linux-kernel - Re: [PATCH v5 2/6] drm: rcar-du: lvds: Improve identification of panels

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Message-ID: <20191216212645.GG4856@pendragon.ideasonboard.com>
Date:   Mon, 16 Dec 2019 23:26:45 +0200
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Fabrizio Castro <fabrizio.castro@...renesas.com>
Cc:     Geert Uytterhoeven <geert+renesas@...der.be>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Thierry Reding <thierry.reding@...il.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Sean Paul <sean@...rly.run>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Simon Horman <horms@...ge.net.au>,
        Magnus Damm <magnus.damm@...il.com>,
        Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
        dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        Chris Paterson <Chris.Paterson2@...esas.com>,
        Biju Das <biju.das@...renesas.com>,
        Jacopo Mondi <jacopo+renesas@...ndi.org>,
        ebiharaml@...linux.co.jp
Subject: Re: [PATCH v5 2/6] drm: rcar-du: lvds: Improve identification of
 panels

Hi Fabrizio,

Thank you for the patch.

On Mon, Dec 16, 2019 at 08:12:30PM +0000, Fabrizio Castro wrote:
> Dual-LVDS panels are mistakenly identified as bridges, this
> commit replaces the current logic with a call to
> drm_of_find_panel_or_bridge to sort that out.
> 
> Signed-off-by: Fabrizio Castro <fabrizio.castro@...renesas.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

> ---
> v4->v5:
> * Addressed comments from Laurent's review
> 
> v3->v4:
> * New patch extracted from patch:
>   "drm: rcar-du: lvds: Add dual-LVDS panels support"
> ---
>  drivers/gpu/drm/rcar-du/rcar_lvds.c | 75 +++++--------------------------------
>  1 file changed, 10 insertions(+), 65 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> index b03b7cd..4d038bd 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> @@ -21,6 +21,7 @@
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_bridge.h>
> +#include <drm/drm_of.h>
>  #include <drm/drm_panel.h>
>  #include <drm/drm_probe_helper.h>
>  
> @@ -716,79 +717,23 @@ static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
>  
>  static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
>  {
> -	struct device_node *local_output = NULL;
> -	struct device_node *remote_input = NULL;
> -	struct device_node *remote = NULL;
> -	struct device_node *node;
> -	bool is_bridge = false;
> -	int ret = 0;
> -
> -	local_output = of_graph_get_endpoint_by_regs(lvds->dev->of_node, 1, 0);
> -	if (!local_output) {
> -		dev_dbg(lvds->dev, "unconnected port@1\n");
> -		ret = -ENODEV;
> -		goto done;
> -	}
> -
> -	/*
> -	 * Locate the connected entity and infer its type from the number of
> -	 * endpoints.
> -	 */
> -	remote = of_graph_get_remote_port_parent(local_output);
> -	if (!remote) {
> -		dev_dbg(lvds->dev, "unconnected endpoint %pOF\n", local_output);
> -		ret = -ENODEV;
> -		goto done;
> -	}
> +	int ret;
>  
> -	if (!of_device_is_available(remote)) {
> -		dev_dbg(lvds->dev, "connected entity %pOF is disabled\n",
> -			remote);
> -		ret = -ENODEV;
> +	ret = drm_of_find_panel_or_bridge(lvds->dev->of_node, 1, 0,
> +					  &lvds->panel, &lvds->next_bridge);
> +	if (ret)
>  		goto done;
> -	}
>  
> -	remote_input = of_graph_get_remote_endpoint(local_output);
> -
> -	for_each_endpoint_of_node(remote, node) {
> -		if (node != remote_input) {
> -			/*
> -			 * We've found one endpoint other than the input, this
> -			 * must be a bridge.
> -			 */
> -			is_bridge = true;
> -			of_node_put(node);
> -			break;
> -		}
> -	}
> -
> -	if (is_bridge) {
> -		lvds->next_bridge = of_drm_find_bridge(remote);
> -		if (!lvds->next_bridge) {
> -			ret = -EPROBE_DEFER;
> -			goto done;
> -		}
> -
> -		if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
> -			lvds->dual_link = lvds->next_bridge->timings
> -					? lvds->next_bridge->timings->dual_link
> -					: false;
> -	} else {
> -		lvds->panel = of_drm_find_panel(remote);
> -		if (IS_ERR(lvds->panel)) {
> -			ret = PTR_ERR(lvds->panel);
> -			goto done;
> -		}
> -	}
> +	if ((lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) &&
> +	    lvds->next_bridge)
> +		lvds->dual_link = lvds->next_bridge->timings
> +				? lvds->next_bridge->timings->dual_link
> +				: false;
>  
>  	if (lvds->dual_link)
>  		ret = rcar_lvds_parse_dt_companion(lvds);
>  
>  done:
> -	of_node_put(local_output);
> -	of_node_put(remote_input);
> -	of_node_put(remote);
> -
>  	/*
>  	 * On D3/E3 the LVDS encoder provides a clock to the DU, which can be
>  	 * used for the DPAD output even when the LVDS output is not connected.

-- 
Regards,

Laurent Pinchart