Commit a2d8be68 authored by Peter Meerwald's avatar Peter Meerwald Committed by Jonathan Cameron
Browse files

iio: Add t5403 barometric pressure sensor driver 

16-bit pressure and temperature sensor

the chip can do I2C and SPI, only the I2C interface is supported
by the driver at the moment

datasheet: http://www.epcos.com/inf/57/ds/T5400.pdf
application note: http://www.epcos.com/blob/993154/download/1/t5403-applicationnote.pdf

an out-of-tree driver targetting the input subsystem is at
https://github.com/unixphere/t5400, it was rejected here:
http://comments.gmane.org/gmane.linux.kernel.input/28107



v2: (thanks Hartmut Knaack)
* fix MODE_HIGH, equals 2
* check INT_TIME mask in write_raw()

Signed-off-by: default avatarPeter Meerwald <pmeerw@pmeerw.net>
Cc: Stefan Nilsson <stefan.nilsson@unixphere.com>
Reviewed-by: default avatarHartmut Knaack <knaack.h@gmx.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 6c0690ec

drivers/iio/pressure/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -70,4 +70,14 @@ config IIO_ST_PRESS_SPI 
	depends on IIO_ST_PRESS

	depends on IIO_ST_SENSORS_SPI



config T5403

	tristate "EPCOS T5403 digital barometric pressure sensor driver"

	depends on I2C

	help

	  Say yes here to build support for the EPCOS T5403 pressure sensor

	  connected via I2C.



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

          will be called t5403.



endmenu

drivers/iio/pressure/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ obj-$(CONFIG_MPL3115) += mpl3115.o 
obj-$(CONFIG_IIO_ST_PRESS) += st_pressure.o

st_pressure-y := st_pressure_core.o

st_pressure-$(CONFIG_IIO_BUFFER) += st_pressure_buffer.o

obj-$(CONFIG_T5403) += t5403.o



obj-$(CONFIG_IIO_ST_PRESS_I2C) += st_pressure_i2c.o

obj-$(CONFIG_IIO_ST_PRESS_SPI) += st_pressure_spi.o

drivers/iio/pressure/t5403.c

0 → 100644
+275 −0
Original line number Diff line number Diff line 
/*

 * t5403.c - Support for EPCOS T5403 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 0x77)

 *

 * TODO: end-of-conversion irq

 */



#include <linux/module.h>

#include <linux/i2c.h>

#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>

#include <linux/delay.h>



#define T5403_DATA 0xf5 /* data, LSB first, 16 bit */

#define T5403_CALIB_DATA 0x8e /* 10 calibration coeff., LSB first, 16 bit */

#define T5403_SLAVE_ADDR 0x88 /* I2C slave address, 0x77 */

#define T5403_COMMAND 0xf1



/* command bits */

#define T5403_MODE_SHIFT 3 /* conversion time: 2, 8, 16, 66 ms */

#define T5403_PT BIT(1) /* 0 .. pressure, 1 .. temperature measurement */

#define T5403_SCO BIT(0) /* start conversion */



#define T5403_MODE_LOW 0

#define T5403_MODE_STANDARD 1

#define T5403_MODE_HIGH 2

#define T5403_MODE_ULTRA_HIGH 3



#define T5403_I2C_MASK (~BIT(7))

#define T5403_I2C_ADDR 0x77



static const int t5403_pressure_conv_ms[] = {2, 8, 16, 66};



struct t5403_data {

	struct i2c_client *client;

	struct mutex lock;

	int mode;

	__le16 c[10];

};



#define T5403_C_U16(i) le16_to_cpu(data->c[(i) - 1])

#define T5403_C(i) sign_extend32(T5403_C_U16(i), 15)



static int t5403_read(struct t5403_data *data, bool pressure)

{

	int wait_time = 3;  /* wakeup time in ms */



	int ret = i2c_smbus_write_byte_data(data->client, T5403_COMMAND,

		(pressure ? (data->mode << T5403_MODE_SHIFT) : T5403_PT) |

		T5403_SCO);

	if (ret < 0)

		return ret;



	wait_time += pressure ? t5403_pressure_conv_ms[data->mode] : 2;



	msleep(wait_time);



	return i2c_smbus_read_word_data(data->client, T5403_DATA);

}



static int t5403_comp_pressure(struct t5403_data *data, int *val, int *val2)

{

	int ret;

	s16 t_r;

	u16 p_r;

	s32 S, O, X;



	mutex_lock(&data->lock);



	ret = t5403_read(data, false);

	if (ret < 0)

		goto done;

	t_r = ret;



	ret = t5403_read(data, true);

	if (ret < 0)

		goto done;

	p_r = ret;



	/* see EPCOS application note */

	S = T5403_C_U16(3) + (s32) T5403_C_U16(4) * t_r / 0x20000 +

		T5403_C(5) * t_r / 0x8000 * t_r / 0x80000 +

		T5403_C(9) * t_r / 0x8000 * t_r / 0x8000 * t_r / 0x10000;



