From patchwork Thu Apr 23 11:27:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yash Shah X-Patchwork-Id: 238397 List-Id: U-Boot discussion From: yash.shah at sifive.com (Yash Shah) Date: Thu, 23 Apr 2020 16:57:15 +0530 Subject: [PATCH v2 1/2] pwm: Add DT documentation for SiFive PWM Controller In-Reply-To: <1587641236-5026-1-git-send-email-yash.shah@sifive.com> References: <1587641236-5026-1-git-send-email-yash.shah@sifive.com> Message-ID: <1587641236-5026-2-git-send-email-yash.shah@sifive.com> DT documentation for PWM controller added from Linux v5.6 commit: daa78cc3408e ("pwm: sifive: Add DT documentation for SiFive PWM Controller") Signed-off-by: Yash Shah Reviewed-by: Heiko Schocher --- doc/device-tree-bindings/pwm/pwm-sifive.txt | 31 +++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 doc/device-tree-bindings/pwm/pwm-sifive.txt diff --git a/doc/device-tree-bindings/pwm/pwm-sifive.txt b/doc/device-tree-bindings/pwm/pwm-sifive.txt new file mode 100644 index 0000000..9a98837 --- /dev/null +++ b/doc/device-tree-bindings/pwm/pwm-sifive.txt @@ -0,0 +1,31 @@ +SiFive PWM controller + +Unlike most other PWM controllers, the SiFive PWM controller currently only +supports one period for all channels in the PWM. All PWMs need to run at +the same period. The period also has significant restrictions on the values +it can achieve, which the driver rounds to the nearest achievable period. +PWM RTL that corresponds to the IP block version numbers can be found +here: + +https://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/pwm + +Required properties: +- compatible: Should be "sifive,-pwm" and "sifive,pwm". + Supported compatible strings are: "sifive,fu540-c000-pwm" for the SiFive + PWM v0 as integrated onto the SiFive FU540 chip, and "sifive,pwm0" for the + SiFive PWM v0 IP block with no chip integration tweaks. +- reg: physical base address and length of the controller's registers +- clocks: Should contain a clock identifier for the PWM's parent clock. +- #pwm-cells: Should be 3. +- interrupts: one interrupt per PWM channel + +Examples: + +pwm: pwm at 10020000 { + compatible = "sifive,fu540-c000-pwm", "sifive,pwm0"; + reg = <0x0 0x10020000 0x0 0x1000>; + clocks = <&tlclk>; + interrupt-parent = <&plic>; + interrupts = <42 43 44 45>; + #pwm-cells = <3>; +};