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Commit 3017d90e authored by Peter Meerwald's avatar Peter Meerwald Committed by Jonathan Cameron
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iio: Add Freescale MPL115A2 pressure / temperature sensor driver 

I2C-controlled sensor with 10-bit pressure and temperature measurement

datasheet: http://cache.freescale.com/files/sensors/doc/data_sheet/MPL3115A2.pdf



v2:
* use devm_iio_device_register()

Signed-off-by: default avatarPeter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 0828eddc

drivers/iio/pressure/Kconfig

+10 −0
Original line number Original line Diff line number Diff line
@@ -19,6 +19,16 @@ config HID_SENSOR_PRESS 
          To compile this driver as a module, choose M here: the module

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

          will be called hid-sensor-press.

          will be called hid-sensor-press.





config MPL115

	tristate "Freescale MPL115A2 pressure sensor driver"

	depends on I2C

	help

	  Say yes here to build support for the Freescale MPL115A2

	  pressure sensor connected via I2C.



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

          will be called mpl115.



config MPL3115

config MPL3115

	tristate "Freescale MPL3115A2 pressure sensor driver"

	tristate "Freescale MPL3115A2 pressure sensor driver"

	depends on I2C

	depends on I2C

drivers/iio/pressure/Makefile

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




# When adding new entries keep the list in alphabetical order

# When adding new entries keep the list in alphabetical order

obj-$(CONFIG_HID_SENSOR_PRESS)   += hid-sensor-press.o

obj-$(CONFIG_HID_SENSOR_PRESS)   += hid-sensor-press.o

obj-$(CONFIG_MPL115) += mpl115.o

obj-$(CONFIG_MPL3115) += mpl3115.o

obj-$(CONFIG_MPL3115) += mpl3115.o

obj-$(CONFIG_IIO_ST_PRESS) += st_pressure.o

obj-$(CONFIG_IIO_ST_PRESS) += st_pressure.o

st_pressure-y := st_pressure_core.o

st_pressure-y := st_pressure_core.o

drivers/iio/pressure/mpl115.c

0 → 100644
+211 −0
Original line number Original line Diff line number Diff line 
/*

 * mpl115.c - Support for Freescale MPL115A2 pressure/temperature sensor

 *

 * Copyright (c) 2014 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 0x60)

 *

 * TODO: shutdown pin

 *

 */



#include <linux/module.h>

#include <linux/i2c.h>

#include <linux/iio/iio.h>

#include <linux/delay.h>



#define MPL115_PADC 0x00 /* pressure ADC output value, MSB first, 10 bit */

#define MPL115_TADC 0x02 /* temperature ADC output value, MSB first, 10 bit */

#define MPL115_A0 0x04 /* 12 bit integer, 3 bit fraction */

#define MPL115_B1 0x06 /* 2 bit integer, 13 bit fraction */

#define MPL115_B2 0x08 /* 1 bit integer, 14 bit fraction */

#define MPL115_C12 0x0a /* 0 bit integer, 13 bit fraction */

#define MPL115_CONVERT 0x12 /* convert temperature and pressure */



struct mpl115_data {

	struct i2c_client *client;

	struct mutex lock;

	s16 a0;

	s16 b1, b2;

	s16 c12;

};



static int mpl115_request(struct mpl115_data *data)

{

	int ret = i2c_smbus_write_byte_data(data->client, MPL115_CONVERT, 0);

	if (ret < 0)

		return ret;



	usleep_range(3000, 4000);



	return 0;

}



static int mpl115_comp_pressure(struct mpl115_data *data, int *val, int *val2)

{

	int ret;

	u16 padc, tadc;

	int a1, y1, pcomp;

	unsigned kpa;



	mutex_lock(&data->lock);

	ret = mpl115_request(data);

	if (ret < 0)

		goto done;



	ret = i2c_smbus_read_word_swapped(data->client, MPL115_PADC);

	if (ret < 0)

		goto done;

	padc = ret >> 6;



	ret = i2c_smbus_read_word_swapped(data->client, MPL115_TADC);

	if (ret < 0)

		goto done;

	tadc = ret >> 6;



