linux-kernel - [PATCH v13 12/13] MIPS: GCW0: Reduce system timer and clocksource to 750 kHz

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Message-Id: <20190624225759.18299-13-paul@crapouillou.net>
Date:   Tue, 25 Jun 2019 00:57:58 +0200
From:   Paul Cercueil <paul@...pouillou.net>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Paul Burton <paul.burton@...s.com>,
        James Hogan <jhogan@...nel.org>,
        Jonathan Corbet <corbet@....net>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Lee Jones <lee.jones@...aro.org>
Cc:     Mathieu Malaterre <malat@...ian.org>, od@...c.me,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mips@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-clk@...r.kernel.org, Paul Cercueil <paul@...pouillou.net>,
        Artur Rojek <contact@...ur-rojek.eu>
Subject: [PATCH v13 12/13] MIPS: GCW0: Reduce system timer and clocksource to 750 kHz

The default clock (12 MHz) is too fast for the system timer.

Signed-off-by: Paul Cercueil <paul@...pouillou.net>
Tested-by: Mathieu Malaterre <malat@...ian.org>
Tested-by: Artur Rojek <contact@...ur-rojek.eu>
---

Notes:
    v8: New patch
    
    v9: Don't configure clock timer1, as the OS Timer is used as
    	clocksource on this SoC
    
    v10: Revert back to v8 bahaviour. Let the user choose what
    	 clocksource should be used.
    
    v11: No change
    
    v12: Move clocksource to channel 2, as channel 1 is used as PWM
    	 for the backlight.
    
    v13: No change

 arch/mips/boot/dts/ingenic/gcw0.dts | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/mips/boot/dts/ingenic/gcw0.dts b/arch/mips/boot/dts/ingenic/gcw0.dts
index 35f0291e8d38..f58d239c2058 100644
--- a/arch/mips/boot/dts/ingenic/gcw0.dts
+++ b/arch/mips/boot/dts/ingenic/gcw0.dts
@@ -2,6 +2,7 @@
 /dts-v1/;
 
 #include "jz4770.dtsi"
+#include <dt-bindings/clock/ingenic,tcu.h>
 
 / {
 	compatible = "gcw,zero", "ingenic,jz4770";
@@ -60,3 +61,12 @@
 	/* The WiFi module is connected to the UHC. */
 	status = "okay";
 };
+
+&tcu {
+	/* 750 kHz for the system timer and clocksource */
+	assigned-clocks = <&tcu TCU_CLK_TIMER0>, <&tcu TCU_CLK_TIMER2>;
+	assigned-clock-rates = <750000>, <750000>;
+
+	/* PWM1 is in use, so reserve channel #2 for the clocksource */
+	ingenic,pwm-channels-mask = <0xfa>;
+};
-- 
2.21.0.593.g511ec345e18