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Message-Id: <1524869998-2805-2-git-send-email-wesley@sifive.com>
Date: Fri, 27 Apr 2018 15:59:56 -0700
From: "Wesley W. Terpstra" <wesley@...ive.com>
To: Thierry Reding <thierry.reding@...il.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Andreas Färber <afaerber@...e.de>,
Noralf Trønnes <noralf@...nnes.org>,
David Lechner <david@...hnology.com>,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
SZ Lin <sz.lin@...a.com>, linux-pwm@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: "Wesley W. Terpstra" <wesley@...ive.com>
Subject: [PATCH 1/3] dt-bindings: added new pwm-sifive driver documentation
Document new PWM device tree bindings for SiFive SoCs.
Signed-off-by: Wesley W. Terpstra <wesley@...ive.com>
---
.../devicetree/bindings/pwm/pwm-sifive.txt | 28 ++++++++++++++++++++++
1 file changed, 28 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pwm/pwm-sifive.txt
diff --git a/Documentation/devicetree/bindings/pwm/pwm-sifive.txt b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt
new file mode 100644
index 0000000..7cea20d
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt
@@ -0,0 +1,28 @@
+SiFive PWM controller
+
+Unlike most other PWM controllers, the SiFive PWM controller currently only
+supports one period for all channels in the PWM. This is set globally in DTS.
+The period also has significant restrictions on the values it can achieve,
+which the driver rounds to the nearest achievable frequency.
+
+Required properties:
+- compatible: should be "sifive,pwm0"
+- reg: physical base address and length of the controller's registers
+- clocks: The frequency the controller runs at
+- #pwm-cells: Should be 2.
+ The first cell is the PWM channel number
+ The second cell is the PWM polarity
+- sifive,approx-period: the driver will get as close to this period as it can
+- interrupts: one interrupt per PWM channel (currently unused in the driver)
+
+Examples:
+
+pwm: pwm@...20000 {
+ compatible = "sifive,pwm0";
+ reg = <0x0 0x10020000 0x0 0x1000>;
+ clocks = <&tlclk>;
+ interrupt-parent = <&plic>;
+ interrupts = <42 43 44 45>;
+ #pwm-cells = <2>;
+ sifive,approx-period = <1000000>;
+};
--
2.7.4
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