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Commit 39631b5f authored by Peter Meerwald's avatar Peter Meerwald Committed by Jonathan Cameron
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iio: Add Freescale mag3110 magnetometer driver 

three-axis digital magnetometer with I2C interface

datasheet is available from
http://cache.freescale.com/files/sensors/doc/data_sheet/MAG3110.pdf



Signed-off-by: default avatarPeter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 2ab61fa0

drivers/iio/magnetometer/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -16,6 +16,16 @@ config AK8975 
	  To compile this driver as a module, choose M here: the module

	  will be called ak8975.



config MAG3110

	tristate "Freescale MAG3110 3-Axis Magnetometer"

	depends on I2C

	help

	  Say yes here to build support for the Freescale MAG3110 3-Axis

	  magnetometer.



	  To compile this driver as a module, choose M here: the module

	  will be called mag3110.



config HID_SENSOR_MAGNETOMETER_3D

	depends on HID_SENSOR_HUB

	select IIO_BUFFER

drivers/iio/magnetometer/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 


# When adding new entries keep the list in alphabetical order

obj-$(CONFIG_AK8975)	+= ak8975.o

obj-$(CONFIG_MAG3110)	+= mag3110.o

obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o



obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o

drivers/iio/magnetometer/mag3110.c

0 → 100644
+401 −0
Original line number Diff line number Diff line 
/*

 * mag3110.c - Support for Freescale MAG3110 magnetometer sensor

 *

 * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>

 *

 * This file is subject to the terms and conditions of version 2 of

 * the GNU General Public License.  See the file COPYING in the main

 * directory of this archive for more details.

 *

 * (7-bit I2C slave address 0x0e)

 *

 * TODO: irq, user offset, oversampling, continuous mode

 */



#include <linux/module.h>

#include <linux/i2c.h>

#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>

#include <linux/iio/trigger_consumer.h>

#include <linux/iio/buffer.h>

#include <linux/iio/triggered_buffer.h>

#include <linux/delay.h>



#define MAG3110_STATUS 0x00

#define MAG3110_OUT_X 0x01 /* MSB first */

#define MAG3110_OUT_Y 0x03

#define MAG3110_OUT_Z 0x05

#define MAG3110_WHO_AM_I 0x07

#define MAG3110_OFF_X 0x09 /* MSB first */

#define MAG3110_OFF_Y 0x0b

#define MAG3110_OFF_Z 0x0d

#define MAG3110_DIE_TEMP 0x0f

#define MAG3110_CTRL_REG1 0x10

#define MAG3110_CTRL_REG2 0x11



#define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))



#define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))

#define MAG3110_CTRL_DR_SHIFT 5

#define MAG3110_CTRL_DR_DEFAULT 0



#define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */

#define MAG3110_CTRL_AC BIT(0) /* continuous measurements */



#define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */

#define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */



#define MAG3110_DEVICE_ID 0xc4



/* Each client has this additional data */

struct mag3110_data {

	struct i2c_client *client;

	struct mutex lock;

	u8 ctrl_reg1;

};



static int mag3110_request(struct mag3110_data *data)

{

	int ret, tries = 150;



	/* trigger measurement */

	ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,

		data->ctrl_reg1 | MAG3110_CTRL_TM);

	if (ret < 0)

		return ret;



	while (tries-- > 0) {

		ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);

		if (ret < 0)

			return ret;

		/* wait for data ready */

		if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)

			break;

		msleep(20);

	}



	if (tries < 0) {

		dev_err(&data->client->dev, "data not ready\n");

		return -EIO;

	}



	return 0;

}



static int mag3110_read(struct mag3110_data *data, __be16 buf[3])

{

	int ret;



	mutex_lock(&data->lock);

	ret = mag3110_request(data);

	if (ret < 0) {

		mutex_unlock(&data->lock);

		return ret;

	}

	ret = i2c_smbus_read_i2c_block_data(data->client,

		MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf);

	mutex_unlock(&data->lock);



	return ret;

