// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * GPIO driver for the SMSC SCH311x Super-I/O chips
 *
 * Copyright (C) 2013 Bruno Randolf <br1@einfach.org>
 *
 * SuperIO functions and chip detection:
 * (c) Copyright 2008 Wim Van Sebroeck <wim@iguana.be>.
 */

#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/gpio/driver.h>
#include <linux/bitops.h>
#include <linux/io.h>

#define DRV_NAME                        "gpio-sch311x"

#define SCH311X_GPIO_CONF_DIR           BIT(0)
#define SCH311X_GPIO_CONF_INVERT        BIT(1)
#define SCH311X_GPIO_CONF_OPEN_DRAIN    BIT(7)

#define SIO_CONFIG_KEY_ENTER            0x55
#define SIO_CONFIG_KEY_EXIT             0xaa

#define GP1                             0x4b

static int sch311x_ioports[] = { 0x2e, 0x4e, 0x162e, 0x164e };

static struct platform_device *sch311x_gpio_pdev;

struct sch311x_pdev_data {              /* platform device data */
        unsigned short runtime_reg;     /* runtime register base address */
};

struct sch311x_gpio_block {             /* one GPIO block runtime data */
        struct gpio_chip chip;
        unsigned short data_reg;        /* from definition below */
        unsigned short *config_regs;    /* pointer to definition below */
        unsigned short runtime_reg;     /* runtime register */
        spinlock_t lock;                /* lock for this GPIO block */
};

struct sch311x_gpio_priv {              /* driver private data */
        struct sch311x_gpio_block blocks[6];
};

struct sch311x_gpio_block_def {         /* register address definitions */
        unsigned short data_reg;
        unsigned short config_regs[8];
        unsigned short base;
};

/* Note: some GPIOs are not available, these are marked with 0x00 */

static struct sch311x_gpio_block_def sch311x_gpio_blocks[] = {
        {
                .data_reg = 0x4b,       /* GP1 */
                .config_regs = {0x23, 0x24, 0x25, 0x26, 0x27, 0x29, 0x2a, 0x2b},
                .base = 10,
        },
        {
                .data_reg = 0x4c,       /* GP2 */
                .config_regs = {0x00, 0x2c, 0x2d, 0x00, 0x00, 0x00, 0x00, 0x32},
                .base = 20,
        },
        {
                .data_reg = 0x4d,       /* GP3 */
                .config_regs = {0x33, 0x34, 0x35, 0x36, 0x37, 0x00, 0x39, 0x3a},
                .base = 30,
        },
        {
                .data_reg = 0x4e,       /* GP4 */
                .config_regs = {0x3b, 0x00, 0x3d, 0x00, 0x6e, 0x6f, 0x72, 0x73},
                .base = 40,
        },
        {
                .data_reg = 0x4f,       /* GP5 */
                .config_regs = {0x3f, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46},
                .base = 50,
        },
        {
                .data_reg = 0x50,       /* GP6 */
                .config_regs = {0x47, 0x48, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59},
                .base = 60,
        },
};

/*
 *      Super-IO functions
 */

static inline int sch311x_sio_enter(int sio_config_port)
{
        /* Don't step on other drivers' I/O space by accident. */
        if (!request_muxed_region(sio_config_port, 2, DRV_NAME)) {
                pr_err(DRV_NAME "I/O address 0x%04x already in use\n",
                       sio_config_port);
                return -EBUSY;
        }

        outb(SIO_CONFIG_KEY_ENTER, sio_config_port);
        return 0;
}

static inline void sch311x_sio_exit(int sio_config_port)
{
        outb(SIO_CONFIG_KEY_EXIT, sio_config_port);
        release_region(sio_config_port, 2);
}

static inline int sch311x_sio_inb(int sio_config_port, int reg)
{
        outb(reg, sio_config_port);
        return inb(sio_config_port + 1);
}

static inline void sch311x_sio_outb(int sio_config_port, int reg, int val)
{
        outb(reg, sio_config_port);
        outb(val, sio_config_port + 1);
}


