linux-kernel - [PATCH] ARM: dts: renesas: r9a06g032: Add support for CPU frequency scaling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260115160144.1200270-1-herve.codina@bootlin.com>
Date: Thu, 15 Jan 2026 17:01:44 +0100
From: "Herve Codina (Schneider Electric)" <herve.codina@...tlin.com>
To: Wolfram Sang <wsa+renesas@...g-engineering.com>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Magnus Damm <magnus.damm@...il.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>
Cc: linux-renesas-soc@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Pascal Eberhard <pascal.eberhard@...com>,
	Miquel Raynal <miquel.raynal@...tlin.com>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
	Herve Codina <herve.codina@...tlin.com>
Subject: [PATCH] ARM: dts: renesas: r9a06g032: Add support for CPU frequency scaling

From: Herve Codina <herve.codina@...tlin.com>

In RZ/N1 SoCs, CPUs are allowed to work at 125, 250 or 500 MHz when the
'ref' clock frequency value is set to 500 MHz which is the default 'ref'
clock frequency value.

Add support for CPU frequency scaling defining those 3 frequencies in
the opp-table with the assumption that the 'ref' clock is set to its
default value.

Signed-off-by: Herve Codina <herve.codina@...tlin.com>
Signed-off-by: Herve Codina (Schneider Electric) <herve.codina@...tlin.com>
---
 arch/arm/boot/dts/renesas/r9a06g032.dtsi | 35 ++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/arch/arm/boot/dts/renesas/r9a06g032.dtsi b/arch/arm/boot/dts/renesas/r9a06g032.dtsi
index 8debb77803bb..9f21d8fba940 100644
--- a/arch/arm/boot/dts/renesas/r9a06g032.dtsi
+++ b/arch/arm/boot/dts/renesas/r9a06g032.dtsi
@@ -15,6 +15,39 @@ / {
 	#size-cells = <1>;
 	interrupt-parent = <&gic>;
 
+	/*
+	 * The CPUs clock is based on the 'ref' clock (output of OPPDIV divisor)
+	 * with x1, x2 or x4 ratio between the CPUs clock frequency and this
+	 * 'ref' clock frequency.
+	 *
+	 * The table below is built on the assumption that the 'ref' clock
+	 * frequency is set to 500MHz which is its default value.
+	 *
+	 * The table should be overridden in the board device-tree file based
+	 * on the 'ref' clock frequency if this frequency value is not the
+	 * default one.
+	 */
+	cpu_opp_table: opp-table-cpu {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp-125000000 {
+			opp-hz = /bits/ 64 <125000000>;
+			/* ~35 clocks cycles at 125mhz */
+			clock-latency-ns = <300>;
+		};
+
+		opp-250000000 {
+			opp-hz = /bits/ 64 <250000000>;
+			clock-latency-ns = <300>;
+		};
+
+		opp-500000000 {
+			opp-hz = /bits/ 64 <500000000>;
+			clock-latency-ns = <300>;
+		};
+	};
+
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
@@ -24,6 +57,7 @@ cpu@0 {
 			compatible = "arm,cortex-a7";
 			reg = <0>;
 			clocks = <&sysctrl R9A06G032_CLK_A7MP>;
+			operating-points-v2 = <&cpu_opp_table>;
 		};
 
 		cpu@1 {
@@ -33,6 +67,7 @@ cpu@1 {
 			clocks = <&sysctrl R9A06G032_CLK_A7MP>;
 			enable-method = "renesas,r9a06g032-smp";
 			cpu-release-addr = <0 0x4000c204>;
+			operating-points-v2 = <&cpu_opp_table>;
 		};
 	};
 
-- 
2.52.0