// SPDX-License-Identifier: GPL-2.0
/*
 * Intel Whiskey Cove PMIC GPIO Driver
 *
 * This driver is written based on gpio-crystalcove.c
 *
 * Copyright (C) 2016 Intel Corporation. All rights reserved.
 */

#include <linux/bitops.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/mfd/intel_soc_pmic.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/seq_file.h>
#include <linux/string_choices.h>

/*
 * Whiskey Cove PMIC has 13 physical GPIO pins divided into 3 banks:
 * Bank 0: Pin  0 - 6
 * Bank 1: Pin  7 - 10
 * Bank 2: Pin 11 - 12
 * Each pin has one output control register and one input control register.
 */
#define BANK0_NR_PINS           7
#define BANK1_NR_PINS           4
#define BANK2_NR_PINS           2
#define WCOVE_GPIO_NUM          (BANK0_NR_PINS + BANK1_NR_PINS + BANK2_NR_PINS)
#define WCOVE_VGPIO_NUM         94
/* GPIO output control registers (one per pin): 0x4e44 - 0x4e50 */
#define GPIO_OUT_CTRL_BASE      0x4e44
/* GPIO input control registers (one per pin): 0x4e51 - 0x4e5d */
#define GPIO_IN_CTRL_BASE       0x4e51

/*
 * GPIO interrupts are organized in two groups:
 * Group 0: Bank 0 pins (Pin 0 - 6)
 * Group 1: Bank 1 and Bank 2 pins (Pin 7 - 12)
 * Each group has two registers (one bit per pin): status and mask.
 */
#define GROUP0_NR_IRQS          7
#define GROUP1_NR_IRQS          6
#define IRQ_MASK_BASE           0x4e19
#define IRQ_STATUS_BASE         0x4e0b
#define GPIO_IRQ0_MASK          GENMASK(6, 0)
#define GPIO_IRQ1_MASK          GENMASK(5, 0)
#define UPDATE_IRQ_TYPE         BIT(0)
#define UPDATE_IRQ_MASK         BIT(1)

#define CTLI_INTCNT_DIS         (0 << 1)
#define CTLI_INTCNT_NE          (1 << 1)
#define CTLI_INTCNT_PE          (2 << 1)
#define CTLI_INTCNT_BE          (3 << 1)

#define CTLO_DIR_IN             (0 << 5)
#define CTLO_DIR_OUT            (1 << 5)

#define CTLO_DRV_MASK           (1 << 4)
#define CTLO_DRV_OD             (0 << 4)
#define CTLO_DRV_CMOS           (1 << 4)

#define CTLO_DRV_REN            (1 << 3)

#define CTLO_RVAL_2KDOWN        (0 << 1)
#define CTLO_RVAL_2KUP          (1 << 1)
#define CTLO_RVAL_50KDOWN       (2 << 1)
#define CTLO_RVAL_50KUP         (3 << 1)

#define CTLO_INPUT_SET          (CTLO_DRV_CMOS | CTLO_DRV_REN | CTLO_RVAL_2KUP)
#define CTLO_OUTPUT_SET         (CTLO_DIR_OUT | CTLO_INPUT_SET)

enum ctrl_register {
        CTRL_IN,
        CTRL_OUT,
        IRQ_STATUS,
        IRQ_MASK,
};

/*
 * struct wcove_gpio - Whiskey Cove GPIO controller
 * @buslock: for bus lock/sync and unlock.
 * @chip: the abstract gpio_chip structure.
 * @dev: the gpio device
 * @regmap: the regmap from the parent device.
 * @regmap_irq_chip: the regmap of the gpio irq chip.
 * @update: pending IRQ setting update, to be written to the chip upon unlock.
 * @intcnt: the Interrupt Detect value to be written.
 * @set_irq_mask: true if the IRQ mask needs to be set, false to clear.
 */
struct wcove_gpio {
        struct mutex buslock;
        struct gpio_chip chip;
        struct device *dev;
        struct regmap *regmap;
        struct regmap_irq_chip_data *regmap_irq_chip;
        int update;
        int intcnt;
        bool set_irq_mask;
};

static inline int to_reg(int gpio, enum ctrl_register type)
{
        unsigned int reg = type == CTRL_IN ? GPIO_IN_CTRL_BASE : GPIO_OUT_CTRL_BASE;

        if (gpio >= WCOVE_GPIO_NUM)
                return -ENOTSUPP;

