Add OFW support to the in tree gpio compatible devices: gpioiic(4) and

gpioled(4).

Tested on RPi and BBB (using the hardware I2C controller and gpioiic(4) for
the I2C tests).  It was also verified for regressions on RSPRO (MIPS/ar71xx)
used as reference for a non OFW-based system.

Update the gpioled(4) and gpioiic(4) man pages with some details and
examples about the FDT/OFW support.

Some compatibility details pointed out by imp@ will follow in subsequent
commits.

Approved by:	adrian (mentor, implicit)

2 files changed, 135 insertions, 3 deletions

diff --git a/share/man/man4/gpioiic.4 b/share/man/man4/gpioiic.4
index cbcaec9..e3f9814 100644
--- a/share/man/man4/gpioiic.4
+++ b/share/man/man4/gpioiic.4
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 5, 2013
+.Dd February 13, 2014
 .Dt GPIOIIC 4
 .Os
 .Sh NAME
@@ -65,7 +65,7 @@ This is a bitmask of the pins on the
 that are to be used for SCLOCK and SDATA from the GPIO IIC
 bit-banging bus.
 To configure pin 0 and 7, use the bitmask of
-10000001 and convert it to a hexadecimal value of 0x0081.
+0b10000001 and convert it to a hexadecimal value of 0x0081.
 Please note that this mask should only ever have two bits set
 (any others bits - i.e., pins - will be ignored).
 .It Va hint.gpioiic.%d.scl
@@ -73,13 +73,77 @@ Indicates which bit in the
 .Va hint.gpioiic.%d.pins
 should be used as the SCLOCK
 source.
+Optional, defaults to 0.
 .It Va hint.gpioiic.%d.sda
 Indicates which bit in the
 .Va hint.gpioiic.%d.pins
 should be used as the SDATA
 source.
+Optional, defaults to 1.
+.El
+.Pp
+On a
+.Xr FDT 4
+based system, like
+.Li ARM , the dts part for a
+.Nm gpioiic
+device usually looks like:
+.Bd -literal
+gpio: gpio {
+
+	gpio-controller;
+	...
+
+	gpioiic0 {
+		compatible = "gpioiic";
+		/*
+		 * Attach to GPIO pins 21 and 22.  Set them
+		 * initially as inputs.
+		 */
+		gpios = <&gpio 21 1 0
+			 &gpio 22 1 0>;
+		scl = <0>;		/* GPIO pin 21 - optional */
+		sda = <1>;		/* GPIO pin 22 - optional */
+
+		/* This is an example of a gpioiic child. */
+		gpioiic-child0 {
+			compatible = "lm75";
+			i2c-address = <0x4f>;
+		};
+	};
+};
+.Ed
+.Pp
+Where:
+.Bl -tag -width ".Va compatible"
+.It Va compatible
+Should always be set to "gpioiic".
+.It Va gpios
+The
+.Va gpios
+property indicates which GPIO pins should be used for SCLOCK and SDATA
+on the GPIO IIC bit-banging bus.
+For more details about the
+.Va gpios
+property, please consult
+.Pa /usr/src/sys/boot/fdt/dts/bindings-gpio.txt .
+.It Va scl
+The
+.Va scl
+option indicates which bit in the
+.Va gpios
+should be used as the SCLOCK source.
+Optional, defaults to 0.
+.It Va sda
+The
+.Va sda
+option indicates which bit in the
+.Va gpios
+should be used as the SDATA source.
+Optional, defaults to 1.
 .El
 .Sh SEE ALSO
+.Xr fdt 4 ,
 .Xr gpio 4 ,
 .Xr gpioled 4 ,
 .Xr iic 4 ,
diff --git a/share/man/man4/gpioled.4 b/share/man/man4/gpioled.4
index 76f59fa..74c28e6 100644
--- a/share/man/man4/gpioled.4
+++ b/share/man/man4/gpioled.4
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 5, 2013
+.Dd February 13, 2014
 .Dt GPIOLED 4
 .Os
 .Sh NAME
@@ -68,7 +68,75 @@ Which pin on the GPIO interface to map to this instance.
 Please note that this mask should only ever have one bit set
 (any others bits - i.e., pins - will be ignored).
 .El
+.Pp
+On a
+.Xr FDT 4
+based system, like
+.Li ARM , the dts part for a
+.Nm gpioled
+device usually looks like:
+.Bd -literal
+gpio: gpio {
+
+	gpio-controller;
+	...
+
+	led0 {
+		compatible = "gpioled";
+		gpios = <&gpio 16 2 0>;		/* GPIO pin 16. */
+		name = "ok";
+	};
+
+	led1 {
+		compatible = "gpioled";
+		gpios = <&gpio 17 2 0>;		/* GPIO pin 17. */
+		name = "user-led1";
+	};
+};
+.Ed
+.Pp
+And optionally, you can choose combine all the leds under a single
+.Dq gpio-leds
+compatible node:
+.Bd -literal
+simplebus0 {
+
+	...
+
+	leds {
+		compatible = "gpio-leds";
+
+		led0 {
+			gpios = <&gpio 16 2 0>;
+			name = "ok"
+		};
+
+		led1 {
+			gpios = <&gpio 17 2 0>;
+			name = "user-led1"
+		};
+	};
+};
+.Ed
+.Pp
+Both methods are equally supported and it is possible to have the leds
+defined with any sort of mix between the methods.
+The only restriction is that a GPIO pin cannot be mapped by two different
+(gpio)leds.
+.Pp
+For more details about the
+.Va gpios
+property, please consult
+.Pa /usr/src/sys/boot/fdt/dts/bindings-gpio.txt .
+.Pp
+The property
+.Va name
+is the arbitrary name of device in
+.Pa /dev/led/
+to create for
+.Xr led 4 .
 .Sh SEE ALSO
+.Xr fdt 4 ,
 .Xr gpio 4 ,
 .Xr led 4 ,
 .Xr gpioiic 4