i2c: Add generic I2C multiplexer using pinctrl API

This is useful for SoCs whose I2C module's signals can be routed to different sets of pins at run-time, using the pinctrl API. +-----+ +-----+ | dev | | dev | +------------------------+ +-----+ +-----+ | SoC | | | | /----|------+--------+ | +---+ +------+ | child bus A, on first set of pins | |I2C|---|Pinmux| | | +---+ +------+ | child bus B, on second set of pins | \----|------+--------+--------+ | | | | | +------------------------+ +-----+ +-----+ +-----+ | dev | | dev | | dev | +-----+ +-----+ +-----+ Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: Add generic I2C multiplexer using pinctrl API
This is useful for SoCs whose I2C module's signals can be routed to different sets of pins at run-time, using the pinctrl API. +-----+ +-----+ | dev | | dev | +------------------------+ +-----+ +-----+ | SoC | | | | /----|------+--------+ | +---+ +------+ | child bus A, on first set of pins | |I2C|---|Pinmux| | | +---+ +------+ | child bus B, on second set of pins | \----|------+--------+--------+ | | | | | +------------------------+ +-----+ +-----+ +-----+ | dev | | dev | | dev | +-----+ +-----+ +-----+ Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Stephen Warren · Wolfram Sang
1 parent f8f5701bda
Showing 5 changed files with 426 additions and 0 deletions Side-by-side Diff
Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
drivers/i2c/muxes/Kconfig
drivers/i2c/muxes/Makefile
drivers/i2c/muxes/i2c-mux-pinctrl.c
include/linux/i2c-mux-pinctrl.h
+Pinctrl-based I2C Bus Mux
+
+This binding describes an I2C bus multiplexer that uses pin multiplexing to
+route the I2C signals, and represents the pin multiplexing configuration
+using the pinctrl device tree bindings.
+
+                                 +-----+  +-----+
+                                 | dev |  | dev |
+    +------------------------+   +-----+  +-----+
+    | SoC                    |      |        |
+    |                   /----|------+--------+
+    |   +---+   +------+     | child bus A, on first set of pins
+    |   |I2C|---|Pinmux|     |
+    |   +---+   +------+     | child bus B, on second set of pins
+    |                   \----|------+--------+--------+
+    |                        |      |        |        |
+    +------------------------+  +-----+  +-----+  +-----+
+                                | dev |  | dev |  | dev |
+                                +-----+  +-----+  +-----+
+
+Required properties:
+- compatible: i2c-mux-pinctrl
+- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
+  port is connected to.
+
+Also required are:
+
+* Standard pinctrl properties that specify the pin mux state for each child
+  bus. See ../pinctrl/pinctrl-bindings.txt.
+
+* Standard I2C mux properties. See mux.txt in this directory.
+
+* I2C child bus nodes. See mux.txt in this directory.
+
+For each named state defined in the pinctrl-names property, an I2C child bus
+will be created. I2C child bus numbers are assigned based on the index into
+the pinctrl-names property.
+
+The only exception is that no bus will be created for a state named "idle". If
+such a state is defined, it must be the last entry in pinctrl-names. For
+example:
+
+	pinctrl-names = "ddc", "pta", "idle"  ->  ddc = bus 0, pta = bus 1
+	pinctrl-names = "ddc", "idle", "pta"  ->  Invalid ("idle" not last)
+	pinctrl-names = "idle", "ddc", "pta"  ->  Invalid ("idle" not last)
+
+Whenever an access is made to a device on a child bus, the relevant pinctrl
+state will be programmed into hardware.
+
+If an idle state is defined, whenever an access is not being made to a device
+on a child bus, the idle pinctrl state will be programmed into hardware.
+
+If an idle state is not defined, the most recently used pinctrl state will be
+left programmed into hardware whenever no access is being made of a device on
+a child bus.
