i2c_gecko.c

/*
 * Copyright (c) 2018 Diego Sueiro
 * Copyright (c) 2024 Capgemini
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT silabs_gecko_i2c

#include <errno.h>
#include <zephyr/drivers/i2c.h>
#include <zephyr/drivers/pinctrl.h>
#include <zephyr/kernel.h>
#include <zephyr/sys/util.h>
#include <em_cmu.h>
#include <em_i2c.h>
#include <em_gpio.h>
#include <soc.h>

#define LOG_LEVEL CONFIG_I2C_LOG_LEVEL
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(i2c_gecko);

#include "i2c-priv.h"

#define DEV_BASE(dev) ((I2C_TypeDef *)((const struct i2c_gecko_config *const)(dev)->config)->base)

struct i2c_gecko_config {
	const struct pinctrl_dev_config *pcfg;
	I2C_TypeDef *base;
	CMU_Clock_TypeDef clock;
	uint32_t bitrate;
#if defined(CONFIG_I2C_TARGET)
	void (*irq_config_func)(const struct device *dev);
#endif
};

struct i2c_gecko_data {
	struct k_sem device_sync_sem;
	struct k_sem bus_lock;
	uint32_t dev_config;
#if defined(CONFIG_I2C_TARGET)
	struct i2c_target_config *target_cfg;
#endif
};

static int i2c_gecko_configure(const struct device *dev, uint32_t dev_config_raw)
{
	I2C_TypeDef *base = DEV_BASE(dev);
	struct i2c_gecko_data *data = dev->data;
	I2C_Init_TypeDef i2cInit = I2C_INIT_DEFAULT;
	uint32_t baudrate;

	if (!(I2C_MODE_CONTROLLER & dev_config_raw)) {
		return -EINVAL;
	}

	switch (I2C_SPEED_GET(dev_config_raw)) {
	case I2C_SPEED_STANDARD:
		baudrate = KHZ(100);
		break;
	case I2C_SPEED_FAST:
		baudrate = KHZ(400);
		break;
	case I2C_SPEED_FAST_PLUS:
		baudrate = MHZ(1);
		break;
	default:
		return -EINVAL;
	}

	k_sem_take(&data->bus_lock, K_FOREVER);

	data->dev_config = dev_config_raw;
	i2cInit.freq = baudrate;

#if defined(CONFIG_I2C_TARGET)
	i2cInit.master = 0;
#endif

	I2C_Init(base, &i2cInit);

	k_sem_give(&data->bus_lock);

	return 0;
}

static int i2c_gecko_transfer(const struct device *dev, struct i2c_msg *msgs, uint8_t num_msgs,
			      uint16_t addr)
{
	I2C_TypeDef *base = DEV_BASE(dev);
	struct i2c_gecko_data *data = dev->data;
	I2C_TransferSeq_TypeDef seq;
	I2C_TransferReturn_TypeDef ret = -EIO;
	uint32_t timeout = 300000U;

	if (!num_msgs) {
		return 0;
	}

	k_sem_take(&data->bus_lock, K_FOREVER);

	seq.addr = addr << 1;

	do {
		seq.buf[0].data = msgs->buf;
		seq.buf[0].len = msgs->len;

		if ((msgs->flags & I2C_MSG_RW_MASK) == I2C_MSG_READ) {
			seq.flags = I2C_FLAG_READ;
		} else {
			seq.flags = I2C_FLAG_WRITE;
			if (num_msgs > 1) {
				/* Next message */
				msgs++;
				num_msgs--;
				if ((msgs->flags & I2C_MSG_RW_MASK) == I2C_MSG_READ) {
					seq.flags = I2C_FLAG_WRITE_READ;
				} else {
					seq.flags = I2C_FLAG_WRITE_WRITE;
				}
				seq.buf[1].data = msgs->buf;
				seq.buf[1].len = msgs->len;
			}
		}

		if (data->dev_config & I2C_ADDR_10_BITS) {
			seq.flags |= I2C_FLAG_10BIT_ADDR;
		}

		/* Do a polled transfer */
		ret = I2C_TransferInit(base, &seq);
		while (ret == i2cTransferInProgress && timeout--) {
			ret = I2C_Transfer(base);
		}

		if (ret != i2cTransferDone) {
			goto finish;
		}

		/* Next message */
		msgs++;
		num_msgs--;
	} while (num_msgs);

finish:
	k_sem_give(&data->bus_lock);

	if (ret != i2cTransferDone) {
		ret = -EIO;
	}
	return ret;
}

static int i2c_gecko_init(const struct device *dev)
{
	struct i2c_gecko_data *data = dev->data;
	const struct i2c_gecko_config *config = dev->config;
	uint32_t bitrate_cfg;
	int error;

	/* Initialize mutex to guarantee that each transaction
	 * is atomic and has exclusive access to the I2C bus
	 */
	k_sem_init(&data->bus_lock, 1, 1);

	CMU_ClockEnable(config->clock, true);

	error = pinctrl_apply_state(config->pcfg, PINCTRL_STATE_DEFAULT);
	if (error < 0) {
		LOG_ERR("Failed to configure I2C pins err[%d]", error);
		return error;
	}

	bitrate_cfg = i2c_map_dt_bitrate(config->bitrate);

	error = i2c_gecko_configure(dev, I2C_MODE_CONTROLLER | bitrate_cfg);
	if (error) {
		return error;
	}

	return 0;
}

#if defined(CONFIG_I2C_TARGET)
static int i2c_gecko_target_register(const struct device *dev, struct i2c_target_config *cfg)
{
	const struct i2c_gecko_config *config = dev->config;
	struct i2c_gecko_data *data = dev->data;

	data->target_cfg = cfg;

