/*
 * Copyright (c) 2016 BayLibre, SAS
 * Copyright (c) 2017 Linaro Ltd
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <clock_control/stm32_clock_control.h>
#include <drivers/clock_control.h>
#include <sys/util.h>
#include <kernel.h>
#include <soc.h>
#include <errno.h>
#include <drivers/i2c.h>
#include "i2c_ll_stm32.h"

#define LOG_LEVEL CONFIG_I2C_LOG_LEVEL
#include <logging/log.h>
LOG_MODULE_REGISTER(i2c_ll_stm32);

#include "i2c-priv.h"

int i2c_stm32_runtime_configure(struct device *dev, u32_t config)
{
	const struct i2c_stm32_config *cfg = DEV_CFG(dev);
	struct i2c_stm32_data *data = DEV_DATA(dev);
	I2C_TypeDef *i2c = cfg->i2c;
	u32_t clock = 0U;
	int ret;

#if defined(CONFIG_SOC_SERIES_STM32F3X) || defined(CONFIG_SOC_SERIES_STM32F0X)
	LL_RCC_ClocksTypeDef rcc_clocks;

	/*
	 * STM32F0/3 I2C's independent clock source supports only
	 * HSI and SYSCLK, not APB1. We force clock variable to
	 * SYSCLK frequency.
	 */
	LL_RCC_GetSystemClocksFreq(&rcc_clocks);
	clock = rcc_clocks.SYSCLK_Frequency;
#else
	clock_control_get_rate(device_get_binding(STM32_CLOCK_CONTROL_NAME),
			(clock_control_subsys_t *) &cfg->pclken, &clock);
#endif /* CONFIG_SOC_SERIES_STM32F3X) || CONFIG_SOC_SERIES_STM32F0X */

	data->dev_config = config;

	k_sem_take(&data->bus_mutex, K_FOREVER);
	LL_I2C_Disable(i2c);
	LL_I2C_SetMode(i2c, LL_I2C_MODE_I2C);
	ret = stm32_i2c_configure_timing(dev, clock);
	k_sem_give(&data->bus_mutex);

	return ret;
}

#define OPERATION(msg) (((struct i2c_msg *) msg)->flags & I2C_MSG_RW_MASK)

static int i2c_stm32_transfer(struct device *dev, struct i2c_msg *msg,
			      u8_t num_msgs, u16_t slave)
{
	struct i2c_stm32_data *data = DEV_DATA(dev);
	struct i2c_msg *current, *next;
	int ret = 0;

	/* Check for validity of all messages, to prevent having to abort
	 * in the middle of a transfer
	 */
	current = msg;

	/*
	 * Set I2C_MSG_RESTART flag on first message in order to send start
	 * condition
	 */
	current->flags |= I2C_MSG_RESTART;

	for (u8_t i = 1; i <= num_msgs; i++) {

		if (i < num_msgs) {
			next = current + 1;

			/*
			 * Restart condition between messages
			 * of different directions is required
			 */
			if (OPERATION(current) != OPERATION(next)) {
				if (!(next->flags & I2C_MSG_RESTART)) {
					ret = -EINVAL;
					break;
				}
			}

			/* Stop condition is only allowed on last message */
			if (current->flags & I2C_MSG_STOP) {
				ret = -EINVAL;
				break;
			}
		} else {
			/* Stop condition is required for the last message */
			current->flags |= I2C_MSG_STOP;
		}

		current++;
	}

	if (ret) {
		return ret;
	}

	/* Send out messages */
	k_sem_take(&data->bus_mutex, K_FOREVER);

	current = msg;

	while (num_msgs > 0) {
		u8_t *next_msg_flags = NULL;

		if (num_msgs > 1) {
			next = current + 1;
			next_msg_flags = &(next->flags);
		}
		while (current->len > 0) {
			u32_t temp_len = current->len;
			u8_t tmp_msg_flags = current->flags & ~I2C_MSG_RESTART;
			u8_t tmp_next_msg_flags = next_msg_flags ?
							*next_msg_flags : 0;

