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Message-Id: <20250801080025.558935-1-amadeus@jmu.edu.cn>
Date: Fri, 1 Aug 2025 16:00:24 +0800
From: Chukun Pan <amadeus@....edu.cn>
To: Heiko Stuebner <heiko@...ech.de>
Cc: Yao Zi <ziyao@...root.org>,
Rob Herring <robh@...nel.org>,
Chukun Pan <amadeus@....edu.cn>,
Jonas Karlman <jonas@...boo.se>,
Conor Dooley <conor+dt@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
linux-arm-kernel@...ts.infradead.org,
linux-rockchip@...ts.infradead.org,
linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org
Subject: [PATCH v3 0/1] arm64: dts: rockchip: rk3528: Add CPU frequency scaling support
By default, the CPUs on RK3528 operates at 1.5GHz. Add CPU frequency and
voltage mapping to the device tree to enable dynamic scaling via cpufreq.
The OPP values come from downstream 5.10 kernel, using a voltage close to
the actual frequency. Frequencies below 1200MHz have been removed as they
currently use the same voltage.
If we want the actual frequency to reach 2016MHz, the voltage
needs to reach 1.13V (+0.03V), not sure if it is safe.
The maximum opp-table voltage of downstream kernel is 1.1V.
Here are the test results using mhz [1] on Radxa E20C:
--------------------------------------
display frequency | actual frequency
1200MHz | 1286MHz
1416MHz | 1430MHz
1608MHz | 1640MHz
1800MHz | 1804MHz
2016MHz | 1946MHz
--------------------------------------
[1] https://github.com/wtarreau/mhz.git
Changed from v3:
Remove frequencies below 1200MHz
Changed from v2:
Rename label opp-table-0 to opp-table-cpu
Adjust the voltage used for 408MHz to 1200MHz
Chukun Pan (1):
arm64: dts: rockchip: rk3528: Add CPU frequency scaling support
arch/arm64/boot/dts/rockchip/rk3528.dtsi | 39 ++++++++++++++++++++++++
1 file changed, 39 insertions(+)
--
2.25.1
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