[PATCH v3] hwmon: twl4030: Driver for twl4030 madc module

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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 type, battery level etc. User can also ask for
the conversion on a particular channel using the sysfs nodes. Tested the
conversion through sysfs nodes. Tested with DEBUG_LOCKDEP enabled.

Signed-off-by: Keerthy <j-keerthy@xxxxxx>
---

Several people have contributed to this driver on the linux-omap list.
V3:

Return check added to all the functions reading and writing via i2c.
In probe function reverting all the steps succeded before a failure
and not reverting the step which failed.
Added the declaration of twl4030_get_madc_conversion function in the
header file.
Formatting the header file.
Comments added.
likely occurance removed since it is not in the hot path.
Renamed the_madc to twl4030_madc.
Added sleep command to avoid busy wait in conversion ready function.

V2:

Error path correction in probe function.
Return checks added.
the_madc pointer could not be removed. The external drivers will not be knowing
device information of the madc.
Added another function which takes the channel number alone and returns
the channel reading if the caller wants TWL4030_MADC_SW2 method for ADC conversion.
IOCTL function is removed.
Work struct is completely removed since request_threaded_irq is used.

 drivers/hwmon/Kconfig            |   11 +
 drivers/hwmon/Makefile           |    1 +
 drivers/hwmon/twl4030-madc.c     |  794 ++++++++++++++++++++++++++++++++++++++
 include/linux/i2c/twl4030-madc.h |  118 ++++++
 4 files changed, 924 insertions(+), 0 deletions(-)
 create mode 100644 drivers/hwmon/twl4030-madc.c
 create mode 100644 include/linux/i2c/twl4030-madc.h

V1:

http://www.mail-archive.com/linux-omap@xxxxxxxxxxxxxxx/msg34947.html

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index a56f6ad..eec1258 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -920,6 +920,17 @@ config SENSORS_TMP421
 	  This driver can also be built as a module.  If so, the module
 	  will be called tmp421.
 