+
+Example:
+
+	i2cmux {
+		compatible = "i2c-mux-pinctrl";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		i2c-parent = <&i2c1>;
+
+		pinctrl-names = "ddc", "pta", "idle";
+		pinctrl-0 = <&state_i2cmux_ddc>;
+		pinctrl-1 = <&state_i2cmux_pta>;
+		pinctrl-2 = <&state_i2cmux_idle>;
+
+		i2c@0 {
+			reg = <0>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			eeprom {
+				compatible = "eeprom";
+				reg = <0x50>;
+			};
+		};
+
+		i2c@1 {
+			reg = <1>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			eeprom {
+				compatible = "eeprom";
+				reg = <0x50>;
+			};
+		};
+	};
@@ -37,5 +37,17 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-mux-pca954x.
  
+config I2C_MUX_PINCTRL
+	tristate "pinctrl-based I2C multiplexer"
+	depends on PINCTRL
+	help
+	  If you say yes to this option, support will be included for an I2C
+	  multiplexer that uses the pinctrl subsystem, i.e. pin multiplexing.
+	  This is useful for SoCs whose I2C module's signals can be routed to
+	  different sets of pins at run-time.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called pinctrl-i2cmux.
+
 endmenu
@@ -4,6 +4,7 @@
 obj-$(CONFIG_I2C_MUX_GPIO)	+= i2c-mux-gpio.o
 obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux-pca9541.o
 obj-$(CONFIG_I2C_MUX_PCA954x)	+= i2c-mux-pca954x.o
+obj-$(CONFIG_I2C_MUX_PINCTRL)	+= i2c-mux-pinctrl.o
  
 ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
+/*
+ * I2C multiplexer using pinctrl API
+ *
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of_i2c.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/i2c-mux-pinctrl.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+struct i2c_mux_pinctrl {
+	struct device *dev;
+	struct i2c_mux_pinctrl_platform_data *pdata;
+	struct pinctrl *pinctrl;
+	struct pinctrl_state **states;
+	struct pinctrl_state *state_idle;
+	struct i2c_adapter *parent;
+	struct i2c_adapter **busses;
+};
+
+static int i2c_mux_pinctrl_select(struct i2c_adapter *adap, void *data,
+				  u32 chan)
+{
+	struct i2c_mux_pinctrl *mux = data;
+
+	return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
+}
+
+static int i2c_mux_pinctrl_deselect(struct i2c_adapter *adap, void *data,
+				    u32 chan)
+{
+	struct i2c_mux_pinctrl *mux = data;
+
+	return pinctrl_select_state(mux->pinctrl, mux->state_idle);
+}
+
+#ifdef CONFIG_OF
+static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
+				struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	int num_names, i, ret;
+	struct device_node *adapter_np;
+	struct i2c_adapter *adapter;
+
+	if (!np)
+		return 0;
+
+	mux->pdata = devm_kzalloc(&pdev->dev, sizeof(*mux->pdata), GFP_KERNEL);
+	if (!mux->pdata) {
+		dev_err(mux->dev,
+			"Cannot allocate i2c_mux_pinctrl_platform_data\n");
+		return -ENOMEM;
+	}
+
+	num_names = of_property_count_strings(np, "pinctrl-names");
+	if (num_names < 0) {
+		dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
+			num_names);
+		return num_names;
+	}
+
+	mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
+		sizeof(*mux->pdata->pinctrl_states) * num_names,
+		GFP_KERNEL);
+	if (!mux->pdata->pinctrl_states) {
+		dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < num_names; i++) {
+		ret = of_property_read_string_index(np, "pinctrl-names", i,
+			&mux->pdata->pinctrl_states[mux->pdata->bus_count]);
+		if (ret < 0) {
