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iio: Add Freescale MPL3115A2 pressure / temperature sensor driver 

I2C-controlled MEMS sensor with 20-bit pressure measurement (pascal) and
12-bit temperature measurement

driver only exposes basic functionality, see TODO remarks
datasheet: http://cache.freescale.com/files/sensors/doc/data_sheet/MPL3115A2.pdf

v2:
* store 20-bit value in 32-bit buffer element (instead of 24-bit)
* zero buffer to prevent kernel data leak to userspace
* fix mutex unlock in trigger handler (thanks Andi Shyti)

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Reviewed-by: Andi Shyti <andi@etezian.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Peter Meerwald 2013-11-12 19:43:00 +00:00 committed by Jonathan Cameron
parent a35e1fd268
commit cc26ad455f
3 changed files with 342 additions and 0 deletions
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12
drivers/iio/pressure/Kconfig
View File

@ -5,6 +5,18 @@
menu "Pressure sensors"
config MPL3115
tristate "Freescale MPL3115A2 pressure sensor driver"
depends on I2C
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
help
Say yes here to build support for the Freescale MPL3115A2
pressure sensor / altimeter.
To compile this driver as a module, choose M here: the module
will be called mpl3115.
config IIO_ST_PRESS
tristate "STMicroelectronics pressure sensor Driver"
depends on (I2C || SPI_MASTER) && SYSFS

1
drivers/iio/pressure/Makefile
View File

@ -3,6 +3,7 @@
#
# When adding new entries keep the list in alphabetical order
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

