/*
   * ADIS16480 and similar IMUs driver
   *
   * Copyright 2012 Analog Devices Inc.
   *
   * 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.
   *
   */
  
  #include <linux/interrupt.h>
  #include <linux/delay.h>
  #include <linux/mutex.h>
  #include <linux/device.h>
  #include <linux/kernel.h>
  #include <linux/spi/spi.h>
  #include <linux/slab.h>
  #include <linux/sysfs.h>
  #include <linux/module.h>
  
  #include <linux/iio/iio.h>
  #include <linux/iio/sysfs.h>
  #include <linux/iio/buffer.h>
  #include <linux/iio/imu/adis.h>
  
  #include <linux/debugfs.h>
  
  #define ADIS16480_PAGE_SIZE 0x80
  
  #define ADIS16480_REG(page, reg) ((page) * ADIS16480_PAGE_SIZE + (reg))
  
  #define ADIS16480_REG_PAGE_ID 0x00 /* Same address on each page */
  #define ADIS16480_REG_SEQ_CNT			ADIS16480_REG(0x00, 0x06)
  #define ADIS16480_REG_SYS_E_FLA			ADIS16480_REG(0x00, 0x08)
  #define ADIS16480_REG_DIAG_STS			ADIS16480_REG(0x00, 0x0A)
  #define ADIS16480_REG_ALM_STS			ADIS16480_REG(0x00, 0x0C)
  #define ADIS16480_REG_TEMP_OUT			ADIS16480_REG(0x00, 0x0E)
  #define ADIS16480_REG_X_GYRO_OUT		ADIS16480_REG(0x00, 0x10)
  #define ADIS16480_REG_Y_GYRO_OUT		ADIS16480_REG(0x00, 0x14)
  #define ADIS16480_REG_Z_GYRO_OUT		ADIS16480_REG(0x00, 0x18)
  #define ADIS16480_REG_X_ACCEL_OUT		ADIS16480_REG(0x00, 0x1C)
  #define ADIS16480_REG_Y_ACCEL_OUT		ADIS16480_REG(0x00, 0x20)
  #define ADIS16480_REG_Z_ACCEL_OUT		ADIS16480_REG(0x00, 0x24)
  #define ADIS16480_REG_X_MAGN_OUT		ADIS16480_REG(0x00, 0x28)
  #define ADIS16480_REG_Y_MAGN_OUT		ADIS16480_REG(0x00, 0x2A)
  #define ADIS16480_REG_Z_MAGN_OUT		ADIS16480_REG(0x00, 0x2C)
  #define ADIS16480_REG_BAROM_OUT			ADIS16480_REG(0x00, 0x2E)
  #define ADIS16480_REG_X_DELTAANG_OUT		ADIS16480_REG(0x00, 0x40)
  #define ADIS16480_REG_Y_DELTAANG_OUT		ADIS16480_REG(0x00, 0x44)
  #define ADIS16480_REG_Z_DELTAANG_OUT		ADIS16480_REG(0x00, 0x48)
  #define ADIS16480_REG_X_DELTAVEL_OUT		ADIS16480_REG(0x00, 0x4C)
  #define ADIS16480_REG_Y_DELTAVEL_OUT		ADIS16480_REG(0x00, 0x50)
  #define ADIS16480_REG_Z_DELTAVEL_OUT		ADIS16480_REG(0x00, 0x54)
  #define ADIS16480_REG_PROD_ID			ADIS16480_REG(0x00, 0x7E)
  
  #define ADIS16480_REG_X_GYRO_SCALE		ADIS16480_REG(0x02, 0x04)
  #define ADIS16480_REG_Y_GYRO_SCALE		ADIS16480_REG(0x02, 0x06)
  #define ADIS16480_REG_Z_GYRO_SCALE		ADIS16480_REG(0x02, 0x08)
  #define ADIS16480_REG_X_ACCEL_SCALE		ADIS16480_REG(0x02, 0x0A)
  #define ADIS16480_REG_Y_ACCEL_SCALE		ADIS16480_REG(0x02, 0x0C)
  #define ADIS16480_REG_Z_ACCEL_SCALE		ADIS16480_REG(0x02, 0x0E)
  #define ADIS16480_REG_X_GYRO_BIAS		ADIS16480_REG(0x02, 0x10)
  #define ADIS16480_REG_Y_GYRO_BIAS		ADIS16480_REG(0x02, 0x14)
  #define ADIS16480_REG_Z_GYRO_BIAS		ADIS16480_REG(0x02, 0x18)
  #define ADIS16480_REG_X_ACCEL_BIAS		ADIS16480_REG(0x02, 0x1C)
  #define ADIS16480_REG_Y_ACCEL_BIAS		ADIS16480_REG(0x02, 0x20)
  #define ADIS16480_REG_Z_ACCEL_BIAS		ADIS16480_REG(0x02, 0x24)
  #define ADIS16480_REG_X_HARD_IRON		ADIS16480_REG(0x02, 0x28)
  #define ADIS16480_REG_Y_HARD_IRON		ADIS16480_REG(0x02, 0x2A)
  #define ADIS16480_REG_Z_HARD_IRON		ADIS16480_REG(0x02, 0x2C)
  #define ADIS16480_REG_BAROM_BIAS		ADIS16480_REG(0x02, 0x40)
  #define ADIS16480_REG_FLASH_CNT			ADIS16480_REG(0x02, 0x7C)
  
