[RFC 1/4] pwm: sifive: Add DT documentation for SiFive PWM Controller.
From: Atish Patra <hidden>
Date: 2018-10-09 18:51:36
Also in:
linux-gpio, linux-pwm, linux-riscv, lkml
Subsystem:
open firmware and flattened device tree bindings, pwm subsystem, the rest · Maintainers:
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König, Linus Torvalds
From: "Wesley W. Terpstra" <redacted> DT documentation for PWM controller added with updated compatible string. Signed-off-by: Wesley W. Terpstra <redacted> [Atish: Compatible string update] Signed-off-by: Atish Patra <redacted> --- .../devicetree/bindings/pwm/pwm-sifive.txt | 32 ++++++++++++++++++++++ 1 file changed, 32 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 00000000..532b10fc
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt@@ -0,0 +1,32 @@ +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 one of + "sifive,fu540-c000-pwm0","sifive,pwm0". + PWM controller is HiFive Unleashed specific chip which warrants a + specific compatible string. The second string is kept for backward + compatibility until a firmware update with latest compatible string. +- 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@10020000 { + compatible = "sifive,fu540-c000-pwm0","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