+config SENSORS_TWL4030_MADC
+	tristate "Texas Instrments 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 part of kernel or can be built
+	as a module.
+
+
 config SENSORS_VIA_CPUTEMP
 	tristate "VIA CPU temperature sensor"
 	depends on X86
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 2479b3d..a54af22 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -100,6 +100,7 @@ obj-$(CONFIG_SENSORS_THMC50)	+= thmc50.o
 obj-$(CONFIG_SENSORS_TMP102)	+= tmp102.o
 obj-$(CONFIG_SENSORS_TMP401)	+= tmp401.o
 obj-$(CONFIG_SENSORS_TMP421)	+= tmp421.o
+obj-$(CONFIG_SENSORS_TWL4030_MADC)+= twl4030-madc.o
 obj-$(CONFIG_SENSORS_VIA_CPUTEMP)+= via-cputemp.o
 obj-$(CONFIG_SENSORS_VIA686A)	+= via686a.o
 obj-$(CONFIG_SENSORS_VT1211)	+= vt1211.o
diff --git a/drivers/hwmon/twl4030-madc.c b/drivers/hwmon/twl4030-madc.c
new file mode 100644
index 0000000..523f19a
--- /dev/null
+++ b/drivers/hwmon/twl4030-madc.c
@@ -0,0 +1,794 @@
+/*
+ *
+ * TWL4030 MADC module driver-This driver monitors the real time
+ * conversion of analog signals like battery temperature,
+ * battery type, battery level etc. User can also ask for the conversion on a
+ * particular channel using the sysfs nodes.
+ *
+ * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com/
+ * J Keerthy <j-keerthy@xxxxxx>
+ *
+ * Based on twl4030-madc.c
+ * Copyright (C) 2008 Nokia Corporation
+ * Mikko Ylinen <mikko.k.ylinen@xxxxxxxxx>
+ *
+ * Amit Kucheria <amit.kucheria@xxxxxxxxxxxxx>
+ *
+ * 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/interrupt.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/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+
+/*
+ * struct twl4030_madc_data - a container for madc info
+ * @hwmon_dev - pointer to device structure for madc
+ * @lock - mutex protecting this data structire
+ * @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 *hwmon_dev;
+	struct mutex lock;/* mutex protecting this data structire */
+	struct twl4030_madc_request requests[TWL4030_MADC_NUM_METHODS];
+	int imr;
+	int isr;
+};
+
+static struct twl4030_madc_data *twl4030_madc;
+
+/*
+ * sysfs hook function
+ */
+static ssize_t madc_read(struct device *dev,
+			 struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct twl4030_madc_request req;
+	long val;
+
+	req.channels = (1 << attr->index);
+	req.method = TWL4030_MADC_SW2;
+	req.func_cb = NULL;
+	val = twl4030_madc_conversion(&req);
+	if (val >= 0)
+		val = req.rbuf[attr->index];
+	else
+		return val;
+	return sprintf(buf, "%ld\n", val);
+}
+
+/*
+ * Structure containing the registers
+ * of different conversion methods supported by MADC.
+ * Hardware or RT real time conversion request intiated by external host
+ * processor for RT Signal conversions.
+ * External host processors can also request for non RT converions
+ * 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 struct
+ * @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 addr of LSB register
+	 */
+	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &msb, reg + 1);
+	if (ret) {
+		dev_dbg(madc->hwmon_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_dbg(madc->hwmon_dev,
+		"unable to read LSB register 0x%X\n", reg);
+		return ret;
+	}
+
+	return (int)(((msb << 8) | lsb) >> 6);
+}
+
+/*
+ * Function to read channel values
+ * @madc - pointer to twl4030_madc_data struct
+ * @reg_base - Base address of the first channel
+ * @Channel - 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, u16 channels, int *buf)
+{
+	int count = 0, count_req = 0;
+	u8 reg, i;
+
+	for (i = 0; i < TWL4030_MADC_MAX_CHANNELS; i++) {
+		if (channels & (1 << i)) {
+			reg = reg_base + 2 * i;
+			buf[i] = twl4030_madc_channel_raw_read(madc, reg);
+			if (buf[i] < 0) {
+				dev_dbg(madc->hwmon_dev,
+					"Unable to read register 0x%X\n",
+					reg);
+				count_req++;
+			} else
+				count++;
+
+		}
+	}
+	if (count_req) {
+		dev_dbg(madc->hwmon_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, int id)
+{
+	u8 val;
+	int ret;
+	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &val, madc->imr);
+	if (ret) {
+		dev_dbg(madc->hwmon_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->hwmon_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, int id)
+{
+	u8 val;
+	int ret;
+
+	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &val, madc->imr);
+	if (ret) {
