zephyr/drivers/i2c/i2c_nrfx_twim.c

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


#include <i2c.h>
#include <nrfx_twim.h>

#define LOG_DOMAIN "i2c_nrfx_twim"
#define LOG_LEVEL CONFIG_I2C_LOG_LEVEL
#include <logging/log.h>
LOG_MODULE_REGISTER(i2c_nrfx_twim);

struct i2c_nrfx_twim_data {
	struct k_sem sync;
	volatile nrfx_err_t res;
};

struct i2c_nrfx_twim_config {
	nrfx_twim_t twim;
};

static inline struct i2c_nrfx_twim_data *get_dev_data(struct device *dev)
{
	return dev->driver_data;
}

static inline
const struct i2c_nrfx_twim_config *get_dev_config(struct device *dev)
{
	return dev->config->config_info;
}

static int i2c_nrfx_twim_transfer(struct device *dev, struct i2c_msg *msgs,
				  u8_t num_msgs, u16_t addr)
{
	for (size_t i = 0; i < num_msgs; i++) {
		if (I2C_MSG_ADDR_10_BITS & msgs[i].flags) {
			return -ENOTSUP;
		}

		nrfx_twim_xfer_desc_t cur_xfer = {
			.p_primary_buf  = msgs[i].buf,
			.primary_length = msgs[i].len,
			.address	= addr,
			.type		= (msgs[i].flags & I2C_MSG_READ) ?
					  NRFX_TWIM_XFER_RX : NRFX_TWIM_XFER_TX
		};

		nrfx_err_t res = nrfx_twim_xfer(&get_dev_config(dev)->twim,
					       &cur_xfer,
					       (msgs[i].flags & I2C_MSG_STOP) ?
					       0 : NRFX_TWIM_FLAG_TX_NO_STOP);
		if (res != NRFX_SUCCESS) {
			return -EIO;
		}

		k_sem_take(&(get_dev_data(dev)->sync), K_FOREVER);
		res = get_dev_data(dev)->res;
		if (res != NRFX_SUCCESS) {
			LOG_ERR("Error %d occurred for message %d", res, i);
			return -EIO;
		}
	}

	return 0;
}

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

	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->sync);
}

static int i2c_nrfx_twim_configure(struct device *dev, u32_t dev_config)
{
	nrfx_twim_t const *inst = &(get_dev_config(dev)->twim);

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

	switch (I2C_SPEED_GET(dev_config)) {
	case I2C_SPEED_STANDARD:
		nrf_twim_frequency_set(inst->p_twim, NRF_TWIM_FREQ_100K);
		break;
	case I2C_SPEED_FAST:
		nrf_twim_frequency_set(inst->p_twim, NRF_TWIM_FREQ_400K);
		break;
	default:
		LOG_ERR("unsupported speed");
		return -EINVAL;
	}

	return 0;
}

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

static int init_twim(struct device *dev, const nrfx_twim_config_t *config)
{
	nrfx_err_t result = nrfx_twim_init(&get_dev_config(dev)->twim, config,
					  event_handler, dev);
	if (result != NRFX_SUCCESS) {
		LOG_ERR("Failed to initialize device: %s",
			    dev->config->name);
		return -EBUSY;
	}

	nrfx_twim_enable(&get_dev_config(dev)->twim);
	return 0;
}

#define I2C_NRFX_TWIM_DEVICE(idx)					\
	static int twim_##idx##_init(struct device *dev)		\
	{								\
		IRQ_CONNECT(CONFIG_I2C_##idx##_IRQ,			\
			    CONFIG_I2C_##idx##_IRQ_PRI,			\
			    nrfx_isr, nrfx_twim_##idx##_irq_handler, 0);\
		const nrfx_twim_config_t config = {			\
			.scl       = CONFIG_I2C_##idx##_SCL_PIN,	\
			.sda       = CONFIG_I2C_##idx##_SDA_PIN,	\
			.frequency = NRF_TWIM_FREQ_100K,		\
		};							\
		return init_twim(dev, &config);				\
	}								\
	static struct i2c_nrfx_twim_data twim_##idx##_data = {		\
		.sync = _K_SEM_INITIALIZER(twim_##idx##_data.sync, 0, 1)\
	};								\
	static const struct i2c_nrfx_twim_config twim_##idx##_config = {\
		.twim = NRFX_TWIM_INSTANCE(idx)				\
	};								\
	DEVICE_AND_API_INIT(twim_##idx, CONFIG_I2C_##idx##_NAME,	\
			    twim_##idx##_init, &twim_##idx##_data,	\
			    &twim_##idx##_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