Messages in this thread | | | Subject | Re: [PATCH v3 5/6] dt-bindings: add the rockchip, dual-channel for dw-mipi-dsi | From | Archit Taneja <> | Date | Fri, 1 Dec 2017 18:29:04 +0530 |
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On 11/30/2017 11:02 PM, Nickey Yang wrote: > Hi Archit, > > > On 2017年10月26日 12:53, Archit Taneja wrote: >> >> >> On 10/25/2017 09:21 AM, Nickey Yang wrote: >>> Configure dsi slave channel when driving a panel >>> which needs 2 DSI links. >>> >>> Signed-off-by: Nickey Yang <nickey.yang@rock-chips.com> >>> --- >>> .../devicetree/bindings/display/rockchip/dw_mipi_dsi_rockchip.txt | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/display/rockchip/dw_mipi_dsi_rockchip.txt >>> b/Documentation/devicetree/bindings/display/rockchip/dw_mipi_dsi_rockchip.txt >>> index 6bb59ab..a2bea22 100644 >>> --- a/Documentation/devicetree/bindings/display/rockchip/dw_mipi_dsi_rockchip.txt >>> +++ b/Documentation/devicetree/bindings/display/rockchip/dw_mipi_dsi_rockchip.txt >>> @@ -19,6 +19,8 @@ Optional properties: >>> - power-domains: a phandle to mipi dsi power domain node. >>> - resets: list of phandle + reset specifier pairs, as described in [3]. >>> - reset-names: string reset name, must be "apb". >>> +- rockchip,dual-channel: phandle to a 2nd DSI channel, useful as a slave >>> +channel when driving a panel which needs 2 DSI links. >> The example below is how dual DSI bindings could look like. Let me know what >> you think of it. >> >> If both DSI outputs drive the same device (i.e, point to the same panel DT >> node), then I think it's reasonable enough to assume that the DSIs are >> operating in a 'dual-channel' mode. That being said, we still need DT to >> describe which of the DSIs generates the clock for both the channels. This >> is done with the 'clock-master' DT binding. >> >> Thanks, >> Archit >> >> mipi_dsi: mipi@ff960000 { >> ... >> ... >> >> clock-master; /* implies that this DSI instance drivers the clock >> * for both the DSIs. >> */ >> >> ports { >> mipi_in: port { >> ... >> ... >> }; >> >> /* add extra output ports for both DSIs */ >> mipi_out: port { >> mipi_panel_out: endpoint { >> remote-endpoint = <&panel_in_channel0>; >> }; >> }; >> }; >> >> panel { >> ... >> ... >> /* >> * panel node can describe its input ports, if both the DSIs output >> * ports are connected to the same device (i.e, the same DSI panel), >> * we can assume that the DSIs need to operate in dual DSI mode >> */ >> ports { >> ... >> port@0 { >> panel_in_channel0: endpoint { >> remote-endpoint = <&mipi_panel_out>; >> }; >> }; >> >> port@1 { >> panel_in_channel1: endpoint { >> remote-endpoint = <&mipi1_panel_out>; >> }; >> >> }; >> }; >> }; >> }; >> >> >> mipi_dsi1: mipi@ff968000 { >> ... >> ... >> >> ports { >> mipi1_in: port { >> ... >> ... >> }; >> >> mipi1_out: port { >> mipi1_panel_out: endpoint { >> remote-endpoint = <&panel_in_channel1>; >> }; >> }; >> }; >> }; >> > I try to follow as you suggested,use > > mipi_dsi: mipi@ff960000 { > ... > ... > clock-master; /* implies that this DSI instance drivers the clock > * for both the DSIs. > */ > ports { > mipi_in: port { > ... > ... > }; > /* add extra output ports for both DSIs */ > mipi_out: port { > mipi_panel_out: endpoint { > remote-endpoint = <&panel_in_channel0>; > }; > }; > }; > panel { > ... > ... > /* > * panel node can describe its input ports, if both the DSIs output > * ports are connected to the same device (i.e, the same DSI panel), > * we can assume that the DSIs need to operate in dual DSI mode > */ > ports { > ... > port@0 { > panel_in_channel0: endpoint { > remote-endpoint = <&mipi_panel_out>; > }; > }; > port@1 { > panel_in_channel1: endpoint { > remote-endpoint = <&mipi1_panel_out>; > }; > > }; > }; > }; > }; > > mipi_dsi1: mipi@ff968000 { > ... > ... > ports { > mipi1_in: port { > ... > ... > }; > mipi1_out: port { > mipi1_panel_out: endpoint { > remote-endpoint = <&panel_in_channel1>; > }; > }; > }; > } > > But it seems we can not use of_drm_find_panel(like below) > > /* > port = of_graph_get_port_by_id(dev->of_node, 1); > if (port) { > endpoint = of_get_child_by_name(port, "endpoint"); > of_node_put(port); > if (!endpoint) { > dev_err(dev, "no output endpoint found\n"); > return -EINVAL; > } > panel_node = of_graph_get_remote_port_parent(endpoint); > of_node_put(endpoint); > if (!panel_node) { > dev_err(dev, "no output node found\n"); > return -EINVAL; > } > panel = of_drm_find_panel(panel_node); > of_node_put(panel_node); > if (!panel) > return -EPROBE_DEFER; > } > */ > to get DSI1 outputs,because of_drm_find_panel need compare > > if (panel->dev->of_node == np) > > in dsi_panel driver innolux->base.dev = &innolux->link->dev; > dsi->dev
Yes, we should only have 1 drm_panel in the global panel list. Shouldn't it be possible to modify the dsi driver such that dsi1 doesn't care whether it has a drm_panel for it or not, if we are in dual dsi mode?
I imagine a sequence like this:
1. dsi0 probes, parses the of-graph, finds the panel and saves its device node.
2. dsi1 probes, parses the of-graph, find the panel's device node - dsi1 checks if it is the same as the panel attached to dsi0. - If so, it just takes the drm_panel pointer from dsi0. - If not, it tries a of_drm_find_panel() on the panel's device node.
A dual DSI panel driver would also be a bit different. It will be a mipi_dsi_driver with the master DSI (dsi0) as the mipi_dsi_device. Using the of-graph helpers, we would get the device node of dsi1 using of_find_mipi_dsi_host_by_node(), and create another DSI device using mipi_dsi_device_register_full(). Then, we call mipi_dsi_attach() on both the dsi devices.
> > struct innolux_panel { > struct drm_panel base; > struct mipi_dsi_device *link; > }; > It means one panel can only be found in his dsi node,(like dsi0 above). > > I'm doubting about it, Or may we follow tegra_dsi_ganged_probe > (drivers/gpu/drm/tergra/dsi.c) method.
This method will add a new binding similar to "nvidia,ganged-mode", which is something we don't want to do.
Archit
> > > Thanks, > Nickey > >>> [1] Documentation/devicetree/bindings/clock/clock-bindings.txt >>> [2] Documentation/devicetree/bindings/media/video-interfaces.txt >>> >> > >
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