322 строки
7.6 KiB
C
322 строки
7.6 KiB
C
/*
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* Linear Technology LTC4306 and LTC4305 I2C multiplexer/switch
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*
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* Copyright (C) 2017 Analog Devices Inc.
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*
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* Licensed under the GPL-2.
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*
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* Based on: i2c-mux-pca954x.c
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*
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* Datasheet: http://cds.linear.com/docs/en/datasheet/4306.pdf
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*/
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#include <linux/gpio/consumer.h>
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#include <linux/gpio/driver.h>
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#include <linux/i2c-mux.h>
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#include <linux/i2c.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/property.h>
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#include <linux/regmap.h>
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#include <linux/slab.h>
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#define LTC4305_MAX_NCHANS 2
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#define LTC4306_MAX_NCHANS 4
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#define LTC_REG_STATUS 0x0
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#define LTC_REG_CONFIG 0x1
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#define LTC_REG_MODE 0x2
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#define LTC_REG_SWITCH 0x3
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#define LTC_DOWNSTREAM_ACCL_EN BIT(6)
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#define LTC_UPSTREAM_ACCL_EN BIT(7)
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#define LTC_GPIO_ALL_INPUT 0xC0
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#define LTC_SWITCH_MASK 0xF0
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enum ltc_type {
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ltc_4305,
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ltc_4306,
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};
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struct chip_desc {
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u8 nchans;
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u8 num_gpios;
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};
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struct ltc4306 {
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struct regmap *regmap;
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struct gpio_chip gpiochip;
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const struct chip_desc *chip;
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};
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static const struct chip_desc chips[] = {
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[ltc_4305] = {
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.nchans = LTC4305_MAX_NCHANS,
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},
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[ltc_4306] = {
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.nchans = LTC4306_MAX_NCHANS,
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.num_gpios = 2,
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},
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};
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static bool ltc4306_is_volatile_reg(struct device *dev, unsigned int reg)
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{
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return (reg == LTC_REG_CONFIG) ? true : false;
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}
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static const struct regmap_config ltc4306_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = LTC_REG_SWITCH,
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.volatile_reg = ltc4306_is_volatile_reg,
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.cache_type = REGCACHE_FLAT,
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};
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static int ltc4306_gpio_get(struct gpio_chip *chip, unsigned int offset)
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{
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struct ltc4306 *data = gpiochip_get_data(chip);
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unsigned int val;
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int ret;
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ret = regmap_read(data->regmap, LTC_REG_CONFIG, &val);
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if (ret < 0)
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return ret;
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return !!(val & BIT(1 - offset));
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}
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static void ltc4306_gpio_set(struct gpio_chip *chip, unsigned int offset,
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int value)
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{
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struct ltc4306 *data = gpiochip_get_data(chip);
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regmap_update_bits(data->regmap, LTC_REG_CONFIG, BIT(5 - offset),
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value ? BIT(5 - offset) : 0);
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}
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static int ltc4306_gpio_get_direction(struct gpio_chip *chip,
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unsigned int offset)
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{
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struct ltc4306 *data = gpiochip_get_data(chip);
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unsigned int val;
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int ret;
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ret = regmap_read(data->regmap, LTC_REG_MODE, &val);
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if (ret < 0)
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return ret;
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return !!(val & BIT(7 - offset));
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}
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static int ltc4306_gpio_direction_input(struct gpio_chip *chip,
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unsigned int offset)
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{
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struct ltc4306 *data = gpiochip_get_data(chip);
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return regmap_update_bits(data->regmap, LTC_REG_MODE,
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BIT(7 - offset), BIT(7 - offset));
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}
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static int ltc4306_gpio_direction_output(struct gpio_chip *chip,
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unsigned int offset, int value)
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{
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struct ltc4306 *data = gpiochip_get_data(chip);
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ltc4306_gpio_set(chip, offset, value);
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return regmap_update_bits(data->regmap, LTC_REG_MODE,
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BIT(7 - offset), 0);
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}
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static int ltc4306_gpio_set_config(struct gpio_chip *chip,
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unsigned int offset, unsigned long config)
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{
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struct ltc4306 *data = gpiochip_get_data(chip);
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unsigned int val;
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switch (pinconf_to_config_param(config)) {
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case PIN_CONFIG_DRIVE_OPEN_DRAIN:
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val = 0;
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break;
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case PIN_CONFIG_DRIVE_PUSH_PULL:
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val = BIT(4 - offset);
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break;
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default:
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return -ENOTSUPP;
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}
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return regmap_update_bits(data->regmap, LTC_REG_MODE,
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BIT(4 - offset), val);
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}
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static int ltc4306_gpio_init(struct ltc4306 *data)
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{
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struct device *dev = regmap_get_device(data->regmap);
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if (!data->chip->num_gpios)
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return 0;
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data->gpiochip.label = dev_name(dev);
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data->gpiochip.base = -1;
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data->gpiochip.ngpio = data->chip->num_gpios;
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data->gpiochip.parent = dev;
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data->gpiochip.can_sleep = true;
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data->gpiochip.get_direction = ltc4306_gpio_get_direction;
