Commit 32133be6 authored by Constantin Musca's avatar Constantin Musca Committed by Jonathan Cameron
Browse files

iio: accel: Add support for Freescale MMA7660FC 

Minimal implementation of an IIO driver for the Freescale
MMA7660FC 3-axis accelerometer. Datasheet:
http://www.nxp.com/files/sensors/doc/data_sheet/MMA7660FC.pdf



Includes:
- ACPI support;
- read_raw for x,y,z axes;
- reading and setting the scale (range) parameter.
- power management

Signed-off-by: default avatarConstantin Musca <constantin.musca@intel.com>
Reviewed-by: default avatarMartin Klepplinger <martink@posteo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent a8175ba3

drivers/iio/accel/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -136,6 +136,16 @@ config MMA7455_SPI 
	  To compile this driver as a module, choose M here: the module

	  will be called mma7455_spi.



config MMA7660

	tristate "Freescale MMA7660FC 3-Axis Accelerometer Driver"

	depends on I2C

	help

	  Say yes here to get support for the Freescale MMA7660FC 3-Axis

	  accelerometer.



	  Choosing M will build the driver as a module. If so, the module

	  will be called mma7660.



config MMA8452

	tristate "Freescale MMA8452Q and similar Accelerometers Driver"

	depends on I2C

drivers/iio/accel/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -15,6 +15,8 @@ obj-$(CONFIG_MMA7455) += mma7455_core.o 
obj-$(CONFIG_MMA7455_I2C)	+= mma7455_i2c.o

obj-$(CONFIG_MMA7455_SPI)	+= mma7455_spi.o



obj-$(CONFIG_MMA7660)	+= mma7660.o



obj-$(CONFIG_MMA8452)	+= mma8452.o



obj-$(CONFIG_MMA9551_CORE)	+= mma9551_core.o

drivers/iio/accel/mma7660.c

0 → 100644
+277 −0
Original line number Diff line number Diff line 
/**

 * Freescale MMA7660FC 3-Axis Accelerometer

 *

 * Copyright (c) 2016, Intel Corporation.

 *

 * 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.

 *

 * IIO driver for Freescale MMA7660FC; 7-bit I2C address: 0x4c.

 */



#include <linux/acpi.h>

#include <linux/i2c.h>

#include <linux/module.h>

#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>



#define MMA7660_DRIVER_NAME	"mma7660"



#define MMA7660_REG_XOUT	0x00

#define MMA7660_REG_YOUT	0x01

#define MMA7660_REG_ZOUT	0x02

#define MMA7660_REG_OUT_BIT_ALERT	BIT(6)



#define MMA7660_REG_MODE	0x07

#define MMA7660_REG_MODE_BIT_MODE	BIT(0)

#define MMA7660_REG_MODE_BIT_TON	BIT(2)



#define MMA7660_I2C_READ_RETRIES	5



/*

 * The accelerometer has one measurement range:

 *

 * -1.5g - +1.5g (6-bit, signed)

 *

 * scale = (1.5 + 1.5) * 9.81 / (2^6 - 1)	= 0.467142857

 */



#define MMA7660_SCALE_AVAIL	"0.467142857"



const int mma7660_nscale = 467142857;



#define MMA7660_CHANNEL(reg, axis) {	\

	.type = IIO_ACCEL,	\

	.address = reg,	\

	.modified = 1,	\

	.channel2 = IIO_MOD_##axis,	\

	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\

	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\

}



static const struct iio_chan_spec mma7660_channels[] = {

	MMA7660_CHANNEL(MMA7660_REG_XOUT, X),

	MMA7660_CHANNEL(MMA7660_REG_YOUT, Y),

	MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z),

};



enum mma7660_mode {

	MMA7660_MODE_STANDBY,

	MMA7660_MODE_ACTIVE

};



struct mma7660_data {

	struct i2c_client *client;

	struct mutex lock;

	enum mma7660_mode mode;

};



static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL);



static struct attribute *mma7660_attributes[] = {

	&iio_const_attr_in_accel_scale_available.dev_attr.attr,

	NULL,

};



static const struct attribute_group mma7660_attribute_group = {

	.attrs = mma7660_attributes

};



static int mma7660_set_mode(struct mma7660_data *data,

				enum mma7660_mode mode)

{

	int ret;

	struct i2c_client *client = data->client;



	if (mode == data->mode)

		return 0;



	ret = i2c_smbus_read_byte_data(client, MMA7660_REG_MODE);

	if (ret < 0) {

		dev_err(&client->dev, "failed to read sensor mode\n");

		return ret;

	}



	if (mode == MMA7660_MODE_ACTIVE) {

		ret &= ~MMA7660_REG_MODE_BIT_TON;

		ret |= MMA7660_REG_MODE_BIT_MODE;

	} else {

		ret &= ~MMA7660_REG_MODE_BIT_TON;

		ret &= ~MMA7660_REG_MODE_BIT_MODE;

	}



	ret = i2c_smbus_write_byte_data(client, MMA7660_REG_MODE, ret);

	if (ret < 0) {

		dev_err(&client->dev, "failed to change sensor mode\n");

		return ret;

	}



	data->mode = mode;



	return ret;

}



static int mma7660_read_accel(struct mma7660_data *data, u8 address)

{

	int ret, retries = MMA7660_I2C_READ_RETRIES;

	struct i2c_client *client = data->client;



	/*

	 * Read data. If the Alert bit is set, the register was read at

	 * the same time as the device was attempting to update the content.

