// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2017
 * Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
 */

#include <common.h>
#include <dm.h>
#include <board.h>
#include <i2c.h>
#include <asm/gpio.h>

#include "gazerbeam.h"

/* Sequence number of I2C bus that holds the GPIO expanders */
static const int I2C_BUS_SEQ_NO = 1;

/* I2C address of SC/MC2 expander */
static const int MC2_EXPANDER_ADDR = 0x20;
/* I2C address of MC4 expander */
static const int MC4_EXPANDER_ADDR = 0x22;

/* Number of the GPIO to read the SC data from */
static const int SC_GPIO_NO;
/* Number of the GPIO to read the CON data from */
static const int CON_GPIO_NO = 1;

/**
 * struct board_gazerbeam_priv - Private data structure for the gazerbeam board
 *                               driver.
 * @reset_gpios:  GPIOs for the board's reset GPIOs.
 * @var_gpios:    GPIOs for the board's hardware variant GPIOs
 * @ver_gpios:    GPIOs for the board's hardware version GPIOs
 * @variant:      Container for the board's hardware variant (CON/CPU)
 * @multichannel: Container for the board's multichannel variant (MC4/MC2/SC)
 * @hwversion:    Container for the board's hardware version
 */
struct board_gazerbeam_priv {
        struct gpio_desc reset_gpios[2];
        struct gpio_desc var_gpios[2];
        struct gpio_desc ver_gpios[4];
        int variant;
        int multichannel;
        int hwversion;
};

/**
 * _read_board_variant_data() - Read variant information from the hardware.
 * @dev: The board device for which to determine the multichannel and device
 *       type information.
 *
 * The data read from the board's hardware (mostly hard-wired GPIOs) is stored
 * in the private data structure of the driver to be used by other driver
 * methods.
 *
 * Return: 0 if OK, -ve on error.
 */
static int _read_board_variant_data(struct udevice *dev)
{
        struct board_gazerbeam_priv *priv = dev_get_priv(dev);
        struct udevice *i2c_bus;
        struct udevice *dummy;
        char *listname;
        int mc4, mc2, sc, mc2_sc, con;
        int gpio_num;
        int res;

        res = uclass_get_device_by_seq(UCLASS_I2C, I2C_BUS_SEQ_NO, &i2c_bus);
        if (res) {
                debug("%s: Could not get I2C bus %d (err = %d)\n",
                      dev->name, I2C_BUS_SEQ_NO, res);
                return res;
        }

        if (!i2c_bus) {
                debug("%s: Could not get I2C bus %d\n",
                      dev->name, I2C_BUS_SEQ_NO);
                return -EIO;
        }

        mc2_sc = !dm_i2c_probe(i2c_bus, MC2_EXPANDER_ADDR, 0, &dummy);
        mc4 = !dm_i2c_probe(i2c_bus, MC4_EXPANDER_ADDR, 0, &dummy);

        if (mc2_sc && mc4) {
                debug("%s: Board hardware configuration inconsistent.\n",
                      dev->name);
                return -EINVAL;
        }

        listname = mc2_sc ? "var-gpios-mc2" : "var-gpios-mc4";

        gpio_num = gpio_request_list_by_name(dev, listname, priv->var_gpios,
                                             ARRAY_SIZE(priv->var_gpios),
                                             GPIOD_IS_IN);
        if (gpio_num < 0) {
                debug("%s: Requesting gpio list %s failed (err = %d).\n",
                      dev->name, listname, gpio_num);
                return gpio_num;
        }

        sc = dm_gpio_get_value(&priv->var_gpios[SC_GPIO_NO]);
        if (sc < 0) {
                debug("%s: Error while reading 'sc' GPIO (err = %d)",
                      dev->name, sc);
                return sc;
        }

        mc2 = mc2_sc ? (sc ? 0 : 1) : 0;

        if ((sc && mc2) || (sc && mc4) || (!sc && !mc2 && !mc4)) {
                debug("%s: Board hardware configuration inconsistent.\n",
                      dev->name);
                return -EINVAL;
        }

        con = dm_gpio_get_value(&priv->var_gpios[CON_GPIO_NO]);
        if (con < 0) {
                debug("%s: Error while reading 'con' GPIO (err = %d)",
                      dev->name, con);
                return con;
        }

