drivers/mfd/twl4030-madc.c - maze/linux - Git at Google

 /*
  *
  * TWL4030 MADC module driver-This driver monitors the real time
  * conversion of analog signals like battery temperature,
  * battery type, battery level etc.
  *
  * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
  * J Keerthy <j-keerthy@ti.com>
  *
  * Based on twl4030-madc.c
  * Copyright (C) 2008 Nokia Corporation
  * Mikko Ylinen <mikko.k.ylinen@nokia.com>
  *
  * Amit Kucheria <amit.kucheria@canonical.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/device.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/i2c/twl.h>
 #include <linux/i2c/twl4030-madc.h>
 #include <linux/module.h>
 #include <linux/stddef.h>
 #include <linux/mutex.h>
 #include <linux/bitops.h>
 #include <linux/jiffies.h>
 #include <linux/types.h>
 #include <linux/gfp.h>
 #include <linux/err.h>

 /*
  * struct twl4030_madc_data - a container for madc info
  * @dev - pointer to device structure for madc
  * @lock - mutex protecting this data structure
  * @requests - Array of request struct corresponding to SW1, SW2 and RT
  * @imr - Interrupt mask register of MADC
  * @isr - Interrupt status register of MADC
  */
 struct twl4030_madc_data {
 	struct device *dev;
 	struct mutex lock;	/* mutex protecting this data structure */
 	struct twl4030_madc_request requests[TWL4030_MADC_NUM_METHODS];
 	int imr;
 	int isr;
 };

 static struct twl4030_madc_data *twl4030_madc;

 struct twl4030_prescale_divider_ratios {
 	s16 numerator;
 	s16 denominator;
 };

 static const struct twl4030_prescale_divider_ratios
 twl4030_divider_ratios[16] = {
 	{1, 1},		/* CHANNEL 0 No Prescaler */
 	{1, 1},		/* CHANNEL 1 No Prescaler */
 	{6, 10},	/* CHANNEL 2 */
 	{6, 10},	/* CHANNEL 3 */
 	{6, 10},	/* CHANNEL 4 */
 	{6, 10},	/* CHANNEL 5 */
 	{6, 10},	/* CHANNEL 6 */
 	{6, 10},	/* CHANNEL 7 */
 	{3, 14},	/* CHANNEL 8 */
 	{1, 3},		/* CHANNEL 9 */
 	{1, 1},		/* CHANNEL 10 No Prescaler */
 	{15, 100},	/* CHANNEL 11 */
 	{1, 4},		/* CHANNEL 12 */
 	{1, 1},		/* CHANNEL 13 Reserved channels */
 	{1, 1},		/* CHANNEL 14 Reseved channels */
 	{5, 11},	/* CHANNEL 15 */
 };


 /*
  * Conversion table from -3 to 55 degree Celcius
  */
 static int therm_tbl[] = {
 30800,	29500,	28300,	27100,
 26000,	24900,	23900,	22900,	22000,	21100,	20300,	19400,	18700,	17900,
 17200,	16500,	15900,	15300,	14700,	14100,	13600,	13100,	12600,	12100,
 11600,	11200,	10800,	10400,	10000,	9630,	9280,	8950,	8620,	8310,
 8020,	7730,	7460,	7200,	6950,	6710,	6470,	6250,	6040,	5830,
 5640,	5450,	5260,	5090,	4920,	4760,	4600,	4450,	4310,	4170,
 4040,	3910,	3790,	3670,	3550
 };

 /*
  * Structure containing the registers
  * of different conversion methods supported by MADC.
  * Hardware or RT real time conversion request initiated by external host
  * processor for RT Signal conversions.
  * External host processors can also request for non RT conversions
  * SW1 and SW2 software conversions also called asynchronous or GPC request.
  */
 static
 const struct twl4030_madc_conversion_method twl4030_conversion_methods[] = {
 	[TWL4030_MADC_RT] = {
 			     .sel = TWL4030_MADC_RTSELECT_LSB,
 			     .avg = TWL4030_MADC_RTAVERAGE_LSB,
 			     .rbase = TWL4030_MADC_RTCH0_LSB,
 			     },
 	[TWL4030_MADC_SW1] = {
 			      .sel = TWL4030_MADC_SW1SELECT_LSB,
 			      .avg = TWL4030_MADC_SW1AVERAGE_LSB,
 			      .rbase = TWL4030_MADC_GPCH0_LSB,
 			      .ctrl = TWL4030_MADC_CTRL_SW1,
 			      },
 	[TWL4030_MADC_SW2] = {
 			      .sel = TWL4030_MADC_SW2SELECT_LSB,
 			      .avg = TWL4030_MADC_SW2AVERAGE_LSB,
 			      .rbase = TWL4030_MADC_GPCH0_LSB,
 			      .ctrl = TWL4030_MADC_CTRL_SW2,
 			      },
 };

 /*
  * Function to read a particular channel value.
  * @madc - pointer to struct twl4030_madc_data
  * @reg - lsb of ADC Channel
  * If the i2c read fails it returns an error else returns 0.
  */
 static int twl4030_madc_channel_raw_read(struct twl4030_madc_data *madc, u8 reg)
 {
 	u8 msb, lsb;
 	int ret;
 	/*
 	 * For each ADC channel, we have MSB and LSB register pair. MSB address
 	 * is always LSB address+1. reg parameter is the address of LSB register
 	 */
 	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &msb, reg + 1);
 	if (ret) {
 		dev_err(madc->dev, "unable to read MSB register 0x%X\n",
 			reg + 1);
 		return ret;
 	}
 	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &lsb, reg);
 	if (ret) {
 		dev_err(madc->dev, "unable to read LSB register 0x%X\n", reg);
 		return ret;
 	}

 	return (int)(((msb << 8) | lsb) >> 6);
 }

 /*
  * Return battery temperature
  * Or < 0 on failure.
  */
 static int twl4030battery_temperature(int raw_volt)
 {
 	u8 val;
 	int temp, curr, volt, res, ret;

 	volt = (raw_volt * TEMP_STEP_SIZE) / TEMP_PSR_R;
 	/* Getting and calculating the supply current in micro ampers */
 	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &val,
 		REG_BCICTL2);
 	if (ret < 0)
 		return ret;
 	curr = ((val & TWL4030_BCI_ITHEN) + 1) * 10;
 	/* Getting and calculating the thermistor resistance in ohms */
 	res = volt * 1000 / curr;
 	/* calculating temperature */
 	for (temp = 58; temp >= 0; temp--) {
 		int actual = therm_tbl[temp];

 		if ((actual - res) >= 0)
 			break;
 	}

 	return temp + 1;
 }

 static int twl4030battery_current(int raw_volt)
 {
 	int ret;
 	u8 val;