	O = T5403_C(6) * 0x4000 + T5403_C(7) * t_r / 8 +

		T5403_C(8) * t_r / 0x8000 * t_r / 16 +

		T5403_C(9) * t_r / 0x8000 * t_r / 0x10000 * t_r;



	X = (S * p_r + O) / 0x4000;



	X += ((X - 75000) * (X - 75000) / 0x10000 - 9537) *

	    T5403_C(10) / 0x10000;



	*val = X / 1000;

	*val2 = (X % 1000) * 1000;



done:

	mutex_unlock(&data->lock);

	return ret;

}



static int t5403_comp_temp(struct t5403_data *data, int *val)

{

	int ret;

	s16 t_r;



	mutex_lock(&data->lock);

	ret = t5403_read(data, false);

	if (ret < 0)

		goto done;

	t_r = ret;



	/* see EPCOS application note */

	*val = ((s32) T5403_C_U16(1) * t_r / 0x100 +

		(s32) T5403_C_U16(2) * 0x40) * 1000 / 0x10000;



done:

	mutex_unlock(&data->lock);

	return ret;

}



static int t5403_read_raw(struct iio_dev *indio_dev,

			  struct iio_chan_spec const *chan,

			  int *val, int *val2, long mask)

{

	struct t5403_data *data = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_PROCESSED:

		switch (chan->type) {

		case IIO_PRESSURE:

			ret = t5403_comp_pressure(data, val, val2);

			if (ret < 0)

				return ret;

			return IIO_VAL_INT_PLUS_MICRO;

		case IIO_TEMP:

			ret = t5403_comp_temp(data, val);

			if (ret < 0)

				return ret;

			return IIO_VAL_INT;

		default:

			return -EINVAL;

	    }

	case IIO_CHAN_INFO_INT_TIME:

		*val = 0;

		*val2 = t5403_pressure_conv_ms[data->mode] * 1000;

		return IIO_VAL_INT_PLUS_MICRO;

	default:

		return -EINVAL;

	}

}



static int t5403_write_raw(struct iio_dev *indio_dev,

			   struct iio_chan_spec const *chan,

			   int val, int val2, long mask)

{

	struct t5403_data *data = iio_priv(indio_dev);

	int i;



	switch (mask) {

	case IIO_CHAN_INFO_INT_TIME:

		if (val != 0)

			return -EINVAL;

		for (i = 0; i < ARRAY_SIZE(t5403_pressure_conv_ms); i++)

			if (val2 == t5403_pressure_conv_ms[i] * 1000) {

				mutex_lock(&data->lock);

				data->mode = i;

				mutex_unlock(&data->lock);

				return 0;

			}

		return -EINVAL;

	default:

		return -EINVAL;

	}

}



static const struct iio_chan_spec t5403_channels[] = {

	{

		.type = IIO_PRESSURE,

		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |

		    BIT(IIO_CHAN_INFO_INT_TIME),

	},

	{

		.type = IIO_TEMP,

		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),

	},

};



static IIO_CONST_ATTR_INT_TIME_AVAIL("0.002 0.008 0.016 0.066");



static struct attribute *t5403_attributes[] = {

	&iio_const_attr_integration_time_available.dev_attr.attr,

	NULL

};



static const struct attribute_group t5403_attribute_group = {

	.attrs = t5403_attributes,

};



static const struct iio_info t5403_info = {

	.read_raw = &t5403_read_raw,

	.write_raw = &t5403_write_raw,

	.attrs = &t5403_attribute_group,

	.driver_module = THIS_MODULE,

};



static int t5403_probe(struct i2c_client *client,

			 const struct i2c_device_id *id)

{

	struct t5403_data *data;

	struct iio_dev *indio_dev;

	int ret;



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

	    I2C_FUNC_SMBUS_I2C_BLOCK))

		return -ENODEV;



	ret = i2c_smbus_read_byte_data(client, T5403_SLAVE_ADDR);

	if (ret < 0)

		return ret;

	if ((ret & T5403_I2C_MASK) != T5403_I2C_ADDR)

		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 = &t5403_info;

	indio_dev->name = id->name;

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

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = t5403_channels;

	indio_dev->num_channels = ARRAY_SIZE(t5403_channels);



	data->mode = T5403_MODE_STANDARD;



	ret = i2c_smbus_read_i2c_block_data(data->client, T5403_CALIB_DATA,

	    sizeof(data->c), (u8 *) data->c);

	if (ret < 0)

		return ret;



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

}



static const struct i2c_device_id t5403_id[] = {

	{ "t5403", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, t5403_id);



static struct i2c_driver t5403_driver = {

	.driver = {

		.name	= "t5403",

	},

	.probe = t5403_probe,

	.id_table = t5403_id,

};

module_i2c_driver(t5403_driver);



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

MODULE_DESCRIPTION("EPCOS T5403 pressure/temperature sensor driver");

MODULE_LICENSE("GPL");

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