zephyr/drivers/i2c/i2c_nrfx_twim.c

/*
 * Copyright (c) 2018, Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */


#include <drivers/i2c.h>
#include <dt-bindings/i2c/i2c.h>
#include <pm/device.h>
#include <nrfx_twim.h>
#include <sys/util.h>

#include <logging/log.h>
LOG_MODULE_REGISTER(i2c_nrfx_twim, CONFIG_I2C_LOG_LEVEL);

#define I2C_TRANSFER_TIMEOUT_MSEC		K_MSEC(500)

struct i2c_nrfx_twim_data {
	struct k_sem transfer_sync;
	struct k_sem completion_sync;
	nrfx_twim_config_t twim_config;
	bool twim_initialized;
	volatile nrfx_err_t res;
	uint8_t *msg_buf;
};

struct i2c_nrfx_twim_config {
	nrfx_twim_t twim;
	uint16_t concat_buf_size;
	uint16_t flash_buf_max_size;
};

static int init_twim(const struct device *dev);

static int i2c_nrfx_twim_transfer(const struct device *dev,
				  struct i2c_msg *msgs,
				  uint8_t num_msgs, uint16_t addr)
{
	struct i2c_nrfx_twim_data *dev_data = dev->data;
	const struct i2c_nrfx_twim_config *dev_config = dev->config;
	int ret = 0;
	uint8_t *msg_buf = dev_data->msg_buf;
	uint16_t msg_buf_used = 0;
	uint16_t concat_buf_size = dev_config->concat_buf_size;
	nrfx_twim_xfer_desc_t cur_xfer = {
		.address = addr
	};

	/* If for whatever reason the TWIM peripheral is still not initialized
	 * at this point, try to initialize it now.
	 */
	if (!dev_data->twim_initialized && init_twim(dev) < 0) {
		return -EIO;
	}

	k_sem_take(&dev_data->transfer_sync, K_FOREVER);

	/* Dummy take on completion_sync sem to be sure that it is empty */
	k_sem_take(&dev_data->completion_sync, K_NO_WAIT);

	nrfx_twim_enable(&dev_config->twim);

	for (size_t i = 0; i < num_msgs; i++) {
		if (I2C_MSG_ADDR_10_BITS & msgs[i].flags) {
			ret = -ENOTSUP;
			break;
		}

		/* This fragment needs to be merged with the next one if:
		 * - it is not the last fragment
		 * - it does not end a bus transaction
		 * - the next fragment does not start a bus transaction
		 * - the direction of the next fragment is the same as this one
		 */
		bool concat_next = ((i + 1) < num_msgs)
				&& !(msgs[i].flags & I2C_MSG_STOP)
				&& !(msgs[i + 1].flags & I2C_MSG_RESTART)
				&& ((msgs[i].flags & I2C_MSG_READ)
				    == (msgs[i + 1].flags & I2C_MSG_READ));

		/* If we need to concatenate the next message, or we've
		 * already committed to concatenate this message, add it to
		 * the buffer after verifying there's room.
		 */
		if (concat_next || (msg_buf_used != 0)) {
			if ((msg_buf_used + msgs[i].len) > concat_buf_size) {
				LOG_ERR("Need to use concatenation buffer and "
					"provided size is insufficient "
					"(%u + %u > %u). "
					"Adjust the zephyr,concat-buf-size "
					"property in the \"%s\" node.",
					msg_buf_used, msgs[i].len,
					concat_buf_size, dev->name);
				ret = -ENOSPC;
				break;
			}
			if (!(msgs[i].flags & I2C_MSG_READ)) {
				memcpy(msg_buf + msg_buf_used,
				       msgs[i].buf,
				       msgs[i].len);
			}
			msg_buf_used += msgs[i].len;