 	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &val,
 		TWL4030_BCI_BCICTL1);
 	if (ret)
 		return ret;
 	if (val & TWL4030_BCI_CGAIN) /* slope of 0.44 mV/mA */
 		return (raw_volt * CURR_STEP_SIZE) / CURR_PSR_R1;
 	else /* slope of 0.88 mV/mA */
 		return (raw_volt * CURR_STEP_SIZE) / CURR_PSR_R2;
 }
 /*
  * Function to read channel values
  * @madc - pointer to twl4030_madc_data struct
  * @reg_base - Base address of the first channel
  * @Channels - 16 bit bitmap. If the bit is set, channel value is read
  * @buf - The channel values are stored here. if read fails error
  * value is stored
  * Returns the number of successfully read channels.
  */
 static int twl4030_madc_read_channels(struct twl4030_madc_data *madc,
 				      u8 reg_base, unsigned
 						long channels, int *buf)
 {
 	int count = 0, count_req = 0, i;
 	u8 reg;

 	for_each_set_bit(i, &channels, TWL4030_MADC_MAX_CHANNELS) {
 		reg = reg_base + 2 * i;
 		buf[i] = twl4030_madc_channel_raw_read(madc, reg);
 		if (buf[i] < 0) {
 			dev_err(madc->dev,
 				"Unable to read register 0x%X\n", reg);
 			count_req++;
 			continue;
 		}
 		switch (i) {
 		case 10:
 			buf[i] = twl4030battery_current(buf[i]);
 			if (buf[i] < 0) {
 				dev_err(madc->dev, "err reading current\n");
 				count_req++;
 			} else {
 				count++;
 				buf[i] = buf[i] - 750;
 			}
 			break;
 		case 1:
 			buf[i] = twl4030battery_temperature(buf[i]);
 			if (buf[i] < 0) {
 				dev_err(madc->dev, "err reading temperature\n");
 				count_req++;
 			} else {
 				buf[i] -= 3;
 				count++;
 			}
 			break;
 		default:
 			count++;
 			/* Analog Input (V) = conv_result * step_size / R
 			 * conv_result = decimal value of 10-bit conversion
 			 *		 result
 			 * step size = 1.5 / (2 ^ 10 -1)
 			 * R = Prescaler ratio for input channels.
 			 * Result given in mV hence multiplied by 1000.
 			 */
 			buf[i] = (buf[i] * 3 * 1000 *
 				 twl4030_divider_ratios[i].denominator)
 				/ (2 * 1023 *
 				twl4030_divider_ratios[i].numerator);
 		}
 	}
 	if (count_req)
 		dev_err(madc->dev, "%d channel conversion failed\n", count_req);

 	return count;
 }

 /*
  * Enables irq.
  * @madc - pointer to twl4030_madc_data struct
  * @id - irq number to be enabled
  * can take one of TWL4030_MADC_RT, TWL4030_MADC_SW1, TWL4030_MADC_SW2
  * corresponding to RT, SW1, SW2 conversion requests.
  * If the i2c read fails it returns an error else returns 0.
  */
 static int twl4030_madc_enable_irq(struct twl4030_madc_data *madc, u8 id)
 {
 	u8 val;
 	int ret;

 	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &val, madc->imr);
 	if (ret) {
 		dev_err(madc->dev, "unable to read imr register 0x%X\n",
 			madc->imr);
 		return ret;
 	}
 	val &= ~(1 << id);
 	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, val, madc->imr);
 	if (ret) {
 		dev_err(madc->dev,
 			"unable to write imr register 0x%X\n", madc->imr);
 		return ret;

 	}

 	return 0;
 }

 /*
  * Disables irq.
  * @madc - pointer to twl4030_madc_data struct
  * @id - irq number to be disabled
  * can take one of TWL4030_MADC_RT, TWL4030_MADC_SW1, TWL4030_MADC_SW2
  * corresponding to RT, SW1, SW2 conversion requests.
  * Returns error if i2c read/write fails.
  */
 static int twl4030_madc_disable_irq(struct twl4030_madc_data *madc, u8 id)
 {
 	u8 val;
 	int ret;

 	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &val, madc->imr);
 	if (ret) {
 		dev_err(madc->dev, "unable to read imr register 0x%X\n",
 			madc->imr);
 		return ret;
 	}
 	val |= (1 << id);
 	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, val, madc->imr);
 	if (ret) {
 		dev_err(madc->dev,
 			"unable to write imr register 0x%X\n", madc->imr);
 		return ret;
 	}

 	return 0;
 }

 static irqreturn_t twl4030_madc_threaded_irq_handler(int irq, void *_madc)
 {
 	struct twl4030_madc_data *madc = _madc;
 	const struct twl4030_madc_conversion_method *method;
 	u8 isr_val, imr_val;
 	int i, len, ret;
 	struct twl4030_madc_request *r;

 	mutex_lock(&madc->lock);
 	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &isr_val, madc->isr);
 	if (ret) {
 		dev_err(madc->dev, "unable to read isr register 0x%X\n",
 			madc->isr);
 		goto err_i2c;
 	}
 	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &imr_val, madc->imr);
 	if (ret) {
 		dev_err(madc->dev, "unable to read imr register 0x%X\n",
 			madc->imr);
 		goto err_i2c;
 	}
 	isr_val &= ~imr_val;
 	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
 		if (!(isr_val & (1 << i)))
 			continue;
 		ret = twl4030_madc_disable_irq(madc, i);
 		if (ret < 0)
 			dev_dbg(madc->dev, "Disable interrupt failed%d\n", i);
 		madc->requests[i].result_pending = 1;
 	}
 	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
 		r = &madc->requests[i];
 		/* No pending results for this method, move to next one */
 		if (!r->result_pending)
 			continue;
 		method = &twl4030_conversion_methods[r->method];
 		/* Read results */
 		len = twl4030_madc_read_channels(madc, method->rbase,
 						 r->channels, r->rbuf);
 		/* Return results to caller */
 		if (r->func_cb != NULL) {
 			r->func_cb(len, r->channels, r->rbuf);
 			r->func_cb = NULL;
 		}
 		/* Free request */
 		r->result_pending = 0;
 		r->active = 0;
 	}
 	mutex_unlock(&madc->lock);

 	return IRQ_HANDLED;

