/*
   * TWL6030 GPADC module driver
   *
   * Copyright (C) 2009-2013 Texas Instruments Inc.
   * Nishant Kamat <nskamat@ti.com>
   * Balaji T K <balajitk@ti.com>
   * Graeme Gregory <gg@slimlogic.co.uk>
   * Girish S Ghongdemath <girishsg@ti.com>
   * Ambresh K <ambresh@ti.com>
   * Oleksandr Kozaruk <oleksandr.kozaruk@ti.com
   *
   * Based on twl4030-madc.c
   * Copyright (C) 2008 Nokia Corporation
   * Mikko Ylinen <mikko.k.ylinen@nokia.com>
   *
   * 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.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA
   *
   */
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/of_platform.h>
  #include <linux/i2c/twl.h>
  #include <linux/iio/iio.h>
  #include <linux/iio/sysfs.h>
  
  #define DRIVER_NAME		"twl6030_gpadc"
  
  /*
   * twl6030 per TRM has 17 channels, and twl6032 has 19 channels
   * 2 test network channels are not used,
   * 2 die temperature channels are not used either, as it is not
   * defined how to convert ADC value to temperature
   */
  #define TWL6030_GPADC_USED_CHANNELS		13
  #define TWL6030_GPADC_MAX_CHANNELS		15
  #define TWL6032_GPADC_USED_CHANNELS		15
  #define TWL6032_GPADC_MAX_CHANNELS		19
  #define TWL6030_GPADC_NUM_TRIM_REGS		16
  
  #define TWL6030_GPADC_CTRL_P1			0x05
  
  #define TWL6032_GPADC_GPSELECT_ISB		0x07
  #define TWL6032_GPADC_CTRL_P1			0x08
  
  #define TWL6032_GPADC_GPCH0_LSB			0x0d
  #define TWL6032_GPADC_GPCH0_MSB			0x0e
  
  #define TWL6030_GPADC_CTRL_P1_SP1		BIT(3)
  
  #define TWL6030_GPADC_GPCH0_LSB			(0x29)
  
  #define TWL6030_GPADC_RT_SW1_EOC_MASK		BIT(5)
  
  #define TWL6030_GPADC_TRIM1			0xCD
  
  #define TWL6030_REG_TOGGLE1			0x90
  #define TWL6030_GPADCS				BIT(1)
  #define TWL6030_GPADCR				BIT(0)
  
  /**
   * struct twl6030_chnl_calib - channel calibration
   * @gain:		slope coefficient for ideal curve
   * @gain_error:		gain error
   * @offset_error:	offset of the real curve
   */
  struct twl6030_chnl_calib {
  	s32 gain;
  	s32 gain_error;
  	s32 offset_error;
  };
  
  /**
   * struct twl6030_ideal_code - GPADC calibration parameters
   * GPADC is calibrated in two points: close to the beginning and
   * to the and of the measurable input range
   *
   * @channel:	channel number
   * @code1:	ideal code for the input at the beginning
   * @code2:	ideal code for at the end of the range
   * @volt1:	voltage input at the beginning(low voltage)
   * @volt2:	voltage input at the end(high voltage)
   */
  struct twl6030_ideal_code {
  	int channel;
  	u16 code1;
  	u16 code2;
  	u16 volt1;
  	u16 volt2;
  };
  
  struct twl6030_gpadc_data;
  
  /**
   * struct twl6030_gpadc_platform_data - platform specific data
   * @nchannels:		number of GPADC channels
   * @iio_channels:	iio channels
   * @twl6030_ideal:	pointer to calibration parameters
   * @start_conversion:	pointer to ADC start conversion function
   * @channel_to_reg	pointer to ADC function to convert channel to
   *			register address for reading conversion result
   * @calibrate:		pointer to calibration function
   */
  struct twl6030_gpadc_platform_data {
  	const int nchannels;
  	const struct iio_chan_spec *iio_channels;
  	const struct twl6030_ideal_code *ideal;
  	int (*start_conversion)(int channel);
  	u8 (*channel_to_reg)(int channel);
  	int (*calibrate)(struct twl6030_gpadc_data *gpadc);
  };
  