  #define ADIS16480_REG_GLOB_CMD			ADIS16480_REG(0x03, 0x02)
  #define ADIS16480_REG_FNCTIO_CTRL		ADIS16480_REG(0x03, 0x06)
  #define ADIS16480_REG_GPIO_CTRL			ADIS16480_REG(0x03, 0x08)
  #define ADIS16480_REG_CONFIG			ADIS16480_REG(0x03, 0x0A)
  #define ADIS16480_REG_DEC_RATE			ADIS16480_REG(0x03, 0x0C)
  #define ADIS16480_REG_SLP_CNT			ADIS16480_REG(0x03, 0x10)
  #define ADIS16480_REG_FILTER_BNK0		ADIS16480_REG(0x03, 0x16)
  #define ADIS16480_REG_FILTER_BNK1		ADIS16480_REG(0x03, 0x18)
  #define ADIS16480_REG_ALM_CNFG0			ADIS16480_REG(0x03, 0x20)
  #define ADIS16480_REG_ALM_CNFG1			ADIS16480_REG(0x03, 0x22)
  #define ADIS16480_REG_ALM_CNFG2			ADIS16480_REG(0x03, 0x24)
  #define ADIS16480_REG_XG_ALM_MAGN		ADIS16480_REG(0x03, 0x28)
  #define ADIS16480_REG_YG_ALM_MAGN		ADIS16480_REG(0x03, 0x2A)
  #define ADIS16480_REG_ZG_ALM_MAGN		ADIS16480_REG(0x03, 0x2C)
  #define ADIS16480_REG_XA_ALM_MAGN		ADIS16480_REG(0x03, 0x2E)
  #define ADIS16480_REG_YA_ALM_MAGN		ADIS16480_REG(0x03, 0x30)
  #define ADIS16480_REG_ZA_ALM_MAGN		ADIS16480_REG(0x03, 0x32)
  #define ADIS16480_REG_XM_ALM_MAGN		ADIS16480_REG(0x03, 0x34)
  #define ADIS16480_REG_YM_ALM_MAGN		ADIS16480_REG(0x03, 0x36)
  #define ADIS16480_REG_ZM_ALM_MAGN		ADIS16480_REG(0x03, 0x38)
  #define ADIS16480_REG_BR_ALM_MAGN		ADIS16480_REG(0x03, 0x3A)
  #define ADIS16480_REG_FIRM_REV			ADIS16480_REG(0x03, 0x78)
  #define ADIS16480_REG_FIRM_DM			ADIS16480_REG(0x03, 0x7A)
  #define ADIS16480_REG_FIRM_Y			ADIS16480_REG(0x03, 0x7C)
  
  #define ADIS16480_REG_SERIAL_NUM		ADIS16480_REG(0x04, 0x20)
  
  /* Each filter coefficent bank spans two pages */
  #define ADIS16480_FIR_COEF(page) (x < 60 ? ADIS16480_REG(page, (x) + 8) : \
  		ADIS16480_REG((page) + 1, (x) - 60 + 8))
  #define ADIS16480_FIR_COEF_A(x)			ADIS16480_FIR_COEF(0x05, (x))
  #define ADIS16480_FIR_COEF_B(x)			ADIS16480_FIR_COEF(0x07, (x))
  #define ADIS16480_FIR_COEF_C(x)			ADIS16480_FIR_COEF(0x09, (x))
  #define ADIS16480_FIR_COEF_D(x)			ADIS16480_FIR_COEF(0x0B, (x))
  
  struct adis16480_chip_info {
  	unsigned int num_channels;
  	const struct iio_chan_spec *channels;
  	unsigned int gyro_max_val;
  	unsigned int gyro_max_scale;
  	unsigned int accel_max_val;
  	unsigned int accel_max_scale;
  };
  
  struct adis16480 {
  	const struct adis16480_chip_info *chip_info;
  
  	struct adis adis;
  };
  
  #ifdef CONFIG_DEBUG_FS
  
  static ssize_t adis16480_show_firmware_revision(struct file *file,
  		char __user *userbuf, size_t count, loff_t *ppos)
  {
  	struct adis16480 *adis16480 = file->private_data;
  	char buf[7];
  	size_t len;
  	u16 rev;
  	int ret;
  
  	ret = adis_read_reg_16(&adis16480->adis, ADIS16480_REG_FIRM_REV, &rev);
  	if (ret < 0)
  		return ret;
  
  	len = scnprintf(buf, sizeof(buf), "%x.%x
  ", rev >> 8, rev & 0xff);
  