 err_i2c:
 	/*
 	 * In case of error check whichever request is active
 	 * and service the same.
 	 */
 	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
 		r = &madc->requests[i];
 		if (r->active == 0)
 			continue;
 		method = &twl4030_conversion_methods[r->method];
 		/* Read results */
 		len = twl4030_madc_read_channels(madc, method->rbase,
 						 r->channels, r->rbuf);
 		/* Return results to caller */
 		if (r->func_cb != NULL) {
 			r->func_cb(len, r->channels, r->rbuf);
 			r->func_cb = NULL;
 		}
 		/* Free request */
 		r->result_pending = 0;
 		r->active = 0;
 	}
 	mutex_unlock(&madc->lock);

 	return IRQ_HANDLED;
 }

 static int twl4030_madc_set_irq(struct twl4030_madc_data *madc,
 				struct twl4030_madc_request *req)
 {
 	struct twl4030_madc_request *p;
 	int ret;

 	p = &madc->requests[req->method];
 	memcpy(p, req, sizeof(*req));
 	ret = twl4030_madc_enable_irq(madc, req->method);
 	if (ret < 0) {
 		dev_err(madc->dev, "enable irq failed!!\n");
 		return ret;
 	}

 	return 0;
 }

 /*
  * Function which enables the madc conversion
  * by writing to the control register.
  * @madc - pointer to twl4030_madc_data struct
  * @conv_method - can be TWL4030_MADC_RT, TWL4030_MADC_SW2, TWL4030_MADC_SW1
  * corresponding to RT SW1 or SW2 conversion methods.
  * Returns 0 if succeeds else a negative error value
  */
 static int twl4030_madc_start_conversion(struct twl4030_madc_data *madc,
 					 int conv_method)
 {
 	const struct twl4030_madc_conversion_method *method;
 	int ret = 0;
 	method = &twl4030_conversion_methods[conv_method];
 	switch (conv_method) {
 	case TWL4030_MADC_SW1:
 	case TWL4030_MADC_SW2:
 		ret = twl_i2c_write_u8(TWL4030_MODULE_MADC,
 				       TWL4030_MADC_SW_START, method->ctrl);
 		if (ret) {
 			dev_err(madc->dev,
 				"unable to write ctrl register 0x%X\n",
 				method->ctrl);
 			return ret;
 		}
 		break;
 	default:
 		break;
 	}

 	return 0;
 }

 /*
  * Function that waits for conversion to be ready
  * @madc - pointer to twl4030_madc_data struct
  * @timeout_ms - timeout value in milliseconds
  * @status_reg - ctrl register
  * returns 0 if succeeds else a negative error value
  */
 static int twl4030_madc_wait_conversion_ready(struct twl4030_madc_data *madc,
 					      unsigned int timeout_ms,
 					      u8 status_reg)
 {
 	unsigned long timeout;
 	int ret;

 	timeout = jiffies + msecs_to_jiffies(timeout_ms);
 	do {
 		u8 reg;

 		ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &reg, status_reg);
 		if (ret) {
 			dev_err(madc->dev,
 				"unable to read status register 0x%X\n",
 				status_reg);
 			return ret;
 		}
 		if (!(reg & TWL4030_MADC_BUSY) && (reg & TWL4030_MADC_EOC_SW))
 			return 0;
 		usleep_range(500, 2000);
 	} while (!time_after(jiffies, timeout));
 	dev_err(madc->dev, "conversion timeout!\n");

 	return -EAGAIN;
 }

 /*
  * An exported function which can be called from other kernel drivers.
  * @req twl4030_madc_request structure
  * req->rbuf will be filled with read values of channels based on the
  * channel index. If a particular channel reading fails there will
  * be a negative error value in the corresponding array element.
  * returns 0 if succeeds else error value
  */
 int twl4030_madc_conversion(struct twl4030_madc_request *req)
 {
 	const struct twl4030_madc_conversion_method *method;
 	u8 ch_msb, ch_lsb;
 	int ret;

 	if (!req || !twl4030_madc)
 		return -EINVAL;

 	mutex_lock(&twl4030_madc->lock);
 	if (req->method < TWL4030_MADC_RT || req->method > TWL4030_MADC_SW2) {
 		ret = -EINVAL;
 		goto out;
 	}
 	/* Do we have a conversion request ongoing */
 	if (twl4030_madc->requests[req->method].active) {
 		ret = -EBUSY;
 		goto out;
 	}
 	ch_msb = (req->channels >> 8) & 0xff;
 	ch_lsb = req->channels & 0xff;
 	method = &twl4030_conversion_methods[req->method];
 	/* Select channels to be converted */
 	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, ch_msb, method->sel + 1);
 	if (ret) {
 		dev_err(twl4030_madc->dev,
 			"unable to write sel register 0x%X\n", method->sel + 1);
 		goto out;
 	}
 	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, ch_lsb, method->sel);
 	if (ret) {
 		dev_err(twl4030_madc->dev,
 			"unable to write sel register 0x%X\n", method->sel + 1);
 		goto out;
 	}
 	/* Select averaging for all channels if do_avg is set */
 	if (req->do_avg) {
 		ret = twl_i2c_write_u8(TWL4030_MODULE_MADC,
 				       ch_msb, method->avg + 1);
 		if (ret) {
 			dev_err(twl4030_madc->dev,
 				"unable to write avg register 0x%X\n",
 				method->avg + 1);
 			goto out;
 		}
 		ret = twl_i2c_write_u8(TWL4030_MODULE_MADC,
 				       ch_lsb, method->avg);
 		if (ret) {
 			dev_err(twl4030_madc->dev,
 				"unable to write sel reg 0x%X\n",
 				method->sel + 1);
 			goto out;
 		}
 	}
 	if (req->type == TWL4030_MADC_IRQ_ONESHOT && req->func_cb != NULL) {
 		ret = twl4030_madc_set_irq(twl4030_madc, req);
 		if (ret < 0)
 			goto out;
 		ret = twl4030_madc_start_conversion(twl4030_madc, req->method);
 		if (ret < 0)
 			goto out;
 		twl4030_madc->requests[req->method].active = 1;
 		ret = 0;
 		goto out;
 	}
 	/* With RT method we should not be here anymore */
 	if (req->method == TWL4030_MADC_RT) {
 		ret = -EINVAL;
 		goto out;
 	}
 	ret = twl4030_madc_start_conversion(twl4030_madc, req->method);
 	if (ret < 0)
 		goto out;
 	twl4030_madc->requests[req->method].active = 1;
 	/* Wait until conversion is ready (ctrl register returns EOC) */
 	ret = twl4030_madc_wait_conversion_ready(twl4030_madc, 5, method->ctrl);
 	if (ret) {
 		twl4030_madc->requests[req->method].active = 0;
 		goto out;
 	}
 	ret = twl4030_madc_read_channels(twl4030_madc, method->rbase,
 					 req->channels, req->rbuf);
 	twl4030_madc->requests[req->method].active = 0;

 out:
 	mutex_unlock(&twl4030_madc->lock);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(twl4030_madc_conversion);