			if (current->len > 255) {
				current->len = 255U;
				current->flags &= ~I2C_MSG_STOP;
				if (next_msg_flags) {
					*next_msg_flags = current->flags &
							  ~I2C_MSG_RESTART;
				}
			}
			if ((current->flags & I2C_MSG_RW_MASK) ==
								I2C_MSG_WRITE) {
				ret = stm32_i2c_msg_write(dev, current,
							  next_msg_flags,
							  slave);
			} else {
				ret = stm32_i2c_msg_read(dev, current,
							 next_msg_flags, slave);
			}

			if (ret < 0) {
				goto exit;
			}
			if (next_msg_flags) {
				*next_msg_flags = tmp_next_msg_flags;
			}
			current->buf += current->len;
			current->flags = tmp_msg_flags;
			current->len = temp_len - current->len;
		}
		current++;
		num_msgs--;
	}
exit:
	k_sem_give(&data->bus_mutex);
	return ret;
}

static const struct i2c_driver_api api_funcs = {
	.configure = i2c_stm32_runtime_configure,
	.transfer = i2c_stm32_transfer,
#if defined(CONFIG_I2C_SLAVE)
	.slave_register = i2c_stm32_slave_register,
	.slave_unregister = i2c_stm32_slave_unregister,
#endif
};

static int i2c_stm32_init(struct device *dev)
{
	struct device *clock = device_get_binding(STM32_CLOCK_CONTROL_NAME);
	const struct i2c_stm32_config *cfg = DEV_CFG(dev);
	u32_t bitrate_cfg;
	int ret;
	struct i2c_stm32_data *data = DEV_DATA(dev);
#ifdef CONFIG_I2C_STM32_INTERRUPT
	k_sem_init(&data->device_sync_sem, 0, UINT_MAX);
	cfg->irq_config_func(dev);
#endif

	/*
	 * initialize mutex used when multiple transfers
	 * are taking place to guarantee that each one is
	 * atomic and has exclusive access to the I2C bus.
	 */
	k_sem_init(&data->bus_mutex, 1, 1);

	__ASSERT_NO_MSG(clock);
	if (clock_control_on(clock,
		(clock_control_subsys_t *) &cfg->pclken) != 0) {
		LOG_ERR("i2c: failure enabling clock");
		return -EIO;
	}

#if defined(CONFIG_SOC_SERIES_STM32F3X) || defined(CONFIG_SOC_SERIES_STM32F0X)
	/*
	 * STM32F0/3 I2C's independent clock source supports only
	 * HSI and SYSCLK, not APB1. We force I2C clock source to SYSCLK.
	 * I2C2 on STM32F0 uses APB1 clock as I2C clock source
	 */

	switch ((u32_t)cfg->i2c) {
#ifdef CONFIG_I2C_1
	case DT_I2C_1_BASE_ADDRESS:
		LL_RCC_SetI2CClockSource(LL_RCC_I2C1_CLKSOURCE_SYSCLK);
		break;
#endif /* CONFIG_I2C_1 */

#if defined(CONFIG_SOC_SERIES_STM32F3X) && defined(CONFIG_I2C_2)
	case DT_I2C_2_BASE_ADDRESS:
		LL_RCC_SetI2CClockSource(LL_RCC_I2C2_CLKSOURCE_SYSCLK);
		break;
#endif /* CONFIG_SOC_SERIES_STM32F3X && CONFIG_I2C_2 */

#ifdef CONFIG_I2C_3
	case DT_I2C_3_BASE_ADDRESS:
		LL_RCC_SetI2CClockSource(LL_RCC_I2C3_CLKSOURCE_SYSCLK);
		break;
#endif /* CONFIG_I2C_3 */
	}
#endif /* CONFIG_SOC_SERIES_STM32F3X) || CONFIG_SOC_SERIES_STM32F0X */

	bitrate_cfg = i2c_map_dt_bitrate(cfg->bitrate);

	ret = i2c_stm32_runtime_configure(dev, I2C_MODE_MASTER | bitrate_cfg);
	if (ret < 0) {
		LOG_ERR("i2c: failure initializing");
		return ret;
	}

