/*
 * AD7887 SPI ADC driver
 *
 * Copyright 2010-2011 Analog Devices Inc.
 *
 * Licensed under the GPL-2.
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/module.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>


#include "ad7887.h"

static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
{
	int ret = spi_sync(st->spi, &st->msg[ch]);
	if (ret)
		return ret;

	return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
}

static int ad7887_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val,
			   int *val2,
			   long m)
{
	int ret;
	struct ad7887_state *st = iio_priv(indio_dev);
	unsigned int scale_uv;

	switch (m) {
	case IIO_CHAN_INFO_RAW:
		mutex_lock(&indio_dev->mlock);
		if (iio_buffer_enabled(indio_dev))
			ret = -EBUSY;
		else
			ret = ad7887_scan_direct(st, chan->address);
		mutex_unlock(&indio_dev->mlock);

		if (ret < 0)
			return ret;
		*val = (ret >> st->chip_info->channel[0].scan_type.shift) &
			RES_MASK(st->chip_info->channel[0].scan_type.realbits);
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		scale_uv = (st->int_vref_mv * 1000)
			>> st->chip_info->channel[0].scan_type.realbits;
		*val =  scale_uv/1000;
		*val2 = (scale_uv%1000)*1000;
		return IIO_VAL_INT_PLUS_MICRO;
	}
	return -EINVAL;
}


static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
	/*
	 * More devices added in future
	 */
	[ID_AD7887] = {
		.channel[0] = {
			.type = IIO_VOLTAGE,
			.indexed = 1,
			.channel = 1,
			.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
			IIO_CHAN_INFO_SCALE_SHARED_BIT,
			.address = 1,
			.scan_index = 1,
			.scan_type = IIO_ST('u', 12, 16, 0),
		},
		.channel[1] = {
			.type = IIO_VOLTAGE,
			.indexed = 1,
			.channel = 0,
			.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
			IIO_CHAN_INFO_SCALE_SHARED_BIT,
			.address = 0,
			.scan_index = 0,
			.scan_type = IIO_ST('u', 12, 16, 0),
		},
		.channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2),
		.int_vref_mv = 2500,
	},
};

static const struct iio_info ad7887_info = {
	.read_raw = &ad7887_read_raw,
	.driver_module = THIS_MODULE,
};

static int __devinit ad7887_probe(struct spi_device *spi)
{
	struct ad7887_platform_data *pdata = spi->dev.platform_data;
	struct ad7887_state *st;
	int ret, voltage_uv = 0;
	struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st));

	if (indio_dev == NULL)
		return -ENOMEM;

	st = iio_priv(indio_dev);

	st->reg = regulator_get(&spi->dev, "vcc");
	if (!IS_ERR(st->reg)) {
		ret = regulator_enable(st->reg);
		if (ret)
			goto error_put_reg;

		voltage_uv = regulator_get_voltage(st->reg);
	}

	st->chip_info =
		&ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];

	spi_set_drvdata(spi, indio_dev);
	st->spi = spi;

	/* Estabilish that the iio_dev is a child of the spi device */
	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->info = &ad7887_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	/* Setup default message */

	st->tx_cmd_buf[0] = AD7887_CH_AIN0 | AD7887_PM_MODE4 |
			    ((pdata && pdata->use_onchip_ref) ?
			    0 : AD7887_REF_DIS);

	st->xfer[0].rx_buf = &st->data[0];
	st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
	st->xfer[0].len = 2;

	spi_message_init(&st->msg[AD7887_CH0]);
	spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);

	if (pdata && pdata->en_dual) {
		st->tx_cmd_buf[0] |= AD7887_DUAL | AD7887_REF_DIS;

		st->tx_cmd_buf[2] = AD7887_CH_AIN1 | AD7887_DUAL |
				    AD7887_REF_DIS | AD7887_PM_MODE4;
		st->tx_cmd_buf[4] = AD7887_CH_AIN0 | AD7887_DUAL |
				    AD7887_REF_DIS | AD7887_PM_MODE4;
		st->tx_cmd_buf[6] = AD7887_CH_AIN1