[PATCH v3 04/10] Documentations: dt-bindings: Add a document of PECI adapter driver for Aspeed AST24xx/25xx SoCs

[Jae Hyun Yoo]

This commit adds a dt-bindings document of PECI adapter driver for Aspeed
AST24xx/25xx SoCs.

Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>
Reviewed-by: Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>
Reviewed-by: James Feist <james.feist@xxxxxxxxxxxxxxx>
Reviewed-by: Vernon Mauery <vernon.mauery@xxxxxxxxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxx>
Cc: Andrew Jeffery <andrew@xxxxxxxx>
Cc: Andrew Lunn <andrew@xxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Fengguang Wu <fengguang.wu@xxxxxxxxx>
Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Jason M Biils <jason.m.bills@xxxxxxxxxxxxxxx>
Cc: Jean Delvare <jdelvare@xxxxxxxx>
Cc: Joel Stanley <joel@xxxxxxxxx>
Cc: Julia Cartwright <juliac@xxxxxxxxxxxx>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx>
Cc: Milton Miller II <miltonm@xxxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Stef van Os <stef.van.os@xxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: Sumeet R Pawnikar <sumeet.r.pawnikar@xxxxxxxxx>
---
 .../devicetree/bindings/peci/peci-aspeed.txt       | 60 ++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/peci/peci-aspeed.txt

diff --git a/Documentation/devicetree/bindings/peci/peci-aspeed.txt b/Documentation/devicetree/bindings/peci/peci-aspeed.txt
new file mode 100644
index 000000000000..4598bb8c20fa
--- /dev/null
+++ b/Documentation/devicetree/bindings/peci/peci-aspeed.txt
@@ -0,0 +1,60 @@
+Device tree configuration for PECI buses on the AST24XX and AST25XX SoCs.
+
+Required properties:
+- compatible        : Should be "aspeed,ast2400-peci" or "aspeed,ast2500-peci"
+		      - aspeed,ast2400-peci: Aspeed AST2400 family PECI
+					     controller
+		      - aspeed,ast2500-peci: Aspeed AST2500 family PECI
+					     controller
+- reg               : Should contain PECI controller registers location and
+		      length.
+- #address-cells    : Should be <1>.
+- #size-cells       : Should be <0>.
+- interrupts        : Should contain PECI controller interrupt.
+- clocks            : Should contain clock source for PECI controller.
+		      Should reference clkin.
+- clock_frequency   : Should contain the operation frequency of PECI controller
+		      in units of Hz.
+		      187500 ~ 24000000
+
+Optional properties:
+- msg-timing-nego   : Message timing negotiation period. This value will
+		      determine the period of message timing negotiation to be
+		      issued by PECI controller. The unit of the programmed
+		      value is four times of PECI clock period.
+		      0 ~ 255 (default: 1)
+- addr-timing-nego  : Address timing negotiation period. This value will
+		      determine the period of address timing negotiation to be
+		      issued by PECI controller. The unit of the programmed
+		      value is four times of PECI clock period.
+		      0 ~ 255 (default: 1)
+- rd-sampling-point : Read sampling point selection. The whole period of a bit
+		      time will be divided into 16 time frames. This value will
+		      determine the time frame in which the controller will
+		      sample PECI signal for data read back. Usually in the
+		      middle of a bit time is the best.
+		      0 ~ 15 (default: 8)
+- cmd_timeout_ms    : Command timeout in units of ms.
+		      1 ~ 60000 (default: 1000)
+
+Example:
+	peci: peci@1e78b000 {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0x0 0x1e78b000 0x60>;
+
+		peci0: peci-bus@0 {
+			compatible = "aspeed,ast2500-peci";
+			reg = <0x0 0x60>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			interrupts = <15>;
+			clocks = <&clk_clkin>;
+			clock-frequency = <24000000>;
+			msg-timing-nego = <1>;
+			addr-timing-nego = <1>;
+			rd-sampling-point = <8>;
+			cmd-timeout-ms = <1000>;
+		};
+	};
-- 
2.16.2