+		dev_dbg(madc->hwmon_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->hwmon_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;
+
+	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &isr_val, madc->isr);
+	if (ret) {
+		dev_dbg(madc->hwmon_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_dbg(madc->hwmon_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->hwmon_dev,
+			"Disable interrupt failed%d\n", i);
+		}
+
+		madc->requests[i].result_pending = 1;
+	}
+	mutex_lock(&madc->lock);
+	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 is active
+	 *   and service the same.
+	 */
+	mutex_lock(&madc->lock);
+	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_dbg(madc->hwmon_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->hwmon_dev,
+			"unable to write ctrl register 0x%X\n", method->ctrl);
+			return ret;
+		}
+		break;
+	case TWL4030_MADC_RT:
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ * Function that waits for conversion to be ready
+ * @madc - pointer to twl4030_madc_data struct
+ * @timeout_ms - timeout value in mili seconds
+ * @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_dbg(madc->hwmon_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_dbg(madc->hwmon_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 correspoding array element.
+ * retuns 0 is 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_dbg(twl4030_madc->hwmon_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_dbg(twl4030_madc->hwmon_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_dbg(twl4030_madc->hwmon_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_dbg(twl4030_madc->hwmon_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 disble bias current for
+ * main battery type reading or temperature sensing
+ * @madc - pointer to twl4030_madc_data struct
+ * @chan - cab 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_dbg(madc->hwmon_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->hwmon_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 diable 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_dbg(madc->hwmon_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_dbg(madc->hwmon_dev,
+		"unable to write madc ctrl1 reg 0x%X\n", TWL4030_MADC_CTRL1);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* sysfs nodes to read individual channels from user side */
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, madc_read, NULL, 0);
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, madc_read, NULL, 1);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, madc_read, NULL, 2);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, madc_read, NULL, 3);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, madc_read, NULL, 4);
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, madc_read, NULL, 5);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, madc_read, NULL, 6);
+static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, madc_read, NULL, 7);
+static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, madc_read, NULL, 8);
+static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, madc_read, NULL, 9);
+static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, madc_read, NULL, 10);
+static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, madc_read, NULL, 11);
+static SENSOR_DEVICE_ATTR(in12_input, S_IRUGO, madc_read, NULL, 12);
+static SENSOR_DEVICE_ATTR(in13_input, S_IRUGO, madc_read, NULL, 13);
+static SENSOR_DEVICE_ATTR(in14_input, S_IRUGO, madc_read, NULL, 14);
+static SENSOR_DEVICE_ATTR(in15_input, S_IRUGO, madc_read, NULL, 15);
+
+static struct attribute *twl4030_madc_attributes[] = {
+	&sensor_dev_attr_in0_input.dev_attr.attr,
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+	&sensor_dev_attr_in5_input.dev_attr.attr,
+	&sensor_dev_attr_in6_input.dev_attr.attr,
+	&sensor_dev_attr_in7_input.dev_attr.attr,
+	&sensor_dev_attr_in8_input.dev_attr.attr,
+	&sensor_dev_attr_in9_input.dev_attr.attr,
+	&sensor_dev_attr_in10_input.dev_attr.attr,
+	&sensor_dev_attr_in11_input.dev_attr.attr,
+	&sensor_dev_attr_in12_input.dev_attr.attr,
+	&sensor_dev_attr_in13_input.dev_attr.attr,
+	&sensor_dev_attr_in14_input.dev_attr.attr,
+	&sensor_dev_attr_in15_input.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group twl4030_madc_group = {
+	.attrs = twl4030_madc_attributes,