  /**
   * struct twl6030_gpadc_data - GPADC data
   * @dev:		device pointer
   * @lock:		mutual exclusion lock for the structure
   * @irq_complete:	completion to signal end of conversion
   * @twl6030_cal_tbl:	pointer to calibration data for each
   *			channel with gain error and offset
   * @pdata:		pointer to device specific data
   */
  struct twl6030_gpadc_data {
  	struct device	*dev;
  	struct mutex	lock;
  	struct completion	irq_complete;
  	struct twl6030_chnl_calib	*twl6030_cal_tbl;
  	const struct twl6030_gpadc_platform_data *pdata;
  };
  
  /*
   * channels 11, 12, 13, 15 and 16 have no calibration data
   * calibration offset is same for channels 1, 3, 4, 5
   *
   * The data is taken from GPADC_TRIM registers description.
   * GPADC_TRIM registers keep difference between the code measured
   * at volt1 and volt2 input voltages and corresponding code1 and code2
   */
  static const struct twl6030_ideal_code
  	twl6030_ideal[TWL6030_GPADC_USED_CHANNELS] = {
  	[0] = { /* ch 0, external, battery type, resistor value */
  		.channel = 0,
  		.code1 = 116,
  		.code2 = 745,
  		.volt1 = 141,
  		.volt2 = 910,
  	},
  	[1] = { /* ch 1, external, battery temperature, NTC resistor value */
  		.channel = 1,
  		.code1 = 82,
  		.code2 = 900,
  		.volt1 = 100,
  		.volt2 = 1100,
  	},
  	[2] = { /* ch 2, external, audio accessory/general purpose */
  		.channel = 2,
  		.code1 = 55,
  		.code2 = 818,
  		.volt1 = 101,
  		.volt2 = 1499,
  	},
  	[3] = { /* ch 3, external, general purpose */
  		.channel = 3,
  		.code1 = 82,
  		.code2 = 900,
  		.volt1 = 100,
  		.volt2 = 1100,
  	},
  	[4] = { /* ch 4, external, temperature measurement/general purpose */
  		.channel = 4,
  		.code1 = 82,
  		.code2 = 900,
  		.volt1 = 100,
  		.volt2 = 1100,
  	},
  	[5] = { /* ch 5, external, general purpose */
  		.channel = 5,
  		.code1 = 82,
  		.code2 = 900,
  		.volt1 = 100,
  		.volt2 = 1100,
  	},
  	[6] = { /* ch 6, external, general purpose */
  		.channel = 6,
  		.code1 = 82,
  		.code2 = 900,
  		.volt1 = 100,
  		.volt2 = 1100,
  	},
  	[7] = { /* ch 7, internal, main battery */
  		.channel = 7,
  		.code1 = 614,
  		.code2 = 941,
  		.volt1 = 3001,
  		.volt2 = 4599,
  	},
  	[8] = { /* ch 8, internal, backup battery */
  		.channel = 8,
  		.code1 = 82,
  		.code2 = 688,
  		.volt1 = 501,
  		.volt2 = 4203,
  	},
  	[9] = { /* ch 9, internal, external charger input */
  		.channel = 9,
  		.code1 = 182,
  		.code2 = 818,
  		.volt1 = 2001,
  		.volt2 = 8996,
  	},
  	[10] = { /* ch 10, internal, VBUS */
  		.channel = 10,
  		.code1 = 149,
  		.code2 = 818,
  		.volt1 = 1001,
  		.volt2 = 5497,
  	},
  	[11] = { /* ch 11, internal, VBUS charging current */
  		.channel = 11,
  	},
  		/* ch 12, internal, Die temperature */
  		/* ch 13, internal, Die temperature */
  	[12] = { /* ch 14, internal, USB ID line */
  		.channel = 14,
  		.code1 = 48,
  		.code2 = 714,
  		.volt1 = 323,
  		.volt2 = 4800,
  	},
  };
  