+			dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
+				ret);
+			return ret;
+		}
+		if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
+			    "idle")) {
+			if (i != num_names - 1) {
+				dev_err(mux->dev, "idle state must be last\n");
+				return -EINVAL;
+			}
+			mux->pdata->pinctrl_state_idle = "idle";
+		} else {
+			mux->pdata->bus_count++;
+		}
+	}
+
+	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
+	if (!adapter_np) {
+		dev_err(mux->dev, "Cannot parse i2c-parent\n");
+		return -ENODEV;
+	}
+	adapter = of_find_i2c_adapter_by_node(adapter_np);
+	if (!adapter) {
+		dev_err(mux->dev, "Cannot find parent bus\n");
+		return -ENODEV;
+	}
+	mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
+	put_device(&adapter->dev);
+
+	return 0;
+}
+#else
+static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
+					   struct platform_device *pdev)
+{
+	return 0;
+}
+#endif
+
+static int __devinit i2c_mux_pinctrl_probe(struct platform_device *pdev)
+{
+	struct i2c_mux_pinctrl *mux;
+	int (*deselect)(struct i2c_adapter *, void *, u32);
+	int i, ret;
+
+	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
+	if (!mux) {
+		dev_err(&pdev->dev, "Cannot allocate i2c_mux_pinctrl\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+	platform_set_drvdata(pdev, mux);
+
+	mux->dev = &pdev->dev;
+
+	mux->pdata = pdev->dev.platform_data;
+	if (!mux->pdata) {
+		ret = i2c_mux_pinctrl_parse_dt(mux, pdev);
+		if (ret < 0)
+			goto err;
+	}
+	if (!mux->pdata) {
+		dev_err(&pdev->dev, "Missing platform data\n");
+		ret = -ENODEV;
+		goto err;
+	}
+
+	mux->states = devm_kzalloc(&pdev->dev,
+				   sizeof(*mux->states) * mux->pdata->bus_count,
+				   GFP_KERNEL);
+	if (!mux->states) {
+		dev_err(&pdev->dev, "Cannot allocate states\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	mux->busses = devm_kzalloc(&pdev->dev,
+				   sizeof(mux->busses) * mux->pdata->bus_count,
+				   GFP_KERNEL);
+	if (!mux->states) {
+		dev_err(&pdev->dev, "Cannot allocate busses\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	mux->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(mux->pinctrl)) {
+		ret = PTR_ERR(mux->pinctrl);
+		dev_err(&pdev->dev, "Cannot get pinctrl: %d\n", ret);
+		goto err;
+	}
+	for (i = 0; i < mux->pdata->bus_count; i++) {
+		mux->states[i] = pinctrl_lookup_state(mux->pinctrl,
+						mux->pdata->pinctrl_states[i]);
+			if (IS_ERR(mux->states[i])) {
+				ret = PTR_ERR(mux->states[i]);
+				dev_err(&pdev->dev,
+					"Cannot look up pinctrl state %s: %d\n",
+					mux->pdata->pinctrl_states[i], ret);
+				goto err;
+			}
+	}
+	if (mux->pdata->pinctrl_state_idle) {
+		mux->state_idle = pinctrl_lookup_state(mux->pinctrl,
+						mux->pdata->pinctrl_state_idle);
+		if (IS_ERR(mux->state_idle)) {
+			ret = PTR_ERR(mux->state_idle);
+			dev_err(&pdev->dev,
+				"Cannot look up pinctrl state %s: %d\n",
+				mux->pdata->pinctrl_state_idle, ret);
+			goto err;
+		}
+
+		deselect = i2c_mux_pinctrl_deselect;
+	} else {
+		deselect = NULL;
+	}
+
+	mux->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
+	if (!mux->parent) {
+		dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
+			mux->pdata->parent_bus_num);
+		ret = -ENODEV;
+		goto err;
+	}
+
+	for (i = 0; i < mux->pdata->bus_count; i++) {
+		u32 bus = mux->pdata->base_bus_num ?
