drivers/iio/accel/stk8ba50.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Sensortek STK8BA50 3-Axis Accelerometer
  *
  * Copyright (c) 2015, Intel Corporation.
  *
  * STK8BA50 7-bit I2C address: 0x18.
  */

 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/trigger.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/iio/trigger_consumer.h>

 #define STK8BA50_REG_XOUT			0x02
 #define STK8BA50_REG_YOUT			0x04
 #define STK8BA50_REG_ZOUT			0x06
 #define STK8BA50_REG_RANGE			0x0F
 #define STK8BA50_REG_BWSEL			0x10
 #define STK8BA50_REG_POWMODE			0x11
 #define STK8BA50_REG_SWRST			0x14
 #define STK8BA50_REG_INTEN2			0x17
 #define STK8BA50_REG_INTMAP2			0x1A

 #define STK8BA50_MODE_NORMAL			0
 #define STK8BA50_MODE_SUSPEND			1
 #define STK8BA50_MODE_POWERBIT			BIT(7)
 #define STK8BA50_DATA_SHIFT			6
 #define STK8BA50_RESET_CMD			0xB6
 #define STK8BA50_SR_1792HZ_IDX			7
 #define STK8BA50_DREADY_INT_MASK		0x10
 #define STK8BA50_DREADY_INT_MAP			0x81
 #define STK8BA50_ALL_CHANNEL_MASK		7
 #define STK8BA50_ALL_CHANNEL_SIZE		6

 #define STK8BA50_DRIVER_NAME			"stk8ba50"
 #define STK8BA50_IRQ_NAME			"stk8ba50_event"

 #define STK8BA50_SCALE_AVAIL			"0.0384 0.0767 0.1534 0.3069"

 /*
  * The accelerometer has four measurement ranges:
  * +/-2g; +/-4g; +/-8g; +/-16g
  *
  * Acceleration values are 10-bit, 2's complement.
  * Scales are calculated as following:
  *
  * scale1 = (2 + 2) * 9.81 / (2^10 - 1)   = 0.0384
  * scale2 = (4 + 4) * 9.81 / (2^10 - 1)   = 0.0767
  * etc.
  *
  * Scales are stored in this format:
  * { <register value>, <scale value> }
  *
  * Locally, the range is stored as a table index.
  */
 static const struct {
 	u8 reg_val;
 	u32 scale_val;
 } stk8ba50_scale_table[] = {
 	{3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
 };

 /* Sample rates are stored as { <register value>, <Hz value> } */
 static const struct {
 	u8 reg_val;
 	u16 samp_freq;
 } stk8ba50_samp_freq_table[] = {
 	{0x08, 14},  {0x09, 25},  {0x0A, 56},  {0x0B, 112},
 	{0x0C, 224}, {0x0D, 448}, {0x0E, 896}, {0x0F, 1792}
 };

 /* Used to map scan mask bits to their corresponding channel register. */
 static const int stk8ba50_channel_table[] = {
 	STK8BA50_REG_XOUT,
 	STK8BA50_REG_YOUT,
 	STK8BA50_REG_ZOUT
 };

 struct stk8ba50_data {
 	struct i2c_client *client;
 	struct mutex lock;
 	int range;
 	u8 sample_rate_idx;
 	struct iio_trigger *dready_trig;
 	bool dready_trigger_on;
 	/* Ensure timestamp is naturally aligned */
 	struct {
 		s16 chans[3];
 		s64 timetamp __aligned(8);
 	} scan;
 };

 #define STK8BA50_ACCEL_CHANNEL(index, 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),		\
 				    BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
 	.scan_index = index,						\
 	.scan_type = {							\
 		.sign = 's',						\
 		.realbits = 10,						\
 		.storagebits = 16,					\
 		.shift = STK8BA50_DATA_SHIFT,				\
 		.endianness = IIO_CPU,					\
 	},								\
 }

 static const struct iio_chan_spec stk8ba50_channels[] = {
 	STK8BA50_ACCEL_CHANNEL(0, STK8BA50_REG_XOUT, X),
 	STK8BA50_ACCEL_CHANNEL(1, STK8BA50_REG_YOUT, Y),
 	STK8BA50_ACCEL_CHANNEL(2, STK8BA50_REG_ZOUT, Z),
 	IIO_CHAN_SOFT_TIMESTAMP(3),
 };

 static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);

