Re: [PATCH v2 3/6] media: adv748x: csi2: Link AFE with TXA and TXB

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Jacopo Mondi <jacopo+renesas@jmondi.org>
Cc: niklas.soderlund+renesas@ragnatech.se,
	kieran.bingham@ideasonboard.com, linux-media@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH v2 3/6] media: adv748x: csi2: Link AFE with TXA and TXB
Date: Wed, 09 Jan 2019 02:11:47 +0200	[thread overview]
Message-ID: <2046845.fJaF8tx5Pb@avalon> (raw)
In-Reply-To: <20190106155413.30666-4-jacopo+renesas@jmondi.org>

Hi Jacopo,

Thank you for the patch.

On Sunday, 6 January 2019 17:54:10 EET Jacopo Mondi wrote:
> The ADV748x chip supports routing AFE output to either TXA or TXB.
> In order to support run-time configuration of video stream path, create an
> additional (not enabled) "AFE:8->TXA:0" link, and remove the IMMUTABLE flag
> from existing ones.
> 
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
>  drivers/media/i2c/adv748x/adv748x-csi2.c | 44 +++++++++++++-----------
>  1 file changed, 23 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/media/i2c/adv748x/adv748x-csi2.c
> b/drivers/media/i2c/adv748x/adv748x-csi2.c index b6b5d8c7ea7c..9d391d6f752e
> 100644
> --- a/drivers/media/i2c/adv748x/adv748x-csi2.c
> +++ b/drivers/media/i2c/adv748x/adv748x-csi2.c
> @@ -27,6 +27,7 @@ static int adv748x_csi2_set_virtual_channel(struct
> adv748x_csi2 *tx, * @v4l2_dev: Video registration device
>   * @src: Source subdevice to establish link
>   * @src_pad: Pad number of source to link to this @tx
> + * @enable: Link enabled flag
>   *
>   * Ensure that the subdevice is registered against the v4l2_device, and
> link the * source pad to the sink pad of the CSI2 bus entity.
> @@ -34,17 +35,11 @@ static int adv748x_csi2_set_virtual_channel(struct
> adv748x_csi2 *tx, static int adv748x_csi2_register_link(struct adv748x_csi2
> *tx,
>  				      struct v4l2_device *v4l2_dev,
>  				      struct v4l2_subdev *src,
> -				      unsigned int src_pad)
> +				      unsigned int src_pad,
> +				      bool enable)
>  {
> -	int enabled = MEDIA_LNK_FL_ENABLED;
>  	int ret;
> 
> -	/*
> -	 * Dynamic linking of the AFE is not supported.
> -	 * Register the links as immutable.
> -	 */
> -	enabled |= MEDIA_LNK_FL_IMMUTABLE;
> -
>  	if (!src->v4l2_dev) {
>  		ret = v4l2_device_register_subdev(v4l2_dev, src);
>  		if (ret)
> @@ -53,7 +48,7 @@ static int adv748x_csi2_register_link(struct adv748x_csi2
> *tx,
> 
>  	return media_create_pad_link(&src->entity, src_pad,
>  				     &tx->sd.entity, ADV748X_CSI2_SINK,
> -				     enabled);
> +				     enable ? MEDIA_LNK_FL_ENABLED : 0);
>  }
> 
>  /* ------------------------------------------------------------------------
> @@ -68,25 +63,32 @@ static int adv748x_csi2_registered(struct v4l2_subdev
> *sd) {
>  	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
>  	struct adv748x_state *state = tx->state;
> +	int ret;
> 
>  	adv_dbg(state, "Registered %s (%s)", is_txa(tx) ? "TXA":"TXB",
>  			sd->name);
> 
>  	/*
> -	 * The adv748x hardware allows the AFE to route through the TXA, however
> -	 * this is not currently supported in this driver.
> +	 * Link TXA to AFE and HDMI, and TXB to AFE only as TXB cannot output
> +	 * HDMI.
>  	 *
> -	 * Link HDMI->TXA, and AFE->TXB directly.
> +	 * The HDMI->TXA link is enabled by default, as the AFE->TXB is.
>  	 */
> -	if (is_txa(tx) && is_hdmi_enabled(state))
> -		return adv748x_csi2_register_link(tx, sd->v4l2_dev,
> -						  &state->hdmi.sd,
> -						  ADV748X_HDMI_SOURCE);
> -	if (is_txb(tx) && is_afe_enabled(state))
> -		return adv748x_csi2_register_link(tx, sd->v4l2_dev,
> -						  &state->afe.sd,
> -						  ADV748X_AFE_SOURCE);
> -	return 0;
> +	if (is_afe_enabled(state)) {
> +		ret = adv748x_csi2_register_link(tx, sd->v4l2_dev,
> +						 &state->afe.sd,
> +						 ADV748X_AFE_SOURCE,
> +						 is_txb(tx));
> +		if (ret)
> +			return ret;
> +	}
> +
> +	/* Register link to HDMI for TXA only. */

I would have written "Create link", but then realized that the function is 
named adv748x_csi2_register_link(). Looking at its definition, I now see this 
means "register and link". That seems a bit of a hack, especially seeing how 
double registration is skipped in the function by checking src->v4l2_dev. 
Kieran, could this be fixed ?

> +	if (is_txb(tx) || !is_hdmi_enabled(state))
> +		return 0;
> +
> +	return adv748x_csi2_register_link(tx, sd->v4l2_dev, &state->hdmi.sd,
> +					  ADV748X_HDMI_SOURCE, true);
>  }
> 
>  static const struct v4l2_subdev_internal_ops adv748x_csi2_internal_ops = {

-- 
Regards,

Laurent Pinchart