/*
   * bma180.c - IIO driver for Bosch BMA180 triaxial acceleration sensor
   *
   * Copyright 2013 Oleksandr Kravchenko <x0199363@ti.com>
   *
   * 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.
   */
  
  #include <linux/module.h>
  #include <linux/i2c.h>
  #include <linux/interrupt.h>
  #include <linux/delay.h>
  #include <linux/of.h>
  #include <linux/bitops.h>
  #include <linux/slab.h>
  #include <linux/string.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>
  
  #define BMA180_DRV_NAME "bma180"
  #define BMA180_IRQ_NAME "bma180_event"
  
  /* Register set */
  #define BMA180_CHIP_ID		0x00 /* Need to distinguish BMA180 from other */
  #define BMA180_ACC_X_LSB	0x02 /* First of 6 registers of accel data */
  #define BMA180_CTRL_REG0	0x0d
  #define BMA180_RESET		0x10
  #define BMA180_BW_TCS		0x20
  #define BMA180_CTRL_REG3	0x21
  #define BMA180_TCO_Z		0x30
  #define BMA180_OFFSET_LSB1	0x35
  
  /* BMA180_CTRL_REG0 bits */
  #define BMA180_DIS_WAKE_UP	BIT(0) /* Disable wake up mode */
  #define BMA180_SLEEP		BIT(1) /* 1 - chip will sleep */
  #define BMA180_EE_W		BIT(4) /* Unlock writing to addr from 0x20 */
  #define BMA180_RESET_INT	BIT(6) /* Reset pending interrupts */
  
  /* BMA180_CTRL_REG3 bits */
  #define BMA180_NEW_DATA_INT	BIT(1) /* Intr every new accel data is ready */
  
  /* BMA180_OFFSET_LSB1 skipping mode bit */
  #define BMA180_SMP_SKIP		BIT(0)
  
  /* Bit masks for registers bit fields */
  #define BMA180_RANGE		0x0e /* Range of measured accel values*/
  #define BMA180_BW		0xf0 /* Accel bandwidth */
  #define BMA180_MODE_CONFIG	0x03 /* Config operation modes */
  
  /* We have to write this value in reset register to do soft reset */
  #define BMA180_RESET_VAL	0xb6
  
  #define BMA_180_ID_REG_VAL	0x03
  
  /* Chip power modes */
  #define BMA180_LOW_NOISE	0x00
  #define BMA180_LOW_POWER	0x03
  
  #define BMA180_LOW_NOISE_STR	"low_noise"
  #define BMA180_LOW_POWER_STR	"low_power"
  
  /* Defaults values */
  #define BMA180_DEF_PMODE	0
  #define BMA180_DEF_BW		20
  #define BMA180_DEF_SCALE	2452
  
  /* Available values for sysfs */
  #define BMA180_FLP_FREQ_AVAILABLE \
  	"10 20 40 75 150 300"
  #define BMA180_SCALE_AVAILABLE \
  	"0.001275 0.001863 0.002452 0.003727 0.004903 0.009709 0.019417"
  
  struct bma180_data {
  	struct i2c_client *client;
  	struct iio_trigger *trig;
  	struct mutex mutex;
  	int sleep_state;
  	int scale;
  	int bw;
  	int pmode;
  	char *buff;
  };
  
  enum bma180_axis {
  	AXIS_X,
  	AXIS_Y,
  	AXIS_Z,
  };
  
  static int bw_table[] = { 10, 20, 40, 75, 150, 300 }; /* Hz */
  static int scale_table[] = { 1275, 1863, 2452, 3727, 4903, 9709, 19417 };
  
  static int bma180_get_acc_reg(struct bma180_data *data, enum bma180_axis axis)
  {
  	u8 reg = BMA180_ACC_X_LSB + axis * 2;
  	int ret;
  
  	if (data->sleep_state)
  		return -EBUSY;
  
  	ret = i2c_smbus_read_word_data(data->client, reg);
  	if (ret < 0)
  		dev_err(&data->client->dev,
  			"failed to read accel_%c registers
  ", 'x' + axis);
  
  	return ret;
  }
  
  static int bma180_set_bits(struct bma180_data *data, u8 reg, u8 mask, u8 val)
  {
  	int ret = i2c_smbus_read_byte_data(data->client, reg);
  	u8 reg_val = (ret & ~mask) | (val << (ffs(mask) - 1));
  
  	if (ret < 0)
  		return ret;
  
