[PATCH] devicetree: Add support for I2C and related devices to TI-NSPIRE platform

[PATCH] devicetree: Add support for I2C and related devices to TI-NSPIRE platform

[Daniel Tang]

This patch adds device tree entries for I2C hardware to the TI-NSPIRE
platforms that have it.

It also adds support for the touchpad that communicates over the I2C
bus.


Signed-off-by: Daniel Tang <dt.tangr@gmail.com>
---
 arch/arm/boot/dts/nspire-cx.dts | 13 +++++++++++++
 arch/arm/boot/dts/nspire-tp.dts | 14 ++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/arch/arm/boot/dts/nspire-cx.dts b/arch/arm/boot/dts/nspire-cx.dts
index 08e0b81..e369e3b 100644
--- a/arch/arm/boot/dts/nspire-cx.dts
+++ b/arch/arm/boot/dts/nspire-cx.dts
@@ -104,9 +104,22 @@
 			#size-cells = <1>;
 
 			i2c@90050000 {
+				#address-cells = <1>;
+				#size-cells = <0>;
+
 				compatible = "snps,designware-i2c";
 				reg = <0x90050000 0x1000>;
 				interrupts = <20>;
+
+				clocks = <&apb_pclk>;
+
+				i2c-sda-falling-time-ns = <810>;
+				i2c-scl-falling-time-ns = <2410>;
+
+				touchpad@20 {
+					compatible = "synaptics_i2c";
+					reg = <0x20>;
+				};
 			};
 		};
 	};
diff --git a/arch/arm/boot/dts/nspire-tp.dts b/arch/arm/boot/dts/nspire-tp.dts
index 621391c..49fb97a 100644
--- a/arch/arm/boot/dts/nspire-tp.dts
+++ b/arch/arm/boot/dts/nspire-tp.dts
@@ -41,4 +41,18 @@
 / {
 	model = "TI-NSPIRE Touchpad";
 	compatible = "ti,nspire-tp";
+
+	i2c@gpio {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		compatible = "i2c-gpio";
+		gpios = < &gpio 3 0 /* sda */
+			  &gpio 1 0 /* scl */ >;
+
+		touchpad@20 {
+			compatible = "synaptics_i2c";
+			reg = <0x20>;
+		};
+	};
 };
-- 
2.2.1

Re: [PATCH] devicetree: Add support for I2C and related devices to TI-NSPIRE platform

[Arnd Bergmann]

On Sunday 31 May 2015 19:44:02 Daniel Tang wrote:
> +
> +                               touchpad@20 {
> +                                       compatible = "synaptics_i2c";
> +                                       reg = <0x20>;
> +                               };
>                         };

While this works, "synaptics_i2c" is not a well-formed DT compatible string,
we should do it right.

Please submit three patches:

a) one patch add "syna" as the vendor string in
   Documentation/devicetree/bindings/vendor-prefixes.txt
   As this is a publicly traded company, we use the stock ticker
   symbol by convention. Cc the patch to devicetree@vger.kernel.org
   for review, but I can merge it along with the dts patch if nobody
   else does

b) a patch to add an of_device_id match table to
   drivers/input/mouse/synaptics_i2c.c, with the proper name of the
   device. Ideally, this would be the full name of the component that
   is used here, something like "syna,abc12345-touchscreen". If you
   have no way of finding out the real name, "syna,i2c-touchscreen"
   will have to suffice.

c) This patch, with the correct string used for compatible.

	Arnd