  static const struct twl6030_ideal_code
  			twl6032_ideal[TWL6032_GPADC_USED_CHANNELS] = {
  	[0] = { /* ch 0, external, battery type, resistor value */
  		.channel = 0,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 440,
  		.volt2 = 1000,
  	},
  	[1] = { /* ch 1, external, battery temperature, NTC resistor value */
  		.channel = 1,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 440,
  		.volt2 = 1000,
  	},
  	[2] = { /* ch 2, external, audio accessory/general purpose */
  		.channel = 2,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 660,
  		.volt2 = 1500,
  	},
  	[3] = { /* ch 3, external, temperature with external diode/general
  								purpose */
  		.channel = 3,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 440,
  		.volt2 = 1000,
  	},
  	[4] = { /* ch 4, external, temperature measurement/general purpose */
  		.channel = 4,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 440,
  		.volt2 = 1000,
  	},
  	[5] = { /* ch 5, external, general purpose */
  		.channel = 5,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 440,
  		.volt2 = 1000,
  	},
  	[6] = { /* ch 6, external, general purpose */
  		.channel = 6,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 440,
  		.volt2 = 1000,
  	},
  	[7] = { /* ch7, internal, system supply */
  		.channel = 7,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 2200,
  		.volt2 = 5000,
  	},
  	[8] = { /* ch8, internal, backup battery */
  		.channel = 8,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 2200,
  		.volt2 = 5000,
  	},
  	[9] = { /* ch 9, internal, external charger input */
  		.channel = 9,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 3960,
  		.volt2 = 9000,
  	},
  	[10] = { /* ch10, internal, VBUS */
  		.channel = 10,
  		.code1 = 150,
  		.code2 = 751,
  		.volt1 = 1000,
  		.volt2 = 5000,
  	},
  	[11] = { /* ch 11, internal, VBUS DC-DC output current */
  		.channel = 11,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 660,
  		.volt2 = 1500,
  	},
  		/* ch 12, internal, Die temperature */
  		/* ch 13, internal, Die temperature */
  	[12] = { /* ch 14, internal, USB ID line */
  		.channel = 14,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 2420,
  		.volt2 = 5500,
  	},
  		/* ch 15, internal, test network */
  		/* ch 16, internal, test network */
  	[13] = { /* ch 17, internal, battery charging current */
  		.channel = 17,
  	},
  	[14] = { /* ch 18, internal, battery voltage */
  		.channel = 18,
  		.code1 = 1441,
  		.code2 = 3276,
  		.volt1 = 2200,
  		.volt2 = 5000,
  	},
  };
  
  static inline int twl6030_gpadc_write(u8 reg, u8 val)
  {
  	return twl_i2c_write_u8(TWL6030_MODULE_GPADC, val, reg);
  }
  
  static inline int twl6030_gpadc_read(u8 reg, u8 *val)
  {
  
  	return twl_i2c_read(TWL6030_MODULE_GPADC, val, reg, 2);
  }
  
  static int twl6030_gpadc_enable_irq(u8 mask)
  {
  	int ret;
  
  	ret = twl6030_interrupt_unmask(mask, REG_INT_MSK_LINE_B);
  	if (ret < 0)
  		return ret;
  
  	ret = twl6030_interrupt_unmask(mask, REG_INT_MSK_STS_B);
  
  	return ret;
  }
  
  static void twl6030_gpadc_disable_irq(u8 mask)
  {
  	twl6030_interrupt_mask(mask, REG_INT_MSK_LINE_B);
  	twl6030_interrupt_mask(mask, REG_INT_MSK_STS_B);
  }
  
  static irqreturn_t twl6030_gpadc_irq_handler(int irq, void *indio_dev)
  {
  	struct twl6030_gpadc_data *gpadc = iio_priv(indio_dev);
  
  	complete(&gpadc->irq_complete);
  
  	return IRQ_HANDLED;
  }
  
  static int twl6030_start_conversion(int channel)
  {
  	return twl6030_gpadc_write(TWL6030_GPADC_CTRL_P1,
  					TWL6030_GPADC_CTRL_P1_SP1);
  }
  
  static int twl6032_start_conversion(int channel)
  {
  	int ret;
  
  	ret = twl6030_gpadc_write(TWL6032_GPADC_GPSELECT_ISB, channel);
  	if (ret)
  		return ret;
  
