/*
   * AD5624R, AD5644R, AD5664R Digital to analog convertors spi driver
   *
   * Copyright 2010-2011 Analog Devices Inc.
   *
   * Licensed under the GPL-2.
   */
  
  #include <linux/interrupt.h>
  #include <linux/fs.h>
  #include <linux/device.h>
  #include <linux/kernel.h>
  #include <linux/spi/spi.h>
  #include <linux/slab.h>
  #include <linux/sysfs.h>
  #include <linux/regulator/consumer.h>
  #include <linux/module.h>
  
  #include <linux/iio/iio.h>
  #include <linux/iio/sysfs.h>
  
  #include "ad5624r.h"
  
  static int ad5624r_spi_write(struct spi_device *spi,
  			     u8 cmd, u8 addr, u16 val, u8 shift)
  {
  	u32 data;
  	u8 msg[3];
  
  	/*
  	 * The input shift register is 24 bits wide. The first two bits are
  	 * don't care bits. The next three are the command bits, C2 to C0,
  	 * followed by the 3-bit DAC address, A2 to A0, and then the
  	 * 16-, 14-, 12-bit data-word. The data-word comprises the 16-,
  	 * 14-, 12-bit input code followed by 0, 2, or 4 don't care bits,
  	 * for the AD5664R, AD5644R, and AD5624R, respectively.
  	 */
  	data = (0 << 22) | (cmd << 19) | (addr << 16) | (val << shift);
  	msg[0] = data >> 16;
  	msg[1] = data >> 8;
  	msg[2] = data;
  
  	return spi_write(spi, msg, 3);
  }
  
  static int ad5624r_read_raw(struct iio_dev *indio_dev,
  			   struct iio_chan_spec const *chan,
  			   int *val,
  			   int *val2,
  			   long m)
  {
  	struct ad5624r_state *st = iio_priv(indio_dev);
  
  	switch (m) {
  	case IIO_CHAN_INFO_SCALE:
  		*val = st->vref_mv;
  		*val2 = chan->scan_type.realbits;
  		return IIO_VAL_FRACTIONAL_LOG2;
  	}
  	return -EINVAL;
  }
  
  static int ad5624r_write_raw(struct iio_dev *indio_dev,
  			       struct iio_chan_spec const *chan,
  			       int val,
  			       int val2,
  			       long mask)
  {
  	struct ad5624r_state *st = iio_priv(indio_dev);
  
  	switch (mask) {
  	case IIO_CHAN_INFO_RAW:
  		if (val >= (1 << chan->scan_type.realbits) || val < 0)
  			return -EINVAL;
  
  		return ad5624r_spi_write(st->us,
  				AD5624R_CMD_WRITE_INPUT_N_UPDATE_N,
  				chan->address, val,
  				chan->scan_type.shift);
  	default:
  		return -EINVAL;
  	}
  }
  
  static const char * const ad5624r_powerdown_modes[] = {
  	"1kohm_to_gnd",
  	"100kohm_to_gnd",
  	"three_state"
  };
  
  static int ad5624r_get_powerdown_mode(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan)
  {
  	struct ad5624r_state *st = iio_priv(indio_dev);
  
  	return st->pwr_down_mode;
  }
  
  static int ad5624r_set_powerdown_mode(struct iio_dev *indio_dev,
  	const struct iio_chan_spec *chan, unsigned int mode)
  {
  	struct ad5624r_state *st = iio_priv(indio_dev);
  
  	st->pwr_down_mode = mode;
  
  	return 0;
  }
  
  static const struct iio_enum ad5624r_powerdown_mode_enum = {
  	.items = ad5624r_powerdown_modes,
  	.num_items = ARRAY_SIZE(ad5624r_powerdown_modes),
  	.get = ad5624r_get_powerdown_mode,
  	.set = ad5624r_set_powerdown_mode,
  };
  
  static ssize_t ad5624r_read_dac_powerdown(struct iio_dev *indio_dev,
  	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
  {
  	struct ad5624r_state *st = iio_priv(indio_dev);
  
  	return sprintf(buf, "%d
  ",
  			!!(st->pwr_down_mask & (1 << chan->channel)));
  }
  
  static ssize_t ad5624r_write_dac_powerdown(struct iio_dev *indio_dev,
  	uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
  	size_t len)
  {
  	bool pwr_down;
  	int ret;
  	struct ad5624r_state *st = iio_priv(indio_dev);
  
  	ret = strtobool(buf, &pwr_down);
  	if (ret)
  		return ret;
  
  	if (pwr_down)
  		st->pwr_down_mask |= (1 << chan->channel);
  	else
  		st->pwr_down_mask &= ~(1 << chan->channel);
  
  	ret = ad5624r_spi_write(st->us, AD5624R_CMD_POWERDOWN_DAC, 0,
  				(st->pwr_down_mode << 4) |
  				st->pwr_down_mask, 16);
  
  	return ret ? ret : len;
  }
  
  static const struct iio_info ad5624r_info = {
  	.write_raw = ad5624r_write_raw,
  	.read_raw = ad5624r_read_raw,
  	.driver_module = THIS_MODULE,
  };
  
  static const struct iio_chan_spec_ext_info ad5624r_ext_info[] = {
  	{
  		.name = "powerdown",
  		.read = ad5624r_read_dac_powerdown,
  		.write = ad5624r_write_dac_powerdown,
  		.shared = IIO_SEPARATE,
  	},
  	IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
  		 &ad5624r_powerdown_mode_enum),
  	IIO_ENUM_AVAILABLE("powerdown_mode", &ad5624r_powerdown_mode_enum),
  	{ },
  };
  
