linux-kernel - Re: [PATCH 1/3] media: rzg2l-cru: Skip ICnMC configuration when ICnSVC is used

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Message-ID: <aYnnRWR-5xOPSHOh@zed>
Date: Mon, 9 Feb 2026 15:21:59 +0100
From: Jacopo Mondi <jacopo.mondi@...asonboard.com>
To: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
Cc: tomm.merciai@...il.com, linux-renesas-soc@...r.kernel.org, 
	biju.das.jz@...renesas.com, Mauro Carvalho Chehab <mchehab@...nel.org>, 
	Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>, Hans Verkuil <hverkuil@...nel.org>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>, Daniel Scally <dan.scally+renesas@...asonboard.com>, 
	Jacopo Mondi <jacopo.mondi@...asonboard.com>, linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, 
	stable@...r.kernel.org
Subject: Re: [PATCH 1/3] media: rzg2l-cru: Skip ICnMC configuration when
 ICnSVC is used

Hi Tommaso

On Tue, Dec 30, 2025 at 06:09:15PM +0100, Tommaso Merciai wrote:
> When the CRU is configured to use ICnSVC for virtual channel mapping,
> as on the RZ/{G3E, V2H/P} SoC, the ICnMC register must not be
> programmed.

I see a difference indeed between the [G3E, V2H/P] and the G2L version
of the IP in the presence of the VCSEL[1:0] field in register ICnMC.

On [G3E, V2H/P] the selection of which virtual channel to accept
doesn't go through VCSEL[1:0] in ICnMC but a dedicated register ICnSVC
is provided for that purpose. So far so good.

>
> Return early after setting up ICnSVC to avoid overriding the ICnMC
> register, which is not applicable in this mode.
>
> This prevents unintended register programming when ICnSVC is enabled.
>
> Fixes: 3c5ca0a48bb0 ("media: rzg2l-cru: Drop function pointer to configure CSI")
> Cc: stable@...r.kernel.org
> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
> ---
>  drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> index 162e2ace6931..480e9b5dbcfe 100644
> --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> @@ -268,6 +268,8 @@ static void rzg2l_cru_csi2_setup(struct rzg2l_cru_dev *cru,
>  		rzg2l_cru_write(cru, ICnSVCNUM, csi_vc);
>  		rzg2l_cru_write(cru, ICnSVC, ICnSVC_SVC0(0) | ICnSVC_SVC1(1) |
>  				ICnSVC_SVC2(2) | ICnSVC_SVC3(3));
> +
> +		return;
>  	}
>
>  	icnmc |= rzg2l_cru_read(cru, info->image_conv) & ~ICnMC_INF_MASK;

However, the rest of the rzg2l_cru_csi2_setup() doesn't only program
the virtual channel filtering through ICnMC (which should be skept for
G3E, V2H/P) but also programs DT filtering in INF[5:0] of register
ICnIPMC_C0 which seems to be available on G3E and V2H/P as well.

Section "9.2.4.3.6 VC/Data Type Selector (for Image Processing)" of
the chip manual (V2H/P) prescribes:

Only one data type can be handled by each SVC and the data types are
selected in the ICnIPMC_C0 to 3.INF[5:0] registers.

And this patch makes the driver skips that part.
Has this patch been tested ? It breaks my V2H/P setup:

 rzg2l-cru 16010000.cru1: Invalid MB address 0x0 (out of range)


> --
> 2.43.0
>
>