Re: [PATCH v2 1/7] drm/vc4: Add devicetree bindings for VC4.

From: Stefan Wahren
Date: Wed Aug 19 2015 - 16:58:43 EST


Hi Eric,

Am 18.08.2015 um 23:54 schrieb Eric Anholt:
VC4 is the GPU (display and 3D) subsystem present on the 2835 and some
other Broadcom SoCs.

This binding follows the model of msm, imx, sti, and others, where
there is a subsystem node for the whole GPU, with nodes for the
individual HW components within it.

Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
---

v2: Extend the commit message, fix several nits from Stephen Warren.

.../devicetree/bindings/gpu/brcm,bcm-vc4.txt | 79 ++++++++++++++++++++++
1 file changed, 79 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpu/brcm,bcm-vc4.txt

diff --git a/Documentation/devicetree/bindings/gpu/brcm,bcm-vc4.txt b/Documentation/devicetree/bindings/gpu/brcm,bcm-vc4.txt
new file mode 100644
index 0000000..1b9fedc
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpu/brcm,bcm-vc4.txt
@@ -0,0 +1,79 @@
+Broadcom VC4 GPU
+
+The VC4 device present on the Raspberry Pi includes a display system
+with HDMI output and the HVS scaler for compositing display planes.
+
+Required properties for VC4:
+- compatible: Should be "brcm,vc4"
+- crtcs: List of phandles of pixelvalve scanout engines
+- hvss: List of phandles of HVS video scalers
+- encoders: List of phandles of output encoders (HDMI, SDTV)
+
+Required properties for Pixel Valve:
+- compatible: Should be "brcm,vc4-pixelvalve"
+- reg: Physical base address and length of the PV's registers
+- interrupts: The interrupt number
+ See bindings/interrupt-controller/brcm,bcm2835-armctrl-ic.txt
+
+Required properties for HVS:
+- compatible: Should be "brcm,vc4-hvs"
+- reg: Physical base address and length of the HVS's registers
+- interrupts: The interrupt number
+ See bindings/interrupt-controller/brcm,bcm2835-armctrl-ic.txt
+
+Required properties for HDMI
+- compatible: Should be "brcm,vc4-hdmi"
+- reg: Physical base address and length of the two register ranges
+ ("HDMI" and "HD", in that order)
+- interrupts: The interrupt numbers
+ See bindings/interrupt-controller/brcm,bcm2835-armctrl-ic.txt
+- ddc: phandle of the I2C controller used for DDC EDID probing
+- crtc: phandle to the pixelvalve CRTC the HDMI encoder is attached to
+
+Optional properties for HDMI:
+- hpd-gpio: The GPIO pin for HDMI hotplug detect (if it doesn't appear
+ as an interrupt/status bit in the HDMI controller
+ itself). See bindings/pinctrl/brcm,bcm2835-gpio.txt
+
+Example:
+pv0: brcm,vc4-pixelvalve@7e206000 {

AFAIK the DT node name should describe the function and usually don't have a vendor prefix. Here some possible suggestions without deeper knowledge of the hardware function:

pv0: pixelvalve

+ compatible = "brcm,vc4-pixelvalve";
+ reg = <0x7e206000 0x100>;
+ interrupts = <2 13>; /* pwa2 */
+};
+
+pv1: brcm,vc4-pixelvalve@7e207000 {

pv1: pixelvalve

+ compatible = "brcm,vc4-pixelvalve";
+ reg = <0x7e207000 0x100>;
+ interrupts = <2 14>; /* pwa1 */
+};
+
+pv2: brcm,vc4-pixelvalve@7e807000 {

pv2: pixelvalve

+ compatible = "brcm,vc4-pixelvalve";
+ reg = <0x7e807000 0x100>;
+ interrupts = <2 10>; /* pixelvalve */
+};
+
+hvs: brcm,hvs@7e400000 {

hvs: hvs

+ compatible = "brcm,vc4-hvs";
+ reg = <0x7e400000 0x6000>;
+ interrupts = <2 1>;
+};
+
+hdmi: brcm,vc4-hdmi@7e902000 {

hdmi: hdmi

+ compatible = "brcm,vc4-hdmi";
+ reg = <0x7e902000 0x600>,
+ <0x7e808000 0x100>;
+ interrupts = <2 8>, <2 9>;
+ ddc = <&i2c2>;
+ hpd-gpio = <&gpio 46 GPIO_ACTIVE_HIGH>;
+ crtc = <&pv2>;
+};
+
+vc4: vc4@0x7e4c0000 {

vc4: gpu

Regards
Stefan

+ compatible = "brcm,vc4";
+
+ crtcs = <&pv0>, <&pv1>, <&pv2>;
+ encoders = <&hdmi>;
+ hvss = <&hvs>;
+};


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