linux-kernel - Re: [PATCH v3 09/13] media: cadence: csi2rx: Use new enable stream APIs

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Message-ID: <20250421132549.GH29483@pendragon.ideasonboard.com>
Date: Mon, 21 Apr 2025 16:25:49 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Rishikesh Donadkar <r-donadkar@...com>
Cc: jai.luthra@...ux.dev, mripard@...nel.org, linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org, devicetree@...r.kernel.org,
	devarsht@...com, y-abhilashchandra@...com, mchehab@...nel.org,
	robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
	vaishnav.a@...com, s-jain1@...com, vigneshr@...com,
	sakari.ailus@...ux.intel.com, hverkuil-cisco@...all.nl,
	tomi.valkeinen@...asonboard.com, jai.luthra@...asonboard.com,
	changhuang.liang@...rfivetech.com, jack.zhu@...rfivetech.com
Subject: Re: [PATCH v3 09/13] media: cadence: csi2rx: Use new enable stream
 APIs

Hi Rishikesh,

Thank you for the patch.

On Thu, Apr 17, 2025 at 12:25:50PM +0530, Rishikesh Donadkar wrote:
> From: Jai Luthra <j-luthra@...com>
> 
> The enable_streams() API in v4l2 supports passing a bitmask to enable
> each pad/stream combination individually on any media subdev instead of
> doing s_stream(1) to start all streams on the subdev at once.
> 
> This API is implemented by ds90ub960 driver (FPDLink deser) and thus the
> caller (cdns-csi2x) is required to use it. For now we only enable
> stream0.
> 
> Signed-off-by: Jai Luthra <j-luthra@...com>
> Signed-off-by: Rishikesh Donadkar <r-donadkar@...com>
> ---
>  drivers/media/platform/cadence/cdns-csi2rx.c | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
> index b7e9225f66a41..df05d278df379 100644
> --- a/drivers/media/platform/cadence/cdns-csi2rx.c
> +++ b/drivers/media/platform/cadence/cdns-csi2rx.c
> @@ -224,10 +224,18 @@ static int csi2rx_configure_ext_dphy(struct csi2rx_priv *csi2rx)
>  static int csi2rx_start(struct csi2rx_priv *csi2rx)
>  {
>  	unsigned int i;
> +	struct media_pad *remote_pad;
>  	unsigned long lanes_used = 0;
>  	u32 reg;
>  	int ret;
>  
> +	remote_pad = media_pad_remote_pad_first(&csi2rx->pads[CSI2RX_PAD_SINK]);

Can't you use csi2rx->source_pad instead ?

> +	if (!remote_pad) {
> +		dev_err(csi2rx->dev,
> +			"Failed to find connected source\n");
> +		return -ENODEV;
> +	}
> +
>  	ret = clk_prepare_enable(csi2rx->p_clk);
>  	if (ret)
>  		return ret;
> @@ -311,7 +319,8 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
>  
>  	reset_control_deassert(csi2rx->sys_rst);
>  
> -	ret = v4l2_subdev_call(csi2rx->source_subdev, video, s_stream, true);
> +	ret = v4l2_subdev_enable_streams(csi2rx->source_subdev,
> +					 remote_pad->index, BIT(0));
>  	if (ret)
>  		goto err_disable_sysclk;
>  
> @@ -339,6 +348,7 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
>  
>  static void csi2rx_stop(struct csi2rx_priv *csi2rx)
>  {
> +	struct media_pad *remote_pad;
>  	unsigned int i;
>  	u32 val;
>  	int ret;
> @@ -367,8 +377,12 @@ static void csi2rx_stop(struct csi2rx_priv *csi2rx)
>  	reset_control_assert(csi2rx->p_rst);
>  	clk_disable_unprepare(csi2rx->p_clk);
>  
> -	if (v4l2_subdev_call(csi2rx->source_subdev, video, s_stream, false))
> +	remote_pad = media_pad_remote_pad_first(&csi2rx->pads[CSI2RX_PAD_SINK]);
> +	if (!remote_pad ||
> +	    v4l2_subdev_disable_streams(csi2rx->source_subdev,
> +					remote_pad->index, BIT(0))) {
>  		dev_warn(csi2rx->dev, "Couldn't disable our subdev\n");
> +	}
>  
>  	if (csi2rx->dphy) {
>  		writel(0, csi2rx->base + CSI2RX_DPHY_LANE_CTRL_REG);

-- 
Regards,

Laurent Pinchart