}



static ssize_t mag3110_show_int_plus_micros(char *buf,

	const int (*vals)[2], int n)

{

	size_t len = 0;



	while (n-- > 0)

		len += scnprintf(buf + len, PAGE_SIZE - len,

			"%d.%d ", vals[n][0], vals[n][1]);



	/* replace trailing space by newline */

	buf[len - 1] = '\n';



	return len;

}



static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,

					int val, int val2)

{

	while (n-- > 0)

		if (val == vals[n][0] && val2 == vals[n][1])

			return n;



	return -EINVAL;

}



static const int mag3110_samp_freq[8][2] = {

	{80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},

	{1, 250000}, {0, 625000}

};



static ssize_t mag3110_show_samp_freq_avail(struct device *dev,

				struct device_attribute *attr, char *buf)

{

	return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);

}



static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);



static int mag3110_get_samp_freq_index(struct mag3110_data *data,

	int val, int val2)

{

	return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,

		val2);

}



static int mag3110_read_raw(struct iio_dev *indio_dev,

			    struct iio_chan_spec const *chan,

			    int *val, int *val2, long mask)

{

	struct mag3110_data *data = iio_priv(indio_dev);

	__be16 buffer[3];

	int i, ret;



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		switch (chan->type) {

		case IIO_MAGN: /* in 0.1 uT / LSB */

			ret = mag3110_read(data, buffer);

			if (ret < 0)

				return ret;

			*val = sign_extend32(

				be16_to_cpu(buffer[chan->scan_index]), 15);

			return IIO_VAL_INT;

		case IIO_TEMP: /* in 1 C / LSB */

			mutex_lock(&data->lock);

			ret = mag3110_request(data);

			if (ret < 0) {

				mutex_unlock(&data->lock);

				return ret;

			}

			ret = i2c_smbus_read_byte_data(data->client,

				MAG3110_DIE_TEMP);

			mutex_unlock(&data->lock);

			if (ret < 0)

				return ret;

			*val = sign_extend32(ret, 7);

			return IIO_VAL_INT;

		default:

			return -EINVAL;

		}

	case IIO_CHAN_INFO_SCALE:

		*val = 0;

		*val2 = 1000;

		return IIO_VAL_INT_PLUS_MICRO;

	case IIO_CHAN_INFO_SAMP_FREQ:

		i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;

		*val = mag3110_samp_freq[i][0];

		*val2 = mag3110_samp_freq[i][1];

		return IIO_VAL_INT_PLUS_MICRO;

	}

	return -EINVAL;

}



static int mag3110_write_raw(struct iio_dev *indio_dev,

			     struct iio_chan_spec const *chan,

			     int val, int val2, long mask)

{

	struct mag3110_data *data = iio_priv(indio_dev);

	int rate;



	switch (mask) {

	case IIO_CHAN_INFO_SAMP_FREQ:

		rate = mag3110_get_samp_freq_index(data, val, val2);

		if (rate < 0)

			return -EINVAL;



		data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;

		data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;

		return i2c_smbus_write_byte_data(data->client,

			MAG3110_CTRL_REG1, data->ctrl_reg1);

	default:

		return -EINVAL;

	}

}



static irqreturn_t mag3110_trigger_handler(int irq, void *p)

{

	struct iio_poll_func *pf = p;

	struct iio_dev *indio_dev = pf->indio_dev;

	struct mag3110_data *data = iio_priv(indio_dev);

	u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */

	int ret;



	ret = mag3110_read(data, (__be16 *) buffer);

	if (ret < 0)

		goto done;



	if (test_bit(3, indio_dev->active_scan_mask)) {

		ret = i2c_smbus_read_byte_data(data->client,

			MAG3110_DIE_TEMP);

		if (ret < 0)

			goto done;

		buffer[6] = ret;

	}



	iio_push_to_buffers_with_timestamp(indio_dev, buffer,

		iio_get_time_ns());



done:

	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;

