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linux/drivers/iio/accel/mma7455_core.c
Joachim Eastwood a84ef0d181 iio: accel: add Freescale MMA7455L/MMA7456L 3-axis accelerometer driver 
Add support for Freescale MMA7455L/MMA7456L 3-axis in 10-bit mode for
I2C and SPI bus. This rather simple driver that currently doesn't
support all the hardware features of MMA7455L/MMA7456L.

Tested on Embedded Artist's LPC4357 Dev Kit with MMA7455L on I2C bus.

Data sheets for the two devices can be found here:
http://cache.freescale.com/files/sensors/doc/data_sheet/MMA7455L.pdf
http://cache.freescale.com/files/sensors/doc/data_sheet/MMA7456L.pdf

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2015-11-01 18:00:35 +00:00

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7.2 KiB
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/*
* IIO accel core driver for Freescale MMA7455L 3-axis 10-bit accelerometer
* Copyright 2015 Joachim Eastwood <manabian@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* UNSUPPORTED hardware features:
* - 8-bit mode with different scales
* - INT1/INT2 interrupts
* - Offset calibration
* - Events
*/
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include "mma7455.h"
#define MMA7455_REG_XOUTL 0x00
#define MMA7455_REG_XOUTH 0x01
#define MMA7455_REG_YOUTL 0x02
#define MMA7455_REG_YOUTH 0x03
#define MMA7455_REG_ZOUTL 0x04
#define MMA7455_REG_ZOUTH 0x05
#define MMA7455_REG_STATUS 0x09
#define MMA7455_STATUS_DRDY BIT(0)
#define MMA7455_REG_WHOAMI 0x0f
#define MMA7455_WHOAMI_ID 0x55
#define MMA7455_REG_MCTL 0x16
#define MMA7455_MCTL_MODE_STANDBY 0x00
#define MMA7455_MCTL_MODE_MEASURE 0x01
#define MMA7455_REG_CTL1 0x18
#define MMA7455_CTL1_DFBW_MASK BIT(7)
#define MMA7455_CTL1_DFBW_125HZ BIT(7)
#define MMA7455_CTL1_DFBW_62_5HZ 0
#define MMA7455_REG_TW 0x1e
/*
* When MMA7455 is used in 10-bit it has a fullscale of -8g
* corresponding to raw value -512. The userspace interface
* uses m/s^2 and we declare micro units.
* So scale factor is given by:
* g * 8 * 1e6 / 512 = 153228.90625, with g = 9.80665
*/
#define MMA7455_10BIT_SCALE 153229
struct mma7455_data {
struct regmap *regmap;
struct device *dev;
};
static int mma7455_drdy(struct mma7455_data *mma7455)
{
unsigned int reg;
int tries = 3;
int ret;
while (tries-- > 0) {
ret = regmap_read(mma7455->regmap, MMA7455_REG_STATUS, &reg);
if (ret)
return ret;
if (reg & MMA7455_STATUS_DRDY)
return 0;
msleep(20);
}
dev_warn(mma7455->dev, "data not ready\n");
return -EIO;
}
static irqreturn_t mma7455_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct mma7455_data *mma7455 = iio_priv(indio_dev);
u8 buf[16]; /* 3 x 16-bit channels + padding + ts */
int ret;
ret = mma7455_drdy(mma7455);
if (ret)
goto done;
ret = regmap_bulk_read(mma7455->regmap, MMA7455_REG_XOUTL, buf,
sizeof(__le16) * 3);
if (ret)
goto done;
iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
done:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int mma7455_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct mma7455_data *mma7455 = iio_priv(indio_dev);
unsigned int reg;
__le16 data;
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (iio_buffer_enabled(indio_dev))
return -EBUSY;
ret = mma7455_drdy(mma7455);
if (ret)
return ret;
ret = regmap_bulk_read(mma7455->regmap, chan->address, &data,
sizeof(data));
if (ret)
return ret;
*val = sign_extend32(le16_to_cpu(data), 9);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 0;
*val2 = MMA7455_10BIT_SCALE;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SAMP_FREQ:
ret = regmap_read(mma7455->regmap, MMA7455_REG_CTL1, &reg);
if (ret)
return ret;
if (reg & MMA7455_CTL1_DFBW_MASK)
*val = 250;
else
*val = 125;
return IIO_VAL_INT;
}
return -EINVAL;
}
static int mma7455_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct mma7455_data *mma7455 = iio_priv(indio_dev);
int i;
switch (mask) {
case IIO_CHAN_INFO_SAMP_FREQ:
if (val == 250 && val2 == 0)
i = MMA7455_CTL1_DFBW_125HZ;
else if (val == 125 && val2 == 0)
i = MMA7455_CTL1_DFBW_62_5HZ;
else
return -EINVAL;
return regmap_update_bits(mma7455->regmap, MMA7455_REG_CTL1,
MMA7455_CTL1_DFBW_MASK, i);
case IIO_CHAN_INFO_SCALE:
/* In 10-bit mode there is only one scale available */
if (val == 0 && val2 == MMA7455_10BIT_SCALE)
return 0;
break;
}
return -EINVAL;
}
static IIO_CONST_ATTR(sampling_frequency_available, "125 250");
static struct attribute *mma7455_attributes[] = {
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
NULL
};
static const struct attribute_group mma7455_group = {
.attrs = mma7455_attributes,
};
static const struct iio_info mma7455_info = {
.attrs = &mma7455_group,
.read_raw = mma7455_read_raw,
.write_raw = mma7455_write_raw,
.driver_module = THIS_MODULE,
};
#define MMA7455_CHANNEL(axis, idx) { \
.type = IIO_ACCEL, \
.modified = 1, \
.address = MMA7455_REG_##axis##OUTL,\
.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 = { \
.sign = 's', \
.realbits = 10, \
.storagebits = 16, \
.endianness = IIO_LE, \
}, \
}
static const struct iio_chan_spec mma7455_channels[] = {
MMA7455_CHANNEL(X, 0),
MMA7455_CHANNEL(Y, 1),
MMA7455_CHANNEL(Z, 2),
IIO_CHAN_SOFT_TIMESTAMP(3),
};
static const unsigned long mma7455_scan_masks[] = {0x7, 0};
const struct regmap_config mma7455_core_regmap = {
.reg_bits = 8,
.val_bits = 8,
.max_register = MMA7455_REG_TW,
};
EXPORT_SYMBOL_GPL(mma7455_core_regmap);
int mma7455_core_probe(struct device *dev, struct regmap *regmap,
const char *name)
{
struct mma7455_data *mma7455;
struct iio_dev *indio_dev;
unsigned int reg;
int ret;
ret = regmap_read(regmap, MMA7455_REG_WHOAMI, &reg);
if (ret) {
dev_err(dev, "unable to read reg\n");
return ret;
}
if (reg != MMA7455_WHOAMI_ID) {
dev_err(dev, "device id mismatch\n");
return -ENODEV;
}
indio_dev = devm_iio_device_alloc(dev, sizeof(*mma7455));
if (!indio_dev)
return -ENOMEM;
dev_set_drvdata(dev, indio_dev);
mma7455 = iio_priv(indio_dev);
mma7455->regmap = regmap;
mma7455->dev = dev;
indio_dev->info = &mma7455_info;
indio_dev->name = name;
indio_dev->dev.parent = dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = mma7455_channels;
indio_dev->num_channels = ARRAY_SIZE(mma7455_channels);
indio_dev->available_scan_masks = mma7455_scan_masks;
regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
MMA7455_MCTL_MODE_MEASURE);
ret = iio_triggered_buffer_setup(indio_dev, NULL,
mma7455_trigger_handler, NULL);
if (ret) {
dev_err(dev, "unable to setup triggered buffer\n");
return ret;
}
ret = iio_device_register(indio_dev);
if (ret) {
dev_err(dev, "unable to register device\n");
iio_triggered_buffer_cleanup(indio_dev);
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(mma7455_core_probe);
int mma7455_core_remove(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct mma7455_data *mma7455 = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
MMA7455_MCTL_MODE_STANDBY);
return 0;
}
EXPORT_SYMBOL_GPL(mma7455_core_remove);
MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
MODULE_DESCRIPTION("Freescale MMA7455L core accelerometer driver");
MODULE_LICENSE("GPL v2");
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