		/* TWIM peripherals cannot transfer data directly from
		 * flash. If a buffer located in flash is provided for
		 * a write transaction, its content must be copied to
		 * RAM before the transfer can be requested.
		 */
		} else if (!(msgs[i].flags & I2C_MSG_READ) &&
			   !nrfx_is_in_ram(msgs[i].buf)) {
			if (msgs[i].len > dev_config->flash_buf_max_size) {
				LOG_ERR("Cannot copy flash buffer of size: %u. "
					"Adjust the zephyr,flash-buf-max-size "
					"property in the \"%s\" node.",
					msgs[i].len, dev->name);
				ret = -EINVAL;
				break;
			}

			memcpy(msg_buf, msgs[i].buf, msgs[i].len);
			msg_buf_used = msgs[i].len;
		}

		if (concat_next) {
			continue;
		}

		if (msg_buf_used == 0) {
			cur_xfer.p_primary_buf = msgs[i].buf;
			cur_xfer.primary_length = msgs[i].len;
		} else {
			cur_xfer.p_primary_buf = msg_buf;
			cur_xfer.primary_length = msg_buf_used;
		}
		cur_xfer.type = (msgs[i].flags & I2C_MSG_READ) ?
			NRFX_TWIM_XFER_RX : NRFX_TWIM_XFER_TX;

		nrfx_err_t res = nrfx_twim_xfer(&dev_config->twim,
						&cur_xfer,
						(msgs[i].flags & I2C_MSG_STOP) ?
						 0 : NRFX_TWIM_FLAG_TX_NO_STOP);
		if (res != NRFX_SUCCESS) {
			if (res == NRFX_ERROR_BUSY) {
				ret = -EBUSY;
				break;
			} else {
				ret = -EIO;
				break;
			}
		}

		ret = k_sem_take(&dev_data->completion_sync,
				 I2C_TRANSFER_TIMEOUT_MSEC);
		if (ret != 0) {
			/* Whatever the frequency, completion_sync should have
			 * been given by the event handler.
			 *
			 * If it hasn't, it's probably due to an hardware issue
			 * on the I2C line, for example a short between SDA and
			 * GND.
			 * This is issue has also been when trying to use the
			 * I2C bus during MCU internal flash erase.
			 *
			 * In many situation, a retry is sufficient.
			 * However, some time the I2C device get stuck and need
			 * help to recover.
			 * Therefore we always call nrfx_twim_bus_recover() to
			 * make sure everything has been done to restore the
			 * bus from this error.
			 */
			LOG_ERR("Error on I2C line occurred for message %d", i);
			nrfx_twim_disable(&dev_config->twim);
			nrfx_twim_bus_recover(dev_data->twim_config.scl,
					      dev_data->twim_config.sda);
			ret = -EIO;
			break;
		}

		res = dev_data->res;

		if (res != NRFX_SUCCESS) {
			LOG_ERR("Error 0x%08X occurred for message %d", res, i);
			ret = -EIO;
			break;
		}

		/* If concatenated messages were I2C_MSG_READ type, then
		 * content of concatenation buffer has to be copied back into
		 * buffers provided by user. */
		if ((msgs[i].flags & I2C_MSG_READ)
		    && cur_xfer.p_primary_buf == msg_buf) {
			int j = i;

			while (msg_buf_used >= msgs[j].len) {
				msg_buf_used -= msgs[j].len;
				memcpy(msgs[j].buf,
				       msg_buf + msg_buf_used,
				       msgs[j].len);
				j--;
			}

		}

		msg_buf_used = 0;
	}

	nrfx_twim_disable(&dev_config->twim);
	k_sem_give(&dev_data->transfer_sync);

	return ret;
}

static void event_handler(nrfx_twim_evt_t const *p_event, void *p_context)
{
	struct i2c_nrfx_twim_data *dev_data = p_context;

	switch (p_event->type) {
	case NRFX_TWIM_EVT_DONE:
		dev_data->res = NRFX_SUCCESS;
		break;
	case NRFX_TWIM_EVT_ADDRESS_NACK:
		dev_data->res = NRFX_ERROR_DRV_TWI_ERR_ANACK;
		break;
	case NRFX_TWIM_EVT_DATA_NACK:
		dev_data->res = NRFX_ERROR_DRV_TWI_ERR_DNACK;
		break;
	default:
		dev_data->res = NRFX_ERROR_INTERNAL;
		break;
	}

