mfd: Add twl4030 madc driver

Introducing a driver for MADC on TWL4030 powerIC. MADC stands for monitoring
ADC. This driver monitors the real time conversion of analog signals like
battery temperature, battery cuurent etc.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 813 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index d71af4531b14..50c476964e48 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -178,6 +178,16 @@ config TWL4030_CORE
 	  high speed USB OTG transceiver, an audio codec (on most
 	  versions) and many other features.
 
+config TWL4030_MADC
+	tristate "Texas Instruments TWL4030 MADC"
+	depends on TWL4030_CORE
+	help
+	This driver provides support for triton TWL4030-MADC. The
+	driver supports both RT and SW conversion methods.
+
+	This driver can be built as a module. If so it will be
+	named twl4030-madc
+
 config TWL4030_POWER
 	bool "Support power resources on TWL4030 family chips"
 	depends on TWL4030_CORE && ARM
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index ad71bd59345f..25f3c7551489 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_TPS6507X)		+= tps6507x.o
 obj-$(CONFIG_MENELAUS)		+= menelaus.o
 
 obj-$(CONFIG_TWL4030_CORE)	+= twl-core.o twl4030-irq.o twl6030-irq.o
+obj-$(CONFIG_TWL4030_MADC)      += twl4030-madc.o
 obj-$(CONFIG_TWL4030_POWER)    += twl4030-power.o
 obj-$(CONFIG_TWL4030_CODEC)	+= twl4030-codec.o
 obj-$(CONFIG_TWL6030_PWM)	+= twl6030-pwm.o
diff --git a/drivers/mfd/twl4030-madc.c b/drivers/mfd/twl4030-madc.c
new file mode 100644
index 000000000000..e9884e2583bf
--- /dev/null
+++ b/drivers/mfd/twl4030-madc.c
@@ -0,0 +1,802 @@
+/*
+ *
+ * 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)
+		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);
+		return ret;
+	}
+	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);
+		return ret;
+	}
+	/* 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);
+			return ret;
+		}
+		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);
+			return ret;
+		}
+	}
+	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;
+
+	/*
+	 * 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("twl4030_madc");