mfd: twl4030-madc: Move driver to drivers/iio/adc

This is a driver for an A/D converter, which belongs into
drivers/iio/adc.

Signed-off-by: Sebastian Reichel <sre@debian.org>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 896 insertions, 0 deletions

diff --git a/drivers/iio/adc/twl4030-madc.c b/drivers/iio/adc/twl4030-madc.c
new file mode 100644
index 000000000000..8a014fbb98bc
--- /dev/null
+++ b/drivers/iio/adc/twl4030-madc.c
@@ -0,0 +1,896 @@
+/*
+ *
+ * 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>
+
+#include <linux/iio/iio.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
+ * @use_second_irq:	IRQ selection (main or co-processor)
+ * @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];
+	bool use_second_irq;
+	u8 imr;
+	u8 isr;
+};
+
+static int twl4030_madc_read(struct iio_dev *iio_dev,
+			     const struct iio_chan_spec *chan,
+			     int *val, int *val2, long mask)
+{
+	struct twl4030_madc_data *madc = iio_priv(iio_dev);
+	struct twl4030_madc_request req;
+	int ret;
+
+	req.method = madc->use_second_irq ? TWL4030_MADC_SW2 : TWL4030_MADC_SW1;
+
+	req.channels = BIT(chan->channel);
+	req.active = false;
+	req.func_cb = NULL;
+	req.type = TWL4030_MADC_WAIT;
+	req.raw = !(mask == IIO_CHAN_INFO_PROCESSED);
+	req.do_avg = (mask == IIO_CHAN_INFO_AVERAGE_RAW);
+
+	ret = twl4030_madc_conversion(&req);
+	if (ret < 0)
+		return ret;
+
+	*val = req.rbuf[chan->channel];
+
+	return IIO_VAL_INT;
+}
+
+static const struct iio_info twl4030_madc_iio_info = {
+	.read_raw = &twl4030_madc_read,
+	.driver_module = THIS_MODULE,
+};
+
+#define TWL4030_ADC_CHANNEL(_channel, _type, _name) {	\
+	.type = _type,					\
+	.channel = _channel,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
+			      BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
+			      BIT(IIO_CHAN_INFO_PROCESSED), \
+	.datasheet_name = _name,			\
+	.indexed = 1,					\
+}
+
+static const struct iio_chan_spec twl4030_madc_iio_channels[] = {
+	TWL4030_ADC_CHANNEL(0, IIO_VOLTAGE, "ADCIN0"),
+	TWL4030_ADC_CHANNEL(1, IIO_TEMP, "ADCIN1"),
+	TWL4030_ADC_CHANNEL(2, IIO_VOLTAGE, "ADCIN2"),
+	TWL4030_ADC_CHANNEL(3, IIO_VOLTAGE, "ADCIN3"),
+	TWL4030_ADC_CHANNEL(4, IIO_VOLTAGE, "ADCIN4"),
+	TWL4030_ADC_CHANNEL(5, IIO_VOLTAGE, "ADCIN5"),
+	TWL4030_ADC_CHANNEL(6, IIO_VOLTAGE, "ADCIN6"),
+	TWL4030_ADC_CHANNEL(7, IIO_VOLTAGE, "ADCIN7"),
+	TWL4030_ADC_CHANNEL(8, IIO_VOLTAGE, "ADCIN8"),
+	TWL4030_ADC_CHANNEL(9, IIO_VOLTAGE, "ADCIN9"),
+	TWL4030_ADC_CHANNEL(10, IIO_CURRENT, "ADCIN10"),
+	TWL4030_ADC_CHANNEL(11, IIO_VOLTAGE, "ADCIN11"),
+	TWL4030_ADC_CHANNEL(12, IIO_VOLTAGE, "ADCIN12"),
+	TWL4030_ADC_CHANNEL(13, IIO_VOLTAGE, "ADCIN13"),
+	TWL4030_ADC_CHANNEL(14, IIO_VOLTAGE, "ADCIN14"),
+	TWL4030_ADC_CHANNEL(15, IIO_VOLTAGE, "ADCIN15"),
+};
+
+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 degrees Celcius */
+static int twl4030_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,
+			      },
+};
+
+/**
+ * twl4030_madc_channel_raw_read() - Function to read a particular channel value
+ * @madc:	pointer to struct twl4030_madc_data
+ * @reg:	lsb of ADC Channel
+ *
+ * Return: 0 on success, an error code otherwise.