 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("14 25 56 112 224 448 896 1792");

 static struct attribute *stk8ba50_attributes[] = {
 	&iio_const_attr_in_accel_scale_available.dev_attr.attr,
 	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
 	NULL,
 };

 static const struct attribute_group stk8ba50_attribute_group = {
 	.attrs = stk8ba50_attributes
 };

 static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
 {
 	int ret;
 	struct i2c_client *client = data->client;

 	ret = i2c_smbus_read_word_data(client, reg);
 	if (ret < 0) {
 		dev_err(&client->dev, "register read failed\n");
 		return ret;
 	}

 	return ret;
 }

 static int stk8ba50_data_rdy_trigger_set_state(struct iio_trigger *trig,
 					       bool state)
 {
 	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
 	struct stk8ba50_data *data = iio_priv(indio_dev);
 	int ret;

 	if (state)
 		ret = i2c_smbus_write_byte_data(data->client,
 			STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
 	else
 		ret = i2c_smbus_write_byte_data(data->client,
 			STK8BA50_REG_INTEN2, 0x00);

 	if (ret < 0)
 		dev_err(&data->client->dev, "failed to set trigger state\n");
 	else
 		data->dready_trigger_on = state;

 	return ret;
 }

 static const struct iio_trigger_ops stk8ba50_trigger_ops = {
 	.set_trigger_state = stk8ba50_data_rdy_trigger_set_state,
 };

 static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
 {
 	int ret;
 	u8 masked_reg;
 	struct i2c_client *client = data->client;

 	ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
 	if (ret < 0)
 		goto exit_err;

 	if (mode)
 		masked_reg = ret | STK8BA50_MODE_POWERBIT;
 	else
 		masked_reg = ret & (~STK8BA50_MODE_POWERBIT);

 	ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
 					masked_reg);
 	if (ret < 0)
 		goto exit_err;

 	return ret;

 exit_err:
 	dev_err(&client->dev, "failed to change sensor mode\n");
 	return ret;
 }

 static int stk8ba50_read_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int *val, int *val2, long mask)
 {
 	struct stk8ba50_data *data = iio_priv(indio_dev);
 	int ret;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		if (iio_buffer_enabled(indio_dev))
 			return -EBUSY;
 		mutex_lock(&data->lock);
 		ret = stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 		if (ret < 0) {
 			mutex_unlock(&data->lock);
 			return -EINVAL;
 		}
 		ret = stk8ba50_read_accel(data, chan->address);
 		if (ret < 0) {
 			stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 			mutex_unlock(&data->lock);
 			return -EINVAL;
 		}
 		*val = sign_extend32(ret >> chan->scan_type.shift,
 				     chan->scan_type.realbits - 1);
 		stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 		mutex_unlock(&data->lock);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		*val = 0;
 		*val2 = stk8ba50_scale_table[data->range].scale_val;
 		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		*val = stk8ba50_samp_freq_table
 				[data->sample_rate_idx].samp_freq;
 		*val2 = 0;
 		return IIO_VAL_INT;
 	}

 	return -EINVAL;
 }

 static int stk8ba50_write_raw(struct iio_dev *indio_dev,
 			      struct iio_chan_spec const *chan,
 			      int val, int val2, long mask)
 {
 	int ret;
 	int i;
 	int index = -1;
 	struct stk8ba50_data *data = iio_priv(indio_dev);

 	switch (mask) {
 	case IIO_CHAN_INFO_SCALE:
 		if (val != 0)
 			return -EINVAL;

