// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Realtek DHC gpio driver
 *
 * Copyright (c) 2023 Realtek Semiconductor Corp.
 */

#include <linux/bitops.h>
#include <linux/cleanup.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/spinlock.h>
#include <linux/types.h>

#define RTD_GPIO_DEBOUNCE_1US 0
#define RTD_GPIO_DEBOUNCE_10US 1
#define RTD_GPIO_DEBOUNCE_100US 2
#define RTD_GPIO_DEBOUNCE_1MS 3
#define RTD_GPIO_DEBOUNCE_10MS 4
#define RTD_GPIO_DEBOUNCE_20MS 5
#define RTD_GPIO_DEBOUNCE_30MS 6

/**
 * struct rtd_gpio_info - Specific GPIO register information
 * @name: GPIO device name
 * @gpio_base: GPIO base number
 * @num_gpios: The number of GPIOs
 * @dir_offset: Offset for GPIO direction registers
 * @dato_offset: Offset for GPIO data output registers
 * @dati_offset: Offset for GPIO data input registers
 * @ie_offset: Offset for GPIO interrupt enable registers
 * @dp_offset: Offset for GPIO detection polarity registers
 * @gpa_offset: Offset for GPIO assert interrupt status registers
 * @gpda_offset: Offset for GPIO deassert interrupt status registers
 * @deb_offset: Offset for GPIO debounce registers
 * @deb_val: Register values representing the GPIO debounce time
 * @get_deb_setval: Used to get the corresponding value for setting the debounce register
 */
struct rtd_gpio_info {
	const char	*name;
	unsigned int	gpio_base;
	unsigned int	num_gpios;
	u8		*dir_offset;
	u8		*dato_offset;
	u8		*dati_offset;
	u8		*ie_offset;
	u8		*dp_offset;
	u8		*gpa_offset;
	u8		*gpda_offset;
	u8		*deb_offset;
	u8		*deb_val;
	u8		(*get_deb_setval)(const struct rtd_gpio_info *info,
					  unsigned int offset, u8 deb_index,
					  u8 *reg_offset, u8 *shift);
};

struct rtd_gpio {
	struct gpio_chip		gpio_chip;
	const struct rtd_gpio_info	*info;
	void __iomem			*base;
	void __iomem			*irq_base;
	unsigned int			irqs[2];
	raw_spinlock_t			lock;
};

static u8 rtd_gpio_get_deb_setval(const struct rtd_gpio_info *info, unsigned int offset,
				  u8 deb_index, u8 *reg_offset, u8 *shift)
{
	*reg_offset = info->deb_offset[offset / 8];
	*shift = (offset % 8) * 4;
	return info->deb_val[deb_index];
}

static u8 rtd1295_misc_gpio_get_deb_setval(const struct rtd_gpio_info *info, unsigned int offset,
					   u8 deb_index, u8 *reg_offset, u8 *shift)
{
	*reg_offset = info->deb_offset[0];
	*shift = (offset % 8) * 4;
	return info->deb_val[deb_index];
}

static u8 rtd1295_iso_gpio_get_deb_setval(const struct rtd_gpio_info *info, unsigned int offset,
					  u8 deb_index, u8 *reg_offset, u8 *shift)
{
	*reg_offset = info->deb_offset[0];
	*shift = 0;
	return info->deb_val[deb_index];
}

static const struct rtd_gpio_info rtd_iso_gpio_info = {
	.name			= "rtd_iso_gpio",
	.gpio_base		= 0,
	.num_gpios		= 82,
	.dir_offset		= (u8 []){ 0x0, 0x18, 0x2c },
	.dato_offset		= (u8 []){ 0x4, 0x1c, 0x30 },
	.dati_offset		= (u8 []){ 0x8, 0x20, 0x34 },
	.ie_offset		= (u8 []){ 0xc, 0x24, 0x38 },
	.dp_offset		= (u8 []){ 0x10, 0x28, 0x3c },
	.gpa_offset		= (u8 []){ 0x8, 0xe0, 0x90 },
	.gpda_offset		= (u8 []){ 0xc, 0xe4, 0x94 },
	.deb_offset		= (u8 []){ 0x44, 0x48, 0x4c, 0x50, 0x54, 0x58, 0x5c,
					   0x60, 0x64, 0x68, 0x6c },
	.deb_val		= (u8 []){ 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6 },
	.get_deb_setval		= rtd_gpio_get_deb_setval,
};

