DT binding for staging vchiq

Stefan Wahren

2018-01-17 18:48:46 UTC

Hi Sergey,

Hello everyone,
I am trying to use RPi3 VC4 gpu with Qt5 quick/qml. When I run my
application Qt5 is always complaining about missing vchiq device in the
system. I know there is vchiq driver available in staging.
1) What is the current status of the driver ? Is it working at all?

From my point of view it's still experimental. It's mostly the same driver as in downstream, but its function highly dependents on the configuration:

arm/bcm2835_defconfig = should work
arm/multi_v7_defconfig = may work
arm64/defconfig = won't work [1]

In order to the function of the driver use vchiq_test from the Raspberry Pi userland.

Btw testers are always welcome :-)

can it be used with Qt5 ?

If your application works with the downstream kernel, there is a high chance.

2) Can I have a working example of DT binding for the driver ?

This is one of my many TODOs [2] to provide a binding document. Please try the following old patch. The cache-line-size depends on the used SoC (BCM2835 = 32, BCM2836/BCM2837 = 64).

Good luck

diff --git a/arch/arm/boot/dts/bcm2835-rpi.dtsi b/arch/arm/boot/dts/bcm2835-rpi.dtsi
index e55b362..7398b96 100644
--- a/arch/arm/boot/dts/bcm2835-rpi.dtsi
+++ b/arch/arm/boot/dts/bcm2835-rpi.dtsi
@@ -27,6 +27,14 @@
firmware = <&firmware>;
#power-domain-cells = <1>;
};
+
+ vchiq: vchiq {
+ compatible = "brcm,bcm2835-vchiq";
+ reg = <0x7e00b840 0xf>;
+ interrupts = <0 2>;
+ cache-line-size = <64>;
+ firmware = <&firmware>;
+ };
};
};

[1] - https://github.com/lategoodbye/rpi-zero/issues/23
[2] - https://github.com/lategoodbye/rpi-zero/issues/8

Thanks
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