+				(mux->pdata->base_bus_num + i) : 0;
+
+		mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
+						     mux, bus, i,
+						     i2c_mux_pinctrl_select,
+						     deselect);
+		if (!mux->busses[i]) {
+			ret = -ENODEV;
+			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
+			goto err_del_adapter;
+		}
+	}
+
+	return 0;
+
+err_del_adapter:
+	for (; i > 0; i--)
+		i2c_del_mux_adapter(mux->busses[i - 1]);
+	i2c_put_adapter(mux->parent);
+err:
+	return ret;
+}
+
+static int __devexit i2c_mux_pinctrl_remove(struct platform_device *pdev)
+{
+	struct i2c_mux_pinctrl *mux = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < mux->pdata->bus_count; i++)
+		i2c_del_mux_adapter(mux->busses[i]);
+
+	i2c_put_adapter(mux->parent);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id i2c_mux_pinctrl_of_match[] __devinitconst = {
+	{ .compatible = "i2c-mux-pinctrl", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);
+#endif
+
+static struct platform_driver i2c_mux_pinctrl_driver = {
+	.driver	= {
+		.name	= "i2c-mux-pinctrl",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match),
+	},
+	.probe	= i2c_mux_pinctrl_probe,
+	.remove	= __devexit_p(i2c_mux_pinctrl_remove),
+};
+module_platform_driver(i2c_mux_pinctrl_driver);
+
+MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");
+MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:i2c-mux-pinctrl");
+/*
+ * i2c-mux-pinctrl platform data
+ *
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _LINUX_I2C_MUX_PINCTRL_H
+#define _LINUX_I2C_MUX_PINCTRL_H
+
+/**
+ * struct i2c_mux_pinctrl_platform_data - Platform data for i2c-mux-pinctrl
+ * @parent_bus_num: Parent I2C bus number
+ * @base_bus_num: Base I2C bus number for the child busses. 0 for dynamic.
+ * @bus_count: Number of child busses. Also the number of elements in
+ *	@pinctrl_states
+ * @pinctrl_states: The names of the pinctrl state to select for each child bus
+ * @pinctrl_state_idle: The pinctrl state to select when no child bus is being
+ *	accessed. If NULL, the most recently used pinctrl state will be left
+ *	selected.
+ */
+struct i2c_mux_pinctrl_platform_data {
+	int parent_bus_num;
+	int base_bus_num;
+	int bus_count;
+	const char **pinctrl_states;
+	const char *pinctrl_state_idle;
+};
+
+#endif
	1	+Pinctrl-based I2C Bus Mux
	2	+
	3	+This binding describes an I2C bus multiplexer that uses pin multiplexing to
	4	+route the I2C signals, and represents the pin multiplexing configuration
	5	+using the pinctrl device tree bindings.
	6	+
	7	+ +-----+ +-----+
	8	+ \| dev \| \| dev \|
	9	+ +------------------------+ +-----+ +-----+
	10	+ \| SoC \| \| \|
	11	+ \| /----\|------+--------+
	12	+ \| +---+ +------+ \| child bus A, on first set of pins
	13	+ \| \|I2C\|---\|Pinmux\| \|
	14	+ \| +---+ +------+ \| child bus B, on second set of pins
	15	+ \| \----\|------+--------+--------+
	16	+ \| \| \| \| \|
	17	+ +------------------------+ +-----+ +-----+ +-----+
	18	+ \| dev \| \| dev \| \| dev \|
	19	+ +-----+ +-----+ +-----+
	20	+
	21	+Required properties:
	22	+- compatible: i2c-mux-pinctrl
	23	+- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
	24	+ port is connected to.
	25	+
	26	+Also required are:
	27	+
	28	+* Standard pinctrl properties that specify the pin mux state for each child
	29	+ bus. See ../pinctrl/pinctrl-bindings.txt.
	30	+
	31	+* Standard I2C mux properties. See mux.txt in this directory.
	32	+
	33	+* I2C child bus nodes. See mux.txt in this directory.
	34	+
	35	+For each named state defined in the pinctrl-names property, an I2C child bus
	36	+will be created. I2C child bus numbers are assigned based on the index into
	37	+the pinctrl-names property.
