Merge branch 'i2c-embedded/for-current' of git://git.pengutronix.de/git/wsa/linux (690efa08) · Commits · 戴 / test

Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt

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		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>;
		};
		};
		};

drivers/i2c/muxes/Kconfig

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		@@ -37,4 +37,16 @@ config I2C_MUX_PCA954x
		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

drivers/i2c/muxes/Makefile

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		@@ -4,5 +4,6 @@
		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

drivers/i2c/muxes/i2c-mux-pinctrl.c

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		/*
		* 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");

include/linux/i2c-mux-pinctrl.h

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		/*
		* 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

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