  	return twl6030_gpadc_write(TWL6032_GPADC_CTRL_P1,
  						TWL6030_GPADC_CTRL_P1_SP1);
  }
  
  static u8 twl6030_channel_to_reg(int channel)
  {
  	return TWL6030_GPADC_GPCH0_LSB + 2 * channel;
  }
  
  static u8 twl6032_channel_to_reg(int channel)
  {
  	/*
  	 * for any prior chosen channel, when the conversion is ready
  	 * the result is avalable in GPCH0_LSB, GPCH0_MSB.
  	 */
  
  	return TWL6032_GPADC_GPCH0_LSB;
  }
  
  static int twl6030_gpadc_lookup(const struct twl6030_ideal_code *ideal,
  		int channel, int size)
  {
  	int i;
  
  	for (i = 0; i < size; i++)
  		if (ideal[i].channel == channel)
  			break;
  
  	return i;
  }
  
  static int twl6030_channel_calibrated(const struct twl6030_gpadc_platform_data
  		*pdata, int channel)
  {
  	const struct twl6030_ideal_code *ideal = pdata->ideal;
  	int i;
  
  	i = twl6030_gpadc_lookup(ideal, channel, pdata->nchannels);
  	/* not calibrated channels have 0 in all structure members */
  	return pdata->ideal[i].code2;
  }
  
  static int twl6030_gpadc_make_correction(struct twl6030_gpadc_data *gpadc,
  		int channel, int raw_code)
  {
  	const struct twl6030_ideal_code *ideal = gpadc->pdata->ideal;
  	int corrected_code;
  	int i;
  
  	i = twl6030_gpadc_lookup(ideal, channel, gpadc->pdata->nchannels);
  	corrected_code = ((raw_code * 1000) -
  		gpadc->twl6030_cal_tbl[i].offset_error) /
  		gpadc->twl6030_cal_tbl[i].gain_error;
  
  	return corrected_code;
  }
  
  static int twl6030_gpadc_get_raw(struct twl6030_gpadc_data *gpadc,
  		int channel, int *res)
  {
  	u8 reg = gpadc->pdata->channel_to_reg(channel);
  	__le16 val;
  	int raw_code;
  	int ret;
  
  	ret = twl6030_gpadc_read(reg, (u8 *)&val);
  	if (ret) {
  		dev_dbg(gpadc->dev, "unable to read register 0x%X
  ", reg);
  		return ret;
  	}
  
  	raw_code = le16_to_cpu(val);
  	dev_dbg(gpadc->dev, "GPADC raw code: %d", raw_code);
  
  	if (twl6030_channel_calibrated(gpadc->pdata, channel))
  		*res = twl6030_gpadc_make_correction(gpadc, channel, raw_code);
  	else
  		*res = raw_code;
  
  	return ret;
  }
  
  static int twl6030_gpadc_get_processed(struct twl6030_gpadc_data *gpadc,
  		int channel, int *val)
  {
  	const struct twl6030_ideal_code *ideal = gpadc->pdata->ideal;
  	int corrected_code;
  	int channel_value;
  	int i;
  	int ret;
  
  	ret = twl6030_gpadc_get_raw(gpadc, channel, &corrected_code);
  	if (ret)
  		return ret;
  
  	i = twl6030_gpadc_lookup(ideal, channel, gpadc->pdata->nchannels);
  	channel_value = corrected_code *
  			gpadc->twl6030_cal_tbl[i].gain;
  
  	/* Shift back into mV range */
  	channel_value /= 1000;
  
  	dev_dbg(gpadc->dev, "GPADC corrected code: %d", corrected_code);
  	dev_dbg(gpadc->dev, "GPADC value: %d", channel_value);
  