	38	+
	39	+The only exception is that no bus will be created for a state named "idle". If
	40	+such a state is defined, it must be the last entry in pinctrl-names. For
	41	+example:
	42	+
	43	+ pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1
	44	+ pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last)
	45	+ pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last)
	46	+
	47	+Whenever an access is made to a device on a child bus, the relevant pinctrl
	48	+state will be programmed into hardware.
	49	+
	50	+If an idle state is defined, whenever an access is not being made to a device
	51	+on a child bus, the idle pinctrl state will be programmed into hardware.
	52	+
	53	+If an idle state is not defined, the most recently used pinctrl state will be
	54	+left programmed into hardware whenever no access is being made of a device on
	55	+a child bus.
	56	+
	57	+Example:
	58	+
	59	+ i2cmux {
	60	+ compatible = "i2c-mux-pinctrl";
	61	+ #address-cells = <1>;
	62	+ #size-cells = <0>;
	63	+
	64	+ i2c-parent = <&i2c1>;
	65	+
	66	+ pinctrl-names = "ddc", "pta", "idle";
	67	+ pinctrl-0 = <&state_i2cmux_ddc>;
	68	+ pinctrl-1 = <&state_i2cmux_pta>;
	69	+ pinctrl-2 = <&state_i2cmux_idle>;
	70	+
	71	+ i2c@0 {
	72	+ reg = <0>;
	73	+ #address-cells = <1>;
	74	+ #size-cells = <0>;
	75	+
	76	+ eeprom {
	77	+ compatible = "eeprom";
	78	+ reg = <0x50>;
	79	+ };
	80	+ };
	81	+
	82	+ i2c@1 {
	83	+ reg = <1>;
	84	+ #address-cells = <1>;
	85	+ #size-cells = <0>;
	86	+
	87	+ eeprom {
	88	+ compatible = "eeprom";
	89	+ reg = <0x50>;
	90	+ };
	91	+ };
	92	+ };
...	...	@@ -37,5 +37,17 @@
37	37	This driver can also be built as a module. If so, the module
38	38	will be called i2c-mux-pca954x.
39	39
	40	+config I2C_MUX_PINCTRL
	41	+ tristate "pinctrl-based I2C multiplexer"
	42	+ depends on PINCTRL
	43	+ help
	44	+ If you say yes to this option, support will be included for an I2C
	45	+ multiplexer that uses the pinctrl subsystem, i.e. pin multiplexing.
	46	+ This is useful for SoCs whose I2C module's signals can be routed to
	47	+ different sets of pins at run-time.
	48	+
	49	+ This driver can also be built as a module. If so, the module will be
	50	+ called pinctrl-i2cmux.
	51	+
40	52	endmenu
...	...	@@ -4,6 +4,7 @@
4	4	obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o
5	5	obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
6	6	obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
	7	+obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
7	8
8	9	ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
	1	+/*
	2	+ * I2C multiplexer using pinctrl API
	3	+ *
	4	+ * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
	5	+ *
	6	+ * This program is free software; you can redistribute it and/or modify it
	7	+ * under the terms and conditions of the GNU General Public License,
	8	+ * version 2, as published by the Free Software Foundation.
	9	+ *
	10	+ * This program is distributed in the hope it will be useful, but WITHOUT
	11	+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	+ * more details.