 /*
  * Return channel value
  * Or < 0 on failure.
  */
 int twl4030_get_madc_conversion(int channel_no)
 {
 	struct twl4030_madc_request req;
 	int temp = 0;
 	int ret;

 	req.channels = (1 << channel_no);
 	req.method = TWL4030_MADC_SW2;
 	req.active = 0;
 	req.func_cb = NULL;
 	ret = twl4030_madc_conversion(&req);
 	if (ret < 0)
 		return ret;
 	if (req.rbuf[channel_no] > 0)
 		temp = req.rbuf[channel_no];

 	return temp;
 }
 EXPORT_SYMBOL_GPL(twl4030_get_madc_conversion);

 /*
  * Function to enable or disable bias current for
  * main battery type reading or temperature sensing
  * @madc - pointer to twl4030_madc_data struct
  * @chan - can be one of the two values
  * TWL4030_BCI_ITHEN - Enables bias current for main battery type reading
  * TWL4030_BCI_TYPEN - Enables bias current for main battery temperature
  * sensing
  * @on - enable or disable chan.
  */
 static int twl4030_madc_set_current_generator(struct twl4030_madc_data *madc,
 					      int chan, int on)
 {
 	int ret;
 	u8 regval;

 	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
 			      &regval, TWL4030_BCI_BCICTL1);
 	if (ret) {
 		dev_err(madc->dev, "unable to read BCICTL1 reg 0x%X",
 			TWL4030_BCI_BCICTL1);
 		return ret;
 	}
 	if (on)
 		regval |= chan ? TWL4030_BCI_ITHEN : TWL4030_BCI_TYPEN;
 	else
 		regval &= chan ? ~TWL4030_BCI_ITHEN : ~TWL4030_BCI_TYPEN;
 	ret = twl_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
 			       regval, TWL4030_BCI_BCICTL1);
 	if (ret) {
 		dev_err(madc->dev, "unable to write BCICTL1 reg 0x%X\n",
 			TWL4030_BCI_BCICTL1);
 		return ret;
 	}

 	return 0;
 }

 /*
  * Function that sets MADC software power on bit to enable MADC
  * @madc - pointer to twl4030_madc_data struct
  * @on - Enable or disable MADC software powen on bit.
  * returns error if i2c read/write fails else 0
  */
 static int twl4030_madc_set_power(struct twl4030_madc_data *madc, int on)
 {
 	u8 regval;
 	int ret;

 	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
 			      &regval, TWL4030_MADC_CTRL1);
 	if (ret) {
 		dev_err(madc->dev, "unable to read madc ctrl1 reg 0x%X\n",
 			TWL4030_MADC_CTRL1);
 		return ret;
 	}
 	if (on)
 		regval |= TWL4030_MADC_MADCON;
 	else
 		regval &= ~TWL4030_MADC_MADCON;
 	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, regval, TWL4030_MADC_CTRL1);
 	if (ret) {
 		dev_err(madc->dev, "unable to write madc ctrl1 reg 0x%X\n",
 			TWL4030_MADC_CTRL1);
 		return ret;
 	}

 	return 0;
 }

 /*
  * Initialize MADC and request for threaded irq
  */
 static int __devinit twl4030_madc_probe(struct platform_device *pdev)
 {
 	struct twl4030_madc_data *madc;
 	struct twl4030_madc_platform_data *pdata = pdev->dev.platform_data;
 	int ret;
 	u8 regval;

 	if (!pdata) {
 		dev_err(&pdev->dev, "platform_data not available\n");
 		return -EINVAL;
 	}
 	madc = kzalloc(sizeof(*madc), GFP_KERNEL);
 	if (!madc)
 		return -ENOMEM;

 	madc->dev = &pdev->dev;

 	/*
 	 * Phoenix provides 2 interrupt lines. The first one is connected to
 	 * the OMAP. The other one can be connected to the other processor such
 	 * as modem. Hence two separate ISR and IMR registers.
 	 */
 	madc->imr = (pdata->irq_line == 1) ?
 	    TWL4030_MADC_IMR1 : TWL4030_MADC_IMR2;
 	madc->isr = (pdata->irq_line == 1) ?
 	    TWL4030_MADC_ISR1 : TWL4030_MADC_ISR2;
 	ret = twl4030_madc_set_power(madc, 1);
 	if (ret < 0)
 		goto err_power;
 	ret = twl4030_madc_set_current_generator(madc, 0, 1);
 	if (ret < 0)
 		goto err_current_generator;

 	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
 			      &regval, TWL4030_BCI_BCICTL1);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to read reg BCI CTL1 0x%X\n",
 			TWL4030_BCI_BCICTL1);
 		goto err_i2c;
 	}
 	regval |= TWL4030_BCI_MESBAT;
 	ret = twl_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
 			       regval, TWL4030_BCI_BCICTL1);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to write reg BCI Ctl1 0x%X\n",
 			TWL4030_BCI_BCICTL1);
 		goto err_i2c;
 	}
 	platform_set_drvdata(pdev, madc);
 	mutex_init(&madc->lock);
 	ret = request_threaded_irq(platform_get_irq(pdev, 0), NULL,
 				   twl4030_madc_threaded_irq_handler,
 				   IRQF_TRIGGER_RISING, "twl4030_madc", madc);
 	if (ret) {
 		dev_dbg(&pdev->dev, "could not request irq\n");
 		goto err_irq;
 	}
 	twl4030_madc = madc;
 	return 0;
 err_irq:
 	platform_set_drvdata(pdev, NULL);
 err_i2c:
 	twl4030_madc_set_current_generator(madc, 0, 0);
 err_current_generator:
 	twl4030_madc_set_power(madc, 0);
 err_power:
 	kfree(madc);

 	return ret;
 }

 static int __devexit twl4030_madc_remove(struct platform_device *pdev)
 {
 	struct twl4030_madc_data *madc = platform_get_drvdata(pdev);

 	free_irq(platform_get_irq(pdev, 0), madc);
 	platform_set_drvdata(pdev, NULL);
 	twl4030_madc_set_current_generator(madc, 0, 0);
 	twl4030_madc_set_power(madc, 0);
 	kfree(madc);

 	return 0;
 }

 static struct platform_driver twl4030_madc_driver = {
 	.probe = twl4030_madc_probe,
 	.remove = __exit_p(twl4030_madc_remove),
 	.driver = {
 		   .name = "twl4030_madc",
 		   .owner = THIS_MODULE,
 		   },
 };

 static int __init twl4030_madc_init(void)
 {
 	return platform_driver_register(&twl4030_madc_driver);
 }

 module_init(twl4030_madc_init);

 static void __exit twl4030_madc_exit(void)
 {
 	platform_driver_unregister(&twl4030_madc_driver);
 }

 module_exit(twl4030_madc_exit);