static const struct rtd_gpio_info rtd1619_iso_gpio_info = {
	.name			= "rtd1619_iso_gpio",
	.gpio_base		= 0,
	.num_gpios		= 86,
	.dir_offset		= (u8 []){ 0x0, 0x18, 0x2c },
	.dato_offset		= (u8 []){ 0x4, 0x1c, 0x30 },
	.dati_offset		= (u8 []){ 0x8, 0x20, 0x34 },
	.ie_offset		= (u8 []){ 0xc, 0x24, 0x38 },
	.dp_offset		= (u8 []){ 0x10, 0x28, 0x3c },
	.gpa_offset		= (u8 []){ 0x8, 0xe0, 0x90 },
	.gpda_offset		= (u8 []){ 0xc, 0xe4, 0x94 },
	.deb_offset		= (u8 []){ 0x44, 0x48, 0x4c, 0x50, 0x54, 0x58, 0x5c,
					   0x60, 0x64, 0x68, 0x6c },
	.deb_val		= (u8 []){ 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6 },
	.get_deb_setval		= rtd_gpio_get_deb_setval,
};

static const struct rtd_gpio_info rtd1395_iso_gpio_info = {
	.name			= "rtd1395_iso_gpio",
	.gpio_base		= 0,
	.num_gpios		= 57,
	.dir_offset		= (u8 []){ 0x0, 0x18 },
	.dato_offset		= (u8 []){ 0x4, 0x1c },
	.dati_offset		= (u8 []){ 0x8, 0x20 },
	.ie_offset		= (u8 []){ 0xc, 0x24 },
	.dp_offset		= (u8 []){ 0x10, 0x28 },
	.gpa_offset		= (u8 []){ 0x8, 0xe0 },
	.gpda_offset		= (u8 []){ 0xc, 0xe4 },
	.deb_offset		= (u8 []){ 0x30, 0x34, 0x38, 0x3c, 0x40, 0x44, 0x48, 0x4c },
	.deb_val		= (u8 []){ 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6 },
	.get_deb_setval		= rtd_gpio_get_deb_setval,
};

static const struct rtd_gpio_info rtd1295_misc_gpio_info = {
	.name			= "rtd1295_misc_gpio",
	.gpio_base		= 0,
	.num_gpios		= 101,
	.dir_offset		= (u8 []){ 0x0, 0x4, 0x8, 0xc },
	.dato_offset		= (u8 []){ 0x10, 0x14, 0x18, 0x1c },
	.dati_offset		= (u8 []){ 0x20, 0x24, 0x28, 0x2c },
	.ie_offset		= (u8 []){ 0x30, 0x34, 0x38, 0x3c },
	.dp_offset		= (u8 []){ 0x40, 0x44, 0x48, 0x4c },
	.gpa_offset		= (u8 []){ 0x40, 0x44, 0xa4, 0xb8 },
	.gpda_offset		= (u8 []){ 0x54, 0x58, 0xa8, 0xbc},
	.deb_offset		= (u8 []){ 0x50 },
	.deb_val		= (u8 []){ 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7 },
	.get_deb_setval		= rtd1295_misc_gpio_get_deb_setval,
};

