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Date: Fri, 11 Aug 2017 10:44:35 -0400
From: Sean Paul <seanpaul@chromium.org>
To: Sandy Huang <sandy.huang@rock-chips.com>
Cc: Sean Paul <seanpaul@chromium.org>, Heiko Stuebner <heiko@sntech.de>,
        David Airlie <airlied@linux.ie>, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org, Sandy Huang <hjc@rock-chips.com>,
        linux-rockchip@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org,
        Mark Yao <mark.yao@rock-chips.com>
Subject: Re: [PATCH 3/3] drm/rockchip: Add support for Rockchip Soc LVDS
Message-ID: <20170811144435.mo6jk5mn2vsj3sz3@art_vandelay>
References: <1502272846-63941-1-git-send-email-hjc@rock-chips.com>
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On Fri, Aug 11, 2017 at 10:15:16AM +0800, Sandy Huang wrote:
> 
> 
> 在 2017/8/11 2:05, Sean Paul 写道:
> > On Thu, Aug 10, 2017 at 05:35:52PM +0800, Sandy Huang wrote:
> > > Hi Sean Paul,
> > >      Thanks for your review.
> > > 
> > > 在 2017/8/10 3:58, Sean Paul 写道:
> > > > On Wed, Aug 09, 2017 at 06:00:59PM +0800, Sandy Huang wrote:
> > > > > This adds support for Rockchip soc lvds found on rk3288
> > > > > Based on the patches from Mark yao and Heiko Stuebner
> > > > > 
> > > > > Signed-off-by: Sandy Huang <hjc@rock-chips.com>
> > > > > Signed-off-by: Mark yao <mark.yao@rock-chips.com>
> > > > > Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> > > > > ---
> > > > >    drivers/gpu/drm/rockchip/Kconfig         |   9 +
> > > > >    drivers/gpu/drm/rockchip/Makefile        |   1 +
> > > > >    drivers/gpu/drm/rockchip/rockchip_lvds.c | 734 +++++++++++++++++++++++++++++++
> > > > >    drivers/gpu/drm/rockchip/rockchip_lvds.h | 112 +++++
> > > > >    4 files changed, 856 insertions(+)
> > > > >    create mode 100644 drivers/gpu/drm/rockchip/rockchip_lvds.c
> > > > >    create mode 100644 drivers/gpu/drm/rockchip/rockchip_lvds.h
> > > > > 
> > 
> > <snip />
> > 
> > > > > diff --git a/drivers/gpu/drm/rockchip/rockchip_lvds.c b/drivers/gpu/drm/rockchip/rockchip_lvds.c
> > > > > new file mode 100644
> > > > > index 0000000..a4ad3f0
> > > > > --- /dev/null
> > > > > +++ b/drivers/gpu/drm/rockchip/rockchip_lvds.c
> > 
> > <snip />
> > 
> > > > > +	lvds->drm_dev = drm_dev;
> > > > > +	port = of_graph_get_port_by_id(dev->of_node, 1);
> > > > > +	if (!port) {
> > > > > +		dev_err(dev, "can't found port point, please init lvds panel port!\n");
> > > > > +		return -EINVAL;
> > > > > +	}
> > > > > +
> > > > > +	for_each_child_of_node(port, endpoint) {
> > > > > +		remote = of_graph_get_remote_port_parent(endpoint);
> > > > > +		if (!remote) {
> > > > > +			dev_err(dev, "can't found panel node, please init!\n");
> > > > > +			ret = -EINVAL;
> > > > > +			goto err_put_port;
> > > > > +		}
> > > > > +		if (!of_device_is_available(remote)) {
> > > > > +			of_node_put(remote);
> > > > > +			remote = NULL;
> > > > > +			continue;
> > > > > +		}
> > > > > +		break;
> > > > > +	}
> > > > > +	if (!remote) {
> > > > > +		dev_err(dev, "can't found remote node, please init!\n");
> > > > > +		ret = -EINVAL;
> > > > > +		goto err_put_port;
> > > > > +	}
> > > > > +
> > > > > +	lvds->panel = of_drm_find_panel(remote);
> > > > > +	if (!lvds->panel)
> > > > > +		lvds->bridge = of_drm_find_bridge(remote);
> > > > 
> > > > drm_of_find_panel_or_bridge()
> > > > 
> > > 
> > > because the lvds ports maybe connect to lvds-panel or connect to
> > > rk1000(which is convert RGB to CVBS output), so i have to get the remote
> > > port parent and check the status, and final get the active remote point.
> > > 
> > 
> > 
> > 
> > > lvds_panel: lvds-panel {
> > > 	status = "disabled";
> > > 	ports {
> > > 		panel_in_lvds: endpoint {
> > > 			remote-endpoint = <&lvds_out_panel>;
> > > 		};
> > > 	};
> > > };
> > > 
> > > rk1000: rk1000@0xff000000 {
> > > 	status = "okay";
> > > 	ports {
> > > 		rk1000_in_lvds: endpoint {
> > > 			remote-endpoint = <&lvds_out_panel>;
> > > 		};
> > > 	};
> > > };
> > > 
> > > &lvds {
> > > 	status = "okay";
> > > 	ports {
> > > 		lvds_out: port@1 {
> > > 			reg = <1>;
> > > 			lvds_out_panel: endpoint@0 {
> > > 				reg = <0>;
> > > 				remote-endpoint = <&panel_in_lvds>;
> > > 			};
> > > 			lvds_out_rk1000: endpoint@1 {
> > > 				reg = <1>;
> > > 				remote-endpoint = <&rk1000_in_lvds>;
> > > 			};
> > > 		};
> > > 
> > > 	};
> > > };
> > 
> > Hi Sandy,
> > Forgive me, this is probably a stupid question. I don't see how this usecase is
> > unique from the other users of drm_of_find_panel_or_bridge. Couldn't you change
> > your devicetree bindings to conform to something drm_of_find_panel_or_bridge()
> > can work with?
> > 
> > Thank you,
> > 
> Hi sean,
>     Maybe i can use the following method to use
> drm_of_find_panel_or_bridge() and no need to change my DT, but there is
> another question:
>     The LVDS output format(rockchip,output、rockchip,data-mapping etc.)
> depend on different panel, so it should be put under remote panel point.
> If use drm_of_find_panel_or_bridge（), this just return panel or bridge, so
> i have to back to get remote panel point and get the output format.

This should be easy since you can grab dev->of_node from panel or bridge once
it's found.

> 
> ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 0, &lvds->panel,
>                                   &lvds->bridge);
> if (ret)
>     ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 1, &lvds->panel,
>                                       &lvds->bridge);

Would be easier to read in a for loop.

Sean

> if (ret) {
>     DRM_DEV_ERROR(dev, "failed to find panel and bridge node\n");
>     ret  = -EPROBE_DEFER;
>     goto err_put_remote;
> }
> 	
> 

-- 
Sean Paul, Software Engineer, Google / Chromium OS