linux-kernel - Re: [PATCH v3 2/3] media: imx-mipi-csis: Store the number of data

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Message-ID: <aNDxd9rWjmgrVCd9@valkosipuli.retiisi.eu>
Date: Mon, 22 Sep 2025 09:49:27 +0300
From: Sakari Ailus <sakari.ailus@....fi>
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>, linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org, imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 2/3] media: imx-mipi-csis: Store the number of
 data_lanes configured in dt

Hi Isaac,

On Mon, Sep 15, 2025 at 02:18:34PM +0100, Isaac Scott wrote:
> The number of lanes actively used by a MIPI CSI transmitter may differ
> from that which is defined in device tree. To allow us to be able to set
> the number of configured lanes without changing the maximum lane count,
> store the number of lanes configured in device tree, and adjust the
> debug print to reflect the device tree value.
> 
> Signed-off-by: Isaac Scott <isaac.scott@...asonboard.com>
> ---
>  drivers/media/platform/nxp/imx-mipi-csis.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/media/platform/nxp/imx-mipi-csis.c b/drivers/media/platform/nxp/imx-mipi-csis.c
> index 2beb5f43c2c0..6afbedfe131e 100644
> --- a/drivers/media/platform/nxp/imx-mipi-csis.c
> +++ b/drivers/media/platform/nxp/imx-mipi-csis.c
> @@ -313,6 +313,8 @@ 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;
> @@ -535,7 +537,7 @@ 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;

Please use 1U or BIT() for bit-shifted values.

>  		val |= (mask & MIPI_CSIS_DPHY_CMN_CTRL_ENABLE);
>  	}
>  	mipi_csis_write(csis, MIPI_CSIS_DPHY_CMN_CTRL, val);
> @@ -586,7 +588,7 @@ 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(src_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);
> @@ -631,7 +633,7 @@ 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);
> @@ -1299,8 +1301,10 @@ static int mipi_csis_async_register(struct mipi_csis_device *csis)
>  	}
>  
>  	csis->bus = vep.bus.mipi_csi2;
> +	csis->bus.num_data_lanes = vep.bus.mipi_csi2.num_data_lanes;
> +	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, "data lanes: %d\n", csis->num_data_lanes);
>  	dev_dbg(csis->dev, "flags: 0x%08x\n", csis->bus.flags);
>  
>  	asd = v4l2_async_nf_add_fwnode_remote(&csis->notifier, ep,
> @@ -1498,7 +1502,7 @@ static int mipi_csis_probe(struct platform_device *pdev)
>  	}
>  
>  	dev_info(dev, "lanes: %d, freq: %u\n",
> -		 csis->bus.num_data_lanes, csis->clk_frequency);
> +		 csis->num_data_lanes, csis->clk_frequency);
>  
>  	return 0;
>  
> 

-- 
Regards,

Sakari Ailus