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data->gpiochip.direction_input = ltc4306_gpio_direction_input;
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data->gpiochip.direction_output = ltc4306_gpio_direction_output;
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data->gpiochip.get = ltc4306_gpio_get;
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data->gpiochip.set = ltc4306_gpio_set;
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data->gpiochip.set_config = ltc4306_gpio_set_config;
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data->gpiochip.owner = THIS_MODULE;
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/* gpiolib assumes all GPIOs default input */
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regmap_write(data->regmap, LTC_REG_MODE, LTC_GPIO_ALL_INPUT);
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return devm_gpiochip_add_data(dev, &data->gpiochip, data);
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}
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static int ltc4306_select_mux(struct i2c_mux_core *muxc, u32 chan)
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{
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struct ltc4306 *data = i2c_mux_priv(muxc);
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return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
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LTC_SWITCH_MASK, BIT(7 - chan));
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}
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static int ltc4306_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
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{
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struct ltc4306 *data = i2c_mux_priv(muxc);
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return regmap_update_bits(data->regmap, LTC_REG_SWITCH,
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LTC_SWITCH_MASK, 0);
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}
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static const struct i2c_device_id ltc4306_id[] = {
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{ "ltc4305", ltc_4305 },
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{ "ltc4306", ltc_4306 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ltc4306_id);
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static const struct of_device_id ltc4306_of_match[] = {
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{ .compatible = "lltc,ltc4305", .data = &chips[ltc_4305] },
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{ .compatible = "lltc,ltc4306", .data = &chips[ltc_4306] },
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{ }
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};
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MODULE_DEVICE_TABLE(of, ltc4306_of_match);
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static int ltc4306_probe(struct i2c_client *client)
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{
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struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
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const struct chip_desc *chip;
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struct i2c_mux_core *muxc;
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struct ltc4306 *data;
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struct gpio_desc *gpio;
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bool idle_disc;
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unsigned int val = 0;
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int num, ret;
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chip = of_device_get_match_data(&client->dev);
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if (!chip)
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chip = &chips[i2c_match_id(ltc4306_id, client)->driver_data];
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idle_disc = device_property_read_bool(&client->dev,
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"i2c-mux-idle-disconnect");
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muxc = i2c_mux_alloc(adap, &client->dev,
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chip->nchans, sizeof(*data),
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I2C_MUX_LOCKED, ltc4306_select_mux,
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idle_disc ? ltc4306_deselect_mux : NULL);
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if (!muxc)
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return -ENOMEM;
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data = i2c_mux_priv(muxc);
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data->chip = chip;
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i2c_set_clientdata(client, muxc);
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data->regmap = devm_regmap_init_i2c(client, <c4306_regmap_config);
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if (IS_ERR(data->regmap)) {
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ret = PTR_ERR(data->regmap);
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dev_err(&client->dev, "Failed to allocate register map: %d\n",
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ret);
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return ret;
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}
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/* Reset and enable the mux if an enable GPIO is specified. */
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gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_LOW);
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if (IS_ERR(gpio))
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return PTR_ERR(gpio);
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if (gpio) {
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udelay(1);
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gpiod_set_value(gpio, 1);
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}
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/*
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* Write the mux register at addr to verify
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* that the mux is in fact present. This also
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* initializes the mux to disconnected state.
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*/
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if (regmap_write(data->regmap, LTC_REG_SWITCH, 0) < 0) {
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dev_warn(&client->dev, "probe failed\n");
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return -ENODEV;
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}
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if (device_property_read_bool(&client->dev,
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"ltc,downstream-accelerators-enable"))
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val |= LTC_DOWNSTREAM_ACCL_EN;
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if (device_property_read_bool(&client->dev,
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"ltc,upstream-accelerators-enable"))
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val |= LTC_UPSTREAM_ACCL_EN;
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if (regmap_write(data->regmap, LTC_REG_CONFIG, val) < 0)
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return -ENODEV;
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ret = ltc4306_gpio_init(data);
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if (ret < 0)
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return ret;
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/* Now create an adapter for each channel */
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for (num = 0; num < chip->nchans; num++) {
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ret = i2c_mux_add_adapter(muxc, 0, num, 0);
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if (ret) {
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i2c_mux_del_adapters(muxc);
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return ret;
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}
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}
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dev_info(&client->dev,
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"registered %d multiplexed busses for I2C switch %s\n",
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num, client->name);
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return 0;
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}
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static int ltc4306_remove(struct i2c_client *client)
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{
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struct i2c_mux_core *muxc = i2c_get_clientdata(client);
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i2c_mux_del_adapters(muxc);
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return 0;
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}
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static struct i2c_driver ltc4306_driver = {
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.driver = {
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.name = "ltc4306",
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.of_match_table = of_match_ptr(ltc4306_of_match),
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},
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.probe_new = ltc4306_probe,
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.remove = ltc4306_remove,
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.id_table = ltc4306_id,
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};
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module_i2c_driver(ltc4306_driver);
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MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
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MODULE_DESCRIPTION("Linear Technology LTC4306, LTC4305 I2C mux/switch driver");
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MODULE_LICENSE("GPL v2");
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