	 * The solution is to read the register again. Do this only

	 * MMA7660_I2C_READ_RETRIES times to avoid spending too much time

	 * in the kernel.

	 */

	do {

		ret = i2c_smbus_read_byte_data(client, address);

		if (ret < 0) {

			dev_err(&client->dev, "register read failed\n");

			return ret;

		}

	} while (retries-- > 0 && ret & MMA7660_REG_OUT_BIT_ALERT);



	if (ret & MMA7660_REG_OUT_BIT_ALERT) {

		dev_err(&client->dev, "all register read retries failed\n");

		return -ETIMEDOUT;

	}



	return ret;

}



static int mma7660_read_raw(struct iio_dev *indio_dev,

				struct iio_chan_spec const *chan,

				int *val, int *val2, long mask)

{

	struct mma7660_data *data = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		mutex_lock(&data->lock);

		ret = mma7660_read_accel(data, chan->address);

		mutex_unlock(&data->lock);

		if (ret < 0)

			return ret;

		*val = sign_extend32(ret, 5);

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:

		*val = 0;

		*val2 = mma7660_nscale;

		return IIO_VAL_INT_PLUS_NANO;

	default:

		return -EINVAL;

	}



	return -EINVAL;

}



static const struct iio_info mma7660_info = {

	.driver_module	= THIS_MODULE,

	.read_raw		= mma7660_read_raw,

	.attrs			= &mma7660_attribute_group,

};



static int mma7660_probe(struct i2c_client *client,

			const struct i2c_device_id *id)

{

	int ret;

	struct iio_dev *indio_dev;

	struct mma7660_data *data;



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

	if (!indio_dev) {

		dev_err(&client->dev, "iio allocation failed!\n");

		return -ENOMEM;

	}



	data = iio_priv(indio_dev);

	data->client = client;

	i2c_set_clientdata(client, indio_dev);

	mutex_init(&data->lock);

	data->mode = MMA7660_MODE_STANDBY;



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

	indio_dev->info = &mma7660_info;

	indio_dev->name = MMA7660_DRIVER_NAME;

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = mma7660_channels;

	indio_dev->num_channels = ARRAY_SIZE(mma7660_channels);



	ret = mma7660_set_mode(data, MMA7660_MODE_ACTIVE);

	if (ret < 0)

		return ret;



	ret = iio_device_register(indio_dev);

	if (ret < 0) {

		dev_err(&client->dev, "device_register failed\n");

		mma7660_set_mode(data, MMA7660_MODE_STANDBY);

	}



	return ret;

}



static int mma7660_remove(struct i2c_client *client)

{

	struct iio_dev *indio_dev = i2c_get_clientdata(client);



	iio_device_unregister(indio_dev);



	return mma7660_set_mode(iio_priv(indio_dev), MMA7660_MODE_STANDBY);

}



#ifdef CONFIG_PM_SLEEP

static int mma7660_suspend(struct device *dev)

{

	struct mma7660_data *data;



	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));



	return mma7660_set_mode(data, MMA7660_MODE_STANDBY);

}



static int mma7660_resume(struct device *dev)

{

	struct mma7660_data *data;



	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));



	return mma7660_set_mode(data, MMA7660_MODE_ACTIVE);

}



static SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend, mma7660_resume);



#define MMA7660_PM_OPS (&mma7660_pm_ops)

#else

#define MMA7660_PM_OPS NULL

#endif



static const struct i2c_device_id mma7660_i2c_id[] = {

	{"mma7660", 0},

	{}

};



static const struct acpi_device_id mma7660_acpi_id[] = {

	{"MMA7660", 0},

	{}

};



MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id);



static struct i2c_driver mma7660_driver = {

	.driver = {

		.name = "mma7660",

		.pm = MMA7660_PM_OPS,

		.acpi_match_table = ACPI_PTR(mma7660_acpi_id),

	},

	.probe		= mma7660_probe,

	.remove		= mma7660_remove,

	.id_table	= mma7660_i2c_id,

};



module_i2c_driver(mma7660_driver);



MODULE_AUTHOR("Constantin Musca <constantin.musca@intel.com>");

MODULE_DESCRIPTION("Freescale MMA7660FC 3-Axis Accelerometer driver");

MODULE_LICENSE("GPL v2");

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