linux-imx

// SPDX-License-Identifier: GPL-2.0-only

/*

 * Linear Technology LTC4306 and LTC4305 I2C multiplexer/switch

 *

 * Copyright (C) 2017 Analog Devices Inc.

 *

 * 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);