dt-bindings: gpio: aspeed: Add SGPIO support

Hello Andrew,

Thanks for reviewing and please see my inline comments.

--Hongwei

From:	Andrew Jeffery <redacted>
Sent:	Wednesday, July 17, 2019 9:48 PM
To:	Hongwei Zhang; Joel Stanley; Linus Walleij; devicetree@vger.kernel.org
Cc:	Rob Herring; Mark Rutland; Bartosz Golaszewski; linux-aspeed@lists.ozlabs.org; linux-
kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-gpio@vger.kernel.org
Subject:	Re: [PATCH 2/3 v4] dt-bindings: gpio: aspeed: Add SGPIO support

The subject is largely correct, but please see the discussion on the driver patch about how to clean up 
the [PATCH ...] prefix.

On Thu, 18 Jul 2019, at 05:42, Hongwei Zhang wrote:

quoted

Add bindings to support SGPIO on AST2400 or AST2500.

Signed-off-by: Hongwei Zhang <redacted>
---
 .../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..2d6305e

--- /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
+
+- nr-gpios		: number of GPIO pins to serialise. 
+			  (should be multiple of 8, up to 80 pins)

Please change the property name to "ngpios", as per the generic GPIO bindings[1].

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindi
ngs/gpio/gpio.txt?h=v5.2#n141

done

Cheers,

Andrew

quoted

+
+- 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@1e780200 {
+		#gpio-cells = <2>;
+		compatible = "aspeed,ast2500-sgpio";
+		gpio-controller;
+		interrupts = <40>;
+		reg = <0x1e780200 0x0100>;
+		clocks = <&syscon ASPEED_CLK_APB>;
+		interrupt-controller;
+		nr-gpios = <8>;
+		bus-frequency = <12000000>;
+	};
--
2.7.4

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