ixgbe: add comment noting recalculation of queues

[linux/fpc-iii.git] / drivers / iio / adc / twl4030-madc.c

/*
 *
 * 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/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.raw = 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");