+ */
+static int twl4030_madc_channel_raw_read(struct twl4030_madc_data *madc, u8 reg)
+{
+	u16 val;
+	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_u16(TWL4030_MODULE_MADC, &val, reg);
+	if (ret) {
+		dev_err(madc->dev, "unable to read register 0x%X\n", reg);
+		return ret;
+	}
+
+	return (int)(val >> 6);
+}
+
+/*
+ * Return battery temperature in degrees Celsius
+ * 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 amperes */
+	ret = twl_i2c_read_u8(TWL_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 = twl4030_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(TWL_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's value is read
+ * @buf - The channel values are stored here. if read fails error
+ * @raw - Return raw values without conversion
+ * 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,
+				      bool raw)
+{
+	int count = 0;
+	int 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);
+			return buf[i];
+		}
+		if (raw) {
+			count++;
+			continue;
+		}
+		switch (i) {
+		case 10:
+			buf[i] = twl4030battery_current(buf[i]);
+			if (buf[i] < 0) {
+				dev_err(madc->dev, "err reading current\n");
+				return buf[i];
+			} 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");
+				return buf[i];
+			} 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);
+		}
+	}
+
+	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, r->raw);
+		/* 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, r->raw);
+		/* 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;
+
+	if (conv_method != TWL4030_MADC_SW1 && conv_method != TWL4030_MADC_SW2)
+		return -ENOTSUPP;
+
+	method = &twl4030_conversion_methods[conv_method];
+	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;
+	}
+
+	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;
+	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;
+	}
+	method = &twl4030_conversion_methods[req->method];
+	/* Select channels to be converted */
+	ret = twl_i2c_write_u16(TWL4030_MODULE_MADC, req->channels, method->sel);
+	if (ret) {
+		dev_err(twl4030_madc->dev,
+			"unable to write sel register 0x%X\n", method->sel);
+		goto out;
+	}
+	/* Select averaging for all channels if do_avg is set */
+	if (req->do_avg) {
+		ret = twl_i2c_write_u16(TWL4030_MODULE_MADC, req->channels,
+				       method->avg);
+		if (ret) {
+			dev_err(twl4030_madc->dev,
+				"unable to write avg register 0x%X\n",
+				method->avg);
+			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, req->raw);
+	twl4030_madc->requests[req->method].active = 0;
+
+out:
+	mutex_unlock(&twl4030_madc->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(twl4030_madc_conversion);
+
+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);
+
+/**
+ * twl4030_madc_set_current_generator() - setup bias current
+ *
+ * @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.
+ *
+ * Function to enable or disable bias current for
+ * main battery type reading or temperature sensing
+ */
+static int twl4030_madc_set_current_generator(struct twl4030_madc_data *madc,
+					      int chan, int on)
+{
+	int ret;
+	int regmask;
+	u8 regval;
+
+	ret = twl_i2c_read_u8(TWL_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;
+	}
+
+	regmask = chan ? TWL4030_BCI_ITHEN : TWL4030_BCI_TYPEN;
+	if (on)
+		regval |= regmask;
+	else
+		regval &= ~regmask;
+
+	ret = twl_i2c_write_u8(TWL_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 power 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(TWL_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 twl4030_madc_probe(struct platform_device *pdev)
+{
+	struct twl4030_madc_data *madc;
+	struct twl4030_madc_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct device_node *np = pdev->dev.of_node;
+	int irq, ret;
+	u8 regval;
+	struct iio_dev *iio_dev = NULL;
+
+	if (!pdata && !np) {
+		dev_err(&pdev->dev, "neither platform data nor Device Tree node available\n");
+		return -EINVAL;
+	}
+
+	iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*madc));
+	if (!iio_dev) {
+		dev_err(&pdev->dev, "failed allocating iio device\n");
+		return -ENOMEM;
+	}
+
+	madc = iio_priv(iio_dev);
+	madc->dev = &pdev->dev;
+
+	iio_dev->name = dev_name(&pdev->dev);
+	iio_dev->dev.parent = &pdev->dev;
+	iio_dev->dev.of_node = pdev->dev.of_node;
+	iio_dev->info = &twl4030_madc_iio_info;
+	iio_dev->modes = INDIO_DIRECT_MODE;
+	iio_dev->channels = twl4030_madc_iio_channels;
+	iio_dev->num_channels = ARRAY_SIZE(twl4030_madc_iio_channels);
+
+	/*
+	 * 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.
