linux-kernel - Re: [PATCH v2 09/18] media: rzg2l-cru: csi2: Make system clock optional for RZ/V2H(P) SoC

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Message-ID: <20250223181955.GD8330@pendragon.ideasonboard.com>
Date: Sun, 23 Feb 2025 20:19:55 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
Cc: tomm.merciai@...il.com, linux-renesas-soc@...r.kernel.org,
	linux-media@...r.kernel.org, biju.das.jz@...renesas.com,
	prabhakar.mahadev-lad.rj@...renesas.com,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Magnus Damm <magnus.damm@...il.com>,
	Hans Verkuil <hverkuil@...all.nl>,
	Uwe Kleine-König <u.kleine-koenig@...libre.com>,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 09/18] media: rzg2l-cru: csi2: Make system clock
 optional for RZ/V2H(P) SoC

Hi Tommaso,

Thank you for the patch.

On Fri, Feb 21, 2025 at 04:55:23PM +0100, Tommaso Merciai wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> 
> The RZ/V2H(P) SoC does not provide a `system` clock for the CSI-2
> interface. To accommodate this, use `devm_clk_get_optional()` instead
> of `devm_clk_get()` when retrieving the clock.

The clock shouldn't be optional. On all SoCs but V2H it should remain
mandatory, and on V2H you shouldn't call clk_get() at all.

I'd recommend adding a flag to the rzg2l_csi2_info structure.

> This patch is in preparation for adding support for RZ/V2H(P) SoC.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
> ---
>  drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c
> index 3a4e720ba732..771fa35558be 100644
> --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c
> +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c
> @@ -796,7 +796,7 @@ static int rzg2l_csi2_probe(struct platform_device *pdev)
>  		return dev_err_probe(dev, PTR_ERR(csi2->presetn),
>  				     "Failed to get cpg presetn\n");
>  
> -	csi2->sysclk = devm_clk_get(dev, "system");
> +	csi2->sysclk = devm_clk_get_optional(dev, "system");
>  	if (IS_ERR(csi2->sysclk))
>  		return dev_err_probe(dev, PTR_ERR(csi2->sysclk),
>  				     "Failed to get system clk\n");

-- 
Regards,

Laurent Pinchart