  	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
  }
  
  static const struct file_operations adis16480_firmware_revision_fops = {
  	.open = simple_open,
  	.read = adis16480_show_firmware_revision,
  	.llseek = default_llseek,
  	.owner = THIS_MODULE,
  };
  
  static ssize_t adis16480_show_firmware_date(struct file *file,
  		char __user *userbuf, size_t count, loff_t *ppos)
  {
  	struct adis16480 *adis16480 = file->private_data;
  	u16 md, year;
  	char buf[12];
  	size_t len;
  	int ret;
  
  	ret = adis_read_reg_16(&adis16480->adis, ADIS16480_REG_FIRM_Y, &year);
  	if (ret < 0)
  		return ret;
  
  	ret = adis_read_reg_16(&adis16480->adis, ADIS16480_REG_FIRM_DM, &md);
  	if (ret < 0)
  		return ret;
  
  	len = snprintf(buf, sizeof(buf), "%.2x-%.2x-%.4x
  ",
  			md >> 8, md & 0xff, year);
  
  	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
  }
  
  static const struct file_operations adis16480_firmware_date_fops = {
  	.open = simple_open,
  	.read = adis16480_show_firmware_date,
  	.llseek = default_llseek,
  	.owner = THIS_MODULE,
  };
  
  static int adis16480_show_serial_number(void *arg, u64 *val)
  {
  	struct adis16480 *adis16480 = arg;
  	u16 serial;
  	int ret;
  
  	ret = adis_read_reg_16(&adis16480->adis, ADIS16480_REG_SERIAL_NUM,
  		&serial);
  	if (ret < 0)
  		return ret;
  
  	*val = serial;
  
  	return 0;
  }
  DEFINE_SIMPLE_ATTRIBUTE(adis16480_serial_number_fops,
  	adis16480_show_serial_number, NULL, "0x%.4llx
  ");
  
  static int adis16480_show_product_id(void *arg, u64 *val)
  {
  	struct adis16480 *adis16480 = arg;
  	u16 prod_id;
  	int ret;
  
  	ret = adis_read_reg_16(&adis16480->adis, ADIS16480_REG_PROD_ID,
  		&prod_id);
  	if (ret < 0)
  		return ret;
  
  	*val = prod_id;
  
  	return 0;
  }
  DEFINE_SIMPLE_ATTRIBUTE(adis16480_product_id_fops,
  	adis16480_show_product_id, NULL, "%llu
  ");
  
  static int adis16480_show_flash_count(void *arg, u64 *val)
  {
  	struct adis16480 *adis16480 = arg;
  	u32 flash_count;
  	int ret;
  
  	ret = adis_read_reg_32(&adis16480->adis, ADIS16480_REG_FLASH_CNT,
  		&flash_count);
  	if (ret < 0)
  		return ret;
  
  	*val = flash_count;
  
  	return 0;
  }
  DEFINE_SIMPLE_ATTRIBUTE(adis16480_flash_count_fops,
  	adis16480_show_flash_count, NULL, "%lld
  ");
  
  static int adis16480_debugfs_init(struct iio_dev *indio_dev)
  {
  	struct adis16480 *adis16480 = iio_priv(indio_dev);
  
  	debugfs_create_file("firmware_revision", 0400,
  		indio_dev->debugfs_dentry, adis16480,
  		&adis16480_firmware_revision_fops);
  	debugfs_create_file("firmware_date", 0400, indio_dev->debugfs_dentry,
  		adis16480, &adis16480_firmware_date_fops);
  	debugfs_create_file("serial_number", 0400, indio_dev->debugfs_dentry,
  		adis16480, &adis16480_serial_number_fops);
  	debugfs_create_file("product_id", 0400, indio_dev->debugfs_dentry,
  		adis16480, &adis16480_product_id_fops);
  	debugfs_create_file("flash_count", 0400, indio_dev->debugfs_dentry,
  		adis16480, &adis16480_flash_count_fops);
  
  	return 0;
  }
  
  #else
  
  static int adis16480_debugfs_init(struct iio_dev *indio_dev)
  {
  	return 0;
  }
  
  #endif
  
  static int adis16480_set_freq(struct iio_dev *indio_dev, int val, int val2)
  {
  	struct adis16480 *st = iio_priv(indio_dev);
  	unsigned int t;
  
  	t =  val * 1000 + val2 / 1000;
  	if (t <= 0)
  		return -EINVAL;
  
  	t = 2460000 / t;
  	if (t > 2048)
  		t = 2048;
  
  	if (t != 0)
  		t--;
  
  	return adis_write_reg_16(&st->adis, ADIS16480_REG_DEC_RATE, t);
  }
  
  static int adis16480_get_freq(struct iio_dev *indio_dev, int *val, int *val2)
  {
  	struct adis16480 *st = iio_priv(indio_dev);
  	uint16_t t;
  	int ret;
  	unsigned freq;
  
  	ret = adis_read_reg_16(&st->adis, ADIS16480_REG_DEC_RATE, &t);
  	if (ret < 0)
  		return ret;
  
  	freq = 2460000 / (t + 1);
  	*val = freq / 1000;
  	*val2 = (freq % 1000) * 1000;
  
