// SPDX-License-Identifier: GPL-2.0
/*
 * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux
 *
 * Copyright (C) 2017 Axentia Technologies AB
 *
 * Author: Peter Rosin <peda@axentia.se>
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mux/driver.h>
#include <linux/property.h>

#define ADG792A_LDSW            BIT(0)
#define ADG792A_RESETB          BIT(1)
#define ADG792A_DISABLE(mux)    (0x50 | (mux))
#define ADG792A_DISABLE_ALL     (0x5f)
#define ADG792A_MUX(mux, state) (0xc0 | (((mux) + 1) << 2) | (state))
#define ADG792A_MUX_ALL(state)  (0xc0 | (state))

static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset)
{
        u8 data = ADG792A_RESETB | ADG792A_LDSW;

        /* ADG792A_RESETB is active low, the chip resets when it is zero. */
        if (reset)
                data &= ~ADG792A_RESETB;

        return i2c_smbus_write_byte_data(i2c, cmd, data);
}

static int adg792a_set(struct mux_control *mux, int state)
{
        struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent);
        u8 cmd;

        if (mux->chip->controllers == 1) {
                /* parallel mux controller operation */
                if (state == MUX_IDLE_DISCONNECT)
                        cmd = ADG792A_DISABLE_ALL;
                else
                        cmd = ADG792A_MUX_ALL(state);
        } else {
                unsigned int controller = mux_control_get_index(mux);

                if (state == MUX_IDLE_DISCONNECT)
                        cmd = ADG792A_DISABLE(controller);
                else
                        cmd = ADG792A_MUX(controller, state);
        }

        return adg792a_write_cmd(i2c, cmd, 0);
}

static const struct mux_control_ops adg792a_ops = {
        .set = adg792a_set,
};

static int adg792a_probe(struct i2c_client *i2c)
{
        struct device *dev = &i2c->dev;
        struct mux_chip *mux_chip;
        s32 idle_state[3];
        u32 cells;
        int ret;
        int i;

        if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                return -ENODEV;

        ret = device_property_read_u32(dev, "#mux-control-cells", &cells);
        if (ret < 0)
                return ret;
        if (cells >= 2)
                return -EINVAL;

        mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0);
        if (IS_ERR(mux_chip))
                return PTR_ERR(mux_chip);

        mux_chip->ops = &adg792a_ops;

        ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1);
        if (ret < 0)
                return ret;

        ret = device_property_read_u32_array(dev, "idle-state",
                                             (u32 *)idle_state,
                                             mux_chip->controllers);
        if (ret < 0) {
                idle_state[0] = MUX_IDLE_AS_IS;
                idle_state[1] = MUX_IDLE_AS_IS;
                idle_state[2] = MUX_IDLE_AS_IS;
        }

        for (i = 0; i < mux_chip->controllers; ++i) {
                struct mux_control *mux = &mux_chip->mux[i];

                mux->states = 4;

                switch (idle_state[i]) {
                case MUX_IDLE_DISCONNECT:
                case MUX_IDLE_AS_IS:
                case 0 ... 4:
                        mux->idle_state = idle_state[i];
                        break;
                default:
                        dev_err(dev, "invalid idle-state %d\n", idle_state[i]);
                        return -EINVAL;
                }
        }

        ret = devm_mux_chip_register(dev, mux_chip);
        if (ret < 0)
                return ret;

        if (cells)
                dev_info(dev, "3x single pole quadruple throw muxes registered\n");
        else
                dev_info(dev, "triple pole quadruple throw mux registered\n");

        return 0;
}

static const struct i2c_device_id adg792a_id[] = {
        { .name = "adg792a", },
        { .name = "adg792g", },
        { }
};
MODULE_DEVICE_TABLE(i2c, adg792a_id);

static const struct of_device_id adg792a_of_match[] = {
        { .compatible = "adi,adg792a", },
        { .compatible = "adi,adg792g", },
        { }
};
MODULE_DEVICE_TABLE(of, adg792a_of_match);

static struct i2c_driver adg792a_driver = {
        .driver         = {
                .name           = "adg792a",
                .of_match_table = adg792a_of_match,
        },
        .probe          = adg792a_probe,
        .id_table       = adg792a_id,
};
module_i2c_driver(adg792a_driver);

MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver");
MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
MODULE_LICENSE("GPL v2");