+	 */
+	if (pdata)
+		madc->use_second_irq = (pdata->irq_line != 1);
+	else
+		madc->use_second_irq = of_property_read_bool(np,
+				       "ti,system-uses-second-madc-irq");
+
+	madc->imr = madc->use_second_irq ? TWL4030_MADC_IMR2 :
+					   TWL4030_MADC_IMR1;
+	madc->isr = madc->use_second_irq ? TWL4030_MADC_ISR2 :
+					   TWL4030_MADC_ISR1;
+
+	ret = twl4030_madc_set_power(madc, 1);
+	if (ret < 0)
+		return ret;
+	ret = twl4030_madc_set_current_generator(madc, 0, 1);
+	if (ret < 0)
+		goto err_current_generator;
+
+	ret = twl_i2c_read_u8(TWL_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(TWL_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;
+	}
+
+	/* Check that MADC clock is on */
+	ret = twl_i2c_read_u8(TWL4030_MODULE_INTBR, &regval, TWL4030_REG_GPBR1);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to read reg GPBR1 0x%X\n",
+				TWL4030_REG_GPBR1);
+		goto err_i2c;
+	}
+
+	/* If MADC clk is not on, turn it on */
+	if (!(regval & TWL4030_GPBR1_MADC_HFCLK_EN)) {
+		dev_info(&pdev->dev, "clk disabled, enabling\n");
+		regval |= TWL4030_GPBR1_MADC_HFCLK_EN;
+		ret = twl_i2c_write_u8(TWL4030_MODULE_INTBR, regval,
+				       TWL4030_REG_GPBR1);
+		if (ret) {
+			dev_err(&pdev->dev, "unable to write reg GPBR1 0x%X\n",
+					TWL4030_REG_GPBR1);
+			goto err_i2c;
+		}
+	}
+
+	platform_set_drvdata(pdev, iio_dev);
+	mutex_init(&madc->lock);
+
+	irq = platform_get_irq(pdev, 0);
+	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+				   twl4030_madc_threaded_irq_handler,
+				   IRQF_TRIGGER_RISING, "twl4030_madc", madc);
+	if (ret) {
+		dev_err(&pdev->dev, "could not request irq\n");
+		goto err_i2c;
+	}
+	twl4030_madc = madc;
+
+	ret = iio_device_register(iio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "could not register iio device\n");
+		goto err_i2c;
+	}
+
+	return 0;
+
+err_i2c:
+	twl4030_madc_set_current_generator(madc, 0, 0);
+err_current_generator:
+	twl4030_madc_set_power(madc, 0);
+	return ret;
+}
+
+static int twl4030_madc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *iio_dev = platform_get_drvdata(pdev);
+	struct twl4030_madc_data *madc = iio_priv(iio_dev);
+
+	iio_device_unregister(iio_dev);
+
+	twl4030_madc_set_current_generator(madc, 0, 0);
+	twl4030_madc_set_power(madc, 0);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id twl_madc_of_match[] = {
+	{ .compatible = "ti,twl4030-madc", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, twl_madc_of_match);
+#endif
+
+static struct platform_driver twl4030_madc_driver = {
+	.probe = twl4030_madc_probe,
+	.remove = twl4030_madc_remove,
+	.driver = {
+		   .name = "twl4030_madc",
+		   .owner = THIS_MODULE,
+		   .of_match_table = of_match_ptr(twl_madc_of_match),
+	},
+};
+
+module_platform_driver(twl4030_madc_driver);
+
+MODULE_DESCRIPTION("TWL4030 ADC driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("J Keerthy");
+MODULE_ALIAS("platform:twl4030_madc");