}



#define MAG3110_CHANNEL(axis, idx) { \

	.type = IIO_MAGN, \

	.modified = 1, \

	.channel2 = IIO_MOD_##axis, \

	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \

	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \

		BIT(IIO_CHAN_INFO_SCALE), \

	.scan_index = idx, \

	.scan_type = IIO_ST('s', 16, 16, IIO_BE), \

}



static const struct iio_chan_spec mag3110_channels[] = {

	MAG3110_CHANNEL(X, 0),

	MAG3110_CHANNEL(Y, 1),

	MAG3110_CHANNEL(Z, 2),

	{

		.type = IIO_TEMP,

		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),

		.scan_index = 3,

		.scan_type = IIO_ST('s', 8, 8, 0),

	},

	IIO_CHAN_SOFT_TIMESTAMP(4),

};



static struct attribute *mag3110_attributes[] = {

	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,

	NULL

};



static const struct attribute_group mag3110_group = {

	.attrs = mag3110_attributes,

};



static const struct iio_info mag3110_info = {

	.attrs = &mag3110_group,

	.read_raw = &mag3110_read_raw,

	.write_raw = &mag3110_write_raw,

	.driver_module = THIS_MODULE,

};



static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};



static int mag3110_probe(struct i2c_client *client,

			 const struct i2c_device_id *id)

{

	struct mag3110_data *data;

	struct iio_dev *indio_dev;

	int ret;



	ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);

	if (ret < 0)

		return ret;

	if (ret != MAG3110_DEVICE_ID)

		return -ENODEV;



	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));

	if (!indio_dev)

		return -ENOMEM;



	data = iio_priv(indio_dev);

	data->client = client;

	mutex_init(&data->lock);



	i2c_set_clientdata(client, indio_dev);

	indio_dev->info = &mag3110_info;

	indio_dev->name = id->name;

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

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = mag3110_channels;

	indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);

	indio_dev->available_scan_masks = mag3110_scan_masks;



	data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT;

	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,

		data->ctrl_reg1);

	if (ret < 0)

		return ret;



	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,

		MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW);

	if (ret < 0)

		return ret;



	ret = iio_triggered_buffer_setup(indio_dev, NULL,

		mag3110_trigger_handler, NULL);

	if (ret < 0)

		return ret;



	ret = iio_device_register(indio_dev);

	if (ret < 0)

		goto buffer_cleanup;

	return 0;



buffer_cleanup:

	iio_triggered_buffer_cleanup(indio_dev);

	return ret;

}



static int mag3110_standby(struct mag3110_data *data)

{

	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,

		data->ctrl_reg1 & ~MAG3110_CTRL_AC);

}



static int mag3110_remove(struct i2c_client *client)

{

	struct iio_dev *indio_dev = i2c_get_clientdata(client);



	iio_device_unregister(indio_dev);

	iio_triggered_buffer_cleanup(indio_dev);

	mag3110_standby(iio_priv(indio_dev));



	return 0;

}



#ifdef CONFIG_PM_SLEEP

static int mag3110_suspend(struct device *dev)

{

	return mag3110_standby(iio_priv(i2c_get_clientdata(

		to_i2c_client(dev))));

}



static int mag3110_resume(struct device *dev)

{

	struct mag3110_data *data = iio_priv(i2c_get_clientdata(

		to_i2c_client(dev)));



	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,

		data->ctrl_reg1);

}



static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);

#define MAG3110_PM_OPS (&mag3110_pm_ops)

#else

#define MAG3110_PM_OPS NULL

#endif



static const struct i2c_device_id mag3110_id[] = {

	{ "mag3110", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, mag3110_id);



static struct i2c_driver mag3110_driver = {

	.driver = {

		.name	= "mag3110",

		.pm	= MAG3110_PM_OPS,

	},

	.probe = mag3110_probe,

	.remove = mag3110_remove,

	.id_table = mag3110_id,

};

module_i2c_driver(mag3110_driver);



MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");

MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");

MODULE_LICENSE("GPL");