drivers/i2c/muxes/i2c-mux-ltc4306.c - linux - Git at Google

 /*
  * Linear Technology LTC4306 and LTC4305 I2C multiplexer/switch
  *
  * Copyright (C) 2017 Analog Devices Inc.
  *
  * Licensed under the GPL-2.
  *
  * Based on: i2c-mux-pca954x.c
  *
  * Datasheet: http://cds.linear.com/docs/en/datasheet/4306.pdf
  */

 #include <linux/gpio/consumer.h>
 #include <linux/gpio/driver.h>
 #include <linux/i2c-mux.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>

 #define LTC4305_MAX_NCHANS 2
 #define LTC4306_MAX_NCHANS 4

 #define LTC_REG_STATUS	0x0
 #define LTC_REG_CONFIG	0x1
 #define LTC_REG_MODE	0x2
 #define LTC_REG_SWITCH	0x3

 #define LTC_DOWNSTREAM_ACCL_EN	BIT(6)
 #define LTC_UPSTREAM_ACCL_EN	BIT(7)

 #define LTC_GPIO_ALL_INPUT	0xC0
 #define LTC_SWITCH_MASK		0xF0

 enum ltc_type {
 	ltc_4305,
 	ltc_4306,
 };

 struct chip_desc {
 	u8 nchans;
 	u8 num_gpios;
 };

 struct ltc4306 {
 	struct regmap *regmap;
 	struct gpio_chip gpiochip;
 	const struct chip_desc *chip;
 };

 static const struct chip_desc chips[] = {
 	[ltc_4305] = {
 		.nchans = LTC4305_MAX_NCHANS,
 	},
 	[ltc_4306] = {
 		.nchans = LTC4306_MAX_NCHANS,
 		.num_gpios = 2,
 	},
 };

 static bool ltc4306_is_volatile_reg(struct device *dev, unsigned int reg)
 {
 	return (reg == LTC_REG_CONFIG) ? true : false;
 }

 static const struct regmap_config ltc4306_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.max_register = LTC_REG_SWITCH,
 	.volatile_reg = ltc4306_is_volatile_reg,
 	.cache_type = REGCACHE_FLAT,
 };

 static int ltc4306_gpio_get(struct gpio_chip *chip, unsigned int offset)
 {
 	struct ltc4306 *data = gpiochip_get_data(chip);
 	unsigned int val;
 	int ret;

 	ret = regmap_read(data->regmap, LTC_REG_CONFIG, &val);
 	if (ret < 0)
 		return ret;

 	return !!(val & BIT(1 - offset));
 }

 static void ltc4306_gpio_set(struct gpio_chip *chip, unsigned int offset,
 			     int value)
 {
 	struct ltc4306 *data = gpiochip_get_data(chip);

 	regmap_update_bits(data->regmap, LTC_REG_CONFIG, BIT(5 - offset),
 			   value ? BIT(5 - offset) : 0);
 }

 static int ltc4306_gpio_get_direction(struct gpio_chip *chip,
 				      unsigned int offset)
 {
 	struct ltc4306 *data = gpiochip_get_data(chip);
 	unsigned int val;
 	int ret;

 	ret = regmap_read(data->regmap, LTC_REG_MODE, &val);
 	if (ret < 0)
 		return ret;

 	return !!(val & BIT(7 - offset));
 }

 static int ltc4306_gpio_direction_input(struct gpio_chip *chip,
 					unsigned int offset)
 {
 	struct ltc4306 *data = gpiochip_get_data(chip);

 	return regmap_update_bits(data->regmap, LTC_REG_MODE,
 				  BIT(7 - offset), BIT(7 - offset));
 }

 static int ltc4306_gpio_direction_output(struct gpio_chip *chip,
 					 unsigned int offset, int value)
 {
 	struct ltc4306 *data = gpiochip_get_data(chip);

 	ltc4306_gpio_set(chip, offset, value);
 	return regmap_update_bits(data->regmap, LTC_REG_MODE,
 				  BIT(7 - offset), 0);
 }