329
drivers/iio/pressure/mpl3115.c Normal file
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@ -0,0 +1,329 @@
/*
* mpl3115.c - Support for Freescale MPL3115A2 pressure/temperature 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 0x60)
*
* TODO: FIFO buffer, altimeter mode, oversampling, continuous mode,
* interrupts, user offset correction, raw 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 MPL3115_STATUS 0x00
#define MPL3115_OUT_PRESS 0x01 /* MSB first, 20 bit */
#define MPL3115_OUT_TEMP 0x04 /* MSB first, 12 bit */
#define MPL3115_WHO_AM_I 0x0c
#define MPL3115_CTRL_REG1 0x26
#define MPL3115_DEVICE_ID 0xc4
#define MPL3115_STATUS_PRESS_RDY BIT(2)
#define MPL3115_STATUS_TEMP_RDY BIT(1)
#define MPL3115_CTRL_RESET BIT(2) /* software reset */
#define MPL3115_CTRL_OST BIT(1) /* initiate measurement */
#define MPL3115_CTRL_ACTIVE BIT(0) /* continuous measurement */
#define MPL3115_CTRL_OS_258MS (BIT(5) | BIT(4)) /* 64x oversampling */
struct mpl3115_data {
struct i2c_client *client;
struct mutex lock;
u8 ctrl_reg1;
};
static int mpl3115_request(struct mpl3115_data *data)
{
int ret, tries = 15;
/* trigger measurement */
ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
data->ctrl_reg1 | MPL3115_CTRL_OST);
if (ret < 0)
return ret;
while (tries-- > 0) {
ret = i2c_smbus_read_byte_data(data->client, MPL3115_CTRL_REG1);
if (ret < 0)
return ret;
/* wait for data ready, i.e. OST cleared */
if (!(ret & MPL3115_CTRL_OST))
break;
msleep(20);
}
if (tries < 0) {
dev_err(&data->client->dev, "data not ready\n");
return -EIO;
}
return 0;
}
static int mpl3115_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct mpl3115_data *data = iio_priv(indio_dev);
s32 tmp = 0;
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (iio_buffer_enabled(indio_dev))
return -EBUSY;
switch (chan->type) {
case IIO_PRESSURE: /* in 0.25 pascal / LSB */
mutex_lock(&data->lock);
ret = mpl3115_request(data);
if (ret < 0) {
mutex_unlock(&data->lock);
return ret;
}
ret = i2c_smbus_read_i2c_block_data(data->client,
MPL3115_OUT_PRESS, 3, (u8 *) &tmp);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = sign_extend32(be32_to_cpu(tmp) >> 12, 23);
return IIO_VAL_INT;
case IIO_TEMP: /* in 0.0625 celsius / LSB */
mutex_lock(&data->lock);
ret = mpl3115_request(data);
if (ret < 0) {
mutex_unlock(&data->lock);
return ret;
}
ret = i2c_smbus_read_i2c_block_data(data->client,
MPL3115_OUT_TEMP, 2, (u8 *) &tmp);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = sign_extend32(be32_to_cpu(tmp) >> 20, 15);
return IIO_VAL_INT;
default:
return -EINVAL;
}
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_PRESSURE:
*val = 0;
*val2 = 250; /* want kilopascal */
return IIO_VAL_INT_PLUS_MICRO;
case IIO_TEMP:
*val = 0;
*val2 = 62500;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
return -EINVAL;
}
static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct mpl3115_data *data = iio_priv(indio_dev);
u8 buffer[16]; /* 32-bit channel + 16-bit channel + padding + ts */
int ret, pos = 0;
mutex_lock(&data->lock);
ret = mpl3115_request(data);
if (ret < 0) {
mutex_unlock(&data->lock);
goto done;
}
memset(buffer, 0, sizeof(buffer));
if (test_bit(0, indio_dev->active_scan_mask)) {
ret = i2c_smbus_read_i2c_block_data(data->client,
MPL3115_OUT_PRESS, 3, &buffer[pos]);
if (ret < 0) {
mutex_unlock(&data->lock);
goto done;
}
pos += 4;
}
if (test_bit(1, indio_dev->active_scan_mask)) {
ret = i2c_smbus_read_i2c_block_data(data->client,
MPL3115_OUT_TEMP, 2, &buffer[pos]);
if (ret < 0) {
mutex_unlock(&data->lock);
goto done;
}
}
mutex_unlock(&data->lock);
iio_push_to_buffers_with_timestamp(indio_dev, buffer,
iio_get_time_ns());
done:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static const struct iio_chan_spec mpl3115_channels[] = {
{
.type = IIO_PRESSURE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 0,
.scan_type = {
.sign = 's',
.realbits = 20,
.storagebits = 32,
.shift = 12,
.endianness = IIO_BE,
}
},
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 1,
.scan_type = {
.sign = 's',
.realbits = 12,
.storagebits = 16,
.shift = 4,
.endianness = IIO_BE,
}
},
IIO_CHAN_SOFT_TIMESTAMP(2),
};
static const struct iio_info mpl3115_info = {
.read_raw = &mpl3115_read_raw,
.driver_module = THIS_MODULE,
};
static int mpl3115_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct mpl3115_data *data;
struct iio_dev *indio_dev;
int ret;
ret = i2c_smbus_read_byte_data(client, MPL3115_WHO_AM_I);
if (ret < 0)
return ret;
if (ret != MPL3115_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 = &mpl3115_info;
indio_dev->name = id->name;
indio_dev->dev.parent = &client->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = mpl3115_channels;
indio_dev->num_channels = ARRAY_SIZE(mpl3115_channels);
/* software reset, I2C transfer is aborted (fails) */
i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
MPL3115_CTRL_RESET);
msleep(50);
data->ctrl_reg1 = MPL3115_CTRL_OS_258MS;
ret = i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
data->ctrl_reg1);
if (ret < 0)
return ret;
ret = iio_triggered_buffer_setup(indio_dev, NULL,
mpl3115_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 mpl3115_standby(struct mpl3115_data *data)
{
return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
data->ctrl_reg1 & ~MPL3115_CTRL_ACTIVE);
}
static int mpl3115_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);
mpl3115_standby(iio_priv(indio_dev));
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int mpl3115_suspend(struct device *dev)
{
return mpl3115_standby(iio_priv(i2c_get_clientdata(
to_i2c_client(dev))));
}
static int mpl3115_resume(struct device *dev)
{
struct mpl3115_data *data = iio_priv(i2c_get_clientdata(
to_i2c_client(dev)));
return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
data->ctrl_reg1);
}
static SIMPLE_DEV_PM_OPS(mpl3115_pm_ops, mpl3115_suspend, mpl3115_resume);
#define MPL3115_PM_OPS (&mpl3115_pm_ops)
#else
#define MPL3115_PM_OPS NULL
#endif
static const struct i2c_device_id mpl3115_id[] = {
{ "mpl3115", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mpl3115_id);
static struct i2c_driver mpl3115_driver = {
.driver = {
.name = "mpl3115",
.pm = MPL3115_PM_OPS,
},
.probe = mpl3115_probe,
.remove = mpl3115_remove,
.id_table = mpl3115_id,
};
module_i2c_driver(mpl3115_driver);
MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("Freescale MPL3115 pressure/temperature driver");
MODULE_LICENSE("GPL");