 		for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
 			if (val2 == stk8ba50_scale_table[i].scale_val) {
 				index = i;
 				break;
 			}
 		if (index < 0)
 			return -EINVAL;

 		ret = i2c_smbus_write_byte_data(data->client,
 				STK8BA50_REG_RANGE,
 				stk8ba50_scale_table[index].reg_val);
 		if (ret < 0)
 			dev_err(&data->client->dev,
 					"failed to set measurement range\n");
 		else
 			data->range = index;

 		return ret;
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		for (i = 0; i < ARRAY_SIZE(stk8ba50_samp_freq_table); i++)
 			if (val == stk8ba50_samp_freq_table[i].samp_freq) {
 				index = i;
 				break;
 			}
 		if (index < 0)
 			return -EINVAL;

 		ret = i2c_smbus_write_byte_data(data->client,
 				STK8BA50_REG_BWSEL,
 				stk8ba50_samp_freq_table[index].reg_val);
 		if (ret < 0)
 			dev_err(&data->client->dev,
 					"failed to set sampling rate\n");
 		else
 			data->sample_rate_idx = index;

 		return ret;
 	}

 	return -EINVAL;
 }

 static const struct iio_info stk8ba50_info = {
 	.read_raw		= stk8ba50_read_raw,
 	.write_raw		= stk8ba50_write_raw,
 	.attrs			= &stk8ba50_attribute_group,
 };

 static irqreturn_t stk8ba50_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct stk8ba50_data *data = iio_priv(indio_dev);
 	int bit, ret, i = 0;

 	mutex_lock(&data->lock);
 	/*
 	 * Do a bulk read if all channels are requested,
 	 * from 0x02 (XOUT1) to 0x07 (ZOUT2)
 	 */
 	if (*(indio_dev->active_scan_mask) == STK8BA50_ALL_CHANNEL_MASK) {
 		ret = i2c_smbus_read_i2c_block_data(data->client,
 						    STK8BA50_REG_XOUT,
 						    STK8BA50_ALL_CHANNEL_SIZE,
 						    (u8 *)data->scan.chans);
 		if (ret < STK8BA50_ALL_CHANNEL_SIZE) {
 			dev_err(&data->client->dev, "register read failed\n");
 			goto err;
 		}
 	} else {
 		iio_for_each_active_channel(indio_dev, bit) {
 			ret = stk8ba50_read_accel(data,
 						  stk8ba50_channel_table[bit]);
 			if (ret < 0)
 				goto err;

 			data->scan.chans[i++] = ret;
 		}
 	}
 	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 					   pf->timestamp);
 err:
 	mutex_unlock(&data->lock);
 	iio_trigger_notify_done(indio_dev->trig);

 	return IRQ_HANDLED;
 }

 static irqreturn_t stk8ba50_data_rdy_trig_poll(int irq, void *private)
 {
 	struct iio_dev *indio_dev = private;
 	struct stk8ba50_data *data = iio_priv(indio_dev);

 	if (data->dready_trigger_on)
 		iio_trigger_poll(data->dready_trig);

 	return IRQ_HANDLED;
 }

 static int stk8ba50_buffer_preenable(struct iio_dev *indio_dev)
 {
 	struct stk8ba50_data *data = iio_priv(indio_dev);

 	return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 }

 static int stk8ba50_buffer_postdisable(struct iio_dev *indio_dev)
 {
 	struct stk8ba50_data *data = iio_priv(indio_dev);

 	return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 }

 static const struct iio_buffer_setup_ops stk8ba50_buffer_setup_ops = {
 	.preenable   = stk8ba50_buffer_preenable,
 	.postdisable = stk8ba50_buffer_postdisable,
 };

 static int stk8ba50_probe(struct i2c_client *client)
 {
 	int ret;
 	struct iio_dev *indio_dev;
 	struct stk8ba50_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);

 	indio_dev->info = &stk8ba50_info;
 	indio_dev->name = STK8BA50_DRIVER_NAME;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = stk8ba50_channels;
 	indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);

