/*
 * Xilinx XADC driver
 *
 * Copyright 2013 Analog Devices Inc.
 *  Author: Lars-Peter Clauen <lars@metafoo.de>
 *
 * Licensed under the GPL-2.
 */

#include <linux/iio/events.h>
#include <linux/iio/iio.h>
#include <linux/kernel.h>

#include "xilinx-xadc.h"

static const struct iio_chan_spec *xadc_event_to_channel(
        struct iio_dev *indio_dev, unsigned int event)
{
        switch (event) {
        case XADC_THRESHOLD_OT_MAX:
        case XADC_THRESHOLD_TEMP_MAX:
                return &indio_dev->channels[0];
        case XADC_THRESHOLD_VCCINT_MAX:
        case XADC_THRESHOLD_VCCAUX_MAX:
                return &indio_dev->channels[event];
        default:
                return &indio_dev->channels[event-1];
        }
}

static void xadc_handle_event(struct iio_dev *indio_dev, unsigned int event)
{
        const struct iio_chan_spec *chan;

        /* Temperature threshold error, we don't handle this yet */
        if (event == 0)
                return;

        chan = xadc_event_to_channel(indio_dev, event);

        if (chan->type == IIO_TEMP) {
                /*
                 * The temperature channel only supports over-temperature
                 * events.
                 */
                iio_push_event(indio_dev,
                        IIO_UNMOD_EVENT_CODE(chan->type, chan->channel,
                                IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING),
                        iio_get_time_ns());
        } else {
                /*
                 * For other channels we don't know whether it is a upper or
                 * lower threshold event. Userspace will have to check the
                 * channel value if it wants to know.
                 */
                iio_push_event(indio_dev,
                        IIO_UNMOD_EVENT_CODE(chan->type, chan->channel,
                                IIO_EV_TYPE_THRESH, IIO_EV_DIR_EITHER),
                        iio_get_time_ns());
        }
}

void xadc_handle_events(struct iio_dev *indio_dev, unsigned long events)
{
        unsigned int i;

        for_each_set_bit(i, &events, 8)
                xadc_handle_event(indio_dev, i);
}

static unsigned xadc_get_threshold_offset(const struct iio_chan_spec *chan,
        enum iio_event_direction dir)
{
        unsigned int offset;

        if (chan->type == IIO_TEMP) {
                offset = XADC_THRESHOLD_OT_MAX;
        } else {
                if (chan->channel < 2)
                        offset = chan->channel + 1;
                else
                        offset = chan->channel + 6;
        }

        if (dir == IIO_EV_DIR_FALLING)
                offset += 4;

        return offset;
}

static unsigned int xadc_get_alarm_mask(const struct iio_chan_spec *chan)
{
        if (chan->type == IIO_TEMP) {
                return XADC_ALARM_OT_MASK;
        } else {
                switch (chan->channel) {
                case 0:
                        return XADC_ALARM_VCCINT_MASK;
                case 1:
                        return XADC_ALARM_VCCAUX_MASK;
                case 2:
                        return XADC_ALARM_VCCBRAM_MASK;
                case 3:
                        return XADC_ALARM_VCCPINT_MASK;
                case 4:
                        return XADC_ALARM_VCCPAUX_MASK;
                case 5:
                        return XADC_ALARM_VCCODDR_MASK;
                default:
                        /* We will never get here */
                        return 0;
                }
        }
}

int xadc_read_event_config(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, enum iio_event_type type,
        enum iio_event_direction dir)
{
        struct xadc *xadc = iio_priv(indio_dev);

        return (bool)(xadc->alarm_mask & xadc_get_alarm_mask(chan));
}

int xadc_write_event_config(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, enum iio_event_type type,
        enum iio_event_direction dir, int state)
{
        unsigned int alarm = xadc_get_alarm_mask(chan);
        struct xadc *xadc = iio_priv(indio_dev);
        uint16_t cfg, old_cfg;
        int ret;

        mutex_lock(&xadc->mutex);

        if (state)
                xadc->alarm_mask |= alarm;
        else
                xadc->alarm_mask &= ~alarm;

        xadc->ops->update_alarm(xadc, xadc->alarm_mask);

        ret = _xadc_read_adc_reg(xadc, XADC_REG_CONF1, &cfg);
        if (ret)
                goto err_out;

        old_cfg = cfg;
        cfg |= XADC_CONF1_ALARM_MASK;
        cfg &= ~((xadc->alarm_mask & 0xf0) << 4); /* bram, pint, paux, ddr */
        cfg &= ~((xadc->alarm_mask & 0x08) >> 3); /* ot */
        cfg &= ~((xadc->alarm_mask & 0x07) << 1); /* temp, vccint, vccaux */
        if (old_cfg != cfg)
                ret = _xadc_write_adc_reg(xadc, XADC_REG_CONF1, cfg);

err_out:
        mutex_unlock(&xadc->mutex);

        return ret;
}

/* Register value is msb aligned, the lower 4 bits are ignored */
#define XADC_THRESHOLD_VALUE_SHIFT 4

int xadc_read_event_value(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, enum iio_event_type type,
        enum iio_event_direction dir, enum iio_event_info info,
        int *val, int *val2)
{
        unsigned int offset = xadc_get_threshold_offset(chan, dir);
        struct xadc *xadc = iio_priv(indio_dev);

        switch (info) {
        case IIO_EV_INFO_VALUE:
                *val = xadc->threshold[offset];
                break;
        case IIO_EV_INFO_HYSTERESIS:
                *val = xadc->temp_hysteresis;
                break;
        default:
                return -EINVAL;
        }

        *val >>= XADC_THRESHOLD_VALUE_SHIFT;

        return IIO_VAL_INT;
}

int xadc_write_event_value(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, enum iio_event_type type,
        enum iio_event_direction dir, enum iio_event_info info,
        int val, int val2)
{
        unsigned int offset = xadc_get_threshold_offset(chan, dir);
        struct xadc *xadc = iio_priv(indio_dev);
        int ret = 0;

        val <<= XADC_THRESHOLD_VALUE_SHIFT;

        if (val < 0 || val > 0xffff)
                return -EINVAL;

        mutex_lock(&xadc->mutex);

        switch (info) {
        case IIO_EV_INFO_VALUE:
                xadc->threshold[offset] = val;
                break;
        case IIO_EV_INFO_HYSTERESIS:
                xadc->temp_hysteresis = val;
                break;
        default:
                mutex_unlock(&xadc->mutex);
                return -EINVAL;
        }

        if (chan->type == IIO_TEMP) {
                /*
                 * According to the datasheet we need to set the lower 4 bits to
                 * 0x3, otherwise 125 degree celsius will be used as the
                 * threshold.
                 */
                val |= 0x3;

                /*
                 * Since we store the hysteresis as relative (to the threshold)
                 * value, but the hardware expects an absolute value we need to
                 * recalcualte this value whenever the hysteresis or the
                 * threshold changes.
                 */
                if (xadc->threshold[offset] < xadc->temp_hysteresis)
                        xadc->threshold[offset + 4] = 0;
                else
                        xadc->threshold[offset + 4] = xadc->threshold[offset] -
                                        xadc->temp_hysteresis;
                ret = _xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(offset + 4),
                        xadc->threshold[offset + 4]);
                if (ret)
                        goto out_unlock;
        }

        if (info == IIO_EV_INFO_VALUE)
                ret = _xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(offset), val);

out_unlock:
        mutex_unlock(&xadc->mutex);

        return ret;
}