forked from mirrors/linux
		
	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>
			
			
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										93
									
								
								Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
									
									
									
									
									
										Normal file
									
								
							
							
						
						
									
										93
									
								
								Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
									
									
									
									
									
										Normal file
									
								
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					@ -0,0 +1,93 @@
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					Pinctrl-based I2C Bus Mux
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					This binding describes an I2C bus multiplexer that uses pin multiplexing to
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					route the I2C signals, and represents the pin multiplexing configuration
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					using the pinctrl device tree bindings.
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					                                 +-----+  +-----+
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					                                 | dev |  | dev |
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					    +------------------------+   +-----+  +-----+
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					    | SoC                    |      |        |
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					    |                   /----|------+--------+
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					    |   +---+   +------+     | child bus A, on first set of pins
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					    |   |I2C|---|Pinmux|     |
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					    |   +---+   +------+     | child bus B, on second set of pins
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					    |                   \----|------+--------+--------+
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					    |                        |      |        |        |
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					    +------------------------+  +-----+  +-----+  +-----+
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					                                | dev |  | dev |  | dev |
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					                                +-----+  +-----+  +-----+
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					Required properties:
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					- compatible: i2c-mux-pinctrl
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					- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
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					  port is connected to.
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					Also required are:
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					* Standard pinctrl properties that specify the pin mux state for each child
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					  bus. See ../pinctrl/pinctrl-bindings.txt.
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					* Standard I2C mux properties. See mux.txt in this directory.
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					* I2C child bus nodes. See mux.txt in this directory.
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					For each named state defined in the pinctrl-names property, an I2C child bus
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					will be created. I2C child bus numbers are assigned based on the index into
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					the pinctrl-names property.
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					The only exception is that no bus will be created for a state named "idle". If
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					such a state is defined, it must be the last entry in pinctrl-names. For
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					example:
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						pinctrl-names = "ddc", "pta", "idle"  ->  ddc = bus 0, pta = bus 1
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						pinctrl-names = "ddc", "idle", "pta"  ->  Invalid ("idle" not last)
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						pinctrl-names = "idle", "ddc", "pta"  ->  Invalid ("idle" not last)
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					Whenever an access is made to a device on a child bus, the relevant pinctrl
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					state will be programmed into hardware.
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					If an idle state is defined, whenever an access is not being made to a device
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					on a child bus, the idle pinctrl state will be programmed into hardware.
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					If an idle state is not defined, the most recently used pinctrl state will be
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					left programmed into hardware whenever no access is being made of a device on
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					a child bus.
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					Example:
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						i2cmux {
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							compatible = "i2c-mux-pinctrl";
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							#address-cells = <1>;
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							#size-cells = <0>;
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							i2c-parent = <&i2c1>;
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							pinctrl-names = "ddc", "pta", "idle";
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							pinctrl-0 = <&state_i2cmux_ddc>;
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							pinctrl-1 = <&state_i2cmux_pta>;
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							pinctrl-2 = <&state_i2cmux_idle>;
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							i2c@0 {
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								reg = <0>;
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								#address-cells = <1>;
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								#size-cells = <0>;
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								eeprom {
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									compatible = "eeprom";
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									reg = <0x50>;
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								};
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							};
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							i2c@1 {
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								reg = <1>;
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								#address-cells = <1>;
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								#size-cells = <0>;
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								eeprom {
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									compatible = "eeprom";
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									reg = <0x50>;
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								};
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							};
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						};
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					@ -37,4 +37,16 @@ config I2C_MUX_PCA954x
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	  This driver can also be built as a module.  If so, the module
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						  This driver can also be built as a module.  If so, the module
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	  will be called i2c-mux-pca954x.
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						  will be called i2c-mux-pca954x.
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					config I2C_MUX_PINCTRL
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						tristate "pinctrl-based I2C multiplexer"
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						depends on PINCTRL
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						help
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						  If you say yes to this option, support will be included for an I2C
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						  multiplexer that uses the pinctrl subsystem, i.e. pin multiplexing.
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						  This is useful for SoCs whose I2C module's signals can be routed to
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						  different sets of pins at run-time.
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						  This driver can also be built as a module. If so, the module will be
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						  called pinctrl-i2cmux.
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endmenu
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					endmenu
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					@ -4,5 +4,6 @@
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obj-$(CONFIG_I2C_MUX_GPIO)	+= i2c-mux-gpio.o
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					obj-$(CONFIG_I2C_MUX_GPIO)	+= i2c-mux-gpio.o
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obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux-pca9541.o
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					obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux-pca9541.o
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obj-$(CONFIG_I2C_MUX_PCA954x)	+= i2c-mux-pca954x.o
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					obj-$(CONFIG_I2C_MUX_PCA954x)	+= i2c-mux-pca954x.o
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					obj-$(CONFIG_I2C_MUX_PINCTRL)	+= i2c-mux-pinctrl.o
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ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
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					ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
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										279
									
								
								drivers/i2c/muxes/i2c-mux-pinctrl.c
									
									
									
									
									
										Normal file
									
								
							
							
						
						
									
