/*
   * ADIS16080/100 Yaw Rate Gyroscope with SPI driver
   *
   * Copyright 2010 Analog Devices Inc.
   *
   * Licensed under the GPL-2 or later.
   */
  #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>
  
  #define ADIS16080_DIN_GYRO   (0 << 10) /* Gyroscope output */
  #define ADIS16080_DIN_TEMP   (1 << 10) /* Temperature output */
  #define ADIS16080_DIN_AIN1   (2 << 10)
  #define ADIS16080_DIN_AIN2   (3 << 10)
  
  /*
   * 1: Write contents on DIN to control register.
   * 0: No changes to control register.
   */
  
  #define ADIS16080_DIN_WRITE  (1 << 15)
  
  struct adis16080_chip_info {
  	int scale_val;
  	int scale_val2;
  };
  
  /**
   * struct adis16080_state - device instance specific data
   * @us:			actual spi_device to write data
   * @info:		chip specific parameters
   * @buf:		transmit or receive buffer
   **/
  struct adis16080_state {
  	struct spi_device		*us;
  	const struct adis16080_chip_info *info;
  
  	__be16 buf ____cacheline_aligned;
  };
  
  static int adis16080_read_sample(struct iio_dev *indio_dev,
  		u16 addr, int *val)
  {
  	struct adis16080_state *st = iio_priv(indio_dev);
  	int ret;
  	struct spi_transfer	t[] = {
  		{
  			.tx_buf		= &st->buf,
  			.len		= 2,
  			.cs_change	= 1,
  		}, {
  			.rx_buf		= &st->buf,
  			.len		= 2,
  		},
  	};
  
  	st->buf = cpu_to_be16(addr | ADIS16080_DIN_WRITE);
  
  	ret = spi_sync_transfer(st->us, t, ARRAY_SIZE(t));
  	if (ret == 0)
  		*val = sign_extend32(be16_to_cpu(st->buf), 11);
  
  	return ret;
  }
  
  static int adis16080_read_raw(struct iio_dev *indio_dev,
  			     struct iio_chan_spec const *chan,
  			     int *val,
  			     int *val2,
  			     long mask)
  {
  	struct adis16080_state *st = iio_priv(indio_dev);
  	int ret;
  
  	switch (mask) {
  	case IIO_CHAN_INFO_RAW:
  		mutex_lock(&indio_dev->mlock);
  		ret = adis16080_read_sample(indio_dev, chan->address, val);
  		mutex_unlock(&indio_dev->mlock);
  		return ret ? ret : IIO_VAL_INT;
  	case IIO_CHAN_INFO_SCALE:
  		switch (chan->type) {
  		case IIO_ANGL_VEL:
  			*val = st->info->scale_val;
  			*val2 = st->info->scale_val2;
  			return IIO_VAL_FRACTIONAL;
  		case IIO_VOLTAGE:
  			/* VREF = 5V, 12 bits */
  			*val = 5000;
  			*val2 = 12;
  			return IIO_VAL_FRACTIONAL_LOG2;
  		case IIO_TEMP:
  			/* 85 C = 585, 25 C = 0 */
  			*val = 85000 - 25000;
  			*val2 = 585;
  			return IIO_VAL_FRACTIONAL;
  		default:
  			return -EINVAL;
  		}
  	case IIO_CHAN_INFO_OFFSET:
  		switch (chan->type) {
  		case IIO_VOLTAGE:
  			/* 2.5 V = 0 */
  			*val = 2048;
  			return IIO_VAL_INT;
  		case IIO_TEMP:
  			/* 85 C = 585, 25 C = 0 */
  			*val = DIV_ROUND_CLOSEST(25 * 585, 85 - 25);
  			return IIO_VAL_INT;
  		default:
  			return -EINVAL;
  		}
  	default:
  		break;
  	}
  
  	return -EINVAL;
  }
  
  static const struct iio_chan_spec adis16080_channels[] = {
  	{
  		.type = IIO_ANGL_VEL,
  		.modified = 1,
  		.channel2 = IIO_MOD_Z,
  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  			BIT(IIO_CHAN_INFO_SCALE),
  		.address = ADIS16080_DIN_GYRO,
  	}, {
  		.type = IIO_VOLTAGE,
  		.indexed = 1,
  		.channel = 0,
  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  			BIT(IIO_CHAN_INFO_SCALE) |
  			BIT(IIO_CHAN_INFO_OFFSET),
  		.address = ADIS16080_DIN_AIN1,
  	}, {
  		.type = IIO_VOLTAGE,
  		.indexed = 1,
  		.channel = 1,
  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  			BIT(IIO_CHAN_INFO_SCALE) |
  			BIT(IIO_CHAN_INFO_OFFSET),
  		.address = ADIS16080_DIN_AIN2,
  	}, {
  		.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),
  		.address = ADIS16080_DIN_TEMP,
  	}
  };
  
  static const struct iio_info adis16080_info = {
  	.read_raw = &adis16080_read_raw,
  	.driver_module = THIS_MODULE,
  };
  
  enum {
  	ID_ADIS16080,
  	ID_ADIS16100,
  };
  
  static const struct adis16080_chip_info adis16080_chip_info[] = {
  	[ID_ADIS16080] = {
  		/* 80 degree = 819, 819 rad = 46925 degree */
  		.scale_val = 80,
  		.scale_val2 = 46925,
  	},
  	[ID_ADIS16100] = {
  		/* 300 degree = 1230, 1230 rad = 70474 degree */
  		.scale_val = 300,
  		.scale_val2 = 70474,
  	},
  };
  
  static int adis16080_probe(struct spi_device *spi)
  {
  	const struct spi_device_id *id = spi_get_device_id(spi);
  	struct adis16080_state *st;
  	struct iio_dev *indio_dev;
  
  	/* setup the industrialio driver allocated elements */
  	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
  	if (!indio_dev)
  		return -ENOMEM;
  	st = iio_priv(indio_dev);
  	/* this is only used for removal purposes */
  	spi_set_drvdata(spi, indio_dev);
  
  	/* Allocate the comms buffers */
  	st->us = spi;
  	st->info = &adis16080_chip_info[id->driver_data];
  
  	indio_dev->name = spi->dev.driver->name;
  	indio_dev->channels = adis16080_channels;
  	indio_dev->num_channels = ARRAY_SIZE(adis16080_channels);
  	indio_dev->dev.parent = &spi->dev;
  	indio_dev->info = &adis16080_info;
  	indio_dev->modes = INDIO_DIRECT_MODE;
  
  	return iio_device_register(indio_dev);
  }
  
  static int adis16080_remove(struct spi_device *spi)
  {
  	iio_device_unregister(spi_get_drvdata(spi));
  	return 0;
  }
  
  static const struct spi_device_id adis16080_ids[] = {
  	{ "adis16080", ID_ADIS16080 },
  	{ "adis16100", ID_ADIS16100 },
  	{},
  };
  MODULE_DEVICE_TABLE(spi, adis16080_ids);
  
  static struct spi_driver adis16080_driver = {
  	.driver = {
  		.name = "adis16080",
  	},
  	.probe = adis16080_probe,
  	.remove = adis16080_remove,
  	.id_table = adis16080_ids,
  };
  module_spi_driver(adis16080_driver);
  
  MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
  MODULE_DESCRIPTION("Analog Devices ADIS16080/100 Yaw Rate Gyroscope Driver");
  MODULE_LICENSE("GPL v2");