 MODULE_DESCRIPTION("TWL4030 ADC driver");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("J Keerthy");
 MODULE_ALIAS("platform:twl4030_madc");
	/*
	*
	* TWL4030 MADC module driver-This driver monitors the real time
	* conversion of analog signals like battery temperature,
	* battery type, battery level etc.
	*
	* Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
	* J Keerthy <j-keerthy@ti.com>
	*
	* Based on twl4030-madc.c
	* Copyright (C) 2008 Nokia Corporation
	* Mikko Ylinen <mikko.k.ylinen@nokia.com>
	*
	* Amit Kucheria <amit.kucheria@canonical.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/device.h>
	#include <linux/interrupt.h>
	#include <linux/kernel.h>
	#include <linux/delay.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/i2c/twl.h>
	#include <linux/i2c/twl4030-madc.h>
	#include <linux/module.h>
	#include <linux/stddef.h>
	#include <linux/mutex.h>
	#include <linux/bitops.h>
	#include <linux/jiffies.h>
	#include <linux/types.h>
	#include <linux/gfp.h>
	#include <linux/err.h>

	/*
	* struct twl4030_madc_data - a container for madc info
	* @dev - pointer to device structure for madc
	* @lock - mutex protecting this data structure
	* @requests - Array of request struct corresponding to SW1, SW2 and RT
	* @imr - Interrupt mask register of MADC
	* @isr - Interrupt status register of MADC
	*/
	struct twl4030_madc_data {
	struct device *dev;
	struct mutex lock; /* mutex protecting this data structure */
	struct twl4030_madc_request requests[TWL4030_MADC_NUM_METHODS];
	int imr;
	int isr;
	};

	static struct twl4030_madc_data *twl4030_madc;

	struct twl4030_prescale_divider_ratios {
	s16 numerator;
	s16 denominator;
	};

	static const struct twl4030_prescale_divider_ratios
	twl4030_divider_ratios[16] = {
	{1, 1}, /* CHANNEL 0 No Prescaler */
	{1, 1}, /* CHANNEL 1 No Prescaler */
	{6, 10}, /* CHANNEL 2 */
	{6, 10}, /* CHANNEL 3 */
	{6, 10}, /* CHANNEL 4 */
	{6, 10}, /* CHANNEL 5 */
	{6, 10}, /* CHANNEL 6 */
	{6, 10}, /* CHANNEL 7 */
	{3, 14}, /* CHANNEL 8 */
	{1, 3}, /* CHANNEL 9 */
	{1, 1}, /* CHANNEL 10 No Prescaler */
	{15, 100}, /* CHANNEL 11 */
	{1, 4}, /* CHANNEL 12 */
	{1, 1}, /* CHANNEL 13 Reserved channels */
	{1, 1}, /* CHANNEL 14 Reseved channels */
	{5, 11}, /* CHANNEL 15 */
	};


	/*
	* Conversion table from -3 to 55 degree Celcius
	*/
	static int therm_tbl[] = {
	30800, 29500, 28300, 27100,
	26000, 24900, 23900, 22900, 22000, 21100, 20300, 19400, 18700, 17900,
	17200, 16500, 15900, 15300, 14700, 14100, 13600, 13100, 12600, 12100,
	11600, 11200, 10800, 10400, 10000, 9630, 9280, 8950, 8620, 8310,
	8020, 7730, 7460, 7200, 6950, 6710, 6470, 6250, 6040, 5830,
	5640, 5450, 5260, 5090, 4920, 4760, 4600, 4450, 4310, 4170,
	4040, 3910, 3790, 3670, 3550
	};

	/*
	* Structure containing the registers
	* of different conversion methods supported by MADC.
	* Hardware or RT real time conversion request initiated by external host
	* processor for RT Signal conversions.
	* External host processors can also request for non RT conversions
	* SW1 and SW2 software conversions also called asynchronous or GPC request.
	*/
	static
	const struct twl4030_madc_conversion_method twl4030_conversion_methods[] = {
	[TWL4030_MADC_RT] = {
	.sel = TWL4030_MADC_RTSELECT_LSB,
	.avg = TWL4030_MADC_RTAVERAGE_LSB,
	.rbase = TWL4030_MADC_RTCH0_LSB,
	},
	[TWL4030_MADC_SW1] = {
	.sel = TWL4030_MADC_SW1SELECT_LSB,
	.avg = TWL4030_MADC_SW1AVERAGE_LSB,
	.rbase = TWL4030_MADC_GPCH0_LSB,
	.ctrl = TWL4030_MADC_CTRL_SW1,
	},
	[TWL4030_MADC_SW2] = {
	.sel = TWL4030_MADC_SW2SELECT_LSB,
	.avg = TWL4030_MADC_SW2AVERAGE_LSB,
	.rbase = TWL4030_MADC_GPCH0_LSB,
	.ctrl = TWL4030_MADC_CTRL_SW2,
	},
	};

	/*
	* Function to read a particular channel value.
	* @madc - pointer to struct twl4030_madc_data
	* @reg - lsb of ADC Channel
	* If the i2c read fails it returns an error else returns 0.
	*/
	static int twl4030_madc_channel_raw_read(struct twl4030_madc_data *madc, u8 reg)
	{
	u8 msb, lsb;
	int ret;
	/*
	* For each ADC channel, we have MSB and LSB register pair. MSB address
	* is always LSB address+1. reg parameter is the address of LSB register
	*/
	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &msb, reg + 1);
	if (ret) {
	dev_err(madc->dev, "unable to read MSB register 0x%X\n",
	reg + 1);
	return ret;
	}
	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &lsb, reg);
	if (ret) {
	dev_err(madc->dev, "unable to read LSB register 0x%X\n", reg);
	return ret;
	}

	return (int)(((msb << 8) \| lsb) >> 6);
	}

	/*
	* Return battery temperature
	* Or < 0 on failure.
	*/
	static int twl4030battery_temperature(int raw_volt)
	{
	u8 val;
	int temp, curr, volt, res, ret;