	return 0;
}

/* Macros for I2C instance declaration */

#ifdef CONFIG_I2C_STM32_INTERRUPT

#ifdef CONFIG_I2C_STM32_COMBINED_INTERRUPT
#define STM32_I2C_IRQ_CONNECT_AND_ENABLE(name)				\
	do {								\
		IRQ_CONNECT(DT_##name##_COMBINED_IRQ,			\
			    DT_##name##_COMBINED_IRQ_PRI,		\
			    stm32_i2c_combined_isr,			\
			    DEVICE_GET(i2c_stm32_##name), 0);		\
		irq_enable(DT_##name##_COMBINED_IRQ);			\
	} while (0)
#else
#define STM32_I2C_IRQ_CONNECT_AND_ENABLE(name)				\
	do {								\
		IRQ_CONNECT(DT_##name##_EVENT_IRQ,			\
			    DT_##name##_EVENT_IRQ_PRI,			\
			    stm32_i2c_event_isr,			\
			    DEVICE_GET(i2c_stm32_##name), 0);		\
		irq_enable(DT_##name##_EVENT_IRQ);			\
									\
		IRQ_CONNECT(DT_##name##_ERROR_IRQ,			\
			    DT_##name##_ERROR_IRQ_PRI,			\
			    stm32_i2c_error_isr,			\
			    DEVICE_GET(i2c_stm32_##name), 0);		\
		irq_enable(DT_##name##_ERROR_IRQ);			\
	} while (0)
#endif /* CONFIG_I2C_STM32_COMBINED_INTERRUPT */

#define STM32_I2C_IRQ_HANDLER_DECL(name)				\
static void i2c_stm32_irq_config_func_##name(struct device *dev)
#define STM32_I2C_IRQ_HANDLER_FUNCTION(name)				\
	.irq_config_func = i2c_stm32_irq_config_func_##name,
#define STM32_I2C_IRQ_HANDLER(name)					\
static void i2c_stm32_irq_config_func_##name(struct device *dev)	\
{									\
	STM32_I2C_IRQ_CONNECT_AND_ENABLE(name);				\
}
#else

#define STM32_I2C_IRQ_HANDLER_DECL(name)
#define STM32_I2C_IRQ_HANDLER_FUNCTION(name)
#define STM32_I2C_IRQ_HANDLER(name)

#endif /* CONFIG_I2C_STM32_INTERRUPT */

#define STM32_I2C_INIT(name)						\
STM32_I2C_IRQ_HANDLER_DECL(name);					\
									\
static const struct i2c_stm32_config i2c_stm32_cfg_##name = {		\
	.i2c = (I2C_TypeDef *)DT_##name##_BASE_ADDRESS,			\
	.pclken = {							\
		.enr = DT_##name##_CLOCK_BITS,				\
		.bus = DT_##name##_CLOCK_BUS,				\
	},								\
	STM32_I2C_IRQ_HANDLER_FUNCTION(name)				\
	.bitrate = DT_##name##_BITRATE,					\
};									\
									\
static struct i2c_stm32_data i2c_stm32_dev_data_##name;			\
									\
DEVICE_AND_API_INIT(i2c_stm32_##name, DT_##name##_NAME,			\
		    &i2c_stm32_init, &i2c_stm32_dev_data_##name,	\
		    &i2c_stm32_cfg_##name,				\
		    POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,	\
		    &api_funcs);					\
									\
STM32_I2C_IRQ_HANDLER(name)

/* I2C instances declaration */

#ifdef CONFIG_I2C_1
STM32_I2C_INIT(I2C_1);
#endif /* CONFIG_I2C_1 */

#ifdef CONFIG_I2C_2
STM32_I2C_INIT(I2C_2);
#endif /* CONFIG_I2C_2 */

#ifdef CONFIG_I2C_3

#ifndef I2C3_BASE
#error "I2C_3 is not available on the platform that you selected"
#endif /* I2C3_BASE */

STM32_I2C_INIT(I2C_3);
#endif /* CONFIG_I2C_3 */

#ifdef CONFIG_I2C_4

#ifndef I2C4_BASE
#error "I2C_4 is not available on the platform that you selected"
#endif /* I2C4_BASE */

STM32_I2C_INIT(I2C_4);
#endif /* CONFIG_I2C_4 */


#ifdef CONFIG_I2C_5

#ifndef I2C5_BASE
#error "I2C_5 is not available on the platform that you selected"
#endif /* I2C5_BASE */

STM32_I2C_INIT(I2C_5);
#endif /* CONFIG_I2C_5 */