  	return i2c_smbus_write_byte_data(data->client, reg, reg_val);
  }
  
  static int bma180_reset_intr(struct bma180_data *data)
  {
  	int ret = bma180_set_bits(data, BMA180_CTRL_REG0, BMA180_RESET_INT, 1);
  
  	if (ret)
  		dev_err(&data->client->dev, "failed to reset interrupt
  ");
  
  	return ret;
  }
  
  static int bma180_set_new_data_intr_state(struct bma180_data *data, int state)
  {
  	u8 reg_val = state ? BMA180_NEW_DATA_INT : 0x00;
  	int ret = i2c_smbus_write_byte_data(data->client, BMA180_CTRL_REG3,
  			reg_val);
  
  	if (ret)
  		goto err;
  	ret = bma180_reset_intr(data);
  	if (ret)
  		goto err;
  
  	return 0;
  
  err:
  	dev_err(&data->client->dev,
  		"failed to set new data interrupt state %d
  ", state);
  	return ret;
  }
  
  static int bma180_set_sleep_state(struct bma180_data *data, int state)
  {
  	int ret = bma180_set_bits(data, BMA180_CTRL_REG0, BMA180_SLEEP, state);
  
  	if (ret) {
  		dev_err(&data->client->dev,
  			"failed to set sleep state %d
  ", state);
  		return ret;
  	}
  	data->sleep_state = state;
  
  	return 0;
  }
  
  static int bma180_set_ee_writing_state(struct bma180_data *data, int state)
  {
  	int ret = bma180_set_bits(data, BMA180_CTRL_REG0, BMA180_EE_W, state);
  
  	if (ret)
  		dev_err(&data->client->dev,
  			"failed to set ee writing state %d
  ", state);
  
  	return ret;
  }
  
  static int bma180_set_bw(struct bma180_data *data, int val)
  {
  	int ret, i;
  
  	if (data->sleep_state)
  		return -EBUSY;
  
  	for (i = 0; i < ARRAY_SIZE(bw_table); ++i) {
  		if (bw_table[i] == val) {
  			ret = bma180_set_bits(data,
  					BMA180_BW_TCS, BMA180_BW, i);
  			if (ret) {
  				dev_err(&data->client->dev,
  					"failed to set bandwidth
  ");
  				return ret;
  			}
  			data->bw = val;
  			return 0;
  		}
  	}
  
  	return -EINVAL;
  }
  
  static int bma180_set_scale(struct bma180_data *data, int val)
  {
  	int ret, i;
  
  	if (data->sleep_state)
  		return -EBUSY;
  
  	for (i = 0; i < ARRAY_SIZE(scale_table); ++i)
  		if (scale_table[i] == val) {
  			ret = bma180_set_bits(data,
  					BMA180_OFFSET_LSB1, BMA180_RANGE, i);
  			if (ret) {
  				dev_err(&data->client->dev,
  					"failed to set scale
  ");
  				return ret;
  			}
  			data->scale = val;
  			return 0;
  		}
  
  	return -EINVAL;
  }
  
  static int bma180_set_pmode(struct bma180_data *data, int mode)
  {
  	u8 reg_val = mode ? BMA180_LOW_POWER : BMA180_LOW_NOISE;
  	int ret = bma180_set_bits(data, BMA180_TCO_Z, BMA180_MODE_CONFIG,
  			reg_val);
  
  	if (ret) {
  		dev_err(&data->client->dev, "failed to set power mode
  ");
  		return ret;
  	}
  	data->pmode = mode;
  
  	return 0;
  }
  
  static int bma180_soft_reset(struct bma180_data *data)
  {
  	int ret = i2c_smbus_write_byte_data(data->client,
  			BMA180_RESET, BMA180_RESET_VAL);
  
  	if (ret)
  		dev_err(&data->client->dev, "failed to reset the chip
  ");
  
  	return ret;
  }
  
  static int bma180_chip_init(struct bma180_data *data)
  {
  	/* Try to read chip_id register. It must return 0x03. */
  	int ret = i2c_smbus_read_byte_data(data->client, BMA180_CHIP_ID);
  
  	if (ret < 0)
  		goto err;
  	if (ret != BMA_180_ID_REG_VAL) {
  		ret = -ENODEV;
  		goto err;
  	}
  
  	ret = bma180_soft_reset(data);
  	if (ret)
  		goto err;
  	/*
  	 * No serial transaction should occur within minimum 10 us
  	 * after soft_reset command
  	 */
  	msleep(20);
  