	volt = (raw_volt * TEMP_STEP_SIZE) / TEMP_PSR_R;
	/* Getting and calculating the supply current in micro ampers */
	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &val,
	REG_BCICTL2);
	if (ret < 0)
	return ret;
	curr = ((val & TWL4030_BCI_ITHEN) + 1) * 10;
	/* Getting and calculating the thermistor resistance in ohms */
	res = volt * 1000 / curr;
	/* calculating temperature */
	for (temp = 58; temp >= 0; temp--) {
	int actual = therm_tbl[temp];

	if ((actual - res) >= 0)
	break;
	}

	return temp + 1;
	}

	static int twl4030battery_current(int raw_volt)
	{
	int ret;
	u8 val;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &val,
	TWL4030_BCI_BCICTL1);
	if (ret)
	return ret;
	if (val & TWL4030_BCI_CGAIN) /* slope of 0.44 mV/mA */
	return (raw_volt * CURR_STEP_SIZE) / CURR_PSR_R1;
	else /* slope of 0.88 mV/mA */
	return (raw_volt * CURR_STEP_SIZE) / CURR_PSR_R2;
	}
	/*
	* Function to read channel values
	* @madc - pointer to twl4030_madc_data struct
	* @reg_base - Base address of the first channel
	* @Channels - 16 bit bitmap. If the bit is set, channel value is read
	* @buf - The channel values are stored here. if read fails error
	* value is stored
	* Returns the number of successfully read channels.
	*/
	static int twl4030_madc_read_channels(struct twl4030_madc_data *madc,
	u8 reg_base, unsigned
	long channels, int *buf)
	{
	int count = 0, count_req = 0, i;
	u8 reg;

	for_each_set_bit(i, &channels, TWL4030_MADC_MAX_CHANNELS) {
	reg = reg_base + 2 * i;
	buf[i] = twl4030_madc_channel_raw_read(madc, reg);
	if (buf[i] < 0) {
	dev_err(madc->dev,
	"Unable to read register 0x%X\n", reg);
	count_req++;
	continue;
	}
	switch (i) {
	case 10:
	buf[i] = twl4030battery_current(buf[i]);
	if (buf[i] < 0) {
	dev_err(madc->dev, "err reading current\n");
	count_req++;
	} else {
	count++;
	buf[i] = buf[i] - 750;
	}
	break;
	case 1:
	buf[i] = twl4030battery_temperature(buf[i]);
	if (buf[i] < 0) {
	dev_err(madc->dev, "err reading temperature\n");
	count_req++;
	} else {
	buf[i] -= 3;
	count++;
	}
	break;
	default:
	count++;
	/* Analog Input (V) = conv_result * step_size / R
	* conv_result = decimal value of 10-bit conversion
	* result
	* step size = 1.5 / (2 ^ 10 -1)
	* R = Prescaler ratio for input channels.
	* Result given in mV hence multiplied by 1000.
	*/
	buf[i] = (buf[i] * 3 * 1000 *
	twl4030_divider_ratios[i].denominator)
	/ (2 * 1023 *
	twl4030_divider_ratios[i].numerator);
	}
	}
	if (count_req)
	dev_err(madc->dev, "%d channel conversion failed\n", count_req);

	return count;
	}

	/*
	* Enables irq.
	* @madc - pointer to twl4030_madc_data struct
	* @id - irq number to be enabled
	* can take one of TWL4030_MADC_RT, TWL4030_MADC_SW1, TWL4030_MADC_SW2
	* corresponding to RT, SW1, SW2 conversion requests.
	* If the i2c read fails it returns an error else returns 0.
	*/
	static int twl4030_madc_enable_irq(struct twl4030_madc_data *madc, u8 id)
	{
	u8 val;
	int ret;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &val, madc->imr);
	if (ret) {
	dev_err(madc->dev, "unable to read imr register 0x%X\n",
	madc->imr);
	return ret;
	}
	val &= ~(1 << id);
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, val, madc->imr);
	if (ret) {
	dev_err(madc->dev,
	"unable to write imr register 0x%X\n", madc->imr);
	return ret;

	}

	return 0;
	}

	/*
	* Disables irq.
	* @madc - pointer to twl4030_madc_data struct
	* @id - irq number to be disabled
	* can take one of TWL4030_MADC_RT, TWL4030_MADC_SW1, TWL4030_MADC_SW2
	* corresponding to RT, SW1, SW2 conversion requests.
	* Returns error if i2c read/write fails.
	*/
	static int twl4030_madc_disable_irq(struct twl4030_madc_data *madc, u8 id)
	{
	u8 val;
	int ret;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &val, madc->imr);
	if (ret) {
	dev_err(madc->dev, "unable to read imr register 0x%X\n",
	madc->imr);
	return ret;
	}
	val \|= (1 << id);
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, val, madc->imr);
	if (ret) {
	dev_err(madc->dev,
	"unable to write imr register 0x%X\n", madc->imr);
	return ret;
	}

	return 0;
	}

	static irqreturn_t twl4030_madc_threaded_irq_handler(int irq, void *_madc)
	{
	struct twl4030_madc_data *madc = _madc;
	const struct twl4030_madc_conversion_method *method;
	u8 isr_val, imr_val;
	int i, len, ret;
	struct twl4030_madc_request *r;

	mutex_lock(&madc->lock);
	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &isr_val, madc->isr);
	if (ret) {
	dev_err(madc->dev, "unable to read isr register 0x%X\n",
	madc->isr);
	goto err_i2c;
	}
	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &imr_val, madc->imr);
	if (ret) {
	dev_err(madc->dev, "unable to read imr register 0x%X\n",
	madc->imr);
	goto err_i2c;
	}
	isr_val &= ~imr_val;
	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
	if (!(isr_val & (1 << i)))
	continue;
	ret = twl4030_madc_disable_irq(madc, i);
	if (ret < 0)
	dev_dbg(madc->dev, "Disable interrupt failed%d\n", i);
	madc->requests[i].result_pending = 1;
	}
	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
	r = &madc->requests[i];
	/* No pending results for this method, move to next one */
	if (!r->result_pending)
	continue;
	method = &twl4030_conversion_methods[r->method];
	/* Read results */
	len = twl4030_madc_read_channels(madc, method->rbase,
	r->channels, r->rbuf);
	/* Return results to caller */
	if (r->func_cb != NULL) {
	r->func_cb(len, r->channels, r->rbuf);
	r->func_cb = NULL;
	}
	/* Free request */
	r->result_pending = 0;
	r->active = 0;
	}
	mutex_unlock(&madc->lock);

	return IRQ_HANDLED;