	14	+ *
	15	+ * You should have received a copy of the GNU General Public License
	16	+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
	17	+ */
	18	+
	19	+#include <linux/i2c.h>
	20	+#include <linux/i2c-mux.h>
	21	+#include <linux/init.h>
	22	+#include <linux/module.h>
	23	+#include <linux/of_i2c.h>
	24	+#include <linux/pinctrl/consumer.h>
	25	+#include <linux/i2c-mux-pinctrl.h>
	26	+#include <linux/platform_device.h>
	27	+#include <linux/slab.h>
	28	+
	29	+struct i2c_mux_pinctrl {
	30	+ struct device *dev;
	31	+ struct i2c_mux_pinctrl_platform_data *pdata;
	32	+ struct pinctrl *pinctrl;
	33	+ struct pinctrl_state **states;
	34	+ struct pinctrl_state *state_idle;
	35	+ struct i2c_adapter *parent;
	36	+ struct i2c_adapter **busses;
	37	+};
	38	+
	39	+static int i2c_mux_pinctrl_select(struct i2c_adapter adap, void data,
	40	+ u32 chan)
	41	+{
	42	+ struct i2c_mux_pinctrl *mux = data;
	43	+
	44	+ return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
	45	+}
	46	+
	47	+static int i2c_mux_pinctrl_deselect(struct i2c_adapter adap, void data,
	48	+ u32 chan)
	49	+{
	50	+ struct i2c_mux_pinctrl *mux = data;
	51	+
	52	+ return pinctrl_select_state(mux->pinctrl, mux->state_idle);
	53	+}
	54	+
	55	+#ifdef CONFIG_OF
	56	+static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
	57	+ struct platform_device *pdev)
	58	+{
	59	+ struct device_node *np = pdev->dev.of_node;
	60	+ int num_names, i, ret;
	61	+ struct device_node *adapter_np;
	62	+ struct i2c_adapter *adapter;
	63	+
	64	+ if (!np)
	65	+ return 0;
	66	+
	67	+ mux->pdata = devm_kzalloc(&pdev->dev, sizeof(*mux->pdata), GFP_KERNEL);
	68	+ if (!mux->pdata) {
	69	+ dev_err(mux->dev,
	70	+ "Cannot allocate i2c_mux_pinctrl_platform_data\n");
	71	+ return -ENOMEM;
	72	+ }
	73	+
	74	+ num_names = of_property_count_strings(np, "pinctrl-names");
	75	+ if (num_names < 0) {
	76	+ dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
	77	+ num_names);
	78	+ return num_names;
	79	+ }
	80	+
	81	+ mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
	82	+ sizeof(mux->pdata->pinctrl_states) num_names,
	83	+ GFP_KERNEL);
	84	+ if (!mux->pdata->pinctrl_states) {
	85	+ dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
	86	+ return -ENOMEM;
	87	+ }
	88	+
	89	+ for (i = 0; i < num_names; i++) {
	90	+ ret = of_property_read_string_index(np, "pinctrl-names", i,
	91	+ &mux->pdata->pinctrl_states[mux->pdata->bus_count]);
	92	+ if (ret < 0) {
	93	+ dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
	94	+ ret);
	95	+ return ret;
	96	+ }
	97	+ if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
	98	+ "idle")) {
	99	+ if (i != num_names - 1) {
	100	+ dev_err(mux->dev, "idle state must be last\n");
	101	+ return -EINVAL;
	102	+ }
	103	+ mux->pdata->pinctrl_state_idle = "idle";
	104	+ } else {
	105	+ mux->pdata->bus_count++;
	106	+ }
	107	+ }
	108	+
	109	+ adapter_np = of_parse_phandle(np, "i2c-parent", 0);
	110	+ if (!adapter_np) {
	111	+ dev_err(mux->dev, "Cannot parse i2c-parent\n");
	112	+ return -ENODEV;
	113	+ }
	114	+ adapter = of_find_i2c_adapter_by_node(adapter_np);
	115	+ if (!adapter) {
