From dbed8a803bd3fb64339a6180adaff2cec46242ce Mon Sep 17 00:00:00 2001 From: Michael Hennerich Date: Tue, 11 Apr 2017 14:16:16 +0200 Subject: i2c: mux: ltc4306: LTC4306 and LTC4305 I2C multiplexer/switch This patch adds support for the Analog Devices / Linear Technology LTC4306 and LTC4305 4/2 Channel I2C Bus Multiplexer/Switches. The LTC4306 optionally provides two general purpose input/output pins (GPIOs) that can be configured as logic inputs, opendrain outputs or push-pull outputs via the generic GPIOLIB framework. Signed-off-by: Michael Hennerich Reviewed-by: Linus Walleij Signed-off-by: Peter Rosin --- drivers/i2c/muxes/Kconfig | 11 ++ drivers/i2c/muxes/Makefile | 1 + drivers/i2c/muxes/i2c-mux-ltc4306.c | 322 ++++++++++++++++++++++++++++++++++++ 3 files changed, 334 insertions(+) create mode 100644 drivers/i2c/muxes/i2c-mux-ltc4306.c (limited to 'drivers/i2c') diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig index 10b3d17ae3ea..1e160fc37ecc 100644 --- a/drivers/i2c/muxes/Kconfig +++ b/drivers/i2c/muxes/Kconfig @@ -30,6 +30,17 @@ config I2C_MUX_GPIO This driver can also be built as a module. If so, the module will be called i2c-mux-gpio. +config I2C_MUX_LTC4306 + tristate "LTC LTC4306/5 I2C multiplexer" + select GPIOLIB + select REGMAP_I2C + help + If you say yes here you get support for the Analog Devices + LTC4306 or LTC4305 I2C mux/switch devices. + + This driver can also be built as a module. If so, the module + will be called i2c-mux-ltc4306. + config I2C_MUX_PCA9541 tristate "NXP PCA9541 I2C Master Selector" help diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile index 9948fa45037f..ff7618cd5312 100644 --- a/drivers/i2c/muxes/Makefile +++ b/drivers/i2c/muxes/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE) += i2c-arb-gpio-challenge.o obj-$(CONFIG_I2C_DEMUX_PINCTRL) += i2c-demux-pinctrl.o obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o +obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o diff --git a/drivers/i2c/muxes/i2c-mux-ltc4306.c b/drivers/i2c/muxes/i2c-mux-ltc4306.c new file mode 100644 index 000000000000..311b1cced0c0 --- /dev/null +++ b/drivers/i2c/muxes/i2c-mux-ltc4306.c @@ -0,0 +1,322 @@ +/* + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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, + const struct i2c_device_id *id) +{ + 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[id->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, <c4306_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 = ltc4306_probe, + .remove = ltc4306_remove, + .id_table = ltc4306_id, +}; + +module_i2c_driver(ltc4306_driver); + +MODULE_AUTHOR("Michael Hennerich "); +MODULE_DESCRIPTION("Linear Technology LTC4306, LTC4305 I2C mux/switch driver"); +MODULE_LICENSE("GPL v2"); -- cgit