static const struct rtd_gpio_info rtd1295_iso_gpio_info = {
	.name			= "rtd1295_iso_gpio",
	.gpio_base		= 101,
	.num_gpios		= 35,
	.dir_offset		= (u8 []){ 0x0, 0x18 },
	.dato_offset		= (u8 []){ 0x4, 0x1c },
	.dati_offset		= (u8 []){ 0x8, 0x20 },
	.ie_offset		= (u8 []){ 0xc, 0x24 },
	.dp_offset		= (u8 []){ 0x10, 0x28 },
	.gpa_offset		= (u8 []){ 0x8, 0xe0 },
	.gpda_offset		= (u8 []){ 0xc, 0xe4 },
	.deb_offset		= (u8 []){ 0x14 },
	.deb_val		= (u8 []){ 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7 },
	.get_deb_setval		= rtd1295_iso_gpio_get_deb_setval,
};

static int rtd_gpio_dir_offset(struct rtd_gpio *data, unsigned int offset)
{
	return data->info->dir_offset[offset / 32];
}

static int rtd_gpio_dato_offset(struct rtd_gpio *data, unsigned int offset)
{
	return data->info->dato_offset[offset / 32];
}

static int rtd_gpio_dati_offset(struct rtd_gpio *data, unsigned int offset)
{
	return data->info->dati_offset[offset / 32];
}

static int rtd_gpio_ie_offset(struct rtd_gpio *data, unsigned int offset)
{
	return data->info->ie_offset[offset / 32];
}

static int rtd_gpio_dp_offset(struct rtd_gpio *data, unsigned int offset)
{
	return data->info->dp_offset[offset / 32];
}


static int rtd_gpio_gpa_offset(struct rtd_gpio *data, unsigned int offset)
{
	/* Each GPIO assert interrupt status register contains 31 GPIOs. */
	return data->info->gpa_offset[offset / 31];
}

static int rtd_gpio_gpda_offset(struct rtd_gpio *data, unsigned int offset)
{
	/* Each GPIO deassert interrupt status register contains 31 GPIOs. */
	return data->info->gpda_offset[offset / 31];
}

static int rtd_gpio_set_debounce(struct gpio_chip *chip, unsigned int offset,
				   unsigned int debounce)
{
	struct rtd_gpio *data = gpiochip_get_data(chip);
	u8 deb_val, deb_index, reg_offset, shift;
	unsigned int write_en;
	u32 val;

	switch (debounce) {
	case 1:
		deb_index = RTD_GPIO_DEBOUNCE_1US;
		break;
	case 10:
		deb_index = RTD_GPIO_DEBOUNCE_10US;
		break;
	case 100:
		deb_index = RTD_GPIO_DEBOUNCE_100US;
		break;
	case 1000:
		deb_index = RTD_GPIO_DEBOUNCE_1MS;
		break;
	case 10000:
		deb_index = RTD_GPIO_DEBOUNCE_10MS;
		break;
	case 20000:
		deb_index = RTD_GPIO_DEBOUNCE_20MS;
		break;
	case 30000:
		deb_index = RTD_GPIO_DEBOUNCE_30MS;
		break;
	default:
		return -ENOTSUPP;
	}

	deb_val = data->info->get_deb_setval(data->info, offset, deb_index, &reg_offset, &shift);
	write_en = BIT(shift + 3);
	val = (deb_val << shift) | write_en;

	guard(raw_spinlock_irqsave)(&data->lock);
	writel_relaxed(val, data->base + reg_offset);

	return 0;
}

static int rtd_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
				 unsigned long config)
{
	int debounce;

	switch (pinconf_to_config_param(config)) {
	case PIN_CONFIG_BIAS_DISABLE:
	case PIN_CONFIG_BIAS_PULL_UP:
	case PIN_CONFIG_BIAS_PULL_DOWN:
		return gpiochip_generic_config(chip, offset, config);
	case PIN_CONFIG_INPUT_DEBOUNCE:
		debounce = pinconf_to_config_argument(config);
		return rtd_gpio_set_debounce(chip, offset, debounce);
	default:
		return -ENOTSUPP;
	}
}