 static int ltc4306_gpio_set_config(struct gpio_chip *chip,
 				   unsigned int offset, unsigned long config)
 {
 	struct ltc4306 *data = gpiochip_get_data(chip);
 	unsigned int val;

 	switch (pinconf_to_config_param(config)) {
 	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
 		val = 0;
 		break;
 	case PIN_CONFIG_DRIVE_PUSH_PULL:
 		val = BIT(4 - offset);
 		break;
 	default:
 		return -ENOTSUPP;
 	}

 	return regmap_update_bits(data->regmap, LTC_REG_MODE,
 				  BIT(4 - offset), val);
 }

 static int ltc4306_gpio_init(struct ltc4306 *data)
 {
 	struct device *dev = regmap_get_device(data->regmap);

 	if (!data->chip->num_gpios)
 		return 0;

 	data->gpiochip.label = dev_name(dev);
 	data->gpiochip.base = -1;
 	data->gpiochip.ngpio = data->chip->num_gpios;
 	data->gpiochip.parent = dev;
 	data->gpiochip.can_sleep = true;
 	data->gpiochip.get_direction = ltc4306_gpio_get_direction;
 	data->gpiochip.direction_input = ltc4306_gpio_direction_input;
 	data->gpiochip.direction_output = ltc4306_gpio_direction_output;
 	data->gpiochip.get = ltc4306_gpio_get;
 	data->gpiochip.set = ltc4306_gpio_set;
 	data->gpiochip.set_config = ltc4306_gpio_set_config;
 	data->gpiochip.owner = THIS_MODULE;

 	/* gpiolib assumes all GPIOs default input */
 	regmap_write(data->regmap, LTC_REG_MODE, LTC_GPIO_ALL_INPUT);

 	return devm_gpiochip_add_data(dev, &data->gpiochip, data);
 }

 static int ltc4306_select_mux(struct i2c_mux_core *muxc, u32 chan)
 {
 	struct ltc4306 *data = i2c_mux_priv(muxc);

 	return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
 				  LTC_SWITCH_MASK, BIT(7 - chan));
 }

 static int ltc4306_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
 {
 	struct ltc4306 *data = i2c_mux_priv(muxc);

 	return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
 				  LTC_SWITCH_MASK, 0);
 }

 static const struct i2c_device_id ltc4306_id[] = {
 	{ "ltc4305", ltc_4305 },
 	{ "ltc4306", ltc_4306 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ltc4306_id);

 static const struct of_device_id ltc4306_of_match[] = {
 	{ .compatible = "lltc,ltc4305", .data = &chips[ltc_4305] },
 	{ .compatible = "lltc,ltc4306", .data = &chips[ltc_4306] },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ltc4306_of_match);

 static int ltc4306_probe(struct i2c_client *client)
 {
 	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
 	const struct chip_desc *chip;
 	struct i2c_mux_core *muxc;
 	struct ltc4306 *data;
 	struct gpio_desc *gpio;
 	bool idle_disc;
 	unsigned int val = 0;
 	int num, ret;

 	chip = of_device_get_match_data(&client->dev);

 	if (!chip)
 		chip = &chips[i2c_match_id(ltc4306_id, client)->driver_data];

 	idle_disc = device_property_read_bool(&client->dev,
 					      "i2c-mux-idle-disconnect");

 	muxc = i2c_mux_alloc(adap, &client->dev,
 			     chip->nchans, sizeof(*data),
 			     I2C_MUX_LOCKED, ltc4306_select_mux,
 			     idle_disc ? ltc4306_deselect_mux : NULL);
 	if (!muxc)
 		return -ENOMEM;
 	data = i2c_mux_priv(muxc);
 	data->chip = chip;

 	i2c_set_clientdata(client, muxc);

 	data->regmap = devm_regmap_init_i2c(client, &ltc4306_regmap_config);
 	if (IS_ERR(data->regmap)) {
 		ret = PTR_ERR(data->regmap);
 		dev_err(&client->dev, "Failed to allocate register map: %d\n",
 			ret);
 		return ret;
 	}

