linux-kernel - Re: [PATCH 2/3] media: nxp: imx8-isi: Keep the default value for BLANK

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Message-ID: <aPuCHltyz9Ed7wcF@lizhi-Precision-Tower-5810>
Date: Fri, 24 Oct 2025 09:41:50 -0400
From: Frank Li <Frank.li@....com>
To: Guoniu Zhou <guoniu.zhou@....nxp.com>
Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>, linux-media@...r.kernel.org,
	devicetree@...r.kernel.org, imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Guoniu Zhou <guoniu.zhou@....com>
Subject: Re: [PATCH 2/3] media: nxp: imx8-isi: Keep the default value for
 BLANK_PXL field

On Fri, Oct 24, 2025 at 05:46:53PM +0800, Guoniu Zhou wrote:
> From: Guoniu Zhou <guoniu.zhou@....com>
>
> The field provides the value of the blank pixel to be inserted in the

The field BLANK_PXL provides

> image in case an overflow error occurs in the output buffers of the
> channel. Its default value is 0xff, so no need to set again.
>
> Besides, the field only exist in i.MX8QM/XP ISI version. Other versions
> like mscale series, remove the field since it won't send data to AXI bus
> when overflow error occurs and set the field as reserved. i.MX9 series

mark BLANK_PXL as reserved. i.MX9 series use it for other purposes.

Reviewed-by: Frank Li <Frank.Li@....com>

> use the field as other purposes.
>
> Signed-off-by: Guoniu Zhou <guoniu.zhou@....com>
> ---
>  drivers/media/platform/nxp/imx8-isi/imx8-isi-hw.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-hw.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-hw.c
> index 9225a7ac1c3ee7e42e64983982eb4b6c27e356fe..0187d4ab97e8e28fca9013f6864a094e08f2c570 100644
> --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-hw.c
> +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-hw.c
> @@ -309,8 +309,8 @@ static void mxc_isi_channel_set_control(struct mxc_isi_pipe *pipe,
>
>  	val = mxc_isi_read(pipe, CHNL_CTRL);
>  	val &= ~(CHNL_CTRL_CHNL_BYPASS | CHNL_CTRL_CHAIN_BUF_MASK |
> -		 CHNL_CTRL_BLANK_PXL_MASK | CHNL_CTRL_SRC_TYPE_MASK |
> -		 CHNL_CTRL_MIPI_VC_ID_MASK | CHNL_CTRL_SRC_INPUT_MASK);
> +		 CHNL_CTRL_SRC_TYPE_MASK | CHNL_CTRL_MIPI_VC_ID_MASK |
> +		 CHNL_CTRL_SRC_INPUT_MASK);
>
>  	/*
>  	 * If no scaling or color space conversion is needed, bypass the
> @@ -323,8 +323,6 @@ static void mxc_isi_channel_set_control(struct mxc_isi_pipe *pipe,
>  	if (pipe->chained)
>  		val |= CHNL_CTRL_CHAIN_BUF(CHNL_CTRL_CHAIN_BUF_2_CHAIN);
>
> -	val |= CHNL_CTRL_BLANK_PXL(0xff);
> -
>  	/* Input source (including VC configuration for CSI-2) */
>  	if (input == MXC_ISI_INPUT_MEM) {
>  		/*
>
> --
> 2.34.1
>