Commit abeb6b1e authored by Daniel Baluta's avatar Daniel Baluta Committed by Jonathan Cameron
Browse files

iio: magnetometer: Add support for MEMSIC MMC35240 sensor 



Minimal implementation for MMC35240 3-axis magnetometer
sensor. It provides processed readings and possiblity to change
the sampling frequency.

Signed-off-by: default avatarDaniel Baluta <daniel.baluta@intel.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 5990dc97

drivers/iio/magnetometer/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -47,6 +47,17 @@ config HID_SENSOR_MAGNETOMETER_3D 
	  Say yes here to build support for the HID SENSOR

	  Magnetometer 3D.



config MMC35240

	tristate "MEMSIC MMC35240 3-axis magnetic sensor"

	select REGMAP_I2C

	depends on I2C

	help

	  Say yes here to build support for the MEMSIC MMC35240 3-axis

	  magnetic sensor.



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

	  will be called mmc35240.



config IIO_ST_MAGN_3AXIS

	tristate "STMicroelectronics magnetometers 3-Axis Driver"

	depends on (I2C || SPI_MASTER) && SYSFS

drivers/iio/magnetometer/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
obj-$(CONFIG_AK8975)	+= ak8975.o

obj-$(CONFIG_MAG3110)	+= mag3110.o

obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o

obj-$(CONFIG_MMC35240)	+= mmc35240.o



obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o

st_magn-y := st_magn_core.o

drivers/iio/magnetometer/mmc35240.c

0 → 100644
+469 −0
Original line number Diff line number Diff line 
/*

 * MMC35240 - MEMSIC 3-axis Magnetic Sensor

 *

 * Copyright (c) 2015, 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 MMC35240 (7-bit I2C slave address 0x30).

 *

 * TODO: offset, ACPI, continuous measurement mode, PM

 */



#include <linux/module.h>

#include <linux/init.h>

#include <linux/i2c.h>

#include <linux/delay.h>

#include <linux/regmap.h>



#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>



#define MMC35240_DRV_NAME "mmc35240"

#define MMC35240_REGMAP_NAME "mmc35240_regmap"



#define MMC35240_REG_XOUT_L	0x00

#define MMC35240_REG_XOUT_H	0x01

#define MMC35240_REG_YOUT_L	0x02

#define MMC35240_REG_YOUT_H	0x03

#define MMC35240_REG_ZOUT_L	0x04

#define MMC35240_REG_ZOUT_H	0x05



#define MMC35240_REG_STATUS	0x06

#define MMC35240_REG_CTRL0	0x07

#define MMC35240_REG_CTRL1	0x08



#define MMC35240_REG_ID		0x20



#define MMC35240_STATUS_MEAS_DONE_BIT	BIT(0)



#define MMC35240_CTRL0_REFILL_BIT	BIT(7)

#define MMC35240_CTRL0_RESET_BIT	BIT(6)

#define MMC35240_CTRL0_SET_BIT		BIT(5)

#define MMC35240_CTRL0_CMM_BIT		BIT(1)

#define MMC35240_CTRL0_TM_BIT		BIT(0)



/* output resolution bits */

#define MMC35240_CTRL1_BW0_BIT		BIT(0)

#define MMC35240_CTRL1_BW1_BIT		BIT(1)



#define MMC35240_CTRL1_BW_MASK	 (MMC35240_CTRL1_BW0_BIT | \

		 MMC35240_CTRL1_BW1_BIT)

#define MMC35240_CTRL1_BW_SHIFT		0



#define MMC35240_WAIT_CHARGE_PUMP	50000	/* us */

#define MMC53240_WAIT_SET_RESET		1000	/* us */



enum mmc35240_resolution {

	MMC35240_16_BITS_SLOW = 0, /* 100 Hz */

	MMC35240_16_BITS_FAST,     /* 200 Hz */

	MMC35240_14_BITS,          /* 333 Hz */

	MMC35240_12_BITS,          /* 666 Hz */

};



enum mmc35240_axis {

	AXIS_X = 0,

	AXIS_Y,

	AXIS_Z,

};



static const struct {

	int sens[3]; /* sensitivity per X, Y, Z axis */

	int nfo; /* null field output */

} mmc35240_props_table[] = {

	/* 16 bits, 100Hz ODR */

	{

		{1024, 1024, 770},

		32768,

	},

	/* 16 bits, 200Hz ODR */

	{

		{1024, 1024, 770},

		32768,

	},

	/* 14 bits, 333Hz ODR */

	{

		{256, 256, 193},

		8192,

	},

	/* 12 bits, 666Hz ODR */

	{

		{64, 64, 48},

		2048,

	},

};



struct mmc35240_data {

	struct i2c_client *client;

	struct mutex mutex;

	struct regmap *regmap;

	enum mmc35240_resolution res;

};



static const int mmc35240_samp_freq[] = {100, 200, 333, 666};



static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("100 200 333 666");