										279
									
								
								drivers/i2c/muxes/i2c-mux-pinctrl.c
									
									
									
									
									
										Normal file
									
								
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					@ -0,0 +1,279 @@
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					/*
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					 * I2C multiplexer using pinctrl API
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					 *
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					 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
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					 *
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					 * This program is free software; you can redistribute it and/or modify it
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					 * under the terms and conditions of the GNU General Public License,
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					 * version 2, as published by the Free Software Foundation.
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					 *
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					 * This program is distributed in the hope it will be useful, but WITHOUT
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					 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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					 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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					 * more details.
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					 *
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					 * You should have received a copy of the GNU General Public License
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					 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
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					 */
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					#include <linux/i2c.h>
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					#include <linux/i2c-mux.h>
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					#include <linux/init.h>
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					#include <linux/module.h>
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					#include <linux/of_i2c.h>
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					#include <linux/pinctrl/consumer.h>
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					#include <linux/i2c-mux-pinctrl.h>
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					#include <linux/platform_device.h>
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					#include <linux/slab.h>
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					struct i2c_mux_pinctrl {
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						struct device *dev;
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						struct i2c_mux_pinctrl_platform_data *pdata;
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						struct pinctrl *pinctrl;
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						struct pinctrl_state **states;
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						struct pinctrl_state *state_idle;
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						struct i2c_adapter *parent;
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						struct i2c_adapter **busses;
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					};
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					static int i2c_mux_pinctrl_select(struct i2c_adapter *adap, void *data,
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									  u32 chan)
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					{
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						struct i2c_mux_pinctrl *mux = data;
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						return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
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					}
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					static int i2c_mux_pinctrl_deselect(struct i2c_adapter *adap, void *data,
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									    u32 chan)
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					{
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						struct i2c_mux_pinctrl *mux = data;
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						return pinctrl_select_state(mux->pinctrl, mux->state_idle);
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					}
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					#ifdef CONFIG_OF
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					static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
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									struct platform_device *pdev)
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					{
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						struct device_node *np = pdev->dev.of_node;
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						int num_names, i, ret;
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						struct device_node *adapter_np;
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						struct i2c_adapter *adapter;
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						if (!np)
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							return 0;
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						mux->pdata = devm_kzalloc(&pdev->dev, sizeof(*mux->pdata), GFP_KERNEL);
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						if (!mux->pdata) {
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							dev_err(mux->dev,
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								"Cannot allocate i2c_mux_pinctrl_platform_data\n");
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							return -ENOMEM;
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						}
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						num_names = of_property_count_strings(np, "pinctrl-names");
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						if (num_names < 0) {
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							dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
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								num_names);
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							return num_names;
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						}
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						mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
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							sizeof(*mux->pdata->pinctrl_states) * num_names,
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							GFP_KERNEL);
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						if (!mux->pdata->pinctrl_states) {
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							dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
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							return -ENOMEM;
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						}
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						for (i = 0; i < num_names; i++) {
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							ret = of_property_read_string_index(np, "pinctrl-names", i,
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								&mux->pdata->pinctrl_states[mux->pdata->bus_count]);
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							if (ret < 0) {
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								dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
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									ret);
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								return ret;
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							}
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							if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
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								    "idle")) {
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								if (i != num_names - 1) {
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									dev_err(mux->dev, "idle state must be last\n");
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									return -EINVAL;
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								}
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								mux->pdata->pinctrl_state_idle = "idle";
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							} else {
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								mux->pdata->bus_count++;
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							}
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						}
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						adapter_np = of_parse_phandle(np, "i2c-parent", 0);
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						if (!adapter_np) {
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							dev_err(mux->dev, "Cannot parse i2c-parent\n");
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							return -ENODEV;
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						}
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						adapter = of_find_i2c_adapter_by_node(adapter_np);
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						if (!adapter) {
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							dev_err(mux->dev, "Cannot find parent bus\n");
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							return -ENODEV;
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						}
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						mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
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						put_device(&adapter->dev);
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						return 0;
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					}
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					#else
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					static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
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										   struct platform_device *pdev)
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					{
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						return 0;
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					}
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					#endif
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					static int __devinit i2c_mux_pinctrl_probe(struct platform_device *pdev)
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					{
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						struct i2c_mux_pinctrl *mux;
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						int (*deselect)(struct i2c_adapter *, void *, u32);
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						int i, ret;
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						mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
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						if (!mux) {
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							dev_err(&pdev->dev, "Cannot allocate i2c_mux_pinctrl\n");
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							ret = -ENOMEM;
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							goto err;
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						}
 | 
				
			||||||
 | 
						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");
 | 
				
			||||||
							
								
								
									
										41
									
								
								include/linux/i2c-mux-pinctrl.h
									
									
									
									
									
										Normal file
									
								
							
							
						
						
									
										41
									
								
								include/linux/i2c-mux-pinctrl.h
									
									
									
									
									
										Normal file
									
								
							| 
						 | 
					@ -0,0 +1,41 @@
 | 
				
			||||||
 | 
					/*
 | 
				
			||||||
 | 
					 * 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
 | 
				
			||||||
		Loading…
	
		Reference in a new issue