        return reg + gpio;
}

static inline int to_ireg(int gpio, enum ctrl_register type, unsigned int *mask)
{
        unsigned int reg = type == IRQ_STATUS ? IRQ_STATUS_BASE : IRQ_MASK_BASE;

        if (gpio < GROUP0_NR_IRQS) {
                reg += 0;
                *mask = BIT(gpio);
        } else {
                reg += 1;
                *mask = BIT(gpio - GROUP0_NR_IRQS);
        }

        return reg;
}

static void wcove_update_irq_mask(struct wcove_gpio *wg, irq_hw_number_t gpio)
{
        unsigned int mask, reg = to_ireg(gpio, IRQ_MASK, &mask);

        if (wg->set_irq_mask)
                regmap_set_bits(wg->regmap, reg, mask);
        else
                regmap_clear_bits(wg->regmap, reg, mask);
}

static void wcove_update_irq_ctrl(struct wcove_gpio *wg, irq_hw_number_t gpio)
{
        int reg = to_reg(gpio, CTRL_IN);

        regmap_update_bits(wg->regmap, reg, CTLI_INTCNT_BE, wg->intcnt);
}

static int wcove_gpio_dir_in(struct gpio_chip *chip, unsigned int gpio)
{
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        int reg = to_reg(gpio, CTRL_OUT);

        if (reg < 0)
                return 0;

        return regmap_write(wg->regmap, reg, CTLO_INPUT_SET);
}

static int wcove_gpio_dir_out(struct gpio_chip *chip, unsigned int gpio,
                                    int value)
{
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        int reg = to_reg(gpio, CTRL_OUT);

        if (reg < 0)
                return 0;

        return regmap_write(wg->regmap, reg, CTLO_OUTPUT_SET | value);
}

static int wcove_gpio_get_direction(struct gpio_chip *chip, unsigned int gpio)
{
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        unsigned int val;
        int ret, reg = to_reg(gpio, CTRL_OUT);

        if (reg < 0)
                return GPIO_LINE_DIRECTION_OUT;

        ret = regmap_read(wg->regmap, reg, &val);
        if (ret)
                return ret;

        if (val & CTLO_DIR_OUT)
                return GPIO_LINE_DIRECTION_OUT;

        return GPIO_LINE_DIRECTION_IN;
}

static int wcove_gpio_get(struct gpio_chip *chip, unsigned int gpio)
{
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        unsigned int val;
        int ret, reg = to_reg(gpio, CTRL_IN);

        if (reg < 0)
                return 0;

        ret = regmap_read(wg->regmap, reg, &val);
        if (ret)
                return ret;

        return val & 0x1;
}

static int wcove_gpio_set(struct gpio_chip *chip, unsigned int gpio, int value)
{
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        int reg = to_reg(gpio, CTRL_OUT);

        if (reg < 0)
                return 0;

        return regmap_assign_bits(wg->regmap, reg, 1, value);
}

static int wcove_gpio_set_config(struct gpio_chip *chip, unsigned int gpio,
                                 unsigned long config)
{
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        int reg = to_reg(gpio, CTRL_OUT);

        if (reg < 0)
                return 0;

        switch (pinconf_to_config_param(config)) {
        case PIN_CONFIG_DRIVE_OPEN_DRAIN:
                return regmap_update_bits(wg->regmap, reg, CTLO_DRV_MASK,
                                          CTLO_DRV_OD);
        case PIN_CONFIG_DRIVE_PUSH_PULL:
                return regmap_update_bits(wg->regmap, reg, CTLO_DRV_MASK,
                                          CTLO_DRV_CMOS);
        default:
                break;
        }

        return -ENOTSUPP;
}

static int wcove_irq_type(struct irq_data *data, unsigned int type)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        irq_hw_number_t gpio = irqd_to_hwirq(data);

        if (gpio >= WCOVE_GPIO_NUM)
                return 0;

        switch (type) {
        case IRQ_TYPE_NONE:
                wg->intcnt = CTLI_INTCNT_DIS;
                break;
        case IRQ_TYPE_EDGE_BOTH:
                wg->intcnt = CTLI_INTCNT_BE;
                break;
        case IRQ_TYPE_EDGE_RISING:
                wg->intcnt = CTLI_INTCNT_PE;
                break;
        case IRQ_TYPE_EDGE_FALLING:
                wg->intcnt = CTLI_INTCNT_NE;
                break;
        default:
                return -EINVAL;
        }

        wg->update |= UPDATE_IRQ_TYPE;

