From: Yash Shah <yash.shah@sifive.com>
To: palmer@sifive.com, linux-pwm@vger.kernel.org,
linux-riscv@lists.infradead.org
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, robh+dt@kernel.org,
sachin.ghadi@sifive.com, Yash Shah <yash.shah@sifive.com>,
thierry.reding@gmail.com, paul.walmsley@sifive.com
Subject: [PATCH 1/2] pwm: sifive: Add DT documentation for SiFive PWM Controller
Date: Fri, 11 Jan 2019 13:52:43 +0530 [thread overview]
Message-ID: <1547194964-16718-2-git-send-email-yash.shah@sifive.com> (raw)
In-Reply-To: <1547194964-16718-1-git-send-email-yash.shah@sifive.com>
DT documentation for PWM controller added with updated compatible
string.
Signed-off-by: Wesley W. Terpstra <wesley@sifive.com>
[Atish: Compatible string update]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Yash Shah <yash.shah@sifive.com>
---
.../devicetree/bindings/pwm/pwm-sifive.txt | 37 ++++++++++++++++++++++
1 file changed, 37 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..e0fc22a
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-sifive.txt
@@ -0,0 +1,37 @@
+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: Please refer to sifive-blocks-ip-versioning.txt
+- 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 2.
+ The first cell is the PWM channel number
+ The second cell is the PWM polarity
+- sifive,approx-period-ns: the driver will get as close to this period as it can
+- interrupts: one interrupt per PWM channel
+
+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
+
+Further information on the format of the IP
+block-specific version numbers can be found in
+Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
+
+Examples:
+
+pwm: pwm@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 = <2>;
+ sifive,approx-period-ns = <1000000>;
+};
--
1.9.1
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next prev parent reply other threads:[~2019-01-11 8:23 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-11 8:22 [PATCH 0/2] PWM support for HiFive Unleashed Yash Shah
2019-01-11 8:22 ` Yash Shah [this message]
2019-01-15 20:11 ` [PATCH 1/2] pwm: sifive: Add DT documentation for SiFive PWM Controller Uwe Kleine-König
2019-01-16 9:21 ` Yash Shah
2019-01-21 11:20 ` Thierry Reding
2019-01-11 8:22 ` [PATCH 2/2] pwm: sifive: Add a driver for SiFive SoC PWM Yash Shah
2019-01-15 15:27 ` Christoph Hellwig
2019-01-15 22:00 ` Uwe Kleine-König
2019-01-16 11:10 ` Yash Shah
2019-01-16 16:46 ` Uwe Kleine-König
2019-01-16 17:18 ` Paul Walmsley
2019-01-16 17:28 ` Uwe Kleine-König
2019-01-16 19:29 ` Paul Walmsley
2019-01-17 8:19 ` Uwe Kleine-König
2019-01-21 11:54 ` Thierry Reding
2019-01-21 15:11 ` Uwe Kleine-König
2019-01-17 6:45 ` Yash Shah
2019-01-17 7:28 ` Uwe Kleine-König
2019-01-21 11:30 ` Thierry Reding
2019-01-21 13:23 ` Uwe Kleine-König
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