/*
 * Copyright (c) 2022 Google LLC
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT gpio_keys

#include <zephyr/device.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/input/input.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
#include <zephyr/pm/device.h>
#include <zephyr/pm/device_runtime.h>
#include <zephyr/sys/atomic.h>

LOG_MODULE_REGISTER(gpio_keys, CONFIG_INPUT_LOG_LEVEL);

struct gpio_keys_callback {
	struct gpio_callback gpio_cb;
	int8_t pin_state;
};

struct gpio_keys_pin_config {
	/** GPIO specification from devicetree */
	struct gpio_dt_spec spec;
	/** Zephyr code from devicetree */
	uint32_t zephyr_code;
};

struct gpio_keys_pin_data {
	const struct device *dev;
	struct gpio_keys_callback cb_data;
	struct k_work_delayable work;
	int8_t pin_state;
};

struct gpio_keys_config {
	/** Debounce interval in milliseconds from devicetree */
	uint32_t debounce_interval_ms;
	const int num_keys;
	const struct gpio_keys_pin_config *pin_cfg;
	struct gpio_keys_pin_data *pin_data;
	k_work_handler_t handler;
	bool polling_mode;
};

struct gpio_keys_data {
#ifdef CONFIG_PM_DEVICE
	atomic_t suspended;
#endif
};

/**
 * Handle debounced gpio pin state.
 */
static void gpio_keys_poll_pin(const struct device *dev, int key_index)
{
	const struct gpio_keys_config *cfg = dev->config;
	const struct gpio_keys_pin_config *pin_cfg = &cfg->pin_cfg[key_index];
	struct gpio_keys_pin_data *pin_data = &cfg->pin_data[key_index];
	int new_pressed;

	new_pressed = gpio_pin_get(pin_cfg->spec.port, pin_cfg->spec.pin);

	LOG_DBG("%s: pin_state=%d, new_pressed=%d, key_index=%d", dev->name,
		pin_data->cb_data.pin_state, new_pressed, key_index);

	/* If gpio changed, report the event */
	if (new_pressed != pin_data->cb_data.pin_state) {
		pin_data->cb_data.pin_state = new_pressed;
		LOG_DBG("Report event %s %d, code=%d", dev->name, new_pressed,
			pin_cfg->zephyr_code);
		input_report_key(dev, pin_cfg->zephyr_code, new_pressed, true, K_FOREVER);
	}
}

static __maybe_unused void gpio_keys_poll_pins(struct k_work *work)
{
	struct k_work_delayable *dwork = k_work_delayable_from_work(work);
	struct gpio_keys_pin_data *pin_data = CONTAINER_OF(dwork, struct gpio_keys_pin_data, work);
	const struct device *dev = pin_data->dev;
	const struct gpio_keys_config *cfg = dev->config;

#ifdef CONFIG_PM_DEVICE
	struct gpio_keys_data *data = dev->data;

	if (atomic_get(&data->suspended) == 1) {
		return;
	}
#endif

	for (int i = 0; i < cfg->num_keys; i++) {
		gpio_keys_poll_pin(dev, i);
	}

	k_work_reschedule(dwork, K_MSEC(cfg->debounce_interval_ms));
}

static __maybe_unused void gpio_keys_change_deferred(struct k_work *work)
{
	struct k_work_delayable *dwork = k_work_delayable_from_work(work);
	struct gpio_keys_pin_data *pin_data = CONTAINER_OF(dwork, struct gpio_keys_pin_data, work);
	const struct device *dev = pin_data->dev;
	const struct gpio_keys_config *cfg = dev->config;
	int key_index = pin_data - (struct gpio_keys_pin_data *)cfg->pin_data;

	gpio_keys_poll_pin(dev, key_index);
}

static void gpio_keys_interrupt(const struct device *dev, struct gpio_callback *cbdata,
				uint32_t pins)
{
	struct gpio_keys_callback *keys_cb = CONTAINER_OF(
			cbdata, struct gpio_keys_callback, gpio_cb);
	struct gpio_keys_pin_data *pin_data = CONTAINER_OF(
			keys_cb, struct gpio_keys_pin_data, cb_data);
	const struct gpio_keys_config *cfg = pin_data->dev->config;

	ARG_UNUSED(dev); /* GPIO device pointer. */
	ARG_UNUSED(pins);

	k_work_reschedule(&pin_data->work, K_MSEC(cfg->debounce_interval_ms));
}

static int gpio_keys_interrupt_configure(const struct gpio_dt_spec *gpio_spec,
					 struct gpio_keys_callback *cb, uint32_t zephyr_code)
{
	int ret;

	gpio_init_callback(&cb->gpio_cb, gpio_keys_interrupt, BIT(gpio_spec->pin));

	ret = gpio_add_callback(gpio_spec->port, &cb->gpio_cb);
	if (ret < 0) {
		LOG_ERR("Could not set gpio callback");
		return ret;
	}

	cb->pin_state = -1;

