#include <errno.h>
#include <stdint.h>

#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/i2c.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
#include <zephyr/sys/util.h>

#include <drivers/pmic/ip5306.h>

#define DT_DRV_COMPAT injoinic_ip5306

LOG_MODULE_REGISTER(ip5306, LOG_LEVEL_INF);

#define IP5306_REG_READ0               0x70
#define IP5306_REG_READ1               0x71
#define IP5306_CHARGING_BIT            BIT(3)
#define IP5306_FULL_BIT                BIT(3)

struct ip5306_config {
	struct i2c_dt_spec bus;
	struct gpio_dt_spec wakeup_gpio;
	uint32_t keepalive_interval_ms;
	uint32_t keepalive_pulse_width_ms;
};

struct ip5306_data {
	const struct device *dev;
	struct k_work_delayable keepalive_work;
	bool started;
	bool pulse_active;
};

static uint32_t keepalive_low_delay_ms(const struct ip5306_config *config)
{
	if (config->keepalive_interval_ms > config->keepalive_pulse_width_ms) {
		return config->keepalive_interval_ms -
		       config->keepalive_pulse_width_ms;
	}

	return 0;
}

static void keepalive_work_handler(struct k_work *work)
{
	struct k_work_delayable *dwork = k_work_delayable_from_work(work);
	struct ip5306_data *data =
		CONTAINER_OF(dwork, struct ip5306_data, keepalive_work);
	const struct device *dev = data->dev;
	const struct ip5306_config *config = dev->config;
	int err;

	if (!data->started) {
		return;
	}

	if (!data->pulse_active) {
		err = gpio_pin_set_dt(&config->wakeup_gpio, 1);
		if (err) {
			LOG_ERR("Failed to assert wakeup pulse (%d)", err);
		}

		data->pulse_active = true;
		k_work_reschedule(&data->keepalive_work,
				  K_MSEC(config->keepalive_pulse_width_ms));
		return;
	}

	err = gpio_pin_set_dt(&config->wakeup_gpio, 0);
	if (err) {
		LOG_ERR("Failed to deassert wakeup pulse (%d)", err);
	}

	data->pulse_active = false;
	k_work_reschedule(&data->keepalive_work,
			  K_MSEC(keepalive_low_delay_ms(config)));
}

static int ip5306_init_api(const struct device *dev)
{
	const struct ip5306_config *config = dev->config;
	struct ip5306_data *data = dev->data;
	uint8_t reg_val;
	int err;

	if (data->started) {
		return 0;
	}

	err = i2c_reg_read_byte_dt(&config->bus, IP5306_REG_READ0, &reg_val);
	if (err) {
		LOG_ERR("IP5306 probe failed (%d)", err);
		return err;
	}

	data->started = true;
	data->pulse_active = false;
	k_work_reschedule(&data->keepalive_work,
			  K_MSEC(keepalive_low_delay_ms(config)));

	return 0;
}

static int ip5306_get_status_api(const struct device *dev,
				 struct ip5306_status *status)
{
	const struct ip5306_config *config = dev->config;
	uint8_t read0;
	uint8_t read1;
	int err;

	if (status == NULL) {
		return -EINVAL;
	}

	err = i2c_reg_read_byte_dt(&config->bus, IP5306_REG_READ0, &read0);
	if (err) {
		return err;
	}

	err = i2c_reg_read_byte_dt(&config->bus, IP5306_REG_READ1, &read1);
	if (err) {
		return err;
	}

	status->charging = (read0 & IP5306_CHARGING_BIT) != 0U;
	status->full = (read1 & IP5306_FULL_BIT) != 0U;

	return 0;
}

static int ip5306_dev_init(const struct device *dev)
{
	const struct ip5306_config *config = dev->config;
	struct ip5306_data *data = dev->data;

	if (!i2c_is_ready_dt(&config->bus)) {
		LOG_ERR("I2C bus not ready");
		return -ENODEV;
	}

	if (!gpio_is_ready_dt(&config->wakeup_gpio)) {
		LOG_ERR("Wakeup GPIO not ready");
		return -ENODEV;
	}

	if (config->keepalive_pulse_width_ms == 0U) {
		LOG_ERR("Invalid keepalive pulse width");
		return -EINVAL;
	}

	if (config->keepalive_interval_ms == 0U) {
		LOG_ERR("Invalid keepalive interval");
		return -EINVAL;
	}

	if (config->keepalive_pulse_width_ms > config->keepalive_interval_ms) {
		LOG_ERR("Pulse width cannot exceed interval");
		return -EINVAL;
	}

	data->dev = dev;
	data->started = false;
	data->pulse_active = false;

	k_work_init_delayable(&data->keepalive_work, keepalive_work_handler);

	return gpio_pin_configure_dt(&config->wakeup_gpio, GPIO_OUTPUT_INACTIVE);
}

static const struct ip5306_driver_api ip5306_driver_api = {
	.init = ip5306_init_api,
	.get_status = ip5306_get_status_api,
};

#define IP5306_DEFINE(inst)                                                     \
	static struct ip5306_data ip5306_data_##inst;                           \
                                                                              \
	static const struct ip5306_config ip5306_config_##inst = {              \
		.bus = I2C_DT_SPEC_INST_GET(inst),                              \
		.wakeup_gpio = GPIO_DT_SPEC_INST_GET(inst, wakeup_gpios),       \
		.keepalive_interval_ms =                                        \
			DT_INST_PROP(inst, keepalive_interval_ms),              \
		.keepalive_pulse_width_ms =                                     \
			DT_INST_PROP(inst, keepalive_pulse_width_ms),          \
	};                                                                     \
                                                                              \
	DEVICE_DT_INST_DEFINE(inst, ip5306_dev_init, NULL,                      \
			      &ip5306_data_##inst, &ip5306_config_##inst,      \
			      POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE, \
			      &ip5306_driver_api)

DT_INST_FOREACH_STATUS_OKAY(IP5306_DEFINE)