linux-kernel - [PATCH v2 1/3] ARM: dts: rockchip: disable GPU 500 MHz OPP for veyron

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Date:   Mon, 20 May 2019 15:00:49 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Heiko Stuebner <heiko@...ech.de>, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Douglas Anderson <dianders@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>
Subject: [PATCH v2 1/3] ARM: dts: rockchip: disable GPU 500 MHz OPP for veyron

The NPLL is the only safe way to generate 500 MHz for the GPU. The
downstream Chrome OS 3.14 kernel ('official' kernel for veyron
devices) re-purposes NPLL to HDMI and hence disables the OPP for
the GPU (see https://crrev.com/c/1574579). Disable it here as well
to keep in sync and avoid problems in case someone decides to
re-purpose NPLL.

Signed-off-by: Matthias Kaehlcke <mka@...omium.org>
---
Changes in v2:
- patch added to the series
---
 arch/arm/boot/dts/rk3288-veyron.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm/boot/dts/rk3288-veyron.dtsi b/arch/arm/boot/dts/rk3288-veyron.dtsi
index 90c8312d01ff..ec10ce4fcf04 100644
--- a/arch/arm/boot/dts/rk3288-veyron.dtsi
+++ b/arch/arm/boot/dts/rk3288-veyron.dtsi
@@ -174,6 +174,14 @@
 	temperature = <100000>;
 };
 
+/*
+ * Remove 500 MHz since the only way to make 500 MHz is via the NPLL
+ * which might be used for HDMI.
+ */
+&gpu_opp_table {
+	/delete-node/ opp-500000000;
+};
+
 &hdmi {
 	ddc-i2c-bus = <&i2c5>;
 	status = "okay";
-- 
2.21.0.1020.gf2820cf01a-goog