  	*val = channel_value;
  
  	return ret;
  }
  
  static int twl6030_gpadc_read_raw(struct iio_dev *indio_dev,
  			     const struct iio_chan_spec *chan,
  			     int *val, int *val2, long mask)
  {
  	struct twl6030_gpadc_data *gpadc = iio_priv(indio_dev);
  	int ret;
  	long timeout;
  
  	mutex_lock(&gpadc->lock);
  
  	ret = gpadc->pdata->start_conversion(chan->channel);
  	if (ret) {
  		dev_err(gpadc->dev, "failed to start conversion
  ");
  		goto err;
  	}
  	/* wait for conversion to complete */
  	timeout = wait_for_completion_interruptible_timeout(
  				&gpadc->irq_complete, msecs_to_jiffies(5000));
  	if (timeout == 0) {
  		ret = -ETIMEDOUT;
  		goto err;
  	} else if (timeout < 0) {
  		ret = -EINTR;
  		goto err;
  	}
  
  	switch (mask) {
  	case IIO_CHAN_INFO_RAW:
  		ret = twl6030_gpadc_get_raw(gpadc, chan->channel, val);
  		ret = ret ? -EIO : IIO_VAL_INT;
  		break;
  
  	case IIO_CHAN_INFO_PROCESSED:
  		ret = twl6030_gpadc_get_processed(gpadc, chan->channel, val);
  		ret = ret ? -EIO : IIO_VAL_INT;
  		break;
  
  	default:
  		break;
  	}
  err:
  	mutex_unlock(&gpadc->lock);
  
  	return ret;
  }
  
  /*
   * The GPADC channels are calibrated using a two point calibration method.
   * The channels measured with two known values: volt1 and volt2, and
   * ideal corresponding output codes are known: code1, code2.
   * The difference(d1, d2) between ideal and measured codes stored in trim
   * registers.
   * The goal is to find offset and gain of the real curve for each calibrated
   * channel.
   * gain: k = 1 + ((d2 - d1) / (x2 - x1))
   * offset: b = d1 + (k - 1) * x1
   */
  static void twl6030_calibrate_channel(struct twl6030_gpadc_data *gpadc,
  		int channel, int d1, int d2)
  {
  	int b, k, gain, x1, x2, i;
  	const struct twl6030_ideal_code *ideal = gpadc->pdata->ideal;
  
  	i = twl6030_gpadc_lookup(ideal, channel, gpadc->pdata->nchannels);
  
  	/* Gain */
  	gain = ((ideal[i].volt2 - ideal[i].volt1) * 1000) /
  		(ideal[i].code2 - ideal[i].code1);
  
  	x1 = ideal[i].code1;
  	x2 = ideal[i].code2;
  
  	/* k - real curve gain */
  	k = 1000 + (((d2 - d1) * 1000) / (x2 - x1));
  
  	/* b - offset of the real curve gain */
  	b = (d1 * 1000) - (k - 1000) * x1;
  
  	gpadc->twl6030_cal_tbl[i].gain = gain;
  	gpadc->twl6030_cal_tbl[i].gain_error = k;
  	gpadc->twl6030_cal_tbl[i].offset_error = b;
  
  	dev_dbg(gpadc->dev, "GPADC d1   for Chn: %d = %d
  ", channel, d1);
  	dev_dbg(gpadc->dev, "GPADC d2   for Chn: %d = %d
  ", channel, d2);
  	dev_dbg(gpadc->dev, "GPADC x1   for Chn: %d = %d
  ", channel, x1);
  	dev_dbg(gpadc->dev, "GPADC x2   for Chn: %d = %d
  ", channel, x2);
  	dev_dbg(gpadc->dev, "GPADC Gain for Chn: %d = %d
  ", channel, gain);
  	dev_dbg(gpadc->dev, "GPADC k    for Chn: %d = %d
  ", channel, k);
  	dev_dbg(gpadc->dev, "GPADC b    for Chn: %d = %d
  ", channel, b);
  }
  
  static inline int twl6030_gpadc_get_trim_offset(s8 d)
  {
  	/*
  	 * XXX NOTE!
  	 * bit 0 - sign, bit 7 - reserved, 6..1 - trim value
  	 * though, the documentation states that trim value
  	 * is absolute value, the correct conversion results are
  	 * obtained if the value is interpreted as 2's complement.
  	 */
  	__u32 temp = ((d & 0x7f) >> 1) | ((d & 1) << 6);
  
  	return sign_extend32(temp, 6);
  }
  
  static int twl6030_calibration(struct twl6030_gpadc_data *gpadc)
  {
  	int ret;
  	int chn;
  	u8 trim_regs[TWL6030_GPADC_NUM_TRIM_REGS];
  	s8 d1, d2;
  