	err_i2c:
	/*
	* In case of error check whichever request is active
	* and service the same.
	*/
	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
	r = &madc->requests[i];
	if (r->active == 0)
	continue;
	method = &twl4030_conversion_methods[r->method];
	/* Read results */
	len = twl4030_madc_read_channels(madc, method->rbase,
	r->channels, r->rbuf);
	/* Return results to caller */
	if (r->func_cb != NULL) {
	r->func_cb(len, r->channels, r->rbuf);
	r->func_cb = NULL;
	}
	/* Free request */
	r->result_pending = 0;
	r->active = 0;
	}
	mutex_unlock(&madc->lock);

	return IRQ_HANDLED;
	}

	static int twl4030_madc_set_irq(struct twl4030_madc_data *madc,
	struct twl4030_madc_request *req)
	{
	struct twl4030_madc_request *p;
	int ret;

	p = &madc->requests[req->method];
	memcpy(p, req, sizeof(*req));
	ret = twl4030_madc_enable_irq(madc, req->method);
	if (ret < 0) {
	dev_err(madc->dev, "enable irq failed!!\n");
	return ret;
	}

	return 0;
	}

	/*
	* Function which enables the madc conversion
	* by writing to the control register.
	* @madc - pointer to twl4030_madc_data struct
	* @conv_method - can be TWL4030_MADC_RT, TWL4030_MADC_SW2, TWL4030_MADC_SW1
	* corresponding to RT SW1 or SW2 conversion methods.
	* Returns 0 if succeeds else a negative error value
	*/
	static int twl4030_madc_start_conversion(struct twl4030_madc_data *madc,
	int conv_method)
	{
	const struct twl4030_madc_conversion_method *method;
	int ret = 0;
	method = &twl4030_conversion_methods[conv_method];
	switch (conv_method) {
	case TWL4030_MADC_SW1:
	case TWL4030_MADC_SW2:
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC,
	TWL4030_MADC_SW_START, method->ctrl);
	if (ret) {
	dev_err(madc->dev,
	"unable to write ctrl register 0x%X\n",
	method->ctrl);
	return ret;
	}
	break;
	default:
	break;
	}

	return 0;
	}

	/*
	* Function that waits for conversion to be ready
	* @madc - pointer to twl4030_madc_data struct
	* @timeout_ms - timeout value in milliseconds
	* @status_reg - ctrl register
	* returns 0 if succeeds else a negative error value
	*/
	static int twl4030_madc_wait_conversion_ready(struct twl4030_madc_data *madc,
	unsigned int timeout_ms,
	u8 status_reg)
	{
	unsigned long timeout;
	int ret;

	timeout = jiffies + msecs_to_jiffies(timeout_ms);
	do {
	u8 reg;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &reg, status_reg);
	if (ret) {
	dev_err(madc->dev,
	"unable to read status register 0x%X\n",
	status_reg);
	return ret;
	}
	if (!(reg & TWL4030_MADC_BUSY) && (reg & TWL4030_MADC_EOC_SW))
	return 0;
	usleep_range(500, 2000);
	} while (!time_after(jiffies, timeout));
	dev_err(madc->dev, "conversion timeout!\n");

	return -EAGAIN;
	}

	/*
	* An exported function which can be called from other kernel drivers.
	* @req twl4030_madc_request structure
	* req->rbuf will be filled with read values of channels based on the
	* channel index. If a particular channel reading fails there will
	* be a negative error value in the corresponding array element.
	* returns 0 if succeeds else error value
	*/
	int twl4030_madc_conversion(struct twl4030_madc_request *req)
	{
	const struct twl4030_madc_conversion_method *method;
	u8 ch_msb, ch_lsb;
	int ret;

	if (!req \|\| !twl4030_madc)
	return -EINVAL;

	mutex_lock(&twl4030_madc->lock);
	if (req->method < TWL4030_MADC_RT \|\| req->method > TWL4030_MADC_SW2) {
	ret = -EINVAL;
	goto out;
	}
	/* Do we have a conversion request ongoing */
	if (twl4030_madc->requests[req->method].active) {
	ret = -EBUSY;
	goto out;
	}
	ch_msb = (req->channels >> 8) & 0xff;
	ch_lsb = req->channels & 0xff;
	method = &twl4030_conversion_methods[req->method];
	/* Select channels to be converted */
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, ch_msb, method->sel + 1);
	if (ret) {
	dev_err(twl4030_madc->dev,
	"unable to write sel register 0x%X\n", method->sel + 1);
	goto out;
	}
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, ch_lsb, method->sel);
	if (ret) {
	dev_err(twl4030_madc->dev,
	"unable to write sel register 0x%X\n", method->sel + 1);
	goto out;
	}
	/* Select averaging for all channels if do_avg is set */
	if (req->do_avg) {
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC,
	ch_msb, method->avg + 1);
	if (ret) {
	dev_err(twl4030_madc->dev,
	"unable to write avg register 0x%X\n",
	method->avg + 1);
	goto out;
	}
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC,
	ch_lsb, method->avg);
	if (ret) {
	dev_err(twl4030_madc->dev,
	"unable to write sel reg 0x%X\n",
	method->sel + 1);
	goto out;
	}
	}
	if (req->type == TWL4030_MADC_IRQ_ONESHOT && req->func_cb != NULL) {
	ret = twl4030_madc_set_irq(twl4030_madc, req);
	if (ret < 0)
	goto out;
	ret = twl4030_madc_start_conversion(twl4030_madc, req->method);
	if (ret < 0)
	goto out;
	twl4030_madc->requests[req->method].active = 1;
	ret = 0;
	goto out;
	}
	/* With RT method we should not be here anymore */
	if (req->method == TWL4030_MADC_RT) {
	ret = -EINVAL;
	goto out;
	}
	ret = twl4030_madc_start_conversion(twl4030_madc, req->method);
	if (ret < 0)
	goto out;
	twl4030_madc->requests[req->method].active = 1;
	/* Wait until conversion is ready (ctrl register returns EOC) */
	ret = twl4030_madc_wait_conversion_ready(twl4030_madc, 5, method->ctrl);
	if (ret) {
	twl4030_madc->requests[req->method].active = 0;
	goto out;
	}
	ret = twl4030_madc_read_channels(twl4030_madc, method->rbase,
	req->channels, req->rbuf);
	twl4030_madc->requests[req->method].active = 0;

	out:
	mutex_unlock(&twl4030_madc->lock);

	return ret;
	}
	EXPORT_SYMBOL_GPL(twl4030_madc_conversion);