	116	+ dev_err(mux->dev, "Cannot find parent bus\n");
	117	+ return -ENODEV;
	118	+ }
	119	+ mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
	120	+ put_device(&adapter->dev);
	121	+
	122	+ return 0;
	123	+}
	124	+#else
	125	+static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
	126	+ struct platform_device *pdev)
	127	+{
	128	+ return 0;
	129	+}
	130	+#endif
	131	+
	132	+static int __devinit i2c_mux_pinctrl_probe(struct platform_device *pdev)
	133	+{
	134	+ struct i2c_mux_pinctrl *mux;
	135	+ int (deselect)(struct i2c_adapter , void *, u32);
	136	+ int i, ret;
	137	+
	138	+ mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
	139	+ if (!mux) {
	140	+ dev_err(&pdev->dev, "Cannot allocate i2c_mux_pinctrl\n");
	141	+ ret = -ENOMEM;
	142	+ goto err;
	143	+ }
	144	+ platform_set_drvdata(pdev, mux);
	145	+
	146	+ mux->dev = &pdev->dev;
	147	+
	148	+ mux->pdata = pdev->dev.platform_data;
	149	+ if (!mux->pdata) {
	150	+ ret = i2c_mux_pinctrl_parse_dt(mux, pdev);
	151	+ if (ret < 0)
	152	+ goto err;
	153	+ }
	154	+ if (!mux->pdata) {
	155	+ dev_err(&pdev->dev, "Missing platform data\n");
	156	+ ret = -ENODEV;
	157	+ goto err;
	158	+ }
	159	+
	160	+ mux->states = devm_kzalloc(&pdev->dev,
	161	+ sizeof(mux->states) mux->pdata->bus_count,
	162	+ GFP_KERNEL);
	163	+ if (!mux->states) {
	164	+ dev_err(&pdev->dev, "Cannot allocate states\n");
	165	+ ret = -ENOMEM;
	166	+ goto err;
	167	+ }
	168	+
	169	+ mux->busses = devm_kzalloc(&pdev->dev,
	170	+ sizeof(mux->busses) * mux->pdata->bus_count,
	171	+ GFP_KERNEL);
	172	+ if (!mux->states) {
	173	+ dev_err(&pdev->dev, "Cannot allocate busses\n");
	174	+ ret = -ENOMEM;
	175	+ goto err;
	176	+ }
	177	+
	178	+ mux->pinctrl = devm_pinctrl_get(&pdev->dev);
	179	+ if (IS_ERR(mux->pinctrl)) {
	180	+ ret = PTR_ERR(mux->pinctrl);
	181	+ dev_err(&pdev->dev, "Cannot get pinctrl: %d\n", ret);
	182	+ goto err;
	183	+ }
	184	+ for (i = 0; i < mux->pdata->bus_count; i++) {
	185	+ mux->states[i] = pinctrl_lookup_state(mux->pinctrl,
	186	+ mux->pdata->pinctrl_states[i]);
	187	+ if (IS_ERR(mux->states[i])) {
	188	+ ret = PTR_ERR(mux->states[i]);
	189	+ dev_err(&pdev->dev,
	190	+ "Cannot look up pinctrl state %s: %d\n",
	191	+ mux->pdata->pinctrl_states[i], ret);
	192	+ goto err;
	193	+ }
	194	+ }
	195	+ if (mux->pdata->pinctrl_state_idle) {
	196	+ mux->state_idle = pinctrl_lookup_state(mux->pinctrl,
	197	+ mux->pdata->pinctrl_state_idle);
	198	+ if (IS_ERR(mux->state_idle)) {
	199	+ ret = PTR_ERR(mux->state_idle);
	200	+ dev_err(&pdev->dev,
	201	+ "Cannot look up pinctrl state %s: %d\n",
	202	+ mux->pdata->pinctrl_state_idle, ret);
	203	+ goto err;
	204	+ }
	205	+
	206	+ deselect = i2c_mux_pinctrl_deselect;
	207	+ } else {
	208	+ deselect = NULL;
	209	+ }
	210	+
	211	+ mux->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
	212	+ if (!mux->parent) {
	213	+ dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
	214	+ mux->pdata->parent_bus_num);
	215	+ ret = -ENODEV;
	216	+ goto err;
	217	+ }
	218	+
	219	+ for (i = 0; i < mux->pdata->bus_count; i++) {
	220	+ u32 bus = mux->pdata->base_bus_num ?