  	return IIO_VAL_INT_PLUS_MICRO;
  }
  
  enum {
  	ADIS16480_SCAN_GYRO_X,
  	ADIS16480_SCAN_GYRO_Y,
  	ADIS16480_SCAN_GYRO_Z,
  	ADIS16480_SCAN_ACCEL_X,
  	ADIS16480_SCAN_ACCEL_Y,
  	ADIS16480_SCAN_ACCEL_Z,
  	ADIS16480_SCAN_MAGN_X,
  	ADIS16480_SCAN_MAGN_Y,
  	ADIS16480_SCAN_MAGN_Z,
  	ADIS16480_SCAN_BARO,
  	ADIS16480_SCAN_TEMP,
  };
  
  static const unsigned int adis16480_calibbias_regs[] = {
  	[ADIS16480_SCAN_GYRO_X] = ADIS16480_REG_X_GYRO_BIAS,
  	[ADIS16480_SCAN_GYRO_Y] = ADIS16480_REG_Y_GYRO_BIAS,
  	[ADIS16480_SCAN_GYRO_Z] = ADIS16480_REG_Z_GYRO_BIAS,
  	[ADIS16480_SCAN_ACCEL_X] = ADIS16480_REG_X_ACCEL_BIAS,
  	[ADIS16480_SCAN_ACCEL_Y] = ADIS16480_REG_Y_ACCEL_BIAS,
  	[ADIS16480_SCAN_ACCEL_Z] = ADIS16480_REG_Z_ACCEL_BIAS,
  	[ADIS16480_SCAN_MAGN_X] = ADIS16480_REG_X_HARD_IRON,
  	[ADIS16480_SCAN_MAGN_Y] = ADIS16480_REG_Y_HARD_IRON,
  	[ADIS16480_SCAN_MAGN_Z] = ADIS16480_REG_Z_HARD_IRON,
  	[ADIS16480_SCAN_BARO] = ADIS16480_REG_BAROM_BIAS,
  };
  
  static const unsigned int adis16480_calibscale_regs[] = {
  	[ADIS16480_SCAN_GYRO_X] = ADIS16480_REG_X_GYRO_SCALE,
  	[ADIS16480_SCAN_GYRO_Y] = ADIS16480_REG_Y_GYRO_SCALE,
  	[ADIS16480_SCAN_GYRO_Z] = ADIS16480_REG_Z_GYRO_SCALE,
  	[ADIS16480_SCAN_ACCEL_X] = ADIS16480_REG_X_ACCEL_SCALE,
  	[ADIS16480_SCAN_ACCEL_Y] = ADIS16480_REG_Y_ACCEL_SCALE,
  	[ADIS16480_SCAN_ACCEL_Z] = ADIS16480_REG_Z_ACCEL_SCALE,
  };
  
  static int adis16480_set_calibbias(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan, int bias)
  {
  	unsigned int reg = adis16480_calibbias_regs[chan->scan_index];
  	struct adis16480 *st = iio_priv(indio_dev);
  
  	switch (chan->type) {
  	case IIO_MAGN:
  	case IIO_PRESSURE:
  		if (bias < -0x8000 || bias >= 0x8000)
  			return -EINVAL;
  		return adis_write_reg_16(&st->adis, reg, bias);
  	case IIO_ANGL_VEL:
  	case IIO_ACCEL:
  		return adis_write_reg_32(&st->adis, reg, bias);
  	default:
  		break;
  	}
  
  	return -EINVAL;
  }
  
  static int adis16480_get_calibbias(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan, int *bias)
  {
  	unsigned int reg = adis16480_calibbias_regs[chan->scan_index];
  	struct adis16480 *st = iio_priv(indio_dev);
  	uint16_t val16;
  	uint32_t val32;
  	int ret;
  
  	switch (chan->type) {
  	case IIO_MAGN:
  	case IIO_PRESSURE:
  		ret = adis_read_reg_16(&st->adis, reg, &val16);
  		*bias = sign_extend32(val16, 15);
  		break;
  	case IIO_ANGL_VEL:
  	case IIO_ACCEL:
  		ret = adis_read_reg_32(&st->adis, reg, &val32);
  		*bias = sign_extend32(val32, 31);
  		break;
  	default:
  			ret = -EINVAL;
  	}
  
  	if (ret < 0)
  		return ret;
  
  	return IIO_VAL_INT;
  }
  
  static int adis16480_set_calibscale(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan, int scale)
  {
  	unsigned int reg = adis16480_calibscale_regs[chan->scan_index];
  	struct adis16480 *st = iio_priv(indio_dev);
  
  	if (scale < -0x8000 || scale >= 0x8000)
  		return -EINVAL;
  
  	return adis_write_reg_16(&st->adis, reg, scale);
  }
  
  static int adis16480_get_calibscale(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan, int *scale)
  {
  	unsigned int reg = adis16480_calibscale_regs[chan->scan_index];
  	struct adis16480 *st = iio_priv(indio_dev);
  	uint16_t val16;
  	int ret;
  
  	ret = adis_read_reg_16(&st->adis, reg, &val16);
  	if (ret < 0)
  		return ret;
  