	k_sem_give(&dev_data->completion_sync);
}

static int init_twim(const struct device *dev)
{
	const struct i2c_nrfx_twim_config *dev_config = dev->config;
	struct i2c_nrfx_twim_data *dev_data = dev->data;
	nrfx_err_t result = nrfx_twim_init(&dev_config->twim,
					   &dev_data->twim_config,
					   event_handler, dev_data);
	if (result != NRFX_SUCCESS) {
		LOG_ERR("Failed to initialize device: %s", dev->name);
		return -EIO;
	}

	dev_data->twim_initialized = true;
	return 0;
}

static void deinit_twim(const struct device *dev)
{
	const struct i2c_nrfx_twim_config *dev_config = dev->config;
	struct i2c_nrfx_twim_data *dev_data = dev->data;

	if (dev_data->twim_initialized) {
		nrfx_twim_uninit(&dev_config->twim);
		dev_data->twim_initialized = false;
	}
}

static int i2c_nrfx_twim_configure(const struct device *dev,
				   uint32_t i2c_config)
{
	struct i2c_nrfx_twim_data *dev_data = dev->data;
	nrf_twim_frequency_t frequency;

	if (I2C_ADDR_10_BITS & i2c_config) {
		return -EINVAL;
	}

	switch (I2C_SPEED_GET(i2c_config)) {
	case I2C_SPEED_STANDARD:
		frequency = NRF_TWIM_FREQ_100K;
		break;
	case I2C_SPEED_FAST:
		frequency = NRF_TWIM_FREQ_400K;
		break;
#if NRF_TWIM_HAS_1000_KHZ_FREQ
	case I2C_SPEED_FAST_PLUS:
		frequency = NRF_TWIM_FREQ_1000K;
		break;
#endif
	default:
		LOG_ERR("unsupported speed");
		return -EINVAL;
	}

	if (frequency != dev_data->twim_config.frequency) {
		dev_data->twim_config.frequency = frequency;

		deinit_twim(dev);
		return init_twim(dev);
	}

	return 0;
}

static int i2c_nrfx_twim_recover_bus(const struct device *dev)
{
	struct i2c_nrfx_twim_data *dev_data = dev->data;

	nrfx_err_t err = nrfx_twim_bus_recover(dev_data->twim_config.scl,
					       dev_data->twim_config.sda);

	return (err == NRFX_SUCCESS ? 0 : -EBUSY);
}

static const struct i2c_driver_api i2c_nrfx_twim_driver_api = {
	.configure   = i2c_nrfx_twim_configure,
	.transfer    = i2c_nrfx_twim_transfer,
	.recover_bus = i2c_nrfx_twim_recover_bus,
};

#ifdef CONFIG_PM_DEVICE
static int twim_nrfx_pm_action(const struct device *dev,
			       enum pm_device_action action)
{
	int ret = 0;

	switch (action) {
	case PM_DEVICE_ACTION_RESUME:
		ret = init_twim(dev);
		break;

	case PM_DEVICE_ACTION_SUSPEND:
		deinit_twim(dev);
		break;

	default:
		ret = -ENOTSUP;
	}

	return ret;
}
#endif /* CONFIG_PM_DEVICE */

#define I2C_NRFX_TWIM_INVALID_FREQUENCY  ((nrf_twim_frequency_t)-1)
#define I2C_NRFX_TWIM_FREQUENCY(bitrate)				       \
	(bitrate == I2C_BITRATE_STANDARD  ? NRF_TWIM_FREQ_100K :	       \
	 bitrate == 250000                ? NRF_TWIM_FREQ_250K :	       \
	 bitrate == I2C_BITRATE_FAST      ? NRF_TWIM_FREQ_400K :	       \
	IF_ENABLED(NRF_TWIM_HAS_1000_KHZ_FREQ,				       \
	(bitrate == I2C_BITRATE_FAST_PLUS ? NRF_TWIM_FREQ_1000K :))	       \
					    I2C_NRFX_TWIM_INVALID_FREQUENCY)

#define I2C(idx) DT_NODELABEL(i2c##idx)
#define I2C_FREQUENCY(idx)						       \
	I2C_NRFX_TWIM_FREQUENCY(DT_PROP(I2C(idx), clock_frequency))