  	/*
  	 * for calibration two measurements have been performed at
  	 * factory, for some channels, during the production test and
  	 * have been stored in registers. This two stored values are
  	 * used to correct the measurements. The values represent
  	 * offsets for the given input from the output on ideal curve.
  	 */
  	ret = twl_i2c_read(TWL6030_MODULE_ID2, trim_regs,
  			TWL6030_GPADC_TRIM1, TWL6030_GPADC_NUM_TRIM_REGS);
  	if (ret < 0) {
  		dev_err(gpadc->dev, "calibration failed
  ");
  		return ret;
  	}
  
  	for (chn = 0; chn < TWL6030_GPADC_MAX_CHANNELS; chn++) {
  
  		switch (chn) {
  		case 0:
  			d1 = trim_regs[0];
  			d2 = trim_regs[1];
  			break;
  		case 1:
  		case 3:
  		case 4:
  		case 5:
  		case 6:
  			d1 = trim_regs[4];
  			d2 = trim_regs[5];
  			break;
  		case 2:
  			d1 = trim_regs[12];
  			d2 = trim_regs[13];
  			break;
  		case 7:
  			d1 = trim_regs[6];
  			d2 = trim_regs[7];
  			break;
  		case 8:
  			d1 = trim_regs[2];
  			d2 = trim_regs[3];
  			break;
  		case 9:
  			d1 = trim_regs[8];
  			d2 = trim_regs[9];
  			break;
  		case 10:
  			d1 = trim_regs[10];
  			d2 = trim_regs[11];
  			break;
  		case 14:
  			d1 = trim_regs[14];
  			d2 = trim_regs[15];
  			break;
  		default:
  			continue;
  		}
  
  		d1 = twl6030_gpadc_get_trim_offset(d1);
  		d2 = twl6030_gpadc_get_trim_offset(d2);
  
  		twl6030_calibrate_channel(gpadc, chn, d1, d2);
  	}
  
  	return 0;
  }
  
  static int twl6032_get_trim_value(u8 *trim_regs, unsigned int reg0,
  		unsigned int reg1, unsigned int mask0, unsigned int mask1,
  		unsigned int shift0)
  {
  	int val;
  
  	val = (trim_regs[reg0] & mask0) << shift0;
  	val |= (trim_regs[reg1] & mask1) >> 1;
  	if (trim_regs[reg1] & 0x01)
  		val = -val;
  
  	return val;
  }
  
  static int twl6032_calibration(struct twl6030_gpadc_data *gpadc)
  {
  	int chn, d1 = 0, d2 = 0, temp;
  	u8 trim_regs[TWL6030_GPADC_NUM_TRIM_REGS];
  	int ret;
  
  	ret = twl_i2c_read(TWL6030_MODULE_ID2, trim_regs,
  			TWL6030_GPADC_TRIM1, TWL6030_GPADC_NUM_TRIM_REGS);
  	if (ret < 0) {
  		dev_err(gpadc->dev, "calibration failed
  ");
  		return ret;
  	}
  
  	/*
  	 * Loop to calculate the value needed for returning voltages from
  	 * GPADC not values.
  	 *
  	 * gain is calculated to 3 decimal places fixed point.
  	 */
  	for (chn = 0; chn < TWL6032_GPADC_MAX_CHANNELS; chn++) {
  
  		switch (chn) {
  		case 0:
  		case 1:
  		case 2:
  		case 3:
  		case 4:
  		case 5:
  		case 6:
  		case 11:
  		case 14:
  			d1 = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
  								0x06, 2);
  			d2 = twl6032_get_trim_value(trim_regs, 3, 1, 0x3f,
  								0x06, 2);
  			break;
  		case 8:
  			temp = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
  								0x06, 2);
  			d1 = temp + twl6032_get_trim_value(trim_regs, 7, 6,
  								0x18, 0x1E, 1);
  
  			temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x3F,
  								0x06, 2);
  			d2 = temp + twl6032_get_trim_value(trim_regs, 9, 7,
  								0x1F, 0x06, 2);
  			break;
  		case 9:
  			temp = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
  								0x06, 2);
  			d1 = temp + twl6032_get_trim_value(trim_regs, 13, 11,
  								0x18, 0x1E, 1);
  
