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Subject: Re: [PATCH v2 10/18] media: cadence: csi2rx: Populate subdev devnode
To:     Pratyush Yadav <p.yadav@ti.com>,
        Maxime Ripard <mripard@kernel.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Vinod Koul <vkoul@kernel.org>,
        Peter Ujfalusi <peter.ujfalusi@gmail.com>,
        Steve Longerbeam <slongerbeam@gmail.com>,
        Benoit Parrot <bparrot@ti.com>, linux-media@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-phy@lists.infradead.org, dmaengine@vger.kernel.org
Cc:     Vignesh Raghavendra <vigneshr@ti.com>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>
References: <20210526152308.16525-1-p.yadav@ti.com>
 <20210526152308.16525-11-p.yadav@ti.com>
From:   Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Message-ID: <9c38a72c-18e8-1e54-b3b4-85ff5d47857a@ideasonboard.com>
Date:   Fri, 28 May 2021 10:16:58 +0300
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On 26/05/2021 18:23, Pratyush Yadav wrote:
> The devnode can be used by media-ctl and other userspace tools to
> perform configurations on the subdev. Without it, media-ctl returns
> ENOENT when setting format on the sensor subdev.
> 
> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> ---
> 
> (no changes since v1)
> 
>   drivers/media/platform/cadence/cdns-csi2rx.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
> index 1df21f462f3c..49bed63d5faa 100644
> --- a/drivers/media/platform/cadence/cdns-csi2rx.c
> +++ b/drivers/media/platform/cadence/cdns-csi2rx.c
> @@ -613,6 +613,7 @@ static int csi2rx_probe(struct platform_device *pdev)
>   	csi2rx->pads[CSI2RX_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
>   	for (i = CSI2RX_PAD_SOURCE_STREAM0; i < CSI2RX_PAD_MAX; i++)
>   		csi2rx->pads[i].flags = MEDIA_PAD_FL_SOURCE;
> +	csi2rx->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>   
>   	ret = media_entity_pads_init(&csi2rx->subdev.entity, CSI2RX_PAD_MAX,
>   				     csi2rx->pads);
> 

I don't understand this one. There's nothing to configure in cdns-csi2rx 
from userspace, as far as I can see, so why is the dev node needed? And 
why would the lack of csi2rx dev node cause sensor subdev config to fail?

  Tomi