static void rtd_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
{
	struct rtd_gpio *data = gpiochip_get_data(chip);
	u32 mask = BIT(offset % 32);
	int dato_reg_offset;
	u32 val;

	dato_reg_offset = rtd_gpio_dato_offset(data, offset);

	guard(raw_spinlock_irqsave)(&data->lock);

	val = readl_relaxed(data->base + dato_reg_offset);
	if (value)
		val |= mask;
	else
		val &= ~mask;
	writel_relaxed(val, data->base + dato_reg_offset);
}

static int rtd_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
	struct rtd_gpio *data = gpiochip_get_data(chip);
	int dato_reg_offset = rtd_gpio_dato_offset(data, offset);
	int dati_reg_offset = rtd_gpio_dati_offset(data, offset);
	int dir_reg_offset = rtd_gpio_dir_offset(data, offset);
	int dat_reg_offset;
	u32 val;

	guard(raw_spinlock_irqsave)(&data->lock);

	val = readl_relaxed(data->base + dir_reg_offset);
	dat_reg_offset = (val & BIT(offset % 32)) ? dato_reg_offset : dati_reg_offset;
	val = readl_relaxed(data->base + dat_reg_offset);

	return !!(val & BIT(offset % 32));
}

static int rtd_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
{
	struct rtd_gpio *data = gpiochip_get_data(chip);
	int reg_offset;
	u32 val;

	reg_offset = rtd_gpio_dir_offset(data, offset);
	val = readl_relaxed(data->base + reg_offset);
	if (val & BIT(offset % 32))
		return GPIO_LINE_DIRECTION_OUT;

	return GPIO_LINE_DIRECTION_IN;
}

static int rtd_gpio_set_direction(struct gpio_chip *chip, unsigned int offset, bool out)
{
	struct rtd_gpio *data = gpiochip_get_data(chip);
	u32 mask = BIT(offset % 32);
	int reg_offset;
	u32 val;

	reg_offset = rtd_gpio_dir_offset(data, offset);

	guard(raw_spinlock_irqsave)(&data->lock);

	val = readl_relaxed(data->base + reg_offset);
	if (out)
		val |= mask;
	else
		val &= ~mask;
	writel_relaxed(val, data->base + reg_offset);

	return 0;
}

static int rtd_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
{
	return rtd_gpio_set_direction(chip, offset, false);
}

static int rtd_gpio_direction_output(struct gpio_chip *chip, unsigned int offset, int value)
{
	rtd_gpio_set(chip, offset, value);

	return rtd_gpio_set_direction(chip, offset, true);
}

static bool rtd_gpio_check_ie(struct rtd_gpio *data, int irq)
{
	int mask = BIT(irq % 32);
	int ie_reg_offset;
	u32 enable;

	ie_reg_offset = rtd_gpio_ie_offset(data, irq);
	enable = readl_relaxed(data->base + ie_reg_offset);

	return enable & mask;
}

static void rtd_gpio_irq_handle(struct irq_desc *desc)
{
	int (*get_reg_offset)(struct rtd_gpio *gpio, unsigned int offset);
	struct rtd_gpio *data = irq_desc_get_handler_data(desc);
	struct irq_domain *domain = data->gpio_chip.irq.domain;
	struct irq_chip *chip = irq_desc_get_chip(desc);
	unsigned int irq = irq_desc_get_irq(desc);
	unsigned long status;
	int reg_offset, i, j;
	unsigned int hwirq;

	if (irq == data->irqs[0])
		get_reg_offset = &rtd_gpio_gpa_offset;
	else if (irq == data->irqs[1])
		get_reg_offset = &rtd_gpio_gpda_offset;

	chained_irq_enter(chip, desc);

	/* Each GPIO interrupt status register contains 31 GPIOs. */
	for (i = 0; i < data->info->num_gpios; i += 31) {
		reg_offset = get_reg_offset(data, i);