 	/* Reset and enable the mux if an enable GPIO is specified. */
 	gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_LOW);
 	if (IS_ERR(gpio))
 		return PTR_ERR(gpio);

 	if (gpio) {
 		udelay(1);
 		gpiod_set_value(gpio, 1);
 	}

 	/*
 	 * Write the mux register at addr to verify
 	 * that the mux is in fact present. This also
 	 * initializes the mux to disconnected state.
 	 */
 	if (regmap_write(data->regmap, LTC_REG_SWITCH, 0) < 0) {
 		dev_warn(&client->dev, "probe failed\n");
 		return -ENODEV;
 	}

 	if (device_property_read_bool(&client->dev,
 				      "ltc,downstream-accelerators-enable"))
 		val |= LTC_DOWNSTREAM_ACCL_EN;

 	if (device_property_read_bool(&client->dev,
 				      "ltc,upstream-accelerators-enable"))
 		val |= LTC_UPSTREAM_ACCL_EN;

 	if (regmap_write(data->regmap, LTC_REG_CONFIG, val) < 0)
 		return -ENODEV;

 	ret = ltc4306_gpio_init(data);
 	if (ret < 0)
 		return ret;

 	/* Now create an adapter for each channel */
 	for (num = 0; num < chip->nchans; num++) {
 		ret = i2c_mux_add_adapter(muxc, 0, num, 0);
 		if (ret) {
 			i2c_mux_del_adapters(muxc);
 			return ret;
 		}
 	}

 	dev_info(&client->dev,
 		 "registered %d multiplexed busses for I2C switch %s\n",
 		 num, client->name);

 	return 0;
 }

 static int ltc4306_remove(struct i2c_client *client)
 {
 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);

 	i2c_mux_del_adapters(muxc);

 	return 0;
 }

 static struct i2c_driver ltc4306_driver = {
 	.driver		= {
 		.name	= "ltc4306",
 		.of_match_table = of_match_ptr(ltc4306_of_match),
 	},
 	.probe_new	= ltc4306_probe,
 	.remove		= ltc4306_remove,
 	.id_table	= ltc4306_id,
 };

 module_i2c_driver(ltc4306_driver);

 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 MODULE_DESCRIPTION("Linear Technology LTC4306, LTC4305 I2C mux/switch driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Linear Technology LTC4306 and LTC4305 I2C multiplexer/switch
	*
	* Copyright (C) 2017 Analog Devices Inc.
	*
	* Licensed under the GPL-2.
	*
	* Based on: i2c-mux-pca954x.c
	*
	* Datasheet: http://cds.linear.com/docs/en/datasheet/4306.pdf
	*/

	#include <linux/gpio/consumer.h>
	#include <linux/gpio/driver.h>
	#include <linux/i2c-mux.h>
	#include <linux/i2c.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/property.h>
	#include <linux/regmap.h>
	#include <linux/slab.h>

	#define LTC4305_MAX_NCHANS 2
	#define LTC4306_MAX_NCHANS 4

	#define LTC_REG_STATUS 0x0
	#define LTC_REG_CONFIG 0x1
	#define LTC_REG_MODE 0x2
	#define LTC_REG_SWITCH 0x3

	#define LTC_DOWNSTREAM_ACCL_EN BIT(6)
	#define LTC_UPSTREAM_ACCL_EN BIT(7)

	#define LTC_GPIO_ALL_INPUT 0xC0
	#define LTC_SWITCH_MASK 0xF0

	enum ltc_type {
	ltc_4305,
	ltc_4306,
	};

	struct chip_desc {
	u8 nchans;
	u8 num_gpios;
	};

	struct ltc4306 {
	struct regmap *regmap;
	struct gpio_chip gpiochip;
	const struct chip_desc *chip;
	};

	static const struct chip_desc chips[] = {
	[ltc_4305] = {
	.nchans = LTC4305_MAX_NCHANS,
	},
	[ltc_4306] = {
	.nchans = LTC4306_MAX_NCHANS,
	.num_gpios = 2,
	},
	};

	static bool ltc4306_is_volatile_reg(struct device *dev, unsigned int reg)
	{
	return (reg == LTC_REG_CONFIG) ? true : false;
	}