        return 0;
}

static void wcove_bus_lock(struct irq_data *data)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct wcove_gpio *wg = gpiochip_get_data(chip);

        mutex_lock(&wg->buslock);
}

static void wcove_bus_sync_unlock(struct irq_data *data)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        irq_hw_number_t gpio = irqd_to_hwirq(data);

        if (wg->update & UPDATE_IRQ_TYPE)
                wcove_update_irq_ctrl(wg, gpio);
        if (wg->update & UPDATE_IRQ_MASK)
                wcove_update_irq_mask(wg, gpio);
        wg->update = 0;

        mutex_unlock(&wg->buslock);
}

static void wcove_irq_unmask(struct irq_data *data)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        irq_hw_number_t gpio = irqd_to_hwirq(data);

        if (gpio >= WCOVE_GPIO_NUM)
                return;

        gpiochip_enable_irq(chip, gpio);

        wg->set_irq_mask = false;
        wg->update |= UPDATE_IRQ_MASK;
}

static void wcove_irq_mask(struct irq_data *data)
{
        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        irq_hw_number_t gpio = irqd_to_hwirq(data);

        if (gpio >= WCOVE_GPIO_NUM)
                return;

        wg->set_irq_mask = true;
        wg->update |= UPDATE_IRQ_MASK;

        gpiochip_disable_irq(chip, gpio);
}

static const struct irq_chip wcove_irqchip = {
        .name                   = "Whiskey Cove",
        .irq_mask               = wcove_irq_mask,
        .irq_unmask             = wcove_irq_unmask,
        .irq_set_type           = wcove_irq_type,
        .irq_bus_lock           = wcove_bus_lock,
        .irq_bus_sync_unlock    = wcove_bus_sync_unlock,
        .flags                  = IRQCHIP_IMMUTABLE,
        GPIOCHIP_IRQ_RESOURCE_HELPERS,
};

static irqreturn_t wcove_gpio_irq_handler(int irq, void *data)
{
        struct wcove_gpio *wg = (struct wcove_gpio *)data;
        unsigned int virq, gpio;
        unsigned long pending;
        u8 p[2];

        if (regmap_bulk_read(wg->regmap, IRQ_STATUS_BASE, p, 2)) {
                dev_err(wg->dev, "Failed to read irq status register\n");
                return IRQ_NONE;
        }

        pending = (p[0] & GPIO_IRQ0_MASK) | ((p[1] & GPIO_IRQ1_MASK) << 7);
        if (!pending)
                return IRQ_NONE;

        /* Iterate until no interrupt is pending */
        while (pending) {
                /* One iteration is for all pending bits */
                for_each_set_bit(gpio, &pending, WCOVE_GPIO_NUM) {
                        unsigned int mask, reg = to_ireg(gpio, IRQ_STATUS, &mask);

                        virq = irq_find_mapping(wg->chip.irq.domain, gpio);
                        handle_nested_irq(virq);
                        regmap_set_bits(wg->regmap, reg, mask);
                }

                /* Next iteration */
                if (regmap_bulk_read(wg->regmap, IRQ_STATUS_BASE, p, 2)) {
                        dev_err(wg->dev, "Failed to read irq status\n");
                        break;
                }

                pending = (p[0] & GPIO_IRQ0_MASK) | ((p[1] & GPIO_IRQ1_MASK) << 7);
        }

        return IRQ_HANDLED;
}

static void wcove_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
        unsigned int ctlo, ctli, irq_mask, irq_status;
        struct wcove_gpio *wg = gpiochip_get_data(chip);
        int gpio, mask, ret = 0;

        for (gpio = 0; gpio < WCOVE_GPIO_NUM; gpio++) {
                ret += regmap_read(wg->regmap, to_reg(gpio, CTRL_OUT), &ctlo);
                ret += regmap_read(wg->regmap, to_reg(gpio, CTRL_IN), &ctli);
                if (ret) {
                        dev_err(wg->dev, "Failed to read registers: CTRL out/in\n");
                        break;
                }

                ret += regmap_read(wg->regmap, to_ireg(gpio, IRQ_MASK, &mask), &irq_mask);
                ret += regmap_read(wg->regmap, to_ireg(gpio, IRQ_STATUS, &mask), &irq_status);
                if (ret) {
                        dev_err(wg->dev, "Failed to read registers: IRQ status/mask\n");
                        break;
                }