+};
+
+/*
+ * Initialize MADC and request for threaded irq
+ * and register as a hwmon device
+ */
+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;
+	int status;
+	u8 regval;
+
+	if (!pdata) {
+		dev_dbg(&pdev->dev, "platform_data not available\n");
+		return -EINVAL;
+	}
+
+	madc = kzalloc(sizeof *madc, GFP_KERNEL);
+	if (!madc)
+		return -ENOMEM;
+	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;
+	}
+
+	ret = sysfs_create_group(&pdev->dev.kobj, &twl4030_madc_group);
+	if (ret)
+		goto err_sysfs;
+
+	madc->hwmon_dev = hwmon_device_register(&pdev->dev);
+	if (IS_ERR(madc->hwmon_dev)) {
+		dev_err(&pdev->dev, "hwmon_device_register failed.\n");
+		status = PTR_ERR(madc->hwmon_dev);
+		goto err_reg;
+	}
+
+	twl4030_madc = madc;
+	return 0;
+
+err_reg:
+	sysfs_remove_group(&pdev->dev.kobj, &twl4030_madc_group);
+
+err_sysfs:
+	free_irq(platform_get_irq(pdev, 0), madc);
+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);
+	hwmon_device_unregister(&pdev->dev);
+	sysfs_remove_group(&pdev->dev.kobj, &twl4030_madc_group);
+	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");
diff --git a/include/linux/i2c/twl4030-madc.h b/include/linux/i2c/twl4030-madc.h
new file mode 100644
index 0000000..5bc9e8c
--- /dev/null
+++ b/include/linux/i2c/twl4030-madc.h
@@ -0,0 +1,118 @@
+/*
+ * 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
+ *
+ */
+
+#ifndef _TWL4030_MADC_H
+#define _TWL4030_MADC_H
+
+struct twl4030_madc_conversion_method {
+	u8 sel;
+	u8 avg;
+	u8 rbase;
+	u8 ctrl;
+};
+
+#define TWL4030_MADC_MAX_CHANNELS 16
+
+struct twl4030_madc_request {
+	u16 channels; /* 16 bit bitmap for individual channels */
+	u16 do_avg; /* sample the input channel for 4 consecutive cycles
+			and provide the average of 4 conversions */
+	u16 method; /* RT, SW1, SW2 */
+	u16 type; /*polling or interrupt based */
+	bool active;
+	bool result_pending;
+	int rbuf[TWL4030_MADC_MAX_CHANNELS];
+	void (*func_cb)(int len, int channels, int *buf);
+};
+
+enum conversion_methods {
+	TWL4030_MADC_RT,
+	TWL4030_MADC_SW1,
+	TWL4030_MADC_SW2,
+	TWL4030_MADC_NUM_METHODS
+};
+
+enum sample_type {
+	TWL4030_MADC_WAIT,
+	TWL4030_MADC_IRQ_ONESHOT,
+	TWL4030_MADC_IRQ_REARM
+};
+
+#define TWL4030_MADC_CTRL1		0x00
+#define TWL4030_MADC_CTRL2		0x01
+
+#define TWL4030_MADC_RTSELECT_LSB	0x02
+#define TWL4030_MADC_SW1SELECT_LSB	0x06
+#define TWL4030_MADC_SW2SELECT_LSB	0x0A
+
+#define TWL4030_MADC_RTAVERAGE_LSB	0x04
+#define TWL4030_MADC_SW1AVERAGE_LSB	0x08
+#define TWL4030_MADC_SW2AVERAGE_LSB	0x0C
+
+#define TWL4030_MADC_CTRL_SW1		0x12
+#define TWL4030_MADC_CTRL_SW2		0x13
+
+#define TWL4030_MADC_RTCH0_LSB		0x17
+#define TWL4030_MADC_GPCH0_LSB		0x37
+
+#define TWL4030_MADC_MADCON	(1 << 0)	/* MADC power on */
+#define TWL4030_MADC_BUSY	(1 << 0)	/* MADC busy */
+/* MADC conversion completion */
+#define TWL4030_MADC_EOC_SW	(1 << 1)
+/* MADC SWx start conversion */
+#define TWL4030_MADC_SW_START	(1 << 5)
+#define TWL4030_MADC_ADCIN0	(1 << 0)
+#define TWL4030_MADC_ADCIN1	(1 << 1)
+#define TWL4030_MADC_ADCIN2	(1 << 2)
+#define TWL4030_MADC_ADCIN3	(1 << 3)
+#define TWL4030_MADC_ADCIN4	(1 << 4)
+#define TWL4030_MADC_ADCIN5	(1 << 5)
+#define TWL4030_MADC_ADCIN6	(1 << 6)
+#define TWL4030_MADC_ADCIN7	(1 << 7)
+#define TWL4030_MADC_ADCIN8	(1 << 8)
+#define TWL4030_MADC_ADCIN9	(1 << 9)
+#define TWL4030_MADC_ADCIN10	(1 << 10)
+#define TWL4030_MADC_ADCIN11	(1 << 11)
+#define TWL4030_MADC_ADCIN12	(1 << 12)
+#define TWL4030_MADC_ADCIN13	(1 << 13)
+#define TWL4030_MADC_ADCIN14	(1 << 14)
+#define TWL4030_MADC_ADCIN15	(1 << 15)
+
+/* Fixed channels */
+#define TWL4030_MADC_BTEMP	TWL4030_MADC_ADCIN1
+#define TWL4030_MADC_VBUS	TWL4030_MADC_ADCIN8
+#define TWL4030_MADC_VBKB	TWL4030_MADC_ADCIN9
+#define TWL4030_MADC_ICHG	TWL4030_MADC_ADCIN10
+#define TWL4030_MADC_VCHG	TWL4030_MADC_ADCIN11
+#define TWL4030_MADC_VBAT	TWL4030_MADC_ADCIN12
+
+#define TWL4030_BCI_BCICTL1	0x23
+#define TWL4030_BCI_MESBAT	(1 << 1)
+#define TWL4030_BCI_TYPEN	(1 << 4)
+#define TWL4030_BCI_ITHEN	(1 << 3)
+
+
+struct twl4030_madc_user_parms {
+	int channel;
+	int average;
+	int status;
+	u16 result;
+};
+
+int twl4030_madc_conversion(struct twl4030_madc_request *conv);
+int twl4030_get_madc_conversion(int channel_no);
+#endif
-- 
1.7.0.4

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