/*
 *      GPIO functions
 */

static int sch311x_gpio_request(struct gpio_chip *chip, unsigned offset)
{
        struct sch311x_gpio_block *block = gpiochip_get_data(chip);

        if (block->config_regs[offset] == 0) /* GPIO is not available */
                return -ENODEV;

        if (!request_region(block->runtime_reg + block->config_regs[offset],
                            1, DRV_NAME)) {
                dev_err(chip->parent, "Failed to request region 0x%04x.\n",
                        block->runtime_reg + block->config_regs[offset]);
                return -EBUSY;
        }
        return 0;
}

static void sch311x_gpio_free(struct gpio_chip *chip, unsigned offset)
{
        struct sch311x_gpio_block *block = gpiochip_get_data(chip);

        if (block->config_regs[offset] == 0) /* GPIO is not available */
                return;

        release_region(block->runtime_reg + block->config_regs[offset], 1);
}

static int sch311x_gpio_get(struct gpio_chip *chip, unsigned offset)
{
        struct sch311x_gpio_block *block = gpiochip_get_data(chip);
        u8 data;

        spin_lock(&block->lock);
        data = inb(block->runtime_reg + block->data_reg);
        spin_unlock(&block->lock);

        return !!(data & BIT(offset));
}

static void __sch311x_gpio_set(struct sch311x_gpio_block *block,
                               unsigned offset, int value)
{
        u8 data = inb(block->runtime_reg + block->data_reg);
        if (value)
                data |= BIT(offset);
        else
                data &= ~BIT(offset);
        outb(data, block->runtime_reg + block->data_reg);
}

static int sch311x_gpio_set(struct gpio_chip *chip, unsigned int offset,
                            int value)
{
        struct sch311x_gpio_block *block = gpiochip_get_data(chip);

        spin_lock(&block->lock);
        __sch311x_gpio_set(block, offset, value);
        spin_unlock(&block->lock);

        return 0;
}

static int sch311x_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
{
        struct sch311x_gpio_block *block = gpiochip_get_data(chip);
        u8 data;

        spin_lock(&block->lock);
        data = inb(block->runtime_reg + block->config_regs[offset]);
        data |= SCH311X_GPIO_CONF_DIR;
        outb(data, block->runtime_reg + block->config_regs[offset]);
        spin_unlock(&block->lock);

        return 0;
}

static int sch311x_gpio_direction_out(struct gpio_chip *chip, unsigned offset,
                                      int value)
{
        struct sch311x_gpio_block *block = gpiochip_get_data(chip);
        u8 data;

        spin_lock(&block->lock);

        data = inb(block->runtime_reg + block->config_regs[offset]);
        data &= ~SCH311X_GPIO_CONF_DIR;
        outb(data, block->runtime_reg + block->config_regs[offset]);
        __sch311x_gpio_set(block, offset, value);

        spin_unlock(&block->lock);
        return 0;
}

static int sch311x_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
        struct sch311x_gpio_block *block = gpiochip_get_data(chip);
        u8 data;

        spin_lock(&block->lock);
        data = inb(block->runtime_reg + block->config_regs[offset]);
        spin_unlock(&block->lock);

        if (data & SCH311X_GPIO_CONF_DIR)
                return GPIO_LINE_DIRECTION_IN;

        return GPIO_LINE_DIRECTION_OUT;
}

static int sch311x_gpio_set_config(struct gpio_chip *chip, unsigned offset,
                                   unsigned long config)
{
        struct sch311x_gpio_block *block = gpiochip_get_data(chip);
        enum pin_config_param param = pinconf_to_config_param(config);
        u8 data;

        switch (param) {
        case PIN_CONFIG_DRIVE_OPEN_DRAIN:
                spin_lock(&block->lock);
                data = inb(block->runtime_reg + block->config_regs[offset]);
                data |= SCH311X_GPIO_CONF_OPEN_DRAIN;
                outb(data, block->runtime_reg + block->config_regs[offset]);
                spin_unlock(&block->lock);
                return 0;
        case PIN_CONFIG_DRIVE_PUSH_PULL:
                spin_lock(&block->lock);
                data = inb(block->runtime_reg + block->config_regs[offset]);
                data &= ~SCH311X_GPIO_CONF_OPEN_DRAIN;
                outb(data, block->runtime_reg + block->config_regs[offset]);
                spin_unlock(&block->lock);
                return 0;
        default:
                break;
        }
        return -ENOTSUPP;
}

static int sch311x_gpio_probe(struct platform_device *pdev)
{
        struct sch311x_pdev_data *pdata = dev_get_platdata(&pdev->dev);
        struct sch311x_gpio_priv *priv;
        struct sch311x_gpio_block *block;
        int err, i;

        /* we can register all GPIO data registers at once */
        if (!devm_request_region(&pdev->dev, pdata->runtime_reg + GP1, 6,
                DRV_NAME)) {
                dev_err(&pdev->dev, "Failed to request region 0x%04x-0x%04x.\n",
                        pdata->runtime_reg + GP1, pdata->runtime_reg + GP1 + 5);
                return -EBUSY;
        }