  	*scale = sign_extend32(val16, 15);
  	return IIO_VAL_INT;
  }
  
  static const unsigned int adis16480_def_filter_freqs[] = {
  	310,
  	55,
  	275,
  	63,
  };
  
  static const unsigned int ad16480_filter_data[][2] = {
  	[ADIS16480_SCAN_GYRO_X]		= { ADIS16480_REG_FILTER_BNK0, 0 },
  	[ADIS16480_SCAN_GYRO_Y]		= { ADIS16480_REG_FILTER_BNK0, 3 },
  	[ADIS16480_SCAN_GYRO_Z]		= { ADIS16480_REG_FILTER_BNK0, 6 },
  	[ADIS16480_SCAN_ACCEL_X]	= { ADIS16480_REG_FILTER_BNK0, 9 },
  	[ADIS16480_SCAN_ACCEL_Y]	= { ADIS16480_REG_FILTER_BNK0, 12 },
  	[ADIS16480_SCAN_ACCEL_Z]	= { ADIS16480_REG_FILTER_BNK1, 0 },
  	[ADIS16480_SCAN_MAGN_X]		= { ADIS16480_REG_FILTER_BNK1, 3 },
  	[ADIS16480_SCAN_MAGN_Y]		= { ADIS16480_REG_FILTER_BNK1, 6 },
  	[ADIS16480_SCAN_MAGN_Z]		= { ADIS16480_REG_FILTER_BNK1, 9 },
  };
  
  static int adis16480_get_filter_freq(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan, int *freq)
  {
  	struct adis16480 *st = iio_priv(indio_dev);
  	unsigned int enable_mask, offset, reg;
  	uint16_t val;
  	int ret;
  
  	reg = ad16480_filter_data[chan->scan_index][0];
  	offset = ad16480_filter_data[chan->scan_index][1];
  	enable_mask = BIT(offset + 2);
  
  	ret = adis_read_reg_16(&st->adis, reg, &val);
  	if (ret < 0)
  		return ret;
  
  	if (!(val & enable_mask))
  		*freq = 0;
  	else
  		*freq = adis16480_def_filter_freqs[(val >> offset) & 0x3];
  
  	return IIO_VAL_INT;
  }
  
  static int adis16480_set_filter_freq(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan, unsigned int freq)
  {
  	struct adis16480 *st = iio_priv(indio_dev);
  	unsigned int enable_mask, offset, reg;
  	unsigned int diff, best_diff;
  	unsigned int i, best_freq;
  	uint16_t val;
  	int ret;
  
  	reg = ad16480_filter_data[chan->scan_index][0];
  	offset = ad16480_filter_data[chan->scan_index][1];
  	enable_mask = BIT(offset + 2);
  
  	ret = adis_read_reg_16(&st->adis, reg, &val);
  	if (ret < 0)
  		return ret;
  
  	if (freq == 0) {
  		val &= ~enable_mask;
  	} else {
  		best_freq = 0;
  		best_diff = 310;
  		for (i = 0; i < ARRAY_SIZE(adis16480_def_filter_freqs); i++) {
  			if (adis16480_def_filter_freqs[i] >= freq) {
  				diff = adis16480_def_filter_freqs[i] - freq;
  				if (diff < best_diff) {
  					best_diff = diff;
  					best_freq = i;
  				}
  			}
  		}
  
  		val &= ~(0x3 << offset);
  		val |= best_freq << offset;
  		val |= enable_mask;
  	}
  
  	return adis_write_reg_16(&st->adis, reg, val);
  }
  
  static int adis16480_read_raw(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan, int *val, int *val2, long info)
  {
  	struct adis16480 *st = iio_priv(indio_dev);
  
  	switch (info) {
  	case IIO_CHAN_INFO_RAW:
  		return adis_single_conversion(indio_dev, chan, 0, val);
  	case IIO_CHAN_INFO_SCALE:
  		switch (chan->type) {
  		case IIO_ANGL_VEL:
  			*val = st->chip_info->gyro_max_scale;
  			*val2 = st->chip_info->gyro_max_val;
  			return IIO_VAL_FRACTIONAL;
  		case IIO_ACCEL:
  			*val = st->chip_info->accel_max_scale;
  			*val2 = st->chip_info->accel_max_val;
  			return IIO_VAL_FRACTIONAL;
  		case IIO_MAGN:
  			*val = 0;
  			*val2 = 100; /* 0.0001 gauss */
  			return IIO_VAL_INT_PLUS_MICRO;
  		case IIO_TEMP:
  			*val = 5;
  			*val2 = 650000; /* 5.65 milli degree Celsius */
  			return IIO_VAL_INT_PLUS_MICRO;
  		case IIO_PRESSURE:
  			*val = 0;
  			*val2 = 4000; /* 40ubar = 0.004 kPa */
  			return IIO_VAL_INT_PLUS_MICRO;
  		default:
  			return -EINVAL;
  		}
  	case IIO_CHAN_INFO_OFFSET:
  		/* Only the temperature channel has a offset */
  		*val = 4425; /* 25 degree Celsius = 0x0000 */
  		return IIO_VAL_INT;
  	case IIO_CHAN_INFO_CALIBBIAS:
  		return adis16480_get_calibbias(indio_dev, chan, val);
  	case IIO_CHAN_INFO_CALIBSCALE:
  		return adis16480_get_calibscale(indio_dev, chan, val);
  	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
  		return adis16480_get_filter_freq(indio_dev, chan, val);
  	case IIO_CHAN_INFO_SAMP_FREQ:
  		return adis16480_get_freq(indio_dev, val, val2);
  	default:
  		return -EINVAL;
  	}
  }
  
