Re: [PATCH v2 1/5] drm/msm/mdp5: Add optional TBU and TBU_RT clocks

[Sean Paul <sean@poorly.run>]

On Thu, Sep 26, 2019 at 12:52:52PM +0200, kholk11@gmail.com wrote:
> From: "Angelo G. Del Regno" <kholk11@gmail.com>

Hi Angelo,
Thank you for your patches!

> 
> Some SoCs, like MSM8956/8976 (and APQ variants), do feature these
> clocks and we need to enable them in order to get the hardware to
> properly work.

Could you add an explanation to the commit message of what these
clocks are/do, for those of us who don't know?

> 
> Signed-off-by: Angelo G. Del Regno <kholk11@gmail.com>
> ---
>  Documentation/devicetree/bindings/display/msm/mdp5.txt |  2 ++
>  drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c               | 10 ++++++++++
>  drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h               |  2 ++
>  3 files changed, 14 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/msm/mdp5.txt b/Documentation/devicetree/bindings/display/msm/mdp5.txt
> index 4e11338548aa..43d11279c925 100644
> --- a/Documentation/devicetree/bindings/display/msm/mdp5.txt
> +++ b/Documentation/devicetree/bindings/display/msm/mdp5.txt
> @@ -76,6 +76,8 @@ Required properties:
>  Optional properties:
>  - clock-names: the following clocks are optional:
>    * "lut"
> +  * "tbu"
> +  * "tbu_rt"

Bindings updates should be in their own patch, and you'll need to cc the correct
dt lists and maintainers (especially Rob Herring) in order to get their
attention. (hint: use scripts/get_maintainer.pl)

Sean

>  
>  Example:
>  
> diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> index fec6ef1ae3b9..23be9b95dd7e 100644
> --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> @@ -293,6 +293,10 @@ int mdp5_disable(struct mdp5_kms *mdp5_kms)
>  	mdp5_kms->enable_count--;
>  	WARN_ON(mdp5_kms->enable_count < 0);
>  
> +	if (mdp5_kms->tbu_rt_clk)
> +		clk_disable_unprepare(mdp5_kms->tbu_rt_clk);
> +	if (mdp5_kms->tbu_clk)
> +		clk_disable_unprepare(mdp5_kms->tbu_clk);
>  	clk_disable_unprepare(mdp5_kms->ahb_clk);
>  	clk_disable_unprepare(mdp5_kms->axi_clk);
>  	clk_disable_unprepare(mdp5_kms->core_clk);
> @@ -313,6 +317,10 @@ int mdp5_enable(struct mdp5_kms *mdp5_kms)
>  	clk_prepare_enable(mdp5_kms->core_clk);
>  	if (mdp5_kms->lut_clk)
>  		clk_prepare_enable(mdp5_kms->lut_clk);
> +	if (mdp5_kms->tbu_clk)
> +		clk_prepare_enable(mdp5_kms->tbu_clk);
> +	if (mdp5_kms->tbu_rt_clk)
> +		clk_prepare_enable(mdp5_kms->tbu_rt_clk);
>  
>  	return 0;
>  }
> @@ -948,6 +956,8 @@ static int mdp5_init(struct platform_device *pdev, struct drm_device *dev)
>  
>  	/* optional clocks: */
>  	get_clk(pdev, &mdp5_kms->lut_clk, "lut", false);
> +	get_clk(pdev, &mdp5_kms->tbu_clk, "tbu", false);
> +	get_clk(pdev, &mdp5_kms->tbu_rt_clk, "tbu_rt", false);
>  
>  	/* we need to set a default rate before enabling.  Set a safe
>  	 * rate first, then figure out hw revision, and then set a
> diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h
> index d1bf4fdfc815..128866742593 100644
> --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h
> +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h
> @@ -53,6 +53,8 @@ struct mdp5_kms {
>  	struct clk *ahb_clk;
>  	struct clk *core_clk;
>  	struct clk *lut_clk;
> +	struct clk *tbu_clk;
> +	struct clk *tbu_rt_clk;
>  	struct clk *vsync_clk;
>  
>  	/*
> -- 
> 2.21.0
> 

-- 
Sean Paul, Software Engineer, Google / Chromium OS