		/*
		 * Bit 0 is the write_en bit, bit 0 to 31 corresponds to 31 GPIOs.
		 * When bit 0 is set to 0, write 1 to the other bits to clear the status.
		 * When bit 0 is set to 1, write 1 to the other bits to set the status.
		 */
		status = readl_relaxed(data->irq_base + reg_offset);
		status &= ~BIT(0);
		writel_relaxed(status, data->irq_base + reg_offset);

		for_each_set_bit(j, &status, 32) {
			hwirq = i + j - 1;
			if (rtd_gpio_check_ie(data, hwirq)) {
				int girq = irq_find_mapping(domain, hwirq);
				u32 irq_type = irq_get_trigger_type(girq);

				if ((irq == data->irqs[1]) && (irq_type != IRQ_TYPE_EDGE_BOTH))
					break;
				generic_handle_domain_irq(domain, hwirq);
			}
		}
	}

	chained_irq_exit(chip, desc);
}

static void rtd_gpio_enable_irq(struct irq_data *d)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct rtd_gpio *data = gpiochip_get_data(gc);
	irq_hw_number_t hwirq = irqd_to_hwirq(d);

	/* Bit 0 is write_en and bit 1 to 31 is correspond to 31 GPIOs. */
	u32 clr_mask = BIT(hwirq % 31) << 1;

	u32 ie_mask = BIT(hwirq % 32);
	int gpda_reg_offset;
	int gpa_reg_offset;
	int ie_reg_offset;
	u32 val;

	ie_reg_offset = rtd_gpio_ie_offset(data, hwirq);
	gpa_reg_offset = rtd_gpio_gpa_offset(data, hwirq);
	gpda_reg_offset = rtd_gpio_gpda_offset(data, hwirq);

	gpiochip_enable_irq(gc, hwirq);

	guard(raw_spinlock_irqsave)(&data->lock);

	writel_relaxed(clr_mask, data->irq_base + gpa_reg_offset);
	writel_relaxed(clr_mask, data->irq_base + gpda_reg_offset);

	val = readl_relaxed(data->base + ie_reg_offset);
	val |= ie_mask;
	writel_relaxed(val, data->base + ie_reg_offset);
}

static void rtd_gpio_disable_irq(struct irq_data *d)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct rtd_gpio *data = gpiochip_get_data(gc);
	irq_hw_number_t hwirq = irqd_to_hwirq(d);
	u32 ie_mask = BIT(hwirq % 32);
	int ie_reg_offset;
	u32 val;

	ie_reg_offset = rtd_gpio_ie_offset(data, hwirq);

	scoped_guard(raw_spinlock_irqsave, &data->lock) {
		val = readl_relaxed(data->base + ie_reg_offset);
		val &= ~ie_mask;
		writel_relaxed(val, data->base + ie_reg_offset);
	}

	gpiochip_disable_irq(gc, hwirq);
}

static int rtd_gpio_irq_set_type(struct irq_data *d, unsigned int type)
{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct rtd_gpio *data = gpiochip_get_data(gc);
	irq_hw_number_t hwirq = irqd_to_hwirq(d);
	u32 mask = BIT(hwirq % 32);
	int dp_reg_offset;
	bool polarity;
	u32 val;

	dp_reg_offset = rtd_gpio_dp_offset(data, hwirq);

	switch (type & IRQ_TYPE_SENSE_MASK) {
	case IRQ_TYPE_EDGE_RISING:
		polarity = 1;
		break;

	case IRQ_TYPE_EDGE_FALLING:
		polarity = 0;
		break;

	case IRQ_TYPE_EDGE_BOTH:
		polarity = 1;
		break;

	default:
		return -EINVAL;
	}

	scoped_guard(raw_spinlock_irqsave, &data->lock) {
		val = readl_relaxed(data->base + dp_reg_offset);
		if (polarity)
			val |= mask;
		else
			val &= ~mask;
		writel_relaxed(val, data->base + dp_reg_offset);
	}

	irq_set_handler_locked(d, handle_simple_irq);

	return 0;
}

static const struct irq_chip rtd_gpio_irq_chip = {
	.name = "rtd-gpio",
	.irq_enable = rtd_gpio_enable_irq,
	.irq_disable = rtd_gpio_disable_irq,
	.irq_set_type = rtd_gpio_irq_set_type,
	.flags = IRQCHIP_IMMUTABLE,
};

static int rtd_gpio_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct gpio_irq_chip *irq_chip;
	struct rtd_gpio *data;
	int ret;