  static int adis16480_write_raw(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan, int val, int val2, long info)
  {
  	switch (info) {
  	case IIO_CHAN_INFO_CALIBBIAS:
  		return adis16480_set_calibbias(indio_dev, chan, val);
  	case IIO_CHAN_INFO_CALIBSCALE:
  		return adis16480_set_calibscale(indio_dev, chan, val);
  	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
  		return adis16480_set_filter_freq(indio_dev, chan, val);
  	case IIO_CHAN_INFO_SAMP_FREQ:
  		return adis16480_set_freq(indio_dev, val, val2);
  
  	default:
  		return -EINVAL;
  	}
  }
  
  #define ADIS16480_MOD_CHANNEL(_type, _mod, _address, _si, _info_sep, _bits) \
  	{ \
  		.type = (_type), \
  		.modified = 1, \
  		.channel2 = (_mod), \
  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
  			BIT(IIO_CHAN_INFO_CALIBBIAS) | \
  			_info_sep, \
  		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
  		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
  		.address = (_address), \
  		.scan_index = (_si), \
  		.scan_type = { \
  			.sign = 's', \
  			.realbits = (_bits), \
  			.storagebits = (_bits), \
  			.endianness = IIO_BE, \
  		}, \
  	}
  
  #define ADIS16480_GYRO_CHANNEL(_mod) \
  	ADIS16480_MOD_CHANNEL(IIO_ANGL_VEL, IIO_MOD_ ## _mod, \
  	ADIS16480_REG_ ## _mod ## _GYRO_OUT, ADIS16480_SCAN_GYRO_ ## _mod, \
  	BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) | \
  	BIT(IIO_CHAN_INFO_CALIBSCALE), \
  	32)
  
  #define ADIS16480_ACCEL_CHANNEL(_mod) \
  	ADIS16480_MOD_CHANNEL(IIO_ACCEL, IIO_MOD_ ## _mod, \
  	ADIS16480_REG_ ## _mod ## _ACCEL_OUT, ADIS16480_SCAN_ACCEL_ ## _mod, \
  	BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) | \
  	BIT(IIO_CHAN_INFO_CALIBSCALE), \
  	32)
  
  #define ADIS16480_MAGN_CHANNEL(_mod) \
  	ADIS16480_MOD_CHANNEL(IIO_MAGN, IIO_MOD_ ## _mod, \
  	ADIS16480_REG_ ## _mod ## _MAGN_OUT, ADIS16480_SCAN_MAGN_ ## _mod, \
  	BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), \
  	16)
  
  #define ADIS16480_PRESSURE_CHANNEL() \
  	{ \
  		.type = IIO_PRESSURE, \
  		.indexed = 1, \
  		.channel = 0, \
  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
  			BIT(IIO_CHAN_INFO_CALIBBIAS) | \
  			BIT(IIO_CHAN_INFO_SCALE), \
  		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
  		.address = ADIS16480_REG_BAROM_OUT, \
  		.scan_index = ADIS16480_SCAN_BARO, \
  		.scan_type = { \
  			.sign = 's', \
  			.realbits = 32, \
  			.storagebits = 32, \
  			.endianness = IIO_BE, \
  		}, \
  	}
  
  #define ADIS16480_TEMP_CHANNEL() { \
  		.type = IIO_TEMP, \
  		.indexed = 1, \
  		.channel = 0, \
  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
  			BIT(IIO_CHAN_INFO_SCALE) | \
  			BIT(IIO_CHAN_INFO_OFFSET), \
  		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
  		.address = ADIS16480_REG_TEMP_OUT, \
  		.scan_index = ADIS16480_SCAN_TEMP, \
  		.scan_type = { \
  			.sign = 's', \
  			.realbits = 16, \
  			.storagebits = 16, \
  			.endianness = IIO_BE, \
  		}, \
  	}
  
  static const struct iio_chan_spec adis16480_channels[] = {
  	ADIS16480_GYRO_CHANNEL(X),
  	ADIS16480_GYRO_CHANNEL(Y),
  	ADIS16480_GYRO_CHANNEL(Z),
  	ADIS16480_ACCEL_CHANNEL(X),
  	ADIS16480_ACCEL_CHANNEL(Y),
  	ADIS16480_ACCEL_CHANNEL(Z),
  	ADIS16480_MAGN_CHANNEL(X),
  	ADIS16480_MAGN_CHANNEL(Y),
  	ADIS16480_MAGN_CHANNEL(Z),
  	ADIS16480_PRESSURE_CHANNEL(),
  	ADIS16480_TEMP_CHANNEL(),
  	IIO_CHAN_SOFT_TIMESTAMP(11)
  };
  
  static const struct iio_chan_spec adis16485_channels[] = {
  	ADIS16480_GYRO_CHANNEL(X),
  	ADIS16480_GYRO_CHANNEL(Y),
  	ADIS16480_GYRO_CHANNEL(Z),
  	ADIS16480_ACCEL_CHANNEL(X),
  	ADIS16480_ACCEL_CHANNEL(Y),
  	ADIS16480_ACCEL_CHANNEL(Z),
  	ADIS16480_TEMP_CHANNEL(),
  	IIO_CHAN_SOFT_TIMESTAMP(7)
  };
  