  	ret = bma180_set_bits(data, BMA180_CTRL_REG0, BMA180_DIS_WAKE_UP, 1);
  	if (ret)
  		goto err;
  	ret = bma180_set_ee_writing_state(data, 1);
  	if (ret)
  		goto err;
  	ret = bma180_set_new_data_intr_state(data, 0);
  	if (ret)
  		goto err;
  	ret = bma180_set_bits(data, BMA180_OFFSET_LSB1, BMA180_SMP_SKIP, 1);
  	if (ret)
  		goto err;
  	ret = bma180_set_pmode(data, BMA180_DEF_PMODE);
  	if (ret)
  		goto err;
  	ret = bma180_set_bw(data, BMA180_DEF_BW);
  	if (ret)
  		goto err;
  	ret = bma180_set_scale(data, BMA180_DEF_SCALE);
  	if (ret)
  		goto err;
  
  	return 0;
  
  err:
  	dev_err(&data->client->dev, "failed to init the chip
  ");
  	return ret;
  }
  
  static void bma180_chip_disable(struct bma180_data *data)
  {
  	if (bma180_set_new_data_intr_state(data, 0))
  		goto err;
  	if (bma180_set_ee_writing_state(data, 0))
  		goto err;
  	if (bma180_set_sleep_state(data, 1))
  		goto err;
  
  	return;
  
  err:
  	dev_err(&data->client->dev, "failed to disable the chip
  ");
  }
  
  static IIO_CONST_ATTR(in_accel_filter_low_pass_3db_frequency_available,
  		BMA180_FLP_FREQ_AVAILABLE);
  static IIO_CONST_ATTR(in_accel_scale_available, BMA180_SCALE_AVAILABLE);
  
  static struct attribute *bma180_attributes[] = {
  	&iio_const_attr_in_accel_filter_low_pass_3db_frequency_available.dev_attr.attr,
  	&iio_const_attr_in_accel_scale_available.dev_attr.attr,
  	NULL,
  };
  
  static const struct attribute_group bma180_attrs_group = {
  	.attrs = bma180_attributes,
  };
  
  static int bma180_read_raw(struct iio_dev *indio_dev,
  		struct iio_chan_spec const *chan, int *val, int *val2,
  		long mask)
  {
  	struct bma180_data *data = iio_priv(indio_dev);
  	int ret;
  
  	switch (mask) {
  	case IIO_CHAN_INFO_RAW:
  		mutex_lock(&data->mutex);
  		if (iio_buffer_enabled(indio_dev))
  			ret = -EBUSY;
  		else
  			ret = bma180_get_acc_reg(data, chan->scan_index);
  		mutex_unlock(&data->mutex);
  		if (ret < 0)
  			return ret;
  		*val = (s16)ret >> chan->scan_type.shift;
  		return IIO_VAL_INT;
  	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
  		*val = data->bw;
  		return IIO_VAL_INT;
  	case IIO_CHAN_INFO_SCALE:
  		*val = 0;
  		*val2 = data->scale;
  		return IIO_VAL_INT_PLUS_MICRO;
  	default:
  		return -EINVAL;
  	}
  }
  
  static int bma180_write_raw(struct iio_dev *indio_dev,
  		struct iio_chan_spec const *chan, int val, int val2, long mask)
  {
  	struct bma180_data *data = iio_priv(indio_dev);
  	int ret;
  
  	switch (mask) {
  	case IIO_CHAN_INFO_SCALE:
  		if (val)
  			return -EINVAL;
  		mutex_lock(&data->mutex);
  		ret = bma180_set_scale(data, val2);
  		mutex_unlock(&data->mutex);
  		return ret;
  	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
  		if (val2)
  			return -EINVAL;
  		mutex_lock(&data->mutex);
  		ret = bma180_set_bw(data, val);
  		mutex_unlock(&data->mutex);
  		return ret;
  	default:
  		return -EINVAL;
  	}
  }
  
  static int bma180_update_scan_mode(struct iio_dev *indio_dev,
  		const unsigned long *scan_mask)
  {
  	struct bma180_data *data = iio_priv(indio_dev);
  
  	if (data->buff)
  		devm_kfree(&indio_dev->dev, data->buff);
  	data->buff = devm_kzalloc(&indio_dev->dev,
  			indio_dev->scan_bytes, GFP_KERNEL);
  	if (!data->buff)
  		return -ENOMEM;
  
  	return 0;
  }
  
  static const struct iio_info bma180_info = {
  	.attrs			= &bma180_attrs_group,
  	.read_raw		= bma180_read_raw,
  	.write_raw		= bma180_write_raw,
  	.update_scan_mode	= bma180_update_scan_mode,
  	.driver_module		= THIS_MODULE,
  };
  