  #define AD5624R_CHANNEL(_chan, _bits) { \
  	.type = IIO_VOLTAGE, \
  	.indexed = 1, \
  	.output = 1, \
  	.channel = (_chan), \
  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
  	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
  	.address = (_chan), \
  	.scan_type = { \
  		.sign = 'u', \
  		.realbits = (_bits), \
  		.storagebits = 16, \
  		.shift = 16 - (_bits), \
  	}, \
  	.ext_info = ad5624r_ext_info, \
  }
  
  #define DECLARE_AD5624R_CHANNELS(_name, _bits) \
  	const struct iio_chan_spec _name##_channels[] = { \
  		AD5624R_CHANNEL(0, _bits), \
  		AD5624R_CHANNEL(1, _bits), \
  		AD5624R_CHANNEL(2, _bits), \
  		AD5624R_CHANNEL(3, _bits), \
  }
  
  static DECLARE_AD5624R_CHANNELS(ad5624r, 12);
  static DECLARE_AD5624R_CHANNELS(ad5644r, 14);
  static DECLARE_AD5624R_CHANNELS(ad5664r, 16);
  
  static const struct ad5624r_chip_info ad5624r_chip_info_tbl[] = {
  	[ID_AD5624R3] = {
  		.channels = ad5624r_channels,
  		.int_vref_mv = 1250,
  	},
  	[ID_AD5624R5] = {
  		.channels = ad5624r_channels,
  		.int_vref_mv = 2500,
  	},
  	[ID_AD5644R3] = {
  		.channels = ad5644r_channels,
  		.int_vref_mv = 1250,
  	},
  	[ID_AD5644R5] = {
  		.channels = ad5644r_channels,
  		.int_vref_mv = 2500,
  	},
  	[ID_AD5664R3] = {
  		.channels = ad5664r_channels,
  		.int_vref_mv = 1250,
  	},
  	[ID_AD5664R5] = {
  		.channels = ad5664r_channels,
  		.int_vref_mv = 2500,
  	},
  };
  
  static int ad5624r_probe(struct spi_device *spi)
  {
  	struct ad5624r_state *st;
  	struct iio_dev *indio_dev;
  	int ret, voltage_uv = 0;
  
  	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
  	if (!indio_dev)
  		return -ENOMEM;
  	st = iio_priv(indio_dev);
  	st->reg = devm_regulator_get(&spi->dev, "vcc");
  	if (!IS_ERR(st->reg)) {
  		ret = regulator_enable(st->reg);
  		if (ret)
  			return ret;
  
  		ret = regulator_get_voltage(st->reg);
  		if (ret < 0)
  			goto error_disable_reg;
  
  		voltage_uv = ret;
  	}
  
  	spi_set_drvdata(spi, indio_dev);
  	st->chip_info =
  		&ad5624r_chip_info_tbl[spi_get_device_id(spi)->driver_data];
  
  	if (voltage_uv)
  		st->vref_mv = voltage_uv / 1000;
  	else
  		st->vref_mv = st->chip_info->int_vref_mv;
  
  	st->us = spi;
  
  	indio_dev->dev.parent = &spi->dev;
  	indio_dev->name = spi_get_device_id(spi)->name;
  	indio_dev->info = &ad5624r_info;
  	indio_dev->modes = INDIO_DIRECT_MODE;
  	indio_dev->channels = st->chip_info->channels;
  	indio_dev->num_channels = AD5624R_DAC_CHANNELS;
  
  	ret = ad5624r_spi_write(spi, AD5624R_CMD_INTERNAL_REFER_SETUP, 0,
  				!!voltage_uv, 16);
  	if (ret)
  		goto error_disable_reg;
  
  	ret = iio_device_register(indio_dev);
  	if (ret)
  		goto error_disable_reg;
  
  	return 0;
  
  error_disable_reg:
  	if (!IS_ERR(st->reg))
  		regulator_disable(st->reg);
  
  	return ret;
  }
  
  static int ad5624r_remove(struct spi_device *spi)
  {
  	struct iio_dev *indio_dev = spi_get_drvdata(spi);
  	struct ad5624r_state *st = iio_priv(indio_dev);
  
  	iio_device_unregister(indio_dev);
  	if (!IS_ERR(st->reg))
  		regulator_disable(st->reg);
  
  	return 0;
  }
  
  static const struct spi_device_id ad5624r_id[] = {
  	{"ad5624r3", ID_AD5624R3},
  	{"ad5644r3", ID_AD5644R3},
  	{"ad5664r3", ID_AD5664R3},
  	{"ad5624r5", ID_AD5624R5},
  	{"ad5644r5", ID_AD5644R5},
  	{"ad5664r5", ID_AD5664R5},
  	{}
  };
  MODULE_DEVICE_TABLE(spi, ad5624r_id);
  
  static struct spi_driver ad5624r_driver = {
  	.driver = {
  		   .name = "ad5624r",
  		   },
  	.probe = ad5624r_probe,
  	.remove = ad5624r_remove,
  	.id_table = ad5624r_id,
  };
  module_spi_driver(ad5624r_driver);
  
  MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
  MODULE_DESCRIPTION("Analog Devices AD5624/44/64R DAC spi driver");
  MODULE_LICENSE("GPL v2");