	LOG_DBG("port=%s, pin=%d", gpio_spec->port->name, gpio_spec->pin);

	ret = gpio_pin_interrupt_configure_dt(gpio_spec, GPIO_INT_EDGE_BOTH);
	if (ret < 0) {
		LOG_ERR("interrupt configuration failed: %d", ret);
		return ret;
	}

	return 0;
}

static int gpio_keys_init(const struct device *dev)
{
	const struct gpio_keys_config *cfg = dev->config;
	struct gpio_keys_pin_data *pin_data = cfg->pin_data;
	int ret;

	for (int i = 0; i < cfg->num_keys; i++) {
		const struct gpio_dt_spec *gpio = &cfg->pin_cfg[i].spec;

		if (!gpio_is_ready_dt(gpio)) {
			LOG_ERR("%s is not ready", gpio->port->name);
			return -ENODEV;
		}

		ret = gpio_pin_configure_dt(gpio, GPIO_INPUT);
		if (ret != 0) {
			LOG_ERR("Pin %d configuration failed: %d", i, ret);
			return ret;
		}

		pin_data[i].dev = dev;
		k_work_init_delayable(&pin_data[i].work, cfg->handler);

		if (cfg->polling_mode) {
			continue;
		}

		ret = gpio_keys_interrupt_configure(&cfg->pin_cfg[i].spec,
						    &pin_data[i].cb_data,
						    cfg->pin_cfg[i].zephyr_code);
		if (ret != 0) {
			LOG_ERR("Pin %d interrupt configuration failed: %d", i, ret);
			return ret;
		}
	}

	if (cfg->polling_mode) {
		/* use pin 0 work to poll all the pins periodically */
		k_work_reschedule(&pin_data[0].work, K_MSEC(cfg->debounce_interval_ms));
	}

	ret = pm_device_runtime_enable(dev);
	if (ret < 0) {
		LOG_ERR("Failed to enable runtime power management");
		return ret;
	}

	return 0;
}

#ifdef CONFIG_PM_DEVICE
static int gpio_keys_pm_action(const struct device *dev,
			       enum pm_device_action action)
{
	const struct gpio_keys_config *cfg = dev->config;
	struct gpio_keys_data *data = dev->data;
	struct gpio_keys_pin_data *pin_data = cfg->pin_data;
	int ret;

	switch (action) {
	case PM_DEVICE_ACTION_SUSPEND:
		atomic_set(&data->suspended, 1);

		for (int i = 0; i < cfg->num_keys; i++) {
			const struct gpio_dt_spec *gpio = &cfg->pin_cfg[i].spec;

			if (!cfg->polling_mode) {
				ret = gpio_pin_interrupt_configure_dt(gpio, GPIO_INT_DISABLE);
				if (ret < 0) {
					LOG_ERR("interrupt configuration failed: %d", ret);
					return ret;
				}
			}

			ret = gpio_pin_configure_dt(gpio, GPIO_DISCONNECTED);
			if (ret != 0) {
				LOG_ERR("Pin %d configuration failed: %d", i, ret);
				return ret;
			}
		}

		return 0;
	case PM_DEVICE_ACTION_RESUME:
		atomic_set(&data->suspended, 0);

		for (int i = 0; i < cfg->num_keys; i++) {
			const struct gpio_dt_spec *gpio = &cfg->pin_cfg[i].spec;

			ret = gpio_pin_configure_dt(gpio, GPIO_INPUT);
			if (ret != 0) {
				LOG_ERR("Pin %d configuration failed: %d", i, ret);
				return ret;
			}

			if (cfg->polling_mode) {
				k_work_reschedule(&pin_data[0].work,
						  K_MSEC(cfg->debounce_interval_ms));
			} else {
				ret = gpio_pin_interrupt_configure_dt(gpio, GPIO_INT_EDGE_BOTH);
				if (ret < 0) {
					LOG_ERR("interrupt configuration failed: %d", ret);
					return ret;
				}
			}
		}

		return 0;
	default:
		return -ENOTSUP;
	}
}
#endif

#define GPIO_KEYS_CFG_CHECK(node_id)                                                               \
	BUILD_ASSERT(DT_NODE_HAS_PROP(node_id, zephyr_code),                                       \
		     "zephyr-code must be specified to use the input-gpio-keys driver");

#define GPIO_KEYS_CFG_DEF(node_id)                                                                 \
	{                                                                                          \
		.spec = GPIO_DT_SPEC_GET(node_id, gpios),                                          \
		.zephyr_code = DT_PROP(node_id, zephyr_code),                                      \
	}

#define GPIO_KEYS_INIT(i)                                                                          \
	DT_INST_FOREACH_CHILD_STATUS_OKAY(i, GPIO_KEYS_CFG_CHECK);                                 \
												   \
	static const struct gpio_keys_pin_config gpio_keys_pin_config_##i[] = {                    \
		DT_INST_FOREACH_CHILD_STATUS_OKAY_SEP(i, GPIO_KEYS_CFG_DEF, (,))};                 \
												   \
	static struct gpio_keys_pin_data                                                           \
		gpio_keys_pin_data_##i[ARRAY_SIZE(gpio_keys_pin_config_##i)];                      \
												   \
	static const struct gpio_keys_config gpio_keys_config_##i = {                              \
		.debounce_interval_ms = DT_INST_PROP(i, debounce_interval_ms),                     \
		.num_keys = ARRAY_SIZE(gpio_keys_pin_config_##i),                                  \
		.pin_cfg = gpio_keys_pin_config_##i,                                               \
		.pin_data = gpio_keys_pin_data_##i,                                                \
		.handler = COND_CODE_1(DT_INST_PROP(i, polling_mode),                              \
				       (gpio_keys_poll_pins), (gpio_keys_change_deferred)),        \
		.polling_mode = DT_INST_PROP(i, polling_mode),                                     \
	};                                                                                         \
												   \
	static struct gpio_keys_data gpio_keys_data_##i;                                           \
												   \
	PM_DEVICE_DT_INST_DEFINE(i, gpio_keys_pm_action);                                          \
												   \
	DEVICE_DT_INST_DEFINE(i, &gpio_keys_init, PM_DEVICE_DT_INST_GET(i),                        \
			      &gpio_keys_data_##i, &gpio_keys_config_##i,                          \
			      POST_KERNEL, CONFIG_INPUT_INIT_PRIORITY, NULL);

DT_INST_FOREACH_STATUS_OKAY(GPIO_KEYS_INIT)