  static const char * const bma180_power_modes[] = {
  	BMA180_LOW_NOISE_STR,
  	BMA180_LOW_POWER_STR,
  };
  
  static int bma180_get_power_mode(struct iio_dev *indio_dev,
  		const struct iio_chan_spec *chan)
  {
  	struct bma180_data *data = iio_priv(indio_dev);
  
  	return data->pmode;
  }
  
  static int bma180_set_power_mode(struct iio_dev *indio_dev,
  		const struct iio_chan_spec *chan, unsigned int mode)
  {
  	struct bma180_data *data = iio_priv(indio_dev);
  	int ret;
  
  	mutex_lock(&data->mutex);
  	ret = bma180_set_pmode(data, mode);
  	mutex_unlock(&data->mutex);
  
  	return ret;
  }
  
  static const struct iio_enum bma180_power_mode_enum = {
  	.items = bma180_power_modes,
  	.num_items = ARRAY_SIZE(bma180_power_modes),
  	.get = bma180_get_power_mode,
  	.set = bma180_set_power_mode,
  };
  
  static const struct iio_chan_spec_ext_info bma180_ext_info[] = {
  	IIO_ENUM("power_mode", true, &bma180_power_mode_enum),
  	IIO_ENUM_AVAILABLE("power_mode", &bma180_power_mode_enum),
  	{ },
  };
  
  #define BMA180_CHANNEL(_axis) {					\
  	.type = IIO_ACCEL,						\
  	.modified = 1,							\
  	.channel2 = IIO_MOD_##_axis,					\
  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |			\
  		BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),	\
  	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),		\
  	.scan_index = AXIS_##_axis,					\
  	.scan_type = {							\
  		.sign = 's',						\
  		.realbits = 14,						\
  		.storagebits = 16,					\
  		.shift = 2,						\
  	},								\
  	.ext_info = bma180_ext_info,					\
  }
  
  static const struct iio_chan_spec bma180_channels[] = {
  	BMA180_CHANNEL(X),
  	BMA180_CHANNEL(Y),
  	BMA180_CHANNEL(Z),
  	IIO_CHAN_SOFT_TIMESTAMP(3),
  };
  
  static irqreturn_t bma180_trigger_handler(int irq, void *p)
  {
  	struct iio_poll_func *pf = p;
  	struct iio_dev *indio_dev = pf->indio_dev;
  	struct bma180_data *data = iio_priv(indio_dev);
  	int64_t time_ns = iio_get_time_ns();
  	int bit, ret, i = 0;
  
  	mutex_lock(&data->mutex);
  
  	for_each_set_bit(bit, indio_dev->buffer->scan_mask,
  			 indio_dev->masklength) {
  		ret = bma180_get_acc_reg(data, bit);
  		if (ret < 0) {
  			mutex_unlock(&data->mutex);
  			goto err;
  		}
  		((s16 *)data->buff)[i++] = ret;
  	}
  	mutex_unlock(&data->mutex);
  
  	iio_push_to_buffers_with_timestamp(indio_dev, data->buff, time_ns);
  err:
  	iio_trigger_notify_done(indio_dev->trig);
  
  	return IRQ_HANDLED;
  }
  
  static int bma180_data_rdy_trigger_set_state(struct iio_trigger *trig,
  		bool state)
  {
  	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
  	struct bma180_data *data = iio_priv(indio_dev);
  
  	return bma180_set_new_data_intr_state(data, state);
  }
  
  static int bma180_trig_try_reen(struct iio_trigger *trig)
  {
  	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
  	struct bma180_data *data = iio_priv(indio_dev);
  
  	return bma180_reset_intr(data);
  }
  
  static const struct iio_trigger_ops bma180_trigger_ops = {
  	.set_trigger_state = bma180_data_rdy_trigger_set_state,
  	.try_reenable = bma180_trig_try_reen,
  	.owner = THIS_MODULE,
  };
  
  static int bma180_probe(struct i2c_client *client,
  		const struct i2c_device_id *id)
  {
  	struct bma180_data *data;
  	struct iio_dev *indio_dev;
  	struct iio_trigger *trig;
  	int ret;
  