#define CONCAT_BUF_SIZE(idx)						       \
	COND_CODE_1(DT_NODE_HAS_PROP(I2C(idx), zephyr_concat_buf_size),	       \
		    (DT_PROP(I2C(idx), zephyr_concat_buf_size)), (0))
#define FLASH_BUF_MAX_SIZE(idx)						       \
	COND_CODE_1(DT_NODE_HAS_PROP(I2C(idx), zephyr_flash_buf_max_size),     \
		    (DT_PROP(I2C(idx), zephyr_flash_buf_max_size)), (0))

#define USES_MSG_BUF(idx)						       \
	COND_CODE_0(CONCAT_BUF_SIZE(idx),				       \
		(COND_CODE_0(FLASH_BUF_MAX_SIZE(idx), (0), (1))),	       \
		(1))
#define MSG_BUF_SIZE(idx)  MAX(CONCAT_BUF_SIZE(idx), FLASH_BUF_MAX_SIZE(idx))

#define I2C_NRFX_TWIM_DEVICE(idx)					       \
	BUILD_ASSERT(I2C_FREQUENCY(idx) !=				       \
		     I2C_NRFX_TWIM_INVALID_FREQUENCY,			       \
		     "Wrong I2C " #idx " frequency setting in dts");	       \
	static int twim_##idx##_init(const struct device *dev)		       \
	{								       \
		IRQ_CONNECT(DT_IRQN(I2C(idx)), DT_IRQ(I2C(idx), priority),     \
			    nrfx_isr, nrfx_twim_##idx##_irq_handler, 0);       \
		return init_twim(dev);					       \
	}								       \
	IF_ENABLED(USES_MSG_BUF(idx),					       \
		(static uint8_t twim_##idx##_msg_buf[MSG_BUF_SIZE(idx)];))     \
	static struct i2c_nrfx_twim_data twim_##idx##_data = {		       \
		.twim_config = {					       \
			.scl       = DT_PROP(I2C(idx), scl_pin),	       \
			.sda       = DT_PROP(I2C(idx), sda_pin),	       \
			.frequency = I2C_FREQUENCY(idx),		       \
		},							       \
		.transfer_sync = Z_SEM_INITIALIZER(			       \
			twim_##idx##_data.transfer_sync, 1, 1),		       \
		.completion_sync = Z_SEM_INITIALIZER(			       \
			twim_##idx##_data.completion_sync, 0, 1),	       \
		IF_ENABLED(USES_MSG_BUF(idx),				       \
			(.msg_buf = twim_##idx##_msg_buf,))		       \
	};								       \
	static const struct i2c_nrfx_twim_config twim_##idx##z_config = {      \
		.twim = NRFX_TWIM_INSTANCE(idx),			       \
		.concat_buf_size = CONCAT_BUF_SIZE(idx),		       \
		.flash_buf_max_size = FLASH_BUF_MAX_SIZE(idx),		       \
	};								       \
	PM_DEVICE_DT_DEFINE(I2C(idx), twim_nrfx_pm_action);		       \
	I2C_DEVICE_DT_DEFINE(I2C(idx),					       \
		      twim_##idx##_init,				       \
		      PM_DEVICE_DT_GET(I2C(idx)),			       \
		      &twim_##idx##_data,				       \
		      &twim_##idx##z_config,				       \
		      POST_KERNEL,					       \
		      CONFIG_I2C_INIT_PRIORITY,				       \
		      &i2c_nrfx_twim_driver_api)

#ifdef CONFIG_I2C_0_NRF_TWIM
I2C_NRFX_TWIM_DEVICE(0);
#endif

#ifdef CONFIG_I2C_1_NRF_TWIM
I2C_NRFX_TWIM_DEVICE(1);
#endif

#ifdef CONFIG_I2C_2_NRF_TWIM
I2C_NRFX_TWIM_DEVICE(2);
#endif

#ifdef CONFIG_I2C_3_NRF_TWIM
I2C_NRFX_TWIM_DEVICE(3);
#endif