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

	ret = platform_get_irq(pdev, 0);
	if (ret < 0)
		return ret;
	data->irqs[0] = ret;

	ret = platform_get_irq(pdev, 1);
	if (ret < 0)
		return ret;
	data->irqs[1] = ret;

	data->info = device_get_match_data(dev);
	if (!data->info)
		return -EINVAL;

	raw_spin_lock_init(&data->lock);

	data->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(data->base))
		return PTR_ERR(data->base);

	data->irq_base = devm_platform_ioremap_resource(pdev, 1);
	if (IS_ERR(data->irq_base))
		return PTR_ERR(data->irq_base);

	data->gpio_chip.label = dev_name(dev);
	data->gpio_chip.base = -1;
	data->gpio_chip.ngpio = data->info->num_gpios;
	data->gpio_chip.request = gpiochip_generic_request;
	data->gpio_chip.free = gpiochip_generic_free;
	data->gpio_chip.get_direction = rtd_gpio_get_direction;
	data->gpio_chip.direction_input = rtd_gpio_direction_input;
	data->gpio_chip.direction_output = rtd_gpio_direction_output;
	data->gpio_chip.set = rtd_gpio_set;
	data->gpio_chip.get = rtd_gpio_get;
	data->gpio_chip.set_config = rtd_gpio_set_config;
	data->gpio_chip.parent = dev;

	irq_chip = &data->gpio_chip.irq;
	irq_chip->handler = handle_bad_irq;
	irq_chip->default_type = IRQ_TYPE_NONE;
	irq_chip->parent_handler = rtd_gpio_irq_handle;
	irq_chip->parent_handler_data = data;
	irq_chip->num_parents = 2;
	irq_chip->parents = data->irqs;

	gpio_irq_chip_set_chip(irq_chip, &rtd_gpio_irq_chip);

	return devm_gpiochip_add_data(dev, &data->gpio_chip, data);
}

static const struct of_device_id rtd_gpio_of_matches[] = {
	{ .compatible = "realtek,rtd1295-misc-gpio", .data = &rtd1295_misc_gpio_info },
	{ .compatible = "realtek,rtd1295-iso-gpio", .data = &rtd1295_iso_gpio_info },
	{ .compatible = "realtek,rtd1395-iso-gpio", .data = &rtd1395_iso_gpio_info },
	{ .compatible = "realtek,rtd1619-iso-gpio", .data = &rtd1619_iso_gpio_info },
	{ .compatible = "realtek,rtd1319-iso-gpio", .data = &rtd_iso_gpio_info },
	{ .compatible = "realtek,rtd1619b-iso-gpio", .data = &rtd_iso_gpio_info },
	{ .compatible = "realtek,rtd1319d-iso-gpio", .data = &rtd_iso_gpio_info },
	{ .compatible = "realtek,rtd1315e-iso-gpio", .data = &rtd_iso_gpio_info },
	{ }
};
MODULE_DEVICE_TABLE(of, rtd_gpio_of_matches);

static struct platform_driver rtd_gpio_platform_driver = {
	.driver = {
		.name = "gpio-rtd",
		.of_match_table = rtd_gpio_of_matches,
	},
	.probe = rtd_gpio_probe,
};
module_platform_driver(rtd_gpio_platform_driver);

MODULE_DESCRIPTION("Realtek DHC SoC gpio driver");
MODULE_LICENSE("GPL v2");