#define MMC35240_CHANNEL(_axis) { \

	.type = IIO_MAGN, \

	.modified = 1, \

	.channel2 = IIO_MOD_ ## _axis, \

	.address = AXIS_ ## _axis, \

	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \

	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \

}



static const struct iio_chan_spec mmc35240_channels[] = {

	MMC35240_CHANNEL(X),

	MMC35240_CHANNEL(Y),

	MMC35240_CHANNEL(Z),

};



static struct attribute *mmc35240_attributes[] = {

	&iio_const_attr_sampling_frequency_available.dev_attr.attr,

};



static const struct attribute_group mmc35240_attribute_group = {

	.attrs = mmc35240_attributes,

};



static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,

					int val, int val2)

{

	int i;



	for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++)

		if (mmc35240_samp_freq[i] == val)

			return i;

	return -EINVAL;

}



static int mmc35240_hw_set(struct mmc35240_data *data, bool set)

{

	int ret;

	u8 coil_bit;



	/*

	 * Recharge the capacitor at VCAP pin, requested to be issued

	 * before a SET/RESET command.

	 */

	ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,

				 MMC35240_CTRL0_REFILL_BIT,

				 MMC35240_CTRL0_REFILL_BIT);

	if (ret < 0)

		return ret;

	usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);



	if (set)

		coil_bit = MMC35240_CTRL0_SET_BIT;

	else

		coil_bit = MMC35240_CTRL0_RESET_BIT;



	return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,

				  MMC35240_CTRL0_REFILL_BIT,

				  coil_bit);

}



static int mmc35240_init(struct mmc35240_data *data)

{

	int ret;

	unsigned int reg_id;



	ret = regmap_read(data->regmap, MMC35240_REG_ID, &reg_id);

	if (ret < 0) {

		dev_err(&data->client->dev, "Error reading product id\n");

		return ret;

	}



	dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);



	/*

	 * make sure we restore sensor characteristics, by doing

	 * a RESET/SET sequence

	 */

	ret = mmc35240_hw_set(data, false);

	if (ret < 0)

		return ret;

	usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1);



	ret = mmc35240_hw_set(data, true);

	if (ret < 0)

		return ret;



	/* set default sampling frequency */

	return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,

				  MMC35240_CTRL1_BW_MASK,

				  data->res << MMC35240_CTRL1_BW_SHIFT);

}



static int mmc35240_take_measurement(struct mmc35240_data *data)

{

	int ret, tries = 100;

	unsigned int reg_status;



	ret = regmap_write(data->regmap, MMC35240_REG_CTRL0,

			   MMC35240_CTRL0_TM_BIT);

	if (ret < 0)

		return ret;



	while (tries-- > 0) {

		ret = regmap_read(data->regmap, MMC35240_REG_STATUS,

				  &reg_status);

		if (ret < 0)

			return ret;

		if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)

			break;

		msleep(20);

	}



	if (tries < 0) {

		dev_err(&data->client->dev, "data not ready\n");

		return -EIO;

	}



	return 0;

}



static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])

{

	int ret;



	ret = mmc35240_take_measurement(data);

	if (ret < 0)

		return ret;



	return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf,

				3 * sizeof(__le16));

}



static int mmc35240_raw_to_gauss(struct mmc35240_data *data, int index,

				 __le16 buf[],

				 int *val, int *val2)

{

	int raw_x, raw_y, raw_z;

	int sens_x, sens_y, sens_z;

	int nfo;



	raw_x = le16_to_cpu(buf[AXIS_X]);

	raw_y = le16_to_cpu(buf[AXIS_Y]);

	raw_z = le16_to_cpu(buf[AXIS_Z]);



	sens_x = mmc35240_props_table[data->res].sens[AXIS_X];

	sens_y = mmc35240_props_table[data->res].sens[AXIS_Y];

	sens_z = mmc35240_props_table[data->res].sens[AXIS_Z];



	nfo = mmc35240_props_table[data->res].nfo;



	switch (index) {

	case AXIS_X:

		*val = (raw_x - nfo) / sens_x;

		*val2 = ((raw_x - nfo) % sens_x) * 1000000;

		break;

	case AXIS_Y:

		*val = (raw_y - nfo) / sens_y - (raw_z - nfo) / sens_z;

		*val2 = (((raw_y - nfo) % sens_y - (raw_z - nfo) % sens_z))

			* 1000000;

		break;

	case AXIS_Z:

		*val = (raw_y - nfo) / sens_y + (raw_z - nfo) / sens_z;

		*val2 = (((raw_y - nfo) % sens_y + (raw_z - nfo) % sens_z))

			* 1000000;

		break;

	default:

		return -EINVAL;

	}

	return 0;

}



static int mmc35240_read_raw(struct iio_dev *indio_dev,

			     struct iio_chan_spec const *chan, int *val,

			     int *val2, long mask)

{

	struct mmc35240_data *data = iio_priv(indio_dev);

	int ret, i;

	unsigned int reg;