	/* see Freescale AN3785 */

	a1 = data->b1 + ((data->c12 * tadc) >> 11);

	y1 = (data->a0 << 10) + a1 * padc;



	/* compensated pressure with 4 fractional bits */

	pcomp = (y1 + ((data->b2 * (int) tadc) >> 1)) >> 9;



	kpa = pcomp * (115 - 50) / 1023 + (50 << 4);

	*val = kpa >> 4;

	*val2 = (kpa & 15) * (1000000 >> 4);

done:

	mutex_unlock(&data->lock);

	return ret;

}



static int mpl115_read_temp(struct mpl115_data *data)

{

	int ret;



	mutex_lock(&data->lock);

	ret = mpl115_request(data);

	if (ret < 0)

		goto done;

	ret = i2c_smbus_read_word_swapped(data->client, MPL115_TADC);

done:

	mutex_unlock(&data->lock);

	return ret;

}



static int mpl115_read_raw(struct iio_dev *indio_dev,

			    struct iio_chan_spec const *chan,

			    int *val, int *val2, long mask)

{

	struct mpl115_data *data = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_PROCESSED:

		ret = mpl115_comp_pressure(data, val, val2);

		if (ret < 0)

			return ret;

		return IIO_VAL_INT_PLUS_MICRO;

	case IIO_CHAN_INFO_RAW:

		/* temperature -5.35 C / LSB, 472 LSB is 25 C */

		ret = mpl115_read_temp(data);

		if (ret < 0)

			return ret;

		*val = ret >> 6;

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_OFFSET:

		*val = 605;

		*val2 = 750000;

		return IIO_VAL_INT_PLUS_MICRO;

	case IIO_CHAN_INFO_SCALE:

		*val = -186;

		*val2 = 915888;

		return IIO_VAL_INT_PLUS_MICRO;

	}

	return -EINVAL;

}



static const struct iio_chan_spec mpl115_channels[] = {

	{

		.type = IIO_PRESSURE,

		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),

	},

	{

		.type = IIO_TEMP,

		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),

			BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE),

	},

};



static const struct iio_info mpl115_info = {

	.read_raw = &mpl115_read_raw,

	.driver_module = THIS_MODULE,

};



static int mpl115_probe(struct i2c_client *client,

			 const struct i2c_device_id *id)

{

	struct mpl115_data *data;

	struct iio_dev *indio_dev;

	int ret;



	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))

		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 = &mpl115_info;

	indio_dev->name = id->name;

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

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = mpl115_channels;

	indio_dev->num_channels = ARRAY_SIZE(mpl115_channels);



	ret = i2c_smbus_read_word_swapped(data->client, MPL115_A0);

	if (ret < 0)

		return ret;

	data->a0 = ret;

	ret = i2c_smbus_read_word_swapped(data->client, MPL115_B1);

	if (ret < 0)

		return ret;

	data->b1 = ret;

	ret = i2c_smbus_read_word_swapped(data->client, MPL115_B2);

	if (ret < 0)

		return ret;

	data->b2 = ret;

	ret = i2c_smbus_read_word_swapped(data->client, MPL115_C12);

	if (ret < 0)

		return ret;

	data->c12 = ret;



	return devm_iio_device_register(&client->dev, indio_dev);

}



static const struct i2c_device_id mpl115_id[] = {

	{ "mpl115", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, mpl115_id);



static struct i2c_driver mpl115_driver = {

	.driver = {

		.name	= "mpl115",

	},

	.probe = mpl115_probe,

	.id_table = mpl115_id,

};

module_i2c_driver(mpl115_driver);



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

MODULE_DESCRIPTION("Freescale MPL115 pressure/temperature driver");

MODULE_LICENSE("GPL");