linux-kernel - Re: [PATCH v4 3/4] media: imx-mipi-csis: Store the number of data

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Message-ID: <aNW4zDRAREUZ7v8k@lizhi-Precision-Tower-5810>
Date: Thu, 25 Sep 2025 17:49:00 -0400
From: Frank Li <Frank.li@....com>
To: Isaac Scott <isaac.scott@...asonboard.com>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
	Rui Miguel Silva <rmfrfs@...il.com>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Martin Kepplinger <martink@...teo.de>,
	Purism Kernel Team <kernel@...i.sm>,
	Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>,
	Sakari Ailus <sakari.ailus@...ux.intel.com>,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
	imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 3/4] media: imx-mipi-csis: Store the number of
 data_lanes configured in dt

On Thu, Sep 25, 2025 at 04:54:28PM +0100, Isaac Scott wrote:
> The number of active data lanes in use on a MIPI CSI2 bus is not
> necessarily always the maximum. To allow us to configure the number of
> data lanes actively in use, store the maximum to ensure we can configure
> a number of data lanes that is supported.
>

This patch just add num_data_lanes, and use csis->num_data_lanes instead
of bus.num_data_lanes.

So commit message not reflect what you did

"
media: imx-mipi-csis: Add num_data_lanes in mipi_csis_device

Add num_data_lanes field in mipi_csis_device, set equal to
csis->bus.num_data_lanes. Prepare to support cases where the number of
active data lanes differs from the maximum supported lanes.

No functional changes.
"

Frank

> Signed-off-by: Isaac Scott <isaac.scott@...asonboard.com>
> ---
>  drivers/media/platform/nxp/imx-mipi-csis.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/platform/nxp/imx-mipi-csis.c b/drivers/media/platform/nxp/imx-mipi-csis.c
> index 7c2a679dca2e..838a1ad123b5 100644
> --- a/drivers/media/platform/nxp/imx-mipi-csis.c
> +++ b/drivers/media/platform/nxp/imx-mipi-csis.c
> @@ -351,6 +351,8 @@ struct mipi_csis_device {
>  	u32 hs_settle;
>  	u32 clk_settle;
>
> +	unsigned int num_data_lanes;
> +
>  	spinlock_t slock;	/* Protect events */
>  	struct mipi_csis_event events[MIPI_CSIS_NUM_EVENTS];
>  	struct dentry *debugfs_root;
> @@ -573,7 +575,7 @@ static void mipi_csis_system_enable(struct mipi_csis_device *csis, int on)
>  	val = mipi_csis_read(csis, MIPI_CSIS_DPHY_CMN_CTRL);
>  	val &= ~MIPI_CSIS_DPHY_CMN_CTRL_ENABLE;
>  	if (on) {
> -		mask = (1 << (csis->bus.num_data_lanes + 1)) - 1;
> +		mask = (1 << (csis->num_data_lanes + 1)) - 1;
>  		val |= (mask & MIPI_CSIS_DPHY_CMN_CTRL_ENABLE);
>  	}
>  	mipi_csis_write(csis, MIPI_CSIS_DPHY_CMN_CTRL, val);
> @@ -623,7 +625,7 @@ static int mipi_csis_calculate_params(struct mipi_csis_device *csis,
>
>  	/* Calculate the line rate from the pixel rate. */
>  	link_freq = v4l2_get_link_freq(csis->source.pad, csis_fmt->width,
> -				       csis->bus.num_data_lanes * 2);
> +				       csis->num_data_lanes * 2);
>  	if (link_freq < 0) {
>  		dev_err(csis->dev, "Unable to obtain link frequency: %d\n",
>  			(int)link_freq);
> @@ -668,7 +670,7 @@ static void mipi_csis_set_params(struct mipi_csis_device *csis,
>  				 const struct v4l2_mbus_framefmt *format,
>  				 const struct csis_pix_format *csis_fmt)
>  {
> -	int lanes = csis->bus.num_data_lanes;
> +	int lanes = csis->num_data_lanes;
>  	u32 val;
>
>  	val = mipi_csis_read(csis, MIPI_CSIS_CMN_CTRL);
> @@ -1366,8 +1368,9 @@ static int mipi_csis_async_register(struct mipi_csis_device *csis)
>  	}
>
>  	csis->bus = vep.bus.mipi_csi2;
> +	csis->num_data_lanes = csis->bus.num_data_lanes;
>
> -	dev_dbg(csis->dev, "data lanes: %d\n", csis->bus.num_data_lanes);
> +	dev_dbg(csis->dev, "max data lanes: %d\n", csis->bus.num_data_lanes);
>  	dev_dbg(csis->dev, "flags: 0x%08x\n", csis->bus.flags);
>
>  	asd = v4l2_async_nf_add_fwnode_remote(&csis->notifier, ep,
>
> --
> 2.43.0
>