  	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
  	if (!indio_dev)
  		return -ENOMEM;
  
  	data = iio_priv(indio_dev);
  	i2c_set_clientdata(client, indio_dev);
  	data->client = client;
  
  	ret = bma180_chip_init(data);
  	if (ret < 0)
  		goto err_chip_disable;
  
  	mutex_init(&data->mutex);
  
  	indio_dev->dev.parent = &client->dev;
  	indio_dev->channels = bma180_channels;
  	indio_dev->num_channels = ARRAY_SIZE(bma180_channels);
  	indio_dev->name = BMA180_DRV_NAME;
  	indio_dev->modes = INDIO_DIRECT_MODE;
  	indio_dev->info = &bma180_info;
  
  	trig = iio_trigger_alloc("%s-dev%d", indio_dev->name, indio_dev->id);
  	if (!trig) {
  		ret = -ENOMEM;
  		goto err_chip_disable;
  	}
  
  	ret = devm_request_irq(&client->dev, client->irq,
  			iio_trigger_generic_data_rdy_poll,
  			IRQF_TRIGGER_RISING, BMA180_IRQ_NAME, trig);
  	if (ret) {
  		dev_err(&client->dev, "unable to request IRQ
  ");
  		goto err_trigger_free;
  	}
  
  	trig->dev.parent = &client->dev;
  	trig->ops = &bma180_trigger_ops;
  	iio_trigger_set_drvdata(trig, indio_dev);
  	data->trig = trig;
  	indio_dev->trig = iio_trigger_get(trig);
  
  	ret = iio_trigger_register(trig);
  	if (ret)
  		goto err_trigger_free;
  
  	ret = iio_triggered_buffer_setup(indio_dev, NULL,
  			bma180_trigger_handler, NULL);
  	if (ret < 0) {
  		dev_err(&client->dev, "unable to setup iio triggered buffer
  ");
  		goto err_trigger_unregister;
  	}
  
  	ret = iio_device_register(indio_dev);
  	if (ret < 0) {
  		dev_err(&client->dev, "unable to register iio device
  ");
  		goto err_buffer_cleanup;
  	}
  
  	return 0;
  
  err_buffer_cleanup:
  	iio_triggered_buffer_cleanup(indio_dev);
  err_trigger_unregister:
  	iio_trigger_unregister(trig);
  err_trigger_free:
  	iio_trigger_free(trig);
  err_chip_disable:
  	bma180_chip_disable(data);
  
  	return ret;
  }
  
  static int bma180_remove(struct i2c_client *client)
  {
  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
  	struct bma180_data *data = iio_priv(indio_dev);
  
  	iio_device_unregister(indio_dev);
  	iio_triggered_buffer_cleanup(indio_dev);
  	iio_trigger_unregister(data->trig);
  	iio_trigger_free(data->trig);
  
  	mutex_lock(&data->mutex);
  	bma180_chip_disable(data);
  	mutex_unlock(&data->mutex);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int bma180_suspend(struct device *dev)
  {
  	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
  	struct bma180_data *data = iio_priv(indio_dev);
  	int ret;
  
  	mutex_lock(&data->mutex);
  	ret = bma180_set_sleep_state(data, 1);
  	mutex_unlock(&data->mutex);
  
  	return ret;
  }
  
  static int bma180_resume(struct device *dev)
  {
  	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
  	struct bma180_data *data = iio_priv(indio_dev);
  	int ret;
  
  	mutex_lock(&data->mutex);
  	ret = bma180_set_sleep_state(data, 0);
  	mutex_unlock(&data->mutex);
  
  	return ret;
  }
  
  static SIMPLE_DEV_PM_OPS(bma180_pm_ops, bma180_suspend, bma180_resume);
  #define BMA180_PM_OPS (&bma180_pm_ops)
  #else
  #define BMA180_PM_OPS NULL
  #endif
  
  static struct i2c_device_id bma180_id[] = {
  	{ BMA180_DRV_NAME, 0 },
  	{ }
  };
  
  MODULE_DEVICE_TABLE(i2c, bma180_id);
  
  static struct i2c_driver bma180_driver = {
  	.driver = {
  		.name	= BMA180_DRV_NAME,
  		.owner	= THIS_MODULE,
  		.pm	= BMA180_PM_OPS,
  	},
  	.probe		= bma180_probe,
  	.remove		= bma180_remove,
  	.id_table	= bma180_id,
  };
  
  module_i2c_driver(bma180_driver);
  
  MODULE_AUTHOR("Kravchenko Oleksandr <x0199363@ti.com>");
  MODULE_AUTHOR("Texas Instruments, Inc.");
  MODULE_DESCRIPTION("Bosch BMA180 triaxial acceleration sensor");
  MODULE_LICENSE("GPL");