 	/* Reset all registers on startup */
 	ret = i2c_smbus_write_byte_data(client,
 			STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
 	if (ret < 0) {
 		dev_err(&client->dev, "failed to reset sensor\n");
 		goto err_power_off;
 	}

 	/* The default range is +/-2g */
 	data->range = 0;

 	/* The default sampling rate is 1792 Hz (maximum) */
 	data->sample_rate_idx = STK8BA50_SR_1792HZ_IDX;

 	/* Set up interrupts */
 	ret = i2c_smbus_write_byte_data(client,
 			STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
 	if (ret < 0) {
 		dev_err(&client->dev, "failed to set up interrupts\n");
 		goto err_power_off;
 	}
 	ret = i2c_smbus_write_byte_data(client,
 			STK8BA50_REG_INTMAP2, STK8BA50_DREADY_INT_MAP);
 	if (ret < 0) {
 		dev_err(&client->dev, "failed to set up interrupts\n");
 		goto err_power_off;
 	}

 	if (client->irq > 0) {
 		ret = devm_request_threaded_irq(&client->dev, client->irq,
 						stk8ba50_data_rdy_trig_poll,
 						NULL,
 						IRQF_TRIGGER_RISING |
 						IRQF_ONESHOT,
 						STK8BA50_IRQ_NAME,
 						indio_dev);
 		if (ret < 0) {
 			dev_err(&client->dev, "request irq %d failed\n",
 				client->irq);
 			goto err_power_off;
 		}

 		data->dready_trig = devm_iio_trigger_alloc(&client->dev,
 							   "%s-dev%d",
 							   indio_dev->name,
 							   iio_device_id(indio_dev));
 		if (!data->dready_trig) {
 			ret = -ENOMEM;
 			goto err_power_off;
 		}

 		data->dready_trig->ops = &stk8ba50_trigger_ops;
 		iio_trigger_set_drvdata(data->dready_trig, indio_dev);
 		ret = iio_trigger_register(data->dready_trig);
 		if (ret) {
 			dev_err(&client->dev, "iio trigger register failed\n");
 			goto err_power_off;
 		}
 	}

 	ret = iio_triggered_buffer_setup(indio_dev,
 					 iio_pollfunc_store_time,
 					 stk8ba50_trigger_handler,
 					 &stk8ba50_buffer_setup_ops);
 	if (ret < 0) {
 		dev_err(&client->dev, "iio triggered buffer setup failed\n");
 		goto err_trigger_unregister;
 	}

 	ret = iio_device_register(indio_dev);
 	if (ret < 0) {
 		dev_err(&client->dev, "device_register failed\n");
 		goto err_buffer_cleanup;
 	}

 	return ret;

 err_buffer_cleanup:
 	iio_triggered_buffer_cleanup(indio_dev);
 err_trigger_unregister:
 	if (data->dready_trig)
 		iio_trigger_unregister(data->dready_trig);
 err_power_off:
 	stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 	return ret;
 }

 static void stk8ba50_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 	struct stk8ba50_data *data = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);

 	if (data->dready_trig)
 		iio_trigger_unregister(data->dready_trig);

 	stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 }

 static int stk8ba50_suspend(struct device *dev)
 {
 	struct stk8ba50_data *data;

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

 	return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 }

 static int stk8ba50_resume(struct device *dev)
 {
 	struct stk8ba50_data *data;

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

 	return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 }

 static DEFINE_SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend,
 				stk8ba50_resume);

 static const struct i2c_device_id stk8ba50_i2c_id[] = {
 	{ "stk8ba50" },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, stk8ba50_i2c_id);

 static const struct acpi_device_id stk8ba50_acpi_id[] = {
 	{"STK8BA50", 0},
 	{}
 };

 MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);

 static struct i2c_driver stk8ba50_driver = {
 	.driver = {
 		.name = "stk8ba50",
 		.pm = pm_sleep_ptr(&stk8ba50_pm_ops),
 		.acpi_match_table = stk8ba50_acpi_id,
 	},
 	.probe =        stk8ba50_probe,
 	.remove =           stk8ba50_remove,
 	.id_table =         stk8ba50_i2c_id,
 };

 module_i2c_driver(stk8ba50_driver);

 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
 MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Sensortek STK8BA50 3-Axis Accelerometer
	*
	* Copyright (c) 2015, Intel Corporation.
	*
	* STK8BA50 7-bit I2C address: 0x18.
	*/

	#include <linux/i2c.h>
	#include <linux/interrupt.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/mod_devicetable.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/iio.h>
	#include <linux/iio/sysfs.h>
	#include <linux/iio/trigger.h>
	#include <linux/iio/triggered_buffer.h>
	#include <linux/iio/trigger_consumer.h>

	#define STK8BA50_REG_XOUT 0x02
	#define STK8BA50_REG_YOUT 0x04
	#define STK8BA50_REG_ZOUT 0x06
	#define STK8BA50_REG_RANGE 0x0F
	#define STK8BA50_REG_BWSEL 0x10
	#define STK8BA50_REG_POWMODE 0x11
	#define STK8BA50_REG_SWRST 0x14
	#define STK8BA50_REG_INTEN2 0x17
	#define STK8BA50_REG_INTMAP2 0x1A

	#define STK8BA50_MODE_NORMAL 0
	#define STK8BA50_MODE_SUSPEND 1
	#define STK8BA50_MODE_POWERBIT BIT(7)
	#define STK8BA50_DATA_SHIFT 6
	#define STK8BA50_RESET_CMD 0xB6
	#define STK8BA50_SR_1792HZ_IDX 7
	#define STK8BA50_DREADY_INT_MASK 0x10
	#define STK8BA50_DREADY_INT_MAP 0x81
	#define STK8BA50_ALL_CHANNEL_MASK 7
	#define STK8BA50_ALL_CHANNEL_SIZE 6

	#define STK8BA50_DRIVER_NAME "stk8ba50"
	#define STK8BA50_IRQ_NAME "stk8ba50_event"

	#define STK8BA50_SCALE_AVAIL "0.0384 0.0767 0.1534 0.3069"

	/*
	* The accelerometer has four measurement ranges:
	* +/-2g; +/-4g; +/-8g; +/-16g
	*
	* Acceleration values are 10-bit, 2's complement.
	* Scales are calculated as following:
	*
	* scale1 = (2 + 2) * 9.81 / (2^10 - 1) = 0.0384
	* scale2 = (4 + 4) * 9.81 / (2^10 - 1) = 0.0767
	* etc.
	*
	* Scales are stored in this format:
	* { <register value>, <scale value> }
	*
	* Locally, the range is stored as a table index.
	*/
	static const struct {
	u8 reg_val;
	u32 scale_val;
	} stk8ba50_scale_table[] = {
	{3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
	};

	/* Sample rates are stored as { <register value>, <Hz value> } */
	static const struct {
	u8 reg_val;
	u16 samp_freq;
	} stk8ba50_samp_freq_table[] = {
	{0x08, 14}, {0x09, 25}, {0x0A, 56}, {0x0B, 112},
	{0x0C, 224}, {0x0D, 448}, {0x0E, 896}, {0x0F, 1792}
	};

	/* Used to map scan mask bits to their corresponding channel register. */
	static const int stk8ba50_channel_table[] = {
	STK8BA50_REG_XOUT,
	STK8BA50_REG_YOUT,
	STK8BA50_REG_ZOUT
	};

	struct stk8ba50_data {
	struct i2c_client *client;
	struct mutex lock;
	int range;
	u8 sample_rate_idx;
	struct iio_trigger *dready_trig;
	bool dready_trigger_on;
	/* Ensure timestamp is naturally aligned */
	struct {
	s16 chans[3];
	s64 timetamp __aligned(8);
	} scan;
	};