  			temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x3f,
  								0x06, 2);
  			d2 = temp + twl6032_get_trim_value(trim_regs, 15, 13,
  								0x1F, 0x06, 1);
  			break;
  		case 10:
  			d1 = twl6032_get_trim_value(trim_regs, 10, 8, 0x0f,
  								0x0E, 3);
  			d2 = twl6032_get_trim_value(trim_regs, 14, 12, 0x0f,
  								0x0E, 3);
  			break;
  		case 7:
  		case 18:
  			temp = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
  								0x06, 2);
  
  			d1 = (trim_regs[4] & 0x7E) >> 1;
  			if (trim_regs[4] & 0x01)
  				d1 = -d1;
  			d1 += temp;
  
  			temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x3f,
  								0x06, 2);
  
  			d2 = (trim_regs[5] & 0xFE) >> 1;
  			if (trim_regs[5] & 0x01)
  				d2 = -d2;
  
  			d2 += temp;
  			break;
  		default:
  			/* No data for other channels */
  			continue;
  		}
  
  		twl6030_calibrate_channel(gpadc, chn, d1, d2);
  	}
  
  	return 0;
  }
  
  #define TWL6030_GPADC_CHAN(chn, _type, chan_info) {	\
  	.type = _type,					\
  	.channel = chn,					\
  	.info_mask_separate = BIT(chan_info),		\
  	.indexed = 1,					\
  }
  
  static const struct iio_chan_spec twl6030_gpadc_iio_channels[] = {
  	TWL6030_GPADC_CHAN(0, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(1, IIO_TEMP, IIO_CHAN_INFO_RAW),
  	TWL6030_GPADC_CHAN(2, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(3, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(4, IIO_TEMP, IIO_CHAN_INFO_RAW),
  	TWL6030_GPADC_CHAN(5, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(6, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(7, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(8, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(9, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(10, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(11, IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
  	TWL6030_GPADC_CHAN(14, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  };
  
  static const struct iio_chan_spec twl6032_gpadc_iio_channels[] = {
  	TWL6030_GPADC_CHAN(0, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(1, IIO_TEMP, IIO_CHAN_INFO_RAW),
  	TWL6030_GPADC_CHAN(2, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(3, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(4, IIO_TEMP, IIO_CHAN_INFO_RAW),
  	TWL6030_GPADC_CHAN(5, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(6, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(7, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(8, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(9, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(10, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(11, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(14, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  	TWL6030_GPADC_CHAN(17, IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
  	TWL6030_GPADC_CHAN(18, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
  };
  
  static const struct iio_info twl6030_gpadc_iio_info = {
  	.read_raw = &twl6030_gpadc_read_raw,
  	.driver_module = THIS_MODULE,
  };
  
  static const struct twl6030_gpadc_platform_data twl6030_pdata = {
  	.iio_channels = twl6030_gpadc_iio_channels,
  	.nchannels = TWL6030_GPADC_USED_CHANNELS,
  	.ideal = twl6030_ideal,
  	.start_conversion = twl6030_start_conversion,
  	.channel_to_reg = twl6030_channel_to_reg,
  	.calibrate = twl6030_calibration,
  };
  
  static const struct twl6030_gpadc_platform_data twl6032_pdata = {
  	.iio_channels = twl6032_gpadc_iio_channels,
  	.nchannels = TWL6032_GPADC_USED_CHANNELS,
  	.ideal = twl6032_ideal,
  	.start_conversion = twl6032_start_conversion,
  	.channel_to_reg = twl6032_channel_to_reg,
  	.calibrate = twl6032_calibration,
  };
  
  static const struct of_device_id of_twl6030_match_tbl[] = {
  	{
  		.compatible = "ti,twl6030-gpadc",
  		.data = &twl6030_pdata,
  	},
  	{
  		.compatible = "ti,twl6032-gpadc",
  		.data = &twl6032_pdata,
  	},
  	{ /* end */ }
  };
  
