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Message-ID: <1548089410.3287.16.camel@pengutronix.de>
Subject: Re: [PATCH 1/4] media: imx: csi: Allow unknown nearest upstream
 entities
From:   Philipp Zabel <p.zabel@pengutronix.de>
To:     Steve Longerbeam <slongerbeam@gmail.com>,
        linux-media@vger.kernel.org
Cc:     stable@vger.kernel.org, Mauro Carvalho Chehab <mchehab@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "open list:STAGING SUBSYSTEM" <devel@driverdev.osuosl.org>,
        open list <linux-kernel@vger.kernel.org>
Date:   Mon, 21 Jan 2019 17:50:10 +0100
In-Reply-To: <20190119214600.30897-2-slongerbeam@gmail.com>
References: <20190119214600.30897-1-slongerbeam@gmail.com>
         <20190119214600.30897-2-slongerbeam@gmail.com>
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On Sat, 2019-01-19 at 13:45 -0800, Steve Longerbeam wrote:
> On i.MX6, the nearest upstream entity to the CSI can only be the
> CSI video muxes or the Synopsys DW MIPI CSI-2 receiver.
> 
> However the i.MX53 has no CSI video muxes or a MIPI CSI-2 receiver.
> So allow for the nearest upstream entity to the CSI to be something
> other than those.
> 
> Fixes: bf3cfaa712e5c ("media: staging/imx: get CSI bus type from nearest
> upstream entity")
> 
> Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/staging/media/imx/imx-media-csi.c | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
> index 555aa45e02e3..b9af7d3d4974 100644
> --- a/drivers/staging/media/imx/imx-media-csi.c
> +++ b/drivers/staging/media/imx/imx-media-csi.c
> @@ -154,9 +154,10 @@ static inline bool requires_passthrough(struct v4l2_fwnode_endpoint *ep,
>  /*
>   * Parses the fwnode endpoint from the source pad of the entity
>   * connected to this CSI. This will either be the entity directly
> - * upstream from the CSI-2 receiver, or directly upstream from the
> - * video mux. The endpoint is needed to determine the bus type and
> - * bus config coming into the CSI.
> + * upstream from the CSI-2 receiver, directly upstream from the
> + * video mux, or directly upstream from the CSI itself. The endpoint
> + * is needed to determine the bus type and bus config coming into
> + * the CSI.
>   */
>  static int csi_get_upstream_endpoint(struct csi_priv *priv,
>  				     struct v4l2_fwnode_endpoint *ep)
> @@ -172,7 +173,8 @@ static int csi_get_upstream_endpoint(struct csi_priv *priv,
>  	if (!priv->src_sd)
>  		return -EPIPE;
>  
> -	src = &priv->src_sd->entity;
> +	sd = priv->src_sd;
> +	src = &sd->entity;
>  
>  	if (src->function == MEDIA_ENT_F_VID_MUX) {
>  		/*
> @@ -186,6 +188,14 @@ static int csi_get_upstream_endpoint(struct csi_priv *priv,
>  			src = &sd->entity;
>  	}
>  
> +	/*
> +	 * If the source is neither the video mux nor the CSI-2 receiver,
> +	 * get the source pad directly upstream from CSI itself.
> +	 */
> +	if (src->function != MEDIA_ENT_F_VID_MUX &&

Will it work correctly if there's an external MUX connected to the CSI?

> +	    sd->grp_id != IMX_MEDIA_GRP_ID_CSI2)
> +		src = &priv->sd.entity;
> +
>  	/* get source pad of entity directly upstream from src */
>  	pad = imx_media_find_upstream_pad(priv->md, src, 0);
>  	if (IS_ERR(pad))

regards
Philipp