional clock. The explicit if (pfdev->bus_clock)
> guards around these calls in the runtime suspend/resume paths are
> therefore unnecessary. Remove them to simplify the code.
>
> Reviewed-by: Steven Price <steven.price@arm.com>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v1->v2:
>  * Collected tag
> ---
>  drivers/gpu/drm/panfrost/panfrost_device.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
> index dedc13e56631..01e702a0b2f0 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.c
> @@ -429,11 +429,9 @@ static int panfrost_device_runtime_resume(struct device *dev)
>  		if (ret)
>  			goto err_clk;
>
> -		if (pfdev->bus_clock) {
> -			ret = clk_enable(pfdev->bus_clock);
> -			if (ret)
> -				goto err_bus_clk;
> -		}
> +		ret = clk_enable(pfdev->bus_clock);
> +		if (ret)
> +			goto err_bus_clk;
>  	}

It seems clk_prepare_enable() can also deal with NULL clock device pointers gracefully,
so maybe you could also do away with pointer checks in panfrost_clk_init?

Other than that,

Reviewed-by: Adrián Larumbe <adrian.larumbe@collabora.com>

>  	panfrost_device_reset(pfdev, true);
> @@ -464,9 +462,7 @@ static int panfrost_device_runtime_suspend(struct device *dev)
>  	panfrost_gpu_power_off(pfdev);
>
>  	if (pfdev->comp->pm_features & BIT(GPU_PM_RT)) {
> -		if (pfdev->bus_clock)
> -			clk_disable(pfdev->bus_clock);
> -
> +		clk_disable(pfdev->bus_clock);
>  		clk_disable(pfdev->clock);
>  		reset_control_assert(pfdev->rstc);
>  	}
> --
> 2.43.0


Adrian Larumbe