// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020 NovaTech LLC
 * George McCollister <george.mccollister@gmail.com>
 */

#include <linux/bits.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include "xrs700x.h"
#include "xrs700x_reg.h"

struct xrs700x_i2c_cmd {
        __be32 reg;
        __be16 val;
} __packed;

static int xrs700x_i2c_reg_read(void *context, unsigned int reg,
                                unsigned int *val)
{
        struct device *dev = context;
        struct i2c_client *i2c = to_i2c_client(dev);
        struct xrs700x_i2c_cmd cmd;
        int ret;

        cmd.reg = cpu_to_be32(reg | 1);

        ret = i2c_master_send(i2c, (char *)&cmd.reg, sizeof(cmd.reg));
        if (ret < 0) {
                dev_err(dev, "xrs i2c_master_send returned %d\n", ret);
                return ret;
        }

        ret = i2c_master_recv(i2c, (char *)&cmd.val, sizeof(cmd.val));
        if (ret < 0) {
                dev_err(dev, "xrs i2c_master_recv returned %d\n", ret);
                return ret;
        }

        *val = be16_to_cpu(cmd.val);
        return 0;
}

static int xrs700x_i2c_reg_write(void *context, unsigned int reg,
                                 unsigned int val)
{
        struct device *dev = context;
        struct i2c_client *i2c = to_i2c_client(dev);
        struct xrs700x_i2c_cmd cmd;
        int ret;

        cmd.reg = cpu_to_be32(reg);
        cmd.val = cpu_to_be16(val);

        ret = i2c_master_send(i2c, (char *)&cmd, sizeof(cmd));
        if (ret < 0) {
                dev_err(dev, "xrs i2c_master_send returned %d\n", ret);
                return ret;
        }

        return 0;
}

static const struct regmap_config xrs700x_i2c_regmap_config = {
        .val_bits = 16,
        .reg_stride = 2,
        .reg_bits = 32,
        .pad_bits = 0,
        .write_flag_mask = 0,
        .read_flag_mask = 0,
        .reg_read = xrs700x_i2c_reg_read,
        .reg_write = xrs700x_i2c_reg_write,
        .max_register = 0,
        .cache_type = REGCACHE_NONE,
        .reg_format_endian = REGMAP_ENDIAN_BIG,
        .val_format_endian = REGMAP_ENDIAN_BIG
};

static int xrs700x_i2c_probe(struct i2c_client *i2c)
{
        struct xrs700x *priv;
        int ret;

        priv = xrs700x_switch_alloc(&i2c->dev, i2c);
        if (!priv)
                return -ENOMEM;

        priv->regmap = devm_regmap_init(&i2c->dev, NULL, &i2c->dev,
                                        &xrs700x_i2c_regmap_config);
        if (IS_ERR(priv->regmap)) {
                ret = PTR_ERR(priv->regmap);
                dev_err(&i2c->dev, "Failed to initialize regmap: %d\n", ret);
                return ret;
        }

        i2c_set_clientdata(i2c, priv);

        ret = xrs700x_switch_register(priv);

        /* Main DSA driver may not be started yet. */
        if (ret)
                return ret;

        return 0;
}

static void xrs700x_i2c_remove(struct i2c_client *i2c)
{
        struct xrs700x *priv = i2c_get_clientdata(i2c);

        if (!priv)
                return;

        xrs700x_switch_remove(priv);
}

static void xrs700x_i2c_shutdown(struct i2c_client *i2c)
{
        struct xrs700x *priv = i2c_get_clientdata(i2c);

        if (!priv)
                return;

        xrs700x_switch_shutdown(priv);

        i2c_set_clientdata(i2c, NULL);
}

static const struct i2c_device_id xrs700x_i2c_id[] = {
        { "xrs700x-switch" },
        {}
};

MODULE_DEVICE_TABLE(i2c, xrs700x_i2c_id);

static const struct of_device_id __maybe_unused xrs700x_i2c_dt_ids[] = {
        { .compatible = "arrow,xrs7003e", .data = &xrs7003e_info },
        { .compatible = "arrow,xrs7003f", .data = &xrs7003f_info },
        { .compatible = "arrow,xrs7004e", .data = &xrs7004e_info },
        { .compatible = "arrow,xrs7004f", .data = &xrs7004f_info },
        {},
};
MODULE_DEVICE_TABLE(of, xrs700x_i2c_dt_ids);

static struct i2c_driver xrs700x_i2c_driver = {
        .driver = {
                .name   = "xrs700x-i2c",
                .of_match_table = of_match_ptr(xrs700x_i2c_dt_ids),
        },
        .probe = xrs700x_i2c_probe,
        .remove = xrs700x_i2c_remove,
        .shutdown = xrs700x_i2c_shutdown,
        .id_table = xrs700x_i2c_id,
};

module_i2c_driver(xrs700x_i2c_driver);

MODULE_AUTHOR("George McCollister <george.mccollister@gmail.com>");
MODULE_DESCRIPTION("Arrow SpeedChips XRS700x DSA I2C driver");
MODULE_LICENSE("GPL v2");