	221	+ (mux->pdata->base_bus_num + i) : 0;
	222	+
	223	+ mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
	224	+ mux, bus, i,
	225	+ i2c_mux_pinctrl_select,
	226	+ deselect);
	227	+ if (!mux->busses[i]) {
	228	+ ret = -ENODEV;
	229	+ dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
	230	+ goto err_del_adapter;
	231	+ }
	232	+ }
	233	+
	234	+ return 0;
	235	+
	236	+err_del_adapter:
	237	+ for (; i > 0; i--)
	238	+ i2c_del_mux_adapter(mux->busses[i - 1]);
	239	+ i2c_put_adapter(mux->parent);
	240	+err:
	241	+ return ret;
	242	+}
	243	+
	244	+static int __devexit i2c_mux_pinctrl_remove(struct platform_device *pdev)
	245	+{
	246	+ struct i2c_mux_pinctrl *mux = platform_get_drvdata(pdev);
	247	+ int i;
	248	+
	249	+ for (i = 0; i < mux->pdata->bus_count; i++)
	250	+ i2c_del_mux_adapter(mux->busses[i]);
	251	+
	252	+ i2c_put_adapter(mux->parent);
	253	+
	254	+ return 0;
	255	+}
	256	+
	257	+#ifdef CONFIG_OF
	258	+static const struct of_device_id i2c_mux_pinctrl_of_match[] __devinitconst = {
	259	+ { .compatible = "i2c-mux-pinctrl", },
	260	+ {},
	261	+};
	262	+MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);
	263	+#endif
	264	+
	265	+static struct platform_driver i2c_mux_pinctrl_driver = {
	266	+ .driver = {
	267	+ .name = "i2c-mux-pinctrl",
	268	+ .owner = THIS_MODULE,
	269	+ .of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match),
	270	+ },
	271	+ .probe = i2c_mux_pinctrl_probe,
	272	+ .remove = __devexit_p(i2c_mux_pinctrl_remove),
	273	+};
	274	+module_platform_driver(i2c_mux_pinctrl_driver);
	275	+
	276	+MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");
	277	+MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");
	278	+MODULE_LICENSE("GPL v2");
	279	+MODULE_ALIAS("platform:i2c-mux-pinctrl");
	1	+/*
	2	+ * i2c-mux-pinctrl platform data
	3	+ *
	4	+ * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
	5	+ *
	6	+ * This program is free software; you can redistribute it and/or modify it
	7	+ * under the terms and conditions of the GNU General Public License,
	8	+ * version 2, as published by the Free Software Foundation.
	9	+ *
	10	+ * This program is distributed in the hope it will be useful, but WITHOUT
	11	+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	+ * more details.
	14	+ *
	15	+ * You should have received a copy of the GNU General Public License
	16	+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
	17	+ */
	18	+
	19	+#ifndef _LINUX_I2C_MUX_PINCTRL_H
	20	+#define _LINUX_I2C_MUX_PINCTRL_H
	21	+
	22	+/**
	23	+ * struct i2c_mux_pinctrl_platform_data - Platform data for i2c-mux-pinctrl
	24	+ * @parent_bus_num: Parent I2C bus number
	25	+ * @base_bus_num: Base I2C bus number for the child busses. 0 for dynamic.
	26	+ * @bus_count: Number of child busses. Also the number of elements in
	27	+ * @pinctrl_states
	28	+ * @pinctrl_states: The names of the pinctrl state to select for each child bus
	29	+ * @pinctrl_state_idle: The pinctrl state to select when no child bus is being
	30	+ * accessed. If NULL, the most recently used pinctrl state will be left
	31	+ * selected.
	32	+ */
	33	+struct i2c_mux_pinctrl_platform_data {
	34	+ int parent_bus_num;
	35	+ int base_bus_num;
	36	+ int bus_count;
	37	+ const char **pinctrl_states;
	38	+ const char *pinctrl_state_idle;
	39	+};
	40	+
	41	+#endif