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Message-ID: <1563564291-9692-2-git-send-email-hongweiz@ami.com>
Date: Fri, 19 Jul 2019 15:24:50 -0400
From: Hongwei Zhang <hongweiz@....com>
To: Andrew Jeffery <andrew@...id.au>,
Linus Walleij <linus.walleij@...aro.org>,
<linux-gpio@...r.kernel.org>
CC: Hongwei Zhang <hongweiz@....com>, Joel Stanley <joel@....id.au>,
<devicetree@...r.kernel.org>, <linux-aspeed@...ts.ozlabs.org>,
Bartosz Golaszewski <bgolaszewski@...libre.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
<linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>
Subject: [v5 1/2] dt-bindings: gpio: aspeed: Add SGPIO support
Add bindings to support SGPIO on AST2400 or AST2500.
Signed-off-by: Hongwei Zhang <hongweiz@....com>
---
.../devicetree/bindings/gpio/sgpio-aspeed.txt | 55 ++++++++++++++++++++++
1 file changed, 55 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt
diff --git a/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt b/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt
new file mode 100644
index 0000000..f9ed438
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt
@@ -0,0 +1,55 @@
+Aspeed SGPIO controller Device Tree Bindings
+-------------------------------------------
+
+This SGPIO controller is for ASPEED AST2500 SoC, it supports up to 80 full
+featured Serial GPIOs. Each of the Serial GPIO pins can be programmed to
+support the following options:
+- Support interrupt option for each input port and various interrupt
+ sensitivity option (level-high, level-low, edge-high, edge-low)
+- Support reset tolerance option for each output port
+- Directly connected to APB bus and its shift clock is from APB bus clock
+ divided by a programmable value.
+- Co-work with external signal-chained TTL components (74LV165/74LV595)
+
+
+Required properties:
+
+- compatible : Either "aspeed,ast2400-sgpio" or "aspeed,ast2500-sgpio"
+
+- #gpio-cells : Should be two
+ - First cell is the GPIO line number
+ - Second cell is used to specify optional
+ parameters (unused)
+
+- reg : Address and length of the register set for the device
+- gpio-controller : Marks the device node as a GPIO controller
+- interrupts : Interrupt specifier (see interrupt bindings for
+ details)
+
+- interrupt-controller : Mark the GPIO controller as an interrupt-controller
+
+- ngpios : number of GPIO pins to serialise.
+ (should be multiple of 8, up to 80 pins)
+
+- clocks : A phandle to the APB clock for SGPM clock division
+
+- bus-frequency : SGPM CLK frequency
+
+
+The sgpio and interrupt properties are further described in their respective bindings documentation:
+
+- Documentation/devicetree/bindings/sgpio/gpio.txt
+- Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
+
+ Example:
+ sgpio: sgpio@...80200 {
+ #gpio-cells = <2>;
+ compatible = "aspeed,ast2500-sgpio";
+ gpio-controller;
+ interrupts = <40>;
+ reg = <0x1e780200 0x0100>;
+ clocks = <&syscon ASPEED_CLK_APB>;
+ interrupt-controller;
+ ngpios = <8>;
+ bus-frequency = <12000000>;
+ };
--
2.7.4
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