linux-libre/drivers/iio/common/st_sensors/st_sensors_i2c.c

/*
 * STMicroelectronics sensors i2c library driver
 *
 * Copyright 2012-2013 STMicroelectronics Inc.
 *
 * Denis Ciocca <denis.ciocca@st.com>
 *
 * Licensed under the GPL-2.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/iio/iio.h>
#include <linux/of_device.h>

#include <linux/iio/common/st_sensors_i2c.h>


#define ST_SENSORS_I2C_MULTIREAD	0x80

static unsigned int st_sensors_i2c_get_irq(struct iio_dev *indio_dev)
{
	struct st_sensor_data *sdata = iio_priv(indio_dev);

	return to_i2c_client(sdata->dev)->irq;
}

static int st_sensors_i2c_read_byte(struct st_sensor_transfer_buffer *tb,
				struct device *dev, u8 reg_addr, u8 *res_byte)
{
	int err;

	err = i2c_smbus_read_byte_data(to_i2c_client(dev), reg_addr);
	if (err < 0)
		goto st_accel_i2c_read_byte_error;

	*res_byte = err & 0xff;

st_accel_i2c_read_byte_error:
	return err < 0 ? err : 0;
}

static int st_sensors_i2c_read_multiple_byte(
		struct st_sensor_transfer_buffer *tb, struct device *dev,
			u8 reg_addr, int len, u8 *data, bool multiread_bit)
{
	if (multiread_bit)
		reg_addr |= ST_SENSORS_I2C_MULTIREAD;

	return i2c_smbus_read_i2c_block_data_or_emulated(to_i2c_client(dev),
							 reg_addr, len, data);
}

static int st_sensors_i2c_write_byte(struct st_sensor_transfer_buffer *tb,
				struct device *dev, u8 reg_addr, u8 data)
{
	return i2c_smbus_write_byte_data(to_i2c_client(dev), reg_addr, data);
}

static const struct st_sensor_transfer_function st_sensors_tf_i2c = {
	.read_byte = st_sensors_i2c_read_byte,
	.write_byte = st_sensors_i2c_write_byte,
	.read_multiple_byte = st_sensors_i2c_read_multiple_byte,
};

void st_sensors_i2c_configure(struct iio_dev *indio_dev,
		struct i2c_client *client, struct st_sensor_data *sdata)
{
	i2c_set_clientdata(client, indio_dev);

	indio_dev->dev.parent = &client->dev;
	indio_dev->name = client->name;

	sdata->dev = &client->dev;
	sdata->tf = &st_sensors_tf_i2c;
	sdata->get_irq_data_ready = st_sensors_i2c_get_irq;
}
EXPORT_SYMBOL(st_sensors_i2c_configure);

#ifdef CONFIG_OF
/**
 * st_sensors_of_i2c_probe() - device tree probe for ST I2C sensors
 * @client: the I2C client device for the sensor
 * @match: the OF match table for the device, containing compatible strings
 *	but also a .data field with the corresponding internal kernel name
 *	used by this sensor.
 *
 * In effect this function matches a compatible string to an internal kernel
 * name for a certain sensor device, so that the rest of the autodetection can
 * rely on that name from this point on. I2C client devices will be renamed
 * to match the internal kernel convention.
 */
void st_sensors_of_i2c_probe(struct i2c_client *client,
			     const struct of_device_id *match)
{
	const struct of_device_id *of_id;

	of_id = of_match_device(match, &client->dev);
	if (!of_id)
		return;

	/* The name from the OF match takes precedence if present */
	strncpy(client->name, of_id->data, sizeof(client->name));
	client->name[sizeof(client->name) - 1] = '\0';
}
EXPORT_SYMBOL(st_sensors_of_i2c_probe);
#endif

MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
MODULE_DESCRIPTION("STMicroelectronics ST-sensors i2c driver");
MODULE_LICENSE("GPL v2");