  enum adis16480_variant {
  	ADIS16375,
  	ADIS16480,
  	ADIS16485,
  	ADIS16488,
  };
  
  static const struct adis16480_chip_info adis16480_chip_info[] = {
  	[ADIS16375] = {
  		.channels = adis16485_channels,
  		.num_channels = ARRAY_SIZE(adis16485_channels),
  		/*
  		 * storing the value in rad/degree and the scale in degree
  		 * gives us the result in rad and better precession than
  		 * storing the scale directly in rad.
  		 */
  		.gyro_max_val = IIO_RAD_TO_DEGREE(22887),
  		.gyro_max_scale = 300,
  		.accel_max_val = IIO_M_S_2_TO_G(21973),
  		.accel_max_scale = 18,
  	},
  	[ADIS16480] = {
  		.channels = adis16480_channels,
  		.num_channels = ARRAY_SIZE(adis16480_channels),
  		.gyro_max_val = IIO_RAD_TO_DEGREE(22500),
  		.gyro_max_scale = 450,
  		.accel_max_val = IIO_M_S_2_TO_G(12500),
  		.accel_max_scale = 5,
  	},
  	[ADIS16485] = {
  		.channels = adis16485_channels,
  		.num_channels = ARRAY_SIZE(adis16485_channels),
  		.gyro_max_val = IIO_RAD_TO_DEGREE(22500),
  		.gyro_max_scale = 450,
  		.accel_max_val = IIO_M_S_2_TO_G(20000),
  		.accel_max_scale = 5,
  	},
  	[ADIS16488] = {
  		.channels = adis16480_channels,
  		.num_channels = ARRAY_SIZE(adis16480_channels),
  		.gyro_max_val = IIO_RAD_TO_DEGREE(22500),
  		.gyro_max_scale = 450,
  		.accel_max_val = IIO_M_S_2_TO_G(22500),
  		.accel_max_scale = 18,
  	},
  };
  
  static const struct iio_info adis16480_info = {
  	.read_raw = &adis16480_read_raw,
  	.write_raw = &adis16480_write_raw,
  	.update_scan_mode = adis_update_scan_mode,
  	.driver_module = THIS_MODULE,
  };
  
  static int adis16480_stop_device(struct iio_dev *indio_dev)
  {
  	struct adis16480 *st = iio_priv(indio_dev);
  	int ret;
  
  	ret = adis_write_reg_16(&st->adis, ADIS16480_REG_SLP_CNT, BIT(9));
  	if (ret)
  		dev_err(&indio_dev->dev,
  			"Could not power down device: %d
  ", ret);
  
  	return ret;
  }
  
  static int adis16480_enable_irq(struct adis *adis, bool enable)
  {
  	return adis_write_reg_16(adis, ADIS16480_REG_FNCTIO_CTRL,
  		enable ? BIT(3) : 0);
  }
  
  static int adis16480_initial_setup(struct iio_dev *indio_dev)
  {
  	struct adis16480 *st = iio_priv(indio_dev);
  	uint16_t prod_id;
  	unsigned int device_id;
  	int ret;
  
  	adis_reset(&st->adis);
  	msleep(70);
  
  	ret = adis_write_reg_16(&st->adis, ADIS16480_REG_GLOB_CMD, BIT(1));
  	if (ret)
  		return ret;
  	msleep(30);
  
  	ret = adis_check_status(&st->adis);
  	if (ret)
  		return ret;
  
  	ret = adis_read_reg_16(&st->adis, ADIS16480_REG_PROD_ID, &prod_id);
  	if (ret)
  		return ret;
  
  	sscanf(indio_dev->name, "adis%u
  ", &device_id);
  
  	if (prod_id != device_id)
  		dev_warn(&indio_dev->dev, "Device ID(%u) and product ID(%u) do not match.",
  				device_id, prod_id);
  
  	return 0;
  }
  
  #define ADIS16480_DIAG_STAT_XGYRO_FAIL 0
  #define ADIS16480_DIAG_STAT_YGYRO_FAIL 1
  #define ADIS16480_DIAG_STAT_ZGYRO_FAIL 2
  #define ADIS16480_DIAG_STAT_XACCL_FAIL 3
  #define ADIS16480_DIAG_STAT_YACCL_FAIL 4
  #define ADIS16480_DIAG_STAT_ZACCL_FAIL 5
  #define ADIS16480_DIAG_STAT_XMAGN_FAIL 8
  #define ADIS16480_DIAG_STAT_YMAGN_FAIL 9
  #define ADIS16480_DIAG_STAT_ZMAGN_FAIL 10
  #define ADIS16480_DIAG_STAT_BARO_FAIL 11
  
