Re: [PATCH v2 4/4] drm/imagination: Skip clocks if platform PM manages resources

[Maxime Ripard <mripard@kernel.org>]

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On Mon, Apr 14, 2025 at 08:52:58PM +0200, Michal Wilczynski wrote:
> Update the Imagination PVR driver to skip clock management during
> initialization if the platform PM has indicated that it manages platform
> resources.
> 
> This is necessary for platforms like the T-HEAD TH1520, where the GPU's
> clocks and resets are managed via a PM domain, and should not be
> manipulated directly by the GPU driver.
> 
> Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
> ---
>  drivers/gpu/drm/imagination/pvr_device.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/imagination/pvr_device.c b/drivers/gpu/drm/imagination/pvr_device.c
> index 1704c0268589bdeb65fa6535f9ec63182b0a3e94..f40468b99cf14da418aeecde086f009695ff877c 100644
> --- a/drivers/gpu/drm/imagination/pvr_device.c
> +++ b/drivers/gpu/drm/imagination/pvr_device.c
> @@ -504,10 +504,16 @@ pvr_device_init(struct pvr_device *pvr_dev)
>  	if (err)
>  		return err;
>  
> -	/* Enable and initialize clocks required for the device to operate. */
> -	err = pvr_device_clk_init(pvr_dev);
> -	if (err)
> -		return err;
> +	/*
> +	 * Only initialize clocks if they are not managed by the platform's
> +	 * PM domain.
> +	 */
> +	if (!device_platform_resources_pm_managed(dev)) {
> +		/* Enable and initialize clocks required for the device to operate. */
> +		err = pvr_device_clk_init(pvr_dev);
> +		if (err)
> +			return err;
> +	}

So, how does that work for devfreq? I can understand the rationale for
resets and the sys clock, but the core clock at least should really be
handled by the driver.

Maxime

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