	__le16 buf[3];



	switch (mask) {

	case IIO_CHAN_INFO_PROCESSED:

		mutex_lock(&data->mutex);

		ret = mmc35240_read_measurement(data, buf);

		mutex_unlock(&data->mutex);

		if (ret < 0)

			return ret;

		ret = mmc35240_raw_to_gauss(data, chan->address,

					    buf, val, val2);

		if (ret < 0)

			return ret;

		return IIO_VAL_INT_PLUS_MICRO;

	case IIO_CHAN_INFO_SAMP_FREQ:

		mutex_lock(&data->mutex);

		ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, &reg);

		mutex_unlock(&data->mutex);

		if (ret < 0)

			return ret;



		i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;

		if (i < 0 || i > ARRAY_SIZE(mmc35240_samp_freq))

			return -EINVAL;



		*val = mmc35240_samp_freq[i];

		*val2 = 0;

		return IIO_VAL_INT;

	default:

		return -EINVAL;

	}

}



static int mmc35240_write_raw(struct iio_dev *indio_dev,

			      struct iio_chan_spec const *chan, int val,

			      int val2, long mask)

{

	struct mmc35240_data *data = iio_priv(indio_dev);

	int i, ret;



	switch (mask) {

	case IIO_CHAN_INFO_SAMP_FREQ:

		i = mmc35240_get_samp_freq_index(data, val, val2);

		if (i < 0)

			return -EINVAL;

		mutex_lock(&data->mutex);

		ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,

					 MMC35240_CTRL1_BW_MASK,

					 i << MMC35240_CTRL1_BW_SHIFT);

		mutex_unlock(&data->mutex);

		return ret;

	default:

		return -EINVAL;

	}

}



static const struct iio_info mmc35240_info = {

	.driver_module	= THIS_MODULE,

	.read_raw	= mmc35240_read_raw,

	.write_raw	= mmc35240_write_raw,

	.attrs		= &mmc35240_attribute_group,

};



static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)

{

	switch (reg) {

	case MMC35240_REG_CTRL0:

	case MMC35240_REG_CTRL1:

		return true;

	default:

		return false;

	}

}



static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg)

{

	switch (reg) {

	case MMC35240_REG_XOUT_L:

	case MMC35240_REG_XOUT_H:

	case MMC35240_REG_YOUT_L:

	case MMC35240_REG_YOUT_H:

	case MMC35240_REG_ZOUT_L:

	case MMC35240_REG_ZOUT_H:

	case MMC35240_REG_STATUS:

	case MMC35240_REG_ID:

		return true;

	default:

		return false;

	}

}



static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)

{

	switch (reg) {

	case MMC35240_REG_CTRL0:

	case MMC35240_REG_CTRL1:

		return false;

	default:

		return true;

	}

}



static struct reg_default mmc35240_reg_defaults[] = {

	{ MMC35240_REG_CTRL0,  0x00 },

	{ MMC35240_REG_CTRL1,  0x00 },

};



static const struct regmap_config mmc35240_regmap_config = {

	.name = MMC35240_REGMAP_NAME,



	.reg_bits = 8,

	.val_bits = 8,



	.max_register = MMC35240_REG_ID,

	.cache_type = REGCACHE_FLAT,



	.writeable_reg = mmc35240_is_writeable_reg,

	.readable_reg = mmc35240_is_readable_reg,

	.volatile_reg = mmc35240_is_volatile_reg,



	.reg_defaults = mmc35240_reg_defaults,

	.num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),

};



static int mmc35240_probe(struct i2c_client *client,

			  const struct i2c_device_id *id)

{

	struct mmc35240_data *data;

	struct iio_dev *indio_dev;

	struct regmap *regmap;

	int ret;



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

	if (!indio_dev)

		return -ENOMEM;



	regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);

	if (IS_ERR(regmap)) {

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

		return PTR_ERR(regmap);

	}



	data = iio_priv(indio_dev);

	data->client = client;

	data->regmap = regmap;

	data->res = MMC35240_16_BITS_SLOW;



	mutex_init(&data->mutex);



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

	indio_dev->info = &mmc35240_info;

	indio_dev->name = MMC35240_DRV_NAME;

	indio_dev->channels = mmc35240_channels;

	indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);

	indio_dev->modes = INDIO_DIRECT_MODE;



	ret = mmc35240_init(data);

	if (ret < 0) {

		dev_err(&client->dev, "mmc35240 chip init failed\n");

		return ret;

	}

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

}



static const struct i2c_device_id mmc35240_id[] = {

	{"MMC35240", 0},

	{}

};

MODULE_DEVICE_TABLE(i2c, mmc35240_id);



static struct i2c_driver mmc35240_driver = {

	.driver = {

		.name = MMC35240_DRV_NAME,

	},

	.probe		= mmc35240_probe,

	.id_table	= mmc35240_id,

};



module_i2c_driver(mmc35240_driver);



MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");

MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");

MODULE_LICENSE("GPL v2");

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