        priv->variant = con ? VAR_CON : VAR_CPU;

        priv->multichannel = mc4 ? 4 : (mc2 ? 2 : (sc ? 1 : 0));

        return 0;
}

/**
 * _read_hwversion() - Read the hardware version from the board.
 * @dev: The board device for which to read the hardware version.
 *
 * The hardware version read from the board (from hard-wired GPIOs) is stored
 * in the private data structure of the driver to be used by other driver
 * methods.
 *
 * Return: 0 if OK, -ve on error.
 */
static int _read_hwversion(struct udevice *dev)
{
        struct board_gazerbeam_priv *priv = dev_get_priv(dev);
        int res;

        res = gpio_request_list_by_name(dev, "ver-gpios", priv->ver_gpios,
                                        ARRAY_SIZE(priv->ver_gpios),
                                        GPIOD_IS_IN);
        if (res < 0) {
                debug("%s: Error getting GPIO list 'ver-gpios' (err = %d)\n",
                      dev->name, res);
                return -ENODEV;
        }

        res = dm_gpio_get_values_as_int(priv->ver_gpios,
                                        ARRAY_SIZE(priv->ver_gpios));
        if (res < 0) {
                debug("%s: Error reading HW version from expander (err = %d)\n",
                      dev->name, res);
                return res;
        }

        priv->hwversion = res;

        res = gpio_free_list(dev, priv->ver_gpios, ARRAY_SIZE(priv->ver_gpios));
        if (res < 0) {
                debug("%s: Error freeing HW version GPIO list (err = %d)\n",
                      dev->name, res);
                return res;
        }

        return 0;
}

static int board_gazerbeam_detect(struct udevice *dev)
{
        int res;

        res = _read_board_variant_data(dev);
        if (res) {
                debug("%s: Error reading multichannel variant (err = %d)\n",
                      dev->name, res);
                return res;
        }

        res = _read_hwversion(dev);
        if (res) {
                debug("%s: Error reading hardware version (err = %d)\n",
                      dev->name, res);
                return res;
        }

        return 0;
}

static int board_gazerbeam_get_int(struct udevice *dev, int id, int *val)
{
        struct board_gazerbeam_priv *priv = dev_get_priv(dev);

        switch (id) {
        case BOARD_MULTICHANNEL:
                *val = priv->multichannel;
                break;
        case BOARD_VARIANT:
                *val = priv->variant;
                break;
        case BOARD_HWVERSION:
                *val = priv->hwversion;
                break;
        default:
                debug("%s: Integer value %d unknown\n", dev->name, id);
                return -EINVAL;
        }

        return 0;
}

static const struct udevice_id board_gazerbeam_ids[] = {
        { .compatible = "gdsys,board_gazerbeam" },
        { /* sentinel */ }
};

static const struct board_ops board_gazerbeam_ops = {
        .detect = board_gazerbeam_detect,
        .get_int = board_gazerbeam_get_int,
};

static int board_gazerbeam_probe(struct udevice *dev)
{
        struct board_gazerbeam_priv *priv = dev_get_priv(dev);
        int gpio_num, i;

        gpio_num = gpio_request_list_by_name(dev, "reset-gpios",
                                             priv->reset_gpios,
                                             ARRAY_SIZE(priv->reset_gpios),
                                             GPIOD_IS_OUT);

        if (gpio_num < 0) {
                debug("%s: Error getting GPIO list 'reset-gpios' (err = %d)\n",
                      dev->name, gpio_num);
                return gpio_num;
        }

        /* Set startup-finished GPIOs */
        for (i = 0; i < ARRAY_SIZE(priv->reset_gpios); i++) {
                int res = dm_gpio_set_value(&priv->reset_gpios[i], 0);

                if (res) {
                        debug("%s: Error while setting GPIO %d (err = %d)\n",
                              dev->name, i, res);
                        return res;
                }
        }

        return 0;
}

U_BOOT_DRIVER(board_gazerbeam) = {
        .name           = "board_gazerbeam",
        .id             = UCLASS_BOARD,
        .of_match       = board_gazerbeam_ids,
        .ops            = &board_gazerbeam_ops,
        .priv_auto_alloc_size = sizeof(struct board_gazerbeam_priv),
        .probe          = board_gazerbeam_probe,
};