	#define STK8BA50_ACCEL_CHANNEL(index, 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), \
	BIT(IIO_CHAN_INFO_SAMP_FREQ), \
	.scan_index = index, \
	.scan_type = { \
	.sign = 's', \
	.realbits = 10, \
	.storagebits = 16, \
	.shift = STK8BA50_DATA_SHIFT, \
	.endianness = IIO_CPU, \
	}, \
	}

	static const struct iio_chan_spec stk8ba50_channels[] = {
	STK8BA50_ACCEL_CHANNEL(0, STK8BA50_REG_XOUT, X),
	STK8BA50_ACCEL_CHANNEL(1, STK8BA50_REG_YOUT, Y),
	STK8BA50_ACCEL_CHANNEL(2, STK8BA50_REG_ZOUT, Z),
	IIO_CHAN_SOFT_TIMESTAMP(3),
	};

	static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);

	static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("14 25 56 112 224 448 896 1792");

	static struct attribute *stk8ba50_attributes[] = {
	&iio_const_attr_in_accel_scale_available.dev_attr.attr,
	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
	NULL,
	};

	static const struct attribute_group stk8ba50_attribute_group = {
	.attrs = stk8ba50_attributes
	};

	static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
	{
	int ret;
	struct i2c_client *client = data->client;

	ret = i2c_smbus_read_word_data(client, reg);
	if (ret < 0) {
	dev_err(&client->dev, "register read failed\n");
	return ret;
	}

	return ret;
	}

	static int stk8ba50_data_rdy_trigger_set_state(struct iio_trigger *trig,
	bool state)
	{
	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
	struct stk8ba50_data *data = iio_priv(indio_dev);
	int ret;

	if (state)
	ret = i2c_smbus_write_byte_data(data->client,
	STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
	else
	ret = i2c_smbus_write_byte_data(data->client,
	STK8BA50_REG_INTEN2, 0x00);

	if (ret < 0)
	dev_err(&data->client->dev, "failed to set trigger state\n");
	else
	data->dready_trigger_on = state;

	return ret;
	}

	static const struct iio_trigger_ops stk8ba50_trigger_ops = {
	.set_trigger_state = stk8ba50_data_rdy_trigger_set_state,
	};

	static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
	{
	int ret;
	u8 masked_reg;
	struct i2c_client *client = data->client;

	ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
	if (ret < 0)
	goto exit_err;

	if (mode)
	masked_reg = ret \| STK8BA50_MODE_POWERBIT;
	else
	masked_reg = ret & (~STK8BA50_MODE_POWERBIT);

	ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
	masked_reg);
	if (ret < 0)
	goto exit_err;

	return ret;

	exit_err:
	dev_err(&client->dev, "failed to change sensor mode\n");
	return ret;
	}

	static int stk8ba50_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct stk8ba50_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	if (iio_buffer_enabled(indio_dev))
	return -EBUSY;
	mutex_lock(&data->lock);
	ret = stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
	if (ret < 0) {
	mutex_unlock(&data->lock);
	return -EINVAL;
	}
	ret = stk8ba50_read_accel(data, chan->address);
	if (ret < 0) {
	stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
	mutex_unlock(&data->lock);
	return -EINVAL;
	}
	*val = sign_extend32(ret >> chan->scan_type.shift,
	chan->scan_type.realbits - 1);
	stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
	mutex_unlock(&data->lock);
	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	*val = 0;
	*val2 = stk8ba50_scale_table[data->range].scale_val;
	return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_SAMP_FREQ:
	*val = stk8ba50_samp_freq_table
	[data->sample_rate_idx].samp_freq;
	*val2 = 0;
	return IIO_VAL_INT;
	}

	return -EINVAL;
	}

	static int stk8ba50_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	int ret;
	int i;
	int index = -1;
	struct stk8ba50_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_SCALE:
	if (val != 0)
	return -EINVAL;