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        for (i = 0; i < ARRAY_SIZE(priv->blocks); i++) {
                block = &priv->blocks[i];

                spin_lock_init(&block->lock);

                block->chip.label = DRV_NAME;
                block->chip.owner = THIS_MODULE;
                block->chip.request = sch311x_gpio_request;
                block->chip.free = sch311x_gpio_free;
                block->chip.direction_input = sch311x_gpio_direction_in;
                block->chip.direction_output = sch311x_gpio_direction_out;
                block->chip.get_direction = sch311x_gpio_get_direction;
                block->chip.set_config = sch311x_gpio_set_config;
                block->chip.get = sch311x_gpio_get;
                block->chip.set = sch311x_gpio_set;
                block->chip.ngpio = 8;
                block->chip.parent = &pdev->dev;
                block->chip.base = sch311x_gpio_blocks[i].base;
                block->config_regs = sch311x_gpio_blocks[i].config_regs;
                block->data_reg = sch311x_gpio_blocks[i].data_reg;
                block->runtime_reg = pdata->runtime_reg;

                err = devm_gpiochip_add_data(&pdev->dev, &block->chip, block);
                if (err < 0) {
                        dev_err(&pdev->dev,
                                "Could not register gpiochip, %d\n", err);
                        return err;
                }
                dev_info(&pdev->dev,
                         "SMSC SCH311x GPIO block %d registered.\n", i);
        }

        return 0;
}

static struct platform_driver sch311x_gpio_driver = {
        .driver.name    = DRV_NAME,
        .probe          = sch311x_gpio_probe,
};


/*
 *      Init & exit routines
 */

static int __init sch311x_detect(int sio_config_port, unsigned short *addr)
{
        int err = 0, reg;
        unsigned short base_addr;
        u8 dev_id;

        err = sch311x_sio_enter(sio_config_port);
        if (err)
                return err;

        /* Check device ID. */
        reg = sch311x_sio_inb(sio_config_port, 0x20);
        switch (reg) {
        case 0x7c: /* SCH3112 */
                dev_id = 2;
                break;
        case 0x7d: /* SCH3114 */
                dev_id = 4;
                break;
        case 0x7f: /* SCH3116 */
                dev_id = 6;
                break;
        default:
                err = -ENODEV;
                goto exit;
        }

        /* Select logical device A (runtime registers) */
        sch311x_sio_outb(sio_config_port, 0x07, 0x0a);

        /* Check if Logical Device Register is currently active */
        if ((sch311x_sio_inb(sio_config_port, 0x30) & 0x01) == 0)
                pr_info("Seems that LDN 0x0a is not active...\n");

        /* Get the base address of the runtime registers */
        base_addr = (sch311x_sio_inb(sio_config_port, 0x60) << 8) |
                           sch311x_sio_inb(sio_config_port, 0x61);
        if (!base_addr) {
                pr_err("Base address not set\n");
                err = -ENODEV;
                goto exit;
        }
        *addr = base_addr;

        pr_info("Found an SMSC SCH311%d chip at 0x%04x\n", dev_id, base_addr);

exit:
        sch311x_sio_exit(sio_config_port);
        return err;
}

static int __init sch311x_gpio_pdev_add(const unsigned short addr)
{
        struct sch311x_pdev_data pdata;
        int err;

        pdata.runtime_reg = addr;

        sch311x_gpio_pdev = platform_device_alloc(DRV_NAME, -1);
        if (!sch311x_gpio_pdev)
                return -ENOMEM;

        err = platform_device_add_data(sch311x_gpio_pdev,
                                       &pdata, sizeof(pdata));
        if (err) {
                pr_err(DRV_NAME "Platform data allocation failed\n");
                goto err;
        }

        err = platform_device_add(sch311x_gpio_pdev);
        if (err) {
                pr_err(DRV_NAME "Device addition failed\n");
                goto err;
        }
        return 0;

err:
        platform_device_put(sch311x_gpio_pdev);
        return err;
}

static int __init sch311x_gpio_init(void)
{
        int err, i;
        unsigned short addr = 0;

        for (i = 0; i < ARRAY_SIZE(sch311x_ioports); i++)
                if (sch311x_detect(sch311x_ioports[i], &addr) == 0)
                        break;

        if (!addr)
                return -ENODEV;

        err = platform_driver_register(&sch311x_gpio_driver);
        if (err)
                return err;

        err = sch311x_gpio_pdev_add(addr);
        if (err)
                goto unreg_platform_driver;

        return 0;

unreg_platform_driver:
        platform_driver_unregister(&sch311x_gpio_driver);
        return err;
}

static void __exit sch311x_gpio_exit(void)
{
        platform_device_unregister(sch311x_gpio_pdev);
        platform_driver_unregister(&sch311x_gpio_driver);
}

module_init(sch311x_gpio_init);
module_exit(sch311x_gpio_exit);

MODULE_AUTHOR("Bruno Randolf <br1@einfach.org>");
MODULE_DESCRIPTION("SMSC SCH311x GPIO Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:gpio-sch311x");