Thread (21 messages) 21 messages, 5 authors, 2018-01-29

[linux-sunxi] Re: [PATCH v3 06/12] dt-bindings: display: sun4i-drm: Add A83T HDMI pipeline

From: icenowy@aosc.io (Icenowy Zheng)
Date: 2018-01-29 18:09:35
Also in: dri-devel, linux-clk, linux-devicetree, lkml


? 2018?1?30? GMT+08:00 ??2:05:26, Rob Herring [off-list ref] ??:
On Wed, Jan 17, 2018 at 09:14:15PM +0100, Jernej Skrabec wrote:
quoted
This commit adds all necessary compatibles and descriptions needed to
implement A83T HDMI pipeline.

Mixer is already properly described, so only compatible is added.

However, A83T TV TCON, which is connected to HDMI, doesn't have
channel 0,
quoted
contrary to all TCONs currently described. Because of that, TCON
documentation is extended.

A83T features Synopsys DW HDMI controller with a custom PHY which
looks
quoted
like Synopsys Gen2 PHY with few additions. Since there is no
documentation, needed properties were found out through
experimentation
quoted
and reading BSP code.

At the end, example is added for newer SoCs, which feature DE2 and DW
HDMI.

Signed-off-by: Jernej Skrabec <redacted>
---
 .../bindings/display/sunxi/sun4i-drm.txt           | 197
++++++++++++++++++++-
quoted
 1 file changed, 190 insertions(+), 7 deletions(-)

diff --git
a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
quoted
index cd626ee1147a..4fb380f3e53d 100644
--- a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
+++ b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
@@ -64,6 +64,52 @@ Required properties:
     first port should be the input endpoint. The second should be
the
quoted
     output, usually to an HDMI connector.
 
+DWC HDMI TX Encoder
+-------------------
+
+The HDMI transmitter is a Synopsys DesignWare HDMI 1.4 TX controller
IP
quoted
+with Allwinner's own PHY IP. It supports audio and video outputs and
CEC.
quoted
+
+These DT bindings follow the Synopsys DWC HDMI TX bindings defined
in
quoted
+Documentation/devicetree/bindings/display/bridge/dw_hdmi.txt with
the
quoted
+following device-specific properties.
+
+Required properties:
+
+  - compatible: value must be one of:
+    * "allwinner,sun8i-a83t-dw-hdmi"
+  - reg: base address and size of memory-mapped region
+  - reg-io-width: See dw_hdmi.txt. Shall be 1.
+  - interrupts: HDMI interrupt number
+  - clocks: phandles to the clocks feeding the HDMI encoder
+    * iahb: the HDMI bus clock
+    * isfr: the HDMI register clock
+  - clock-names: the clock names mentioned above
+  - resets: phandle to the reset controller
+  - reset-names: must be "ctrl"
+  - phys: phandle to the DWC HDMI PHY
+  - phy-names: must be "phy"
+
+  - ports: A ports node with endpoint definitions as defined in
+    Documentation/devicetree/bindings/media/video-interfaces.txt.
The
quoted
+    first port should be the input endpoint. The second should be
the
quoted
+    output, usually to an HDMI connector.
+
+DWC HDMI PHY
+------------
+
+Required properties:
+  - compatible: value must be one of:
+    * allwinner,sun8i-a83t-hdmi-phy
+  - reg: base address and size of memory-mapped region
+  - clocks: phandles to the clocks feeding the HDMI PHY
+    * bus: the HDMI PHY interface clock
+    * mod: the HDMI PHY module clock
+    * tmds: TMDS clock
+  - clock-names: the clock names mentioned above
+  - resets: phandle to the reset controller driving the PHY
+  - reset-names: must be "phy"
+
 TV Encoder
 ----------
 
@@ -94,24 +140,23 @@ Required properties:
    * allwinner,sun7i-a20-tcon
    * allwinner,sun8i-a33-tcon
    * allwinner,sun8i-a83t-tcon-lcd
+   * allwinner,sun8i-a83t-tcon-tv
    * allwinner,sun8i-v3s-tcon
  - reg: base address and size of memory-mapped region
  - interrupts: interrupt associated to this IP
- - clocks: phandles to the clocks feeding the TCON. Three are
needed:
quoted
+ - clocks: phandles to the clocks feeding the TCON. One is needed:
    - 'ahb': the interface clocks
-   - 'tcon-ch0': The clock driving the TCON channel 0
Well, it didn't look right before saying 3 are needed, but listing 2. 
However, you can't just change this as it affects all the other SoCs. 
This should probably be a separate patch.
quoted
  - resets: phandles to the reset controllers driving the encoder
    - "lcd": the reset line for the TCON channel 0
 
  - clock-names: the clock names mentioned above
  - reset-names: the reset names mentioned above
- - clock-output-names: Name of the pixel clock created
Why is this removed?
quoted
 
 - ports: A ports node with endpoint definitions as defined in
   Documentation/devicetree/bindings/media/video-interfaces.txt. The
   first port should be the input endpoint, the second one the output
 
-  The output may have multiple endpoints. The TCON has two channels,
+  The output may have multiple endpoints. TCON can have two
channels,

Perhaps you should say "can have 1 or 2 channels".
quoted
   usually with the first channel being used for the panels
interfaces
quoted
   (RGB, LVDS, etc.), and the second being used for the outputs that
   require another controller (TV Encoder, HDMI, etc.). The endpoints
@@ -119,11 +164,16 @@ Required properties:
   channel the endpoint is associated to. If that property is not
   present, the endpoint number will be used as the channel number.
 
+When TCON supports channel 0 (all TCONs except TV TCON on A83T), two
+more clocks are needed:
+   - 'tcon-ch0': The clock driving the TCON channel 0
Looks like one clock to me.
He should mean one input and one output.
quoted
+   - clock-output-names: Name of the pixel clock created
It's better to not move this, but just add what compatibles it does or 
doesn't apply to.
The existence of pclk out is tied with ch0 input, as ch0 input
is the parent of pclk output.
quoted
+
 On SoCs other than the A33 and V3s, there is one more clock
required:
quoted
    - 'tcon-ch1': The clock driving the TCON channel 1
 
-On SoCs that support LVDS (all SoCs but the A13, H3, H5 and V3s),
you
quoted
-need one more reset line:
+When TCON support LVDS (all TCONs except TV TCON on A83T and those
found
quoted
+in A13, H3, H5 and V3s SoCs), you need one more reset line:
    - 'lvds': The reset line driving the LVDS logic
 
 And on the A23, A31, A31s and A33, you need one more clock line:
@@ -226,6 +276,7 @@ supported.
 Required properties:
   - compatible: value must be one of:
     * allwinner,sun8i-a83t-de2-mixer-0
+    * allwinner,sun8i-a83t-de2-mixer-1
     * allwinner,sun8i-v3s-de2-mixer
   - reg: base address and size of the memory-mapped region.
   - clocks: phandles to the clocks feeding the mixer
@@ -261,7 +312,7 @@ Required properties:
   - allwinner,pipelines: list of phandle to the display engine
     frontends (DE 1.0) or mixers (DE 2.0) available.
 
-Example:
+Example 1:
 
 panel: panel {
 	compatible = "olimex,lcd-olinuxino-43-ts";
@@ -460,3 +511,135 @@ display-engine {
 	compatible = "allwinner,sun5i-a13-display-engine";
 	allwinner,pipelines = <&fe0>;
 };
+
+Example 2:
Is this really different enough to need an example? Examples don't 
need to enumerate all possible options. They are often wrong because 
they don't compile on their own and that creates a maintenance burden.

Rob
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