	static const struct regmap_config ltc4306_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = LTC_REG_SWITCH,
	.volatile_reg = ltc4306_is_volatile_reg,
	.cache_type = REGCACHE_FLAT,
	};

	static int ltc4306_gpio_get(struct gpio_chip *chip, unsigned int offset)
	{
	struct ltc4306 *data = gpiochip_get_data(chip);
	unsigned int val;
	int ret;

	ret = regmap_read(data->regmap, LTC_REG_CONFIG, &val);
	if (ret < 0)
	return ret;

	return !!(val & BIT(1 - offset));
	}

	static void ltc4306_gpio_set(struct gpio_chip *chip, unsigned int offset,
	int value)
	{
	struct ltc4306 *data = gpiochip_get_data(chip);

	regmap_update_bits(data->regmap, LTC_REG_CONFIG, BIT(5 - offset),
	value ? BIT(5 - offset) : 0);
	}

	static int ltc4306_gpio_get_direction(struct gpio_chip *chip,
	unsigned int offset)
	{
	struct ltc4306 *data = gpiochip_get_data(chip);
	unsigned int val;
	int ret;

	ret = regmap_read(data->regmap, LTC_REG_MODE, &val);
	if (ret < 0)
	return ret;

	return !!(val & BIT(7 - offset));
	}

	static int ltc4306_gpio_direction_input(struct gpio_chip *chip,
	unsigned int offset)
	{
	struct ltc4306 *data = gpiochip_get_data(chip);

	return regmap_update_bits(data->regmap, LTC_REG_MODE,
	BIT(7 - offset), BIT(7 - offset));
	}

	static int ltc4306_gpio_direction_output(struct gpio_chip *chip,
	unsigned int offset, int value)
	{
	struct ltc4306 *data = gpiochip_get_data(chip);

	ltc4306_gpio_set(chip, offset, value);
	return regmap_update_bits(data->regmap, LTC_REG_MODE,
	BIT(7 - offset), 0);
	}

	static int ltc4306_gpio_set_config(struct gpio_chip *chip,
	unsigned int offset, unsigned long config)
	{
	struct ltc4306 *data = gpiochip_get_data(chip);
	unsigned int val;

	switch (pinconf_to_config_param(config)) {
	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
	val = 0;
	break;
	case PIN_CONFIG_DRIVE_PUSH_PULL:
	val = BIT(4 - offset);
	break;
	default:
	return -ENOTSUPP;
	}

	return regmap_update_bits(data->regmap, LTC_REG_MODE,
	BIT(4 - offset), val);
	}

	static int ltc4306_gpio_init(struct ltc4306 *data)
	{
	struct device *dev = regmap_get_device(data->regmap);

	if (!data->chip->num_gpios)
	return 0;

	data->gpiochip.label = dev_name(dev);
	data->gpiochip.base = -1;
	data->gpiochip.ngpio = data->chip->num_gpios;
	data->gpiochip.parent = dev;
	data->gpiochip.can_sleep = true;
	data->gpiochip.get_direction = ltc4306_gpio_get_direction;
	data->gpiochip.direction_input = ltc4306_gpio_direction_input;
	data->gpiochip.direction_output = ltc4306_gpio_direction_output;
	data->gpiochip.get = ltc4306_gpio_get;
	data->gpiochip.set = ltc4306_gpio_set;
	data->gpiochip.set_config = ltc4306_gpio_set_config;
	data->gpiochip.owner = THIS_MODULE;