	for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
	if (val2 == stk8ba50_scale_table[i].scale_val) {
	index = i;
	break;
	}
	if (index < 0)
	return -EINVAL;

	ret = i2c_smbus_write_byte_data(data->client,
	STK8BA50_REG_RANGE,
	stk8ba50_scale_table[index].reg_val);
	if (ret < 0)
	dev_err(&data->client->dev,
	"failed to set measurement range\n");
	else
	data->range = index;

	return ret;
	case IIO_CHAN_INFO_SAMP_FREQ:
	for (i = 0; i < ARRAY_SIZE(stk8ba50_samp_freq_table); i++)
	if (val == stk8ba50_samp_freq_table[i].samp_freq) {
	index = i;
	break;
	}
	if (index < 0)
	return -EINVAL;

	ret = i2c_smbus_write_byte_data(data->client,
	STK8BA50_REG_BWSEL,
	stk8ba50_samp_freq_table[index].reg_val);
	if (ret < 0)
	dev_err(&data->client->dev,
	"failed to set sampling rate\n");
	else
	data->sample_rate_idx = index;

	return ret;
	}

	return -EINVAL;
	}

	static const struct iio_info stk8ba50_info = {
	.read_raw = stk8ba50_read_raw,
	.write_raw = stk8ba50_write_raw,
	.attrs = &stk8ba50_attribute_group,
	};

	static irqreturn_t stk8ba50_trigger_handler(int irq, void *p)
	{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct stk8ba50_data *data = iio_priv(indio_dev);
	int bit, ret, i = 0;

	mutex_lock(&data->lock);
	/*
	* Do a bulk read if all channels are requested,
	* from 0x02 (XOUT1) to 0x07 (ZOUT2)
	*/
	if (*(indio_dev->active_scan_mask) == STK8BA50_ALL_CHANNEL_MASK) {
	ret = i2c_smbus_read_i2c_block_data(data->client,
	STK8BA50_REG_XOUT,
	STK8BA50_ALL_CHANNEL_SIZE,
	(u8 *)data->scan.chans);
	if (ret < STK8BA50_ALL_CHANNEL_SIZE) {
	dev_err(&data->client->dev, "register read failed\n");
	goto err;
	}
	} else {
	iio_for_each_active_channel(indio_dev, bit) {
	ret = stk8ba50_read_accel(data,
	stk8ba50_channel_table[bit]);
	if (ret < 0)
	goto err;

	data->scan.chans[i++] = ret;
	}
	}
	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
	pf->timestamp);
	err:
	mutex_unlock(&data->lock);
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
	}

	static irqreturn_t stk8ba50_data_rdy_trig_poll(int irq, void *private)
	{
	struct iio_dev *indio_dev = private;
	struct stk8ba50_data *data = iio_priv(indio_dev);

	if (data->dready_trigger_on)
	iio_trigger_poll(data->dready_trig);

	return IRQ_HANDLED;
	}

	static int stk8ba50_buffer_preenable(struct iio_dev *indio_dev)
	{
	struct stk8ba50_data *data = iio_priv(indio_dev);

	return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
	}

	static int stk8ba50_buffer_postdisable(struct iio_dev *indio_dev)
	{
	struct stk8ba50_data *data = iio_priv(indio_dev);

	return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
	}

	static const struct iio_buffer_setup_ops stk8ba50_buffer_setup_ops = {
	.preenable = stk8ba50_buffer_preenable,
	.postdisable = stk8ba50_buffer_postdisable,
	};

	static int stk8ba50_probe(struct i2c_client *client)
	{
	int ret;
	struct iio_dev *indio_dev;
	struct stk8ba50_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);

	indio_dev->info = &stk8ba50_info;
	indio_dev->name = STK8BA50_DRIVER_NAME;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = stk8ba50_channels;
	indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);

	/* Reset all registers on startup */
	ret = i2c_smbus_write_byte_data(client,
	STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
	if (ret < 0) {
	dev_err(&client->dev, "failed to reset sensor\n");
	goto err_power_off;
	}