  static int twl6030_gpadc_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	struct twl6030_gpadc_data *gpadc;
  	const struct twl6030_gpadc_platform_data *pdata;
  	const struct of_device_id *match;
  	struct iio_dev *indio_dev;
  	int irq;
  	int ret;
  
  	match = of_match_device(of_twl6030_match_tbl, dev);
  	if (!match)
  		return -EINVAL;
  
  	pdata = match->data;
  
  	indio_dev = devm_iio_device_alloc(dev, sizeof(*gpadc));
  	if (!indio_dev)
  		return -ENOMEM;
  
  	gpadc = iio_priv(indio_dev);
  
  	gpadc->twl6030_cal_tbl = devm_kzalloc(dev,
  					sizeof(*gpadc->twl6030_cal_tbl) *
  					pdata->nchannels, GFP_KERNEL);
  	if (!gpadc->twl6030_cal_tbl)
  		return -ENOMEM;
  
  	gpadc->dev = dev;
  	gpadc->pdata = pdata;
  
  	platform_set_drvdata(pdev, indio_dev);
  	mutex_init(&gpadc->lock);
  	init_completion(&gpadc->irq_complete);
  
  	ret = pdata->calibrate(gpadc);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "failed to read calibration registers
  ");
  		return ret;
  	}
  
  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0) {
  		dev_err(&pdev->dev, "failed to get irq
  ");
  		return irq;
  	}
  
  	ret = devm_request_threaded_irq(dev, irq, NULL,
  				twl6030_gpadc_irq_handler,
  				IRQF_ONESHOT, "twl6030_gpadc", indio_dev);
  
  	ret = twl6030_gpadc_enable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "failed to enable GPADC interrupt
  ");
  		return ret;
  	}
  
  	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
  					TWL6030_REG_TOGGLE1);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "failed to enable GPADC module
  ");
  		return ret;
  	}
  
  	indio_dev->name = DRIVER_NAME;
  	indio_dev->dev.parent = dev;
  	indio_dev->info = &twl6030_gpadc_iio_info;
  	indio_dev->modes = INDIO_DIRECT_MODE;
  	indio_dev->channels = pdata->iio_channels;
  	indio_dev->num_channels = pdata->nchannels;
  
  	return iio_device_register(indio_dev);
  }
  
  static int twl6030_gpadc_remove(struct platform_device *pdev)
  {
  	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
  
  	twl6030_gpadc_disable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
  	iio_device_unregister(indio_dev);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int twl6030_gpadc_suspend(struct device *pdev)
  {
  	int ret;
  
  	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCR,
  				TWL6030_REG_TOGGLE1);
  	if (ret)
  		dev_err(pdev, "error resetting GPADC (%d)!
  ", ret);
  
  	return 0;
  };
  
  static int twl6030_gpadc_resume(struct device *pdev)
  {
  	int ret;
  
  	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
  				TWL6030_REG_TOGGLE1);
  	if (ret)
  		dev_err(pdev, "error setting GPADC (%d)!
  ", ret);
  
  	return 0;
  };
  #endif
  
  static SIMPLE_DEV_PM_OPS(twl6030_gpadc_pm_ops, twl6030_gpadc_suspend,
  					twl6030_gpadc_resume);
  
  static struct platform_driver twl6030_gpadc_driver = {
  	.probe		= twl6030_gpadc_probe,
  	.remove		= twl6030_gpadc_remove,
  	.driver		= {
  		.name	= DRIVER_NAME,
  		.owner	= THIS_MODULE,
  		.pm	= &twl6030_gpadc_pm_ops,
  		.of_match_table = of_twl6030_match_tbl,
  	},
  };
  
  module_platform_driver(twl6030_gpadc_driver);
  
  MODULE_ALIAS("platform: " DRIVER_NAME);
  MODULE_AUTHOR("Balaji T K <balajitk@ti.com>");
  MODULE_AUTHOR("Graeme Gregory <gg@slimlogic.co.uk>");
  MODULE_AUTHOR("Oleksandr Kozaruk <oleksandr.kozaruk@ti.com");
  MODULE_DESCRIPTION("twl6030 ADC driver");
  MODULE_LICENSE("GPL");