linux-kernel - Re: [PATCH v6 12/12] drm: renesas: rz-du: mipi_dsi: Add support for LPCLK clock handling

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Message-ID: <20250602094243.GB3645@pendragon.ideasonboard.com>
Date: Mon, 2 Jun 2025 12:42:43 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Prabhakar <prabhakar.csengg@...il.com>
Cc: Biju Das <biju.das.jz@...renesas.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Magnus Damm <magnus.damm@...il.com>,
	dri-devel@...ts.freedesktop.org, linux-renesas-soc@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v6 12/12] drm: renesas: rz-du: mipi_dsi: Add support for
 LPCLK clock handling

Hi Prabhakar,

Thank you for the patch.

On Fri, May 30, 2025 at 05:59:06PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> 
> Add LPCLK clock support in the RZ/G2L MIPI DSI driver via the optional
> clock API. This clock is required by some SoCs like RZ/V2H(P) for proper
> DPHY configuration, whereas it is absent on others like RZ/G2L.
> 
> Introduce a new `lpclk` field in the `rzg2l_mipi_dsi` structure and
> conditionally acquire the "lpclk" clock using `devm_clk_get_optional()`
> during probe. This allows LPCLK-aware SoCs to pass the clock via device
> tree without impacting existing platforms.
> 
> Co-developed-by: Fabrizio Castro <fabrizio.castro.jz@...esas.com>
> Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@...esas.com>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> Reviewed-by: Biju Das <biju.das.jz@...renesas.com>
> ---
> v5->v6:
> - No changes
> 
> v4->v5:
> - Made use of devm_clk_get_optional() for lpclk
> - Added Reviewed tag from Biju
> 
> v3->v4
> - No changes
> 
> v2->v3:
> - No changes
> 
> v1->v2:
> - Added LPCLK as feature flag
> ---
>  drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> index f9f2d883c40d..a31f9b6aa920 100644
> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> @@ -62,6 +62,7 @@ struct rzg2l_mipi_dsi {
>  	struct drm_bridge *next_bridge;
>  
>  	struct clk *vclk;
> +	struct clk *lpclk;
>  
>  	enum mipi_dsi_pixel_format format;
>  	unsigned int num_data_lanes;
> @@ -791,6 +792,10 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
>  	if (IS_ERR(dsi->vclk))
>  		return PTR_ERR(dsi->vclk);
>  
> +	dsi->lpclk = devm_clk_get_optional(dsi->dev, "lpclk");
> +	if (IS_ERR(dsi->lpclk))
> +		return PTR_ERR(dsi->lpclk);
> +

This clock isn't used in this series, it will only be used when you will
submit the next version of "[PATCH v4 15/15] drm: renesas: rz-du:
mipi_dsi: Add support for RZ/V2H(P) SoC". As this patch doesn't bring
any used feature, I'm tempted to say it could be bundled with the
RZ/V2H(P) support patch.

>  	dsi->rstc = devm_reset_control_get_optional_exclusive(dsi->dev, "rst");
>  	if (IS_ERR(dsi->rstc))
>  		return dev_err_probe(dsi->dev, PTR_ERR(dsi->rstc),

-- 
Regards,

Laurent Pinchart