From c70bad9211f831e4dd9150c30f3dd4d844703234 Mon Sep 17 00:00:00 2001
From: David Daney <david.daney@cavium.com>
Date: Thu, 12 Apr 2012 14:14:23 -0700
Subject: [PATCH] --- yaml --- r: 308466 b: refs/heads/master c:
 bc45449b1444611d68466ae7f45f235420d79019 h: refs/heads/master v: v3

---
 [refs]                                        |  2 +-
 .../devicetree/bindings/i2c/mux.txt           | 60 +++++++++++++++++++
 trunk/drivers/i2c/i2c-mux.c                   | 23 +++++++
 3 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 trunk/Documentation/devicetree/bindings/i2c/mux.txt

diff --git a/[refs] b/[refs]
index 921c0bfac444..eba7eb4106b3 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5a3ecd5f9877b963a581ca5d4495a1a24dafc88c
+refs/heads/master: bc45449b1444611d68466ae7f45f235420d79019
diff --git a/trunk/Documentation/devicetree/bindings/i2c/mux.txt b/trunk/Documentation/devicetree/bindings/i2c/mux.txt
new file mode 100644
index 000000000000..af84cce5cd7b
--- /dev/null
+++ b/trunk/Documentation/devicetree/bindings/i2c/mux.txt
@@ -0,0 +1,60 @@
+Common i2c bus multiplexer/switch properties.
+
+An i2c bus multiplexer/switch will have several child busses that are
+numbered uniquely in a device dependent manner.  The nodes for an i2c bus
+multiplexer/switch will have one child node for each child
+bus.
+
+Required properties:
+- #address-cells = <1>;
+- #size-cells = <0>;
+
+Required properties for child nodes:
+- #address-cells = <1>;
+- #size-cells = <0>;
+- reg : The sub-bus number.
+
+Optional properties for child nodes:
+- Other properties specific to the multiplexer/switch hardware.
+- Child nodes conforming to i2c bus binding
+
+
+Example :
+
+	/*
+	   An NXP pca9548 8 channel I2C multiplexer at address 0x70
+	   with two NXP pca8574 GPIO expanders attached, one each to
+	   ports 3 and 4.
+	 */
+
+	mux@70 {
+		compatible = "nxp,pca9548";
+		reg = <0x70>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		i2c@3 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			reg = <3>;
+
+			gpio1: gpio@38 {
+				compatible = "nxp,pca8574";
+				reg = <0x38>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+		};
+		i2c@4 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			reg = <4>;
+
+			gpio2: gpio@38 {
+				compatible = "nxp,pca8574";
+				reg = <0x38>;
+				#gpio-cells = <2>;
+				gpio-controller;
+			};
+		};
+	};
diff --git a/trunk/drivers/i2c/i2c-mux.c b/trunk/drivers/i2c/i2c-mux.c
index 26ab31dd742b..1038c381aea5 100644
--- a/trunk/drivers/i2c/i2c-mux.c
+++ b/trunk/drivers/i2c/i2c-mux.c
@@ -24,6 +24,8 @@
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/i2c-mux.h>
+#include <linux/of.h>
+#include <linux/of_i2c.h>
 
 /* multiplexer per channel data */
 struct i2c_mux_priv {
@@ -125,6 +127,25 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
 	priv->adap.algo_data = priv;
 	priv->adap.dev.parent = &parent->dev;
 
+	/*
+	 * Try to populate the mux adapter's of_node, expands to
+	 * nothing if !CONFIG_OF.
+	 */
+	if (mux_dev->of_node) {
+		struct device_node *child;
+		u32 reg;
+
+		for_each_child_of_node(mux_dev->of_node, child) {
+			ret = of_property_read_u32(child, "reg", &reg);
+			if (ret)
+				continue;
+			if (chan_id == reg) {
+				priv->adap.dev.of_node = child;
+				break;
+			}
+		}
+	}
+
 	if (force_nr) {
 		priv->adap.nr = force_nr;
 		ret = i2c_add_numbered_adapter(&priv->adap);
@@ -142,6 +163,8 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
 	dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
 		 i2c_adapter_id(&priv->adap));
 
+	of_i2c_register_devices(&priv->adap);
+
 	return &priv->adap;
 }
 EXPORT_SYMBOL_GPL(i2c_add_mux_adapter);