Thread (33 messages) 33 messages, 3 authors, 2015-02-12

[PATCH RFC v8 11/21] Documentation: dt-bindings: Add bindings for Synopsys DW MIPI DSI DRM bridge driver

From: p.zabel@pengutronix.de (Philipp Zabel)
Date: 2015-02-05 10:10:30
Also in: dri-devel, linux-devicetree, lkml

Am Mittwoch, den 31.12.2014, 16:23 +0800 schrieb Liu Ying:
quoted hunk ↗ jump to hunk
This patch adds device tree bindings for Synopsys DesignWare MIPI DSI
host controller DRM bridge driver.

Signed-off-by: Liu Ying <redacted>
---
v7->v8:
 * None.

v6->v7:
 * None.

v5->v6:
 * Add the #address-cells and #size-cells properties in the example 'ports'
   node.
 * Remove the useless input-port properties from the example port at 0 and port at 1
   nodes.

v4->v5:
 * None.

v3->v4:
 * Newly introduced in v4.  This is separated from the relevant driver patch
   in v3 to address Stefan Wahren's comment.

 .../devicetree/bindings/drm/bridge/dw_mipi_dsi.txt | 73 ++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/drm/bridge/dw_mipi_dsi.txt
diff --git a/Documentation/devicetree/bindings/drm/bridge/dw_mipi_dsi.txt b/Documentation/devicetree/bindings/drm/bridge/dw_mipi_dsi.txt
new file mode 100644
index 0000000..f88a8d6
--- /dev/null
+++ b/Documentation/devicetree/bindings/drm/bridge/dw_mipi_dsi.txt
@@ -0,0 +1,73 @@
+Device-Tree bindings for Synopsys DesignWare MIPI DSI host controller
+
+The controller is a digital core that implements all protocol functions
+defined in the MIPI DSI specification, providing an interface between
+the system and the MIPI DPHY, and allowing communication with a MIPI DSI
+compliant display.
+
+Required properties:
+ - #address-cells: Should be <1>.
+ - #size-cells: Should be <0>.
+ - compatible: The compatible string should be "fsl,imx6q-mipi-dsi" for
+   i.MX6q/sdl SoCs.  For other SoCs, please refer to their specific
+   device tree binding documentations.
I think the compatible property should additionally contain
"snps,dw-mipi-dsi". Also I think other SoCs using the same IP core
should eventually list their compatibles here, but that's for later.

How about:
+ - compatible: The compatible string contain "fsl,imx6q-mipi-dsi" for
+   i.MX6q/sdl SoCs.  For other SoCs, please refer to their specific
+   device tree binding documentations. A common compatible string
+   "snps,dw-mipi-dsi" should be appended for all SoCs.
+ - reg: Represent the physical address range of the controller.
+ - interrupts: Represent the controller's interrupt to the CPU(s).
+ - clocks, clock-names: Phandles to the controller pll reference and
+   core configuration clocks, as described in [1].
From the MIPI CSI-2 datasheets it looks like the D-PHY has a refclk and
a cfg_clk input. So I suspect from the name of the "core_cfg" clock,
that it actually represents two clock inputs, the "cfg_clk" wired to the
D-PHY and a core clock wired to the MIPI DSI host controller. I am not
sure if there are designs that control those clocks separately, but I
think it'd be safer to split this into two clocks in the device tree.

Also I am not sure which input to the MIPI DSI host controller the core
clock represents. The i.MX6DQ Reference Manual v2 calls the remaining
clock inputs gated by mipi_core_cfg_clk_enable "ac_clk_125m" and
"ips_clk" (I think the latter is the ABP clock driving the register
bank, just called "pclk" in the MIPI CSI-2 documentation).

regards
Philipp
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