	I2C_SlaveAddressSet(config->base, cfg->address << _I2C_SADDR_ADDR_SHIFT);
	/* Match with specified address, no wildcards in address */
	I2C_SlaveAddressMaskSet(config->base, _I2C_SADDRMASK_SADDRMASK_MASK);

	I2C_IntDisable(config->base, _I2C_IEN_MASK);
	I2C_IntEnable(config->base, I2C_IEN_ADDR | I2C_IEN_RXDATAV | I2C_IEN_ACK | I2C_IEN_SSTOP |
					    I2C_IEN_BUSERR | I2C_IEN_ARBLOST);

	config->irq_config_func(dev);

	return 0;
}

static int i2c_gecko_target_unregister(const struct device *dev, struct i2c_target_config *cfg)
{
	const struct i2c_gecko_config *config = dev->config;
	struct i2c_gecko_data *data = dev->data;

	data->target_cfg = NULL;

	I2C_IntDisable(config->base, _I2C_IEN_MASK);

	return 0;
}
#endif

static const struct i2c_driver_api i2c_gecko_driver_api = {
	.configure = i2c_gecko_configure,
	.transfer = i2c_gecko_transfer,
#if defined(CONFIG_I2C_TARGET)
	.target_register = i2c_gecko_target_register,
	.target_unregister = i2c_gecko_target_unregister,
#endif
#ifdef CONFIG_I2C_RTIO
	.iodev_submit = i2c_iodev_submit_fallback,
#endif
};

#if defined(CONFIG_I2C_TARGET)
void i2c_gecko_isr(const struct device *dev)
{
	const struct i2c_gecko_config *config = dev->config;
	struct i2c_gecko_data *data = dev->data;

	uint32_t pending;
	uint32_t rx_byte;
	uint8_t tx_byte;

	pending = config->base->IF;

	/* If some sort of fault, abort transfer. */
	if (pending & (I2C_IF_BUSERR | I2C_IF_ARBLOST)) {
		LOG_ERR("I2C Bus Error");
		I2C_IntClear(config->base, I2C_IF_BUSERR);
		I2C_IntClear(config->base, I2C_IF_ARBLOST);
	} else {
		if (pending & I2C_IF_ADDR) {
			/* Address Match, indicating that reception is started */
			rx_byte = config->base->RXDATA;
			config->base->CMD = I2C_CMD_ACK;

			/* Check if read bit set */
			if (rx_byte & 0x1) {
				data->target_cfg->callbacks->read_requested(data->target_cfg,
									    &tx_byte);
				config->base->TXDATA = tx_byte;
			} else {
				data->target_cfg->callbacks->write_requested(data->target_cfg);
			}

			I2C_IntClear(config->base, I2C_IF_ADDR | I2C_IF_RXDATAV);
		} else if (pending & I2C_IF_RXDATAV) {
			rx_byte = config->base->RXDATA;
			/* Read new data and write to target address */
			data->target_cfg->callbacks->write_received(data->target_cfg, rx_byte);
			config->base->CMD = I2C_CMD_ACK;

			I2C_IntClear(config->base, I2C_IF_RXDATAV);
		}

		if (pending & I2C_IF_ACK) {
			/* Leader ACK'ed, so requesting more data */
			data->target_cfg->callbacks->read_processed(data->target_cfg, &tx_byte);
			config->base->TXDATA = tx_byte;

			I2C_IntClear(config->base, I2C_IF_ACK);
		}

		if (pending & I2C_IF_SSTOP) {
			/* End of transaction */
			data->target_cfg->callbacks->stop(data->target_cfg);
			I2C_IntClear(config->base, I2C_IF_SSTOP);
		}
	}
}
#endif

#if defined(CONFIG_I2C_TARGET)
#define GECKO_I2C_IRQ_DEF(idx)  static void i2c_gecko_config_func_##idx(const struct device *dev);
#define GECKO_I2C_IRQ_DATA(idx) .irq_config_func = i2c_gecko_config_func_##idx,
#define GECKO_I2C_IRQ_HANDLER(idx)                                                                 \
	static void i2c_gecko_config_func_##idx(const struct device *dev)                          \
	{                                                                                          \
		IRQ_CONNECT(DT_INST_IRQ(idx, irq), DT_INST_IRQ(idx, priority), i2c_gecko_isr,      \
			    DEVICE_DT_INST_GET(idx), 0);                                           \
		irq_enable(DT_INST_IRQ(idx, irq));                                                 \
	}
#else
#define GECKO_I2C_IRQ_HANDLER(idx)
#define GECKO_I2C_IRQ_DEF(idx)
#define GECKO_I2C_IRQ_DATA(idx)
#endif

#define I2C_INIT(idx)										\
	PINCTRL_DT_INST_DEFINE(idx);								\
	GECKO_I2C_IRQ_DEF(idx);									\
												\
	static const struct i2c_gecko_config i2c_gecko_config_##idx = {				\
		.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(idx),					\
		.base = (I2C_TypeDef *)DT_INST_REG_ADDR(idx),					\
		.clock = cmuClock_I2C##idx,							\
		.bitrate = DT_INST_PROP(idx, clock_frequency),					\
		GECKO_I2C_IRQ_DATA(idx)};							\
												\
	static struct i2c_gecko_data i2c_gecko_data_##idx;					\
												\
	I2C_DEVICE_DT_INST_DEFINE(idx, i2c_gecko_init, NULL, &i2c_gecko_data_##idx,		\
				  &i2c_gecko_config_##idx, POST_KERNEL,				\
					CONFIG_I2C_INIT_PRIORITY, &i2c_gecko_driver_api);	\
												\
	GECKO_I2C_IRQ_HANDLER(idx)

DT_INST_FOREACH_STATUS_OKAY(I2C_INIT)