// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ADGS1408/ADGS1409 SPI MUX driver
 *
 * Copyright 2018 Analog Devices Inc.
 */

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

#define ADGS1408_SW_DATA       (0x01)
#define ADGS1408_REG_READ(reg) ((reg) | 0x80)
#define ADGS1408_DISABLE       (0x00)
#define ADGS1408_MUX(state)    (((state) << 1) | 1)

enum adgs1408_chip_id {
        ADGS1408 = 1,
        ADGS1409,
};

static int adgs1408_spi_reg_write(struct spi_device *spi,
                                  u8 reg_addr, u8 reg_data)
{
        u8 tx_buf[2];

        tx_buf[0] = reg_addr;
        tx_buf[1] = reg_data;

        return spi_write_then_read(spi, tx_buf, sizeof(tx_buf), NULL, 0);
}

static int adgs1408_set(struct mux_control *mux, int state)
{
        struct spi_device *spi = to_spi_device(mux->chip->dev.parent);
        u8 reg;

        if (state == MUX_IDLE_DISCONNECT)
                reg = ADGS1408_DISABLE;
        else
                reg = ADGS1408_MUX(state);

        return adgs1408_spi_reg_write(spi, ADGS1408_SW_DATA, reg);
}

static const struct mux_control_ops adgs1408_ops = {
        .set = adgs1408_set,
};

static int adgs1408_probe(struct spi_device *spi)
{
        struct device *dev = &spi->dev;
        enum adgs1408_chip_id chip_id;
        struct mux_chip *mux_chip;
        struct mux_control *mux;
        s32 idle_state;
        int ret;

        chip_id = (kernel_ulong_t)spi_get_device_match_data(spi);

        mux_chip = devm_mux_chip_alloc(dev, 1, 0);
        if (IS_ERR(mux_chip))
                return PTR_ERR(mux_chip);

        mux_chip->ops = &adgs1408_ops;

        ret = adgs1408_spi_reg_write(spi, ADGS1408_SW_DATA, ADGS1408_DISABLE);
        if (ret < 0)
                return ret;

        ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
        if (ret < 0)
                idle_state = MUX_IDLE_AS_IS;

        mux = mux_chip->mux;

        if (chip_id == ADGS1408)
                mux->states = 8;
        else
                mux->states = 4;

        switch (idle_state) {
        case MUX_IDLE_DISCONNECT:
        case MUX_IDLE_AS_IS:
        case 0 ... 7:
                /* adgs1409 supports only 4 states */
                if (idle_state < mux->states) {
                        mux->idle_state = idle_state;
                        break;
                }
                fallthrough;
        default:
                dev_err(dev, "invalid idle-state %d\n", idle_state);
                return -EINVAL;
        }

        return devm_mux_chip_register(dev, mux_chip);
}

static const struct spi_device_id adgs1408_spi_id[] = {
        { "adgs1408", ADGS1408 },
        { "adgs1409", ADGS1409 },
        { }
};
MODULE_DEVICE_TABLE(spi, adgs1408_spi_id);

static const struct of_device_id adgs1408_of_match[] = {
        { .compatible = "adi,adgs1408", .data = (void *)ADGS1408, },
        { .compatible = "adi,adgs1409", .data = (void *)ADGS1409, },
        { }
};
MODULE_DEVICE_TABLE(of, adgs1408_of_match);

static struct spi_driver adgs1408_driver = {
        .driver = {
                .name = "adgs1408",
                .of_match_table = adgs1408_of_match,
        },
        .probe = adgs1408_probe,
        .id_table = adgs1408_spi_id,
};
module_spi_driver(adgs1408_driver);

MODULE_AUTHOR("Mircea Caprioru <mircea.caprioru@analog.com>");
MODULE_DESCRIPTION("Analog Devices ADGS1408 MUX driver");
MODULE_LICENSE("GPL");