  static const char * const adis16480_status_error_msgs[] = {
  	[ADIS16480_DIAG_STAT_XGYRO_FAIL] = "X-axis gyroscope self-test failure",
  	[ADIS16480_DIAG_STAT_YGYRO_FAIL] = "Y-axis gyroscope self-test failure",
  	[ADIS16480_DIAG_STAT_ZGYRO_FAIL] = "Z-axis gyroscope self-test failure",
  	[ADIS16480_DIAG_STAT_XACCL_FAIL] = "X-axis accelerometer self-test failure",
  	[ADIS16480_DIAG_STAT_YACCL_FAIL] = "Y-axis accelerometer self-test failure",
  	[ADIS16480_DIAG_STAT_ZACCL_FAIL] = "Z-axis accelerometer self-test failure",
  	[ADIS16480_DIAG_STAT_XMAGN_FAIL] = "X-axis magnetometer self-test failure",
  	[ADIS16480_DIAG_STAT_YMAGN_FAIL] = "Y-axis magnetometer self-test failure",
  	[ADIS16480_DIAG_STAT_ZMAGN_FAIL] = "Z-axis magnetometer self-test failure",
  	[ADIS16480_DIAG_STAT_BARO_FAIL] = "Barometer self-test failure",
  };
  
  static const struct adis_data adis16480_data = {
  	.diag_stat_reg = ADIS16480_REG_DIAG_STS,
  	.glob_cmd_reg = ADIS16480_REG_GLOB_CMD,
  	.has_paging = true,
  
  	.read_delay = 5,
  	.write_delay = 5,
  
  	.status_error_msgs = adis16480_status_error_msgs,
  	.status_error_mask = BIT(ADIS16480_DIAG_STAT_XGYRO_FAIL) |
  		BIT(ADIS16480_DIAG_STAT_YGYRO_FAIL) |
  		BIT(ADIS16480_DIAG_STAT_ZGYRO_FAIL) |
  		BIT(ADIS16480_DIAG_STAT_XACCL_FAIL) |
  		BIT(ADIS16480_DIAG_STAT_YACCL_FAIL) |
  		BIT(ADIS16480_DIAG_STAT_ZACCL_FAIL) |
  		BIT(ADIS16480_DIAG_STAT_XMAGN_FAIL) |
  		BIT(ADIS16480_DIAG_STAT_YMAGN_FAIL) |
  		BIT(ADIS16480_DIAG_STAT_ZMAGN_FAIL) |
  		BIT(ADIS16480_DIAG_STAT_BARO_FAIL),
  
  	.enable_irq = adis16480_enable_irq,
  };
  
  static int adis16480_probe(struct spi_device *spi)
  {
  	const struct spi_device_id *id = spi_get_device_id(spi);
  	struct iio_dev *indio_dev;
  	struct adis16480 *st;
  	int ret;
  
  	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
  	if (indio_dev == NULL)
  		return -ENOMEM;
  
  	spi_set_drvdata(spi, indio_dev);
  
  	st = iio_priv(indio_dev);
  
  	st->chip_info = &adis16480_chip_info[id->driver_data];
  	indio_dev->dev.parent = &spi->dev;
  	indio_dev->name = spi_get_device_id(spi)->name;
  	indio_dev->channels = st->chip_info->channels;
  	indio_dev->num_channels = st->chip_info->num_channels;
  	indio_dev->info = &adis16480_info;
  	indio_dev->modes = INDIO_DIRECT_MODE;
  
  	ret = adis_init(&st->adis, indio_dev, spi, &adis16480_data);
  	if (ret)
  		return ret;
  
  	ret = adis_setup_buffer_and_trigger(&st->adis, indio_dev, NULL);
  	if (ret)
  		return ret;
  
  	ret = adis16480_initial_setup(indio_dev);
  	if (ret)
  		goto error_cleanup_buffer;
  
  	ret = iio_device_register(indio_dev);
  	if (ret)
  		goto error_stop_device;
  
  	adis16480_debugfs_init(indio_dev);
  
  	return 0;
  
  error_stop_device:
  	adis16480_stop_device(indio_dev);
  error_cleanup_buffer:
  	adis_cleanup_buffer_and_trigger(&st->adis, indio_dev);
  	return ret;
  }
  
  static int adis16480_remove(struct spi_device *spi)
  {
  	struct iio_dev *indio_dev = spi_get_drvdata(spi);
  	struct adis16480 *st = iio_priv(indio_dev);
  
  	iio_device_unregister(indio_dev);
  	adis16480_stop_device(indio_dev);
  
  	adis_cleanup_buffer_and_trigger(&st->adis, indio_dev);
  
  	return 0;
  }
  
  static const struct spi_device_id adis16480_ids[] = {
  	{ "adis16375", ADIS16375 },
  	{ "adis16480", ADIS16480 },
  	{ "adis16485", ADIS16485 },
  	{ "adis16488", ADIS16488 },
  	{ }
  };
  MODULE_DEVICE_TABLE(spi, adis16480_ids);
  
  static struct spi_driver adis16480_driver = {
  	.driver = {
  		.name = "adis16480",
  	},
  	.id_table = adis16480_ids,
  	.probe = adis16480_probe,
  	.remove = adis16480_remove,
  };
  module_spi_driver(adis16480_driver);
  
  MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
  MODULE_DESCRIPTION("Analog Devices ADIS16480 IMU driver");
  MODULE_LICENSE("GPL v2");