                seq_printf(s, " gpio-%-2d %s %s %s %s ctlo=%2x,%s %s\n",
                           gpio, ctlo & CTLO_DIR_OUT ? "out" : "in ",
                           str_hi_lo(ctli & 0x1),
                           ctli & CTLI_INTCNT_NE ? "fall" : "    ",
                           ctli & CTLI_INTCNT_PE ? "rise" : "    ",
                           ctlo,
                           irq_mask & mask ? "mask  " : "unmask",
                           irq_status & mask ? "pending" : "       ");
        }
}

static int wcove_gpio_probe(struct platform_device *pdev)
{
        struct intel_soc_pmic *pmic;
        struct wcove_gpio *wg;
        int virq, ret, irq;
        struct device *dev;
        struct gpio_irq_chip *girq;

        /*
         * This gpio platform device is created by a mfd device (see
         * drivers/mfd/intel_soc_pmic_bxtwc.c for details). Information
         * shared by all sub-devices created by the mfd device, the regmap
         * pointer for instance, is stored as driver data of the mfd device
         * driver.
         */
        pmic = dev_get_drvdata(pdev->dev.parent);
        if (!pmic)
                return -ENODEV;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        dev = &pdev->dev;

        wg = devm_kzalloc(dev, sizeof(*wg), GFP_KERNEL);
        if (!wg)
                return -ENOMEM;

        wg->regmap_irq_chip = pmic->irq_chip_data;

        platform_set_drvdata(pdev, wg);

        mutex_init(&wg->buslock);
        wg->chip.label = KBUILD_MODNAME;
        wg->chip.direction_input = wcove_gpio_dir_in;
        wg->chip.direction_output = wcove_gpio_dir_out;
        wg->chip.get_direction = wcove_gpio_get_direction;
        wg->chip.get = wcove_gpio_get;
        wg->chip.set = wcove_gpio_set;
        wg->chip.set_config = wcove_gpio_set_config;
        wg->chip.base = -1;
        wg->chip.ngpio = WCOVE_VGPIO_NUM;
        wg->chip.can_sleep = true;
        wg->chip.parent = pdev->dev.parent;
        wg->chip.dbg_show = wcove_gpio_dbg_show;
        wg->dev = dev;
        wg->regmap = pmic->regmap;

        virq = regmap_irq_get_virq(wg->regmap_irq_chip, irq);
        if (virq < 0) {
                dev_err(dev, "Failed to get virq by irq %d\n", irq);
                return virq;
        }

        girq = &wg->chip.irq;
        gpio_irq_chip_set_chip(girq, &wcove_irqchip);
        /* This will let us handle the parent IRQ in the driver */
        girq->parent_handler = NULL;
        girq->num_parents = 0;
        girq->parents = NULL;
        girq->default_type = IRQ_TYPE_NONE;
        girq->handler = handle_simple_irq;
        girq->threaded = true;

        ret = devm_request_threaded_irq(dev, virq, NULL, wcove_gpio_irq_handler,
                                        IRQF_ONESHOT, pdev->name, wg);
        if (ret) {
                dev_err(dev, "Failed to request irq %d\n", virq);
                return ret;
        }

        ret = devm_gpiochip_add_data(dev, &wg->chip, wg);
        if (ret) {
                dev_err(dev, "Failed to add gpiochip: %d\n", ret);
                return ret;
        }

        /* Enable GPIO0 interrupts */
        ret = regmap_clear_bits(wg->regmap, IRQ_MASK_BASE + 0, GPIO_IRQ0_MASK);
        if (ret)
                return ret;

        /* Enable GPIO1 interrupts */
        ret = regmap_clear_bits(wg->regmap, IRQ_MASK_BASE + 1, GPIO_IRQ1_MASK);
        if (ret)
                return ret;

        return 0;
}

/*
 * Whiskey Cove PMIC itself is a analog device(but with digital control
 * interface) providing power management support for other devices in
 * the accompanied SoC, so we have no .pm for Whiskey Cove GPIO driver.
 */
static struct platform_driver wcove_gpio_driver = {
        .driver = {
                .name = "bxt_wcove_gpio",
        },
        .probe = wcove_gpio_probe,
};

module_platform_driver(wcove_gpio_driver);

MODULE_AUTHOR("Ajay Thomas <ajay.thomas.david.rajamanickam@intel.com>");
MODULE_AUTHOR("Bin Gao <bin.gao@intel.com>");
MODULE_DESCRIPTION("Intel Whiskey Cove GPIO Driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:bxt_wcove_gpio");