	/* The default range is +/-2g */
	data->range = 0;

	/* The default sampling rate is 1792 Hz (maximum) */
	data->sample_rate_idx = STK8BA50_SR_1792HZ_IDX;

	/* Set up interrupts */
	ret = i2c_smbus_write_byte_data(client,
	STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
	if (ret < 0) {
	dev_err(&client->dev, "failed to set up interrupts\n");
	goto err_power_off;
	}
	ret = i2c_smbus_write_byte_data(client,
	STK8BA50_REG_INTMAP2, STK8BA50_DREADY_INT_MAP);
	if (ret < 0) {
	dev_err(&client->dev, "failed to set up interrupts\n");
	goto err_power_off;
	}

	if (client->irq > 0) {
	ret = devm_request_threaded_irq(&client->dev, client->irq,
	stk8ba50_data_rdy_trig_poll,
	NULL,
	IRQF_TRIGGER_RISING \|
	IRQF_ONESHOT,
	STK8BA50_IRQ_NAME,
	indio_dev);
	if (ret < 0) {
	dev_err(&client->dev, "request irq %d failed\n",
	client->irq);
	goto err_power_off;
	}

	data->dready_trig = devm_iio_trigger_alloc(&client->dev,
	"%s-dev%d",
	indio_dev->name,
	iio_device_id(indio_dev));
	if (!data->dready_trig) {
	ret = -ENOMEM;
	goto err_power_off;
	}

	data->dready_trig->ops = &stk8ba50_trigger_ops;
	iio_trigger_set_drvdata(data->dready_trig, indio_dev);
	ret = iio_trigger_register(data->dready_trig);
	if (ret) {
	dev_err(&client->dev, "iio trigger register failed\n");
	goto err_power_off;
	}
	}

	ret = iio_triggered_buffer_setup(indio_dev,
	iio_pollfunc_store_time,
	stk8ba50_trigger_handler,
	&stk8ba50_buffer_setup_ops);
	if (ret < 0) {
	dev_err(&client->dev, "iio triggered buffer setup failed\n");
	goto err_trigger_unregister;
	}

	ret = iio_device_register(indio_dev);
	if (ret < 0) {
	dev_err(&client->dev, "device_register failed\n");
	goto err_buffer_cleanup;
	}

	return ret;

	err_buffer_cleanup:
	iio_triggered_buffer_cleanup(indio_dev);
	err_trigger_unregister:
	if (data->dready_trig)
	iio_trigger_unregister(data->dready_trig);
	err_power_off:
	stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
	return ret;
	}

	static void stk8ba50_remove(struct i2c_client *client)
	{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct stk8ba50_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);

	if (data->dready_trig)
	iio_trigger_unregister(data->dready_trig);

	stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
	}

	static int stk8ba50_suspend(struct device *dev)
	{
	struct stk8ba50_data *data;

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

	return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
	}

	static int stk8ba50_resume(struct device *dev)
	{
	struct stk8ba50_data *data;

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

	return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
	}

	static DEFINE_SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend,
	stk8ba50_resume);

	static const struct i2c_device_id stk8ba50_i2c_id[] = {
	{ "stk8ba50" },
	{}
	};
	MODULE_DEVICE_TABLE(i2c, stk8ba50_i2c_id);

	static const struct acpi_device_id stk8ba50_acpi_id[] = {
	{"STK8BA50", 0},
	{}
	};

	MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);

	static struct i2c_driver stk8ba50_driver = {
	.driver = {
	.name = "stk8ba50",
	.pm = pm_sleep_ptr(&stk8ba50_pm_ops),
	.acpi_match_table = stk8ba50_acpi_id,
	},
	.probe = stk8ba50_probe,
	.remove = stk8ba50_remove,
	.id_table = stk8ba50_i2c_id,
	};

	module_i2c_driver(stk8ba50_driver);

	MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
	MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
	MODULE_LICENSE("GPL v2");