	/*
	* Return channel value
	* Or < 0 on failure.
	*/
	int twl4030_get_madc_conversion(int channel_no)
	{
	struct twl4030_madc_request req;
	int temp = 0;
	int ret;

	req.channels = (1 << channel_no);
	req.method = TWL4030_MADC_SW2;
	req.active = 0;
	req.func_cb = NULL;
	ret = twl4030_madc_conversion(&req);
	if (ret < 0)
	return ret;
	if (req.rbuf[channel_no] > 0)
	temp = req.rbuf[channel_no];

	return temp;
	}
	EXPORT_SYMBOL_GPL(twl4030_get_madc_conversion);

	/*
	* Function to enable or disable bias current for
	* main battery type reading or temperature sensing
	* @madc - pointer to twl4030_madc_data struct
	* @chan - can be one of the two values
	* TWL4030_BCI_ITHEN - Enables bias current for main battery type reading
	* TWL4030_BCI_TYPEN - Enables bias current for main battery temperature
	* sensing
	* @on - enable or disable chan.
	*/
	static int twl4030_madc_set_current_generator(struct twl4030_madc_data *madc,
	int chan, int on)
	{
	int ret;
	u8 regval;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
	&regval, TWL4030_BCI_BCICTL1);
	if (ret) {
	dev_err(madc->dev, "unable to read BCICTL1 reg 0x%X",
	TWL4030_BCI_BCICTL1);
	return ret;
	}
	if (on)
	regval \|= chan ? TWL4030_BCI_ITHEN : TWL4030_BCI_TYPEN;
	else
	regval &= chan ? ~TWL4030_BCI_ITHEN : ~TWL4030_BCI_TYPEN;
	ret = twl_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
	regval, TWL4030_BCI_BCICTL1);
	if (ret) {
	dev_err(madc->dev, "unable to write BCICTL1 reg 0x%X\n",
	TWL4030_BCI_BCICTL1);
	return ret;
	}

	return 0;
	}

	/*
	* Function that sets MADC software power on bit to enable MADC
	* @madc - pointer to twl4030_madc_data struct
	* @on - Enable or disable MADC software powen on bit.
	* returns error if i2c read/write fails else 0
	*/
	static int twl4030_madc_set_power(struct twl4030_madc_data *madc, int on)
	{
	u8 regval;
	int ret;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
	&regval, TWL4030_MADC_CTRL1);
	if (ret) {
	dev_err(madc->dev, "unable to read madc ctrl1 reg 0x%X\n",
	TWL4030_MADC_CTRL1);
	return ret;
	}
	if (on)
	regval \|= TWL4030_MADC_MADCON;
	else
	regval &= ~TWL4030_MADC_MADCON;
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, regval, TWL4030_MADC_CTRL1);
	if (ret) {
	dev_err(madc->dev, "unable to write madc ctrl1 reg 0x%X\n",
	TWL4030_MADC_CTRL1);
	return ret;
	}

	return 0;
	}

	/*
	* Initialize MADC and request for threaded irq
	*/
	static int __devinit twl4030_madc_probe(struct platform_device *pdev)
	{
	struct twl4030_madc_data *madc;
	struct twl4030_madc_platform_data *pdata = pdev->dev.platform_data;
	int ret;
	u8 regval;

	if (!pdata) {
	dev_err(&pdev->dev, "platform_data not available\n");
	return -EINVAL;
	}
	madc = kzalloc(sizeof(*madc), GFP_KERNEL);
	if (!madc)
	return -ENOMEM;

	madc->dev = &pdev->dev;

	/*
	* Phoenix provides 2 interrupt lines. The first one is connected to
	* the OMAP. The other one can be connected to the other processor such
	* as modem. Hence two separate ISR and IMR registers.
	*/
	madc->imr = (pdata->irq_line == 1) ?
	TWL4030_MADC_IMR1 : TWL4030_MADC_IMR2;
	madc->isr = (pdata->irq_line == 1) ?
	TWL4030_MADC_ISR1 : TWL4030_MADC_ISR2;
	ret = twl4030_madc_set_power(madc, 1);
	if (ret < 0)
	goto err_power;
	ret = twl4030_madc_set_current_generator(madc, 0, 1);
	if (ret < 0)
	goto err_current_generator;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
	&regval, TWL4030_BCI_BCICTL1);
	if (ret) {
	dev_err(&pdev->dev, "unable to read reg BCI CTL1 0x%X\n",
	TWL4030_BCI_BCICTL1);
	goto err_i2c;
	}
	regval \|= TWL4030_BCI_MESBAT;
	ret = twl_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
	regval, TWL4030_BCI_BCICTL1);
	if (ret) {
	dev_err(&pdev->dev, "unable to write reg BCI Ctl1 0x%X\n",
	TWL4030_BCI_BCICTL1);
	goto err_i2c;
	}
	platform_set_drvdata(pdev, madc);
	mutex_init(&madc->lock);
	ret = request_threaded_irq(platform_get_irq(pdev, 0), NULL,
	twl4030_madc_threaded_irq_handler,
	IRQF_TRIGGER_RISING, "twl4030_madc", madc);
	if (ret) {
	dev_dbg(&pdev->dev, "could not request irq\n");
	goto err_irq;
	}
	twl4030_madc = madc;
	return 0;
	err_irq:
	platform_set_drvdata(pdev, NULL);
	err_i2c:
	twl4030_madc_set_current_generator(madc, 0, 0);
	err_current_generator:
	twl4030_madc_set_power(madc, 0);
	err_power:
	kfree(madc);

	return ret;
	}

	static int __devexit twl4030_madc_remove(struct platform_device *pdev)
	{
	struct twl4030_madc_data *madc = platform_get_drvdata(pdev);

	free_irq(platform_get_irq(pdev, 0), madc);
	platform_set_drvdata(pdev, NULL);
	twl4030_madc_set_current_generator(madc, 0, 0);
	twl4030_madc_set_power(madc, 0);
	kfree(madc);

	return 0;
	}

	static struct platform_driver twl4030_madc_driver = {
	.probe = twl4030_madc_probe,
	.remove = __exit_p(twl4030_madc_remove),
	.driver = {
	.name = "twl4030_madc",
	.owner = THIS_MODULE,
	},
	};

	static int __init twl4030_madc_init(void)
	{
	return platform_driver_register(&twl4030_madc_driver);
	}

	module_init(twl4030_madc_init);

	static void __exit twl4030_madc_exit(void)
	{
	platform_driver_unregister(&twl4030_madc_driver);
	}

	module_exit(twl4030_madc_exit);

	MODULE_DESCRIPTION("TWL4030 ADC driver");
	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("J Keerthy");
	MODULE_ALIAS("platform:twl4030_madc");