	/* gpiolib assumes all GPIOs default input */
	regmap_write(data->regmap, LTC_REG_MODE, LTC_GPIO_ALL_INPUT);

	return devm_gpiochip_add_data(dev, &data->gpiochip, data);
	}

	static int ltc4306_select_mux(struct i2c_mux_core *muxc, u32 chan)
	{
	struct ltc4306 *data = i2c_mux_priv(muxc);

	return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
	LTC_SWITCH_MASK, BIT(7 - chan));
	}

	static int ltc4306_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
	{
	struct ltc4306 *data = i2c_mux_priv(muxc);

	return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
	LTC_SWITCH_MASK, 0);
	}

	static const struct i2c_device_id ltc4306_id[] = {
	{ "ltc4305", ltc_4305 },
	{ "ltc4306", ltc_4306 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, ltc4306_id);

	static const struct of_device_id ltc4306_of_match[] = {
	{ .compatible = "lltc,ltc4305", .data = &chips[ltc_4305] },
	{ .compatible = "lltc,ltc4306", .data = &chips[ltc_4306] },
	{ }
	};
	MODULE_DEVICE_TABLE(of, ltc4306_of_match);

	static int ltc4306_probe(struct i2c_client *client)
	{
	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
	const struct chip_desc *chip;
	struct i2c_mux_core *muxc;
	struct ltc4306 *data;
	struct gpio_desc *gpio;
	bool idle_disc;
	unsigned int val = 0;
	int num, ret;

	chip = of_device_get_match_data(&client->dev);

	if (!chip)
	chip = &chips[i2c_match_id(ltc4306_id, client)->driver_data];

	idle_disc = device_property_read_bool(&client->dev,
	"i2c-mux-idle-disconnect");

	muxc = i2c_mux_alloc(adap, &client->dev,
	chip->nchans, sizeof(*data),
	I2C_MUX_LOCKED, ltc4306_select_mux,
	idle_disc ? ltc4306_deselect_mux : NULL);
	if (!muxc)
	return -ENOMEM;
	data = i2c_mux_priv(muxc);
	data->chip = chip;

	i2c_set_clientdata(client, muxc);

	data->regmap = devm_regmap_init_i2c(client, &ltc4306_regmap_config);
	if (IS_ERR(data->regmap)) {
	ret = PTR_ERR(data->regmap);
	dev_err(&client->dev, "Failed to allocate register map: %d\n",
	ret);
	return ret;
	}

	/* Reset and enable the mux if an enable GPIO is specified. */
	gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_LOW);
	if (IS_ERR(gpio))
	return PTR_ERR(gpio);

	if (gpio) {
	udelay(1);
	gpiod_set_value(gpio, 1);
	}

	/*
	* Write the mux register at addr to verify
	* that the mux is in fact present. This also
	* initializes the mux to disconnected state.
	*/
	if (regmap_write(data->regmap, LTC_REG_SWITCH, 0) < 0) {
	dev_warn(&client->dev, "probe failed\n");
	return -ENODEV;
	}

	if (device_property_read_bool(&client->dev,
	"ltc,downstream-accelerators-enable"))
	val \|= LTC_DOWNSTREAM_ACCL_EN;

	if (device_property_read_bool(&client->dev,
	"ltc,upstream-accelerators-enable"))
	val \|= LTC_UPSTREAM_ACCL_EN;

	if (regmap_write(data->regmap, LTC_REG_CONFIG, val) < 0)
	return -ENODEV;

	ret = ltc4306_gpio_init(data);
	if (ret < 0)
	return ret;

	/* Now create an adapter for each channel */
	for (num = 0; num < chip->nchans; num++) {
	ret = i2c_mux_add_adapter(muxc, 0, num, 0);
	if (ret) {
	i2c_mux_del_adapters(muxc);
	return ret;
	}
	}

	dev_info(&client->dev,
	"registered %d multiplexed busses for I2C switch %s\n",
	num, client->name);

	return 0;
	}

	static int ltc4306_remove(struct i2c_client *client)
	{
	struct i2c_mux_core *muxc = i2c_get_clientdata(client);

	i2c_mux_del_adapters(muxc);

	return 0;
	}

	static struct i2c_driver ltc4306_driver = {
	.driver = {
	.name = "ltc4306",
	.of_match_table = of_match_ptr(ltc4306_of_match),
	},
	.probe_new = ltc4306_probe,
	.remove = ltc4306_remove,
	.id_table = ltc4306_id,
	};

	module_i2c_driver(ltc4306_driver);

	MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
	MODULE_DESCRIPTION("Linear Technology LTC4306, LTC4305 I2C mux/switch driver");
	MODULE_LICENSE("GPL v2");