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Message-Id: <1448766190-11345-6-git-send-email-wens@csie.org>
Date: Sun, 29 Nov 2015 11:03:10 +0800
From: Chen-Yu Tsai <wens@...e.org>
To: Maxime Ripard <maxime.ripard@...e-electrons.com>,
Emilio Lopez <emilio@...pez.com.ar>,
Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...eaurora.org>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>
Cc: linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
linux-sunxi@...glegroups.com, Chen-Yu Tsai <wens@...e.org>
Subject: [PATCH v4 5/5] ARM: dts: sun9i: Add TODO comments for the main and low power clocks
The main (24MHz) clock on the A80 is configurable via the PRCM address
space. The low power/speed (32kHz) clock is from an external chip, the
AC100.
Signed-off-by: Chen-Yu Tsai <wens@...e.org>
---
arch/arm/boot/dts/sun9i-a80.dtsi | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/arch/arm/boot/dts/sun9i-a80.dtsi b/arch/arm/boot/dts/sun9i-a80.dtsi
index a4ce348c0831..eb69a62f6bc4 100644
--- a/arch/arm/boot/dts/sun9i-a80.dtsi
+++ b/arch/arm/boot/dts/sun9i-a80.dtsi
@@ -128,6 +128,17 @@
*/
ranges = <0 0 0 0x20000000>;
+ /*
+ * This clock is actually configurable from the PRCM address
+ * space. The external 24M oscillator can be turned off, and
+ * the clock switched to an internal 16M RC oscillator. Under
+ * normal operation there's no reason to do this, and the
+ * default is to use the external good one, so just model this
+ * as a fixed clock. Also it is not entirely clear if the
+ * osc24M mux in the PRCM affects the entire clock tree, which
+ * would also throw all the PLL clock rates off, or just the
+ * downstream clocks in the PRCM.
+ */
osc24M: osc24M_clk {
#clock-cells = <0>;
compatible = "fixed-clock";
@@ -135,6 +146,13 @@
clock-output-names = "osc24M";
};
+ /*
+ * The 32k clock is from an external source, normally the
+ * AC100 codec/RTC chip. This clock is by default enabled
+ * and clocked at 32768 Hz, from the oscillator connected
+ * to the AC100. It is configurable, but no such driver or
+ * bindings exist yet.
+ */
osc32k: osc32k_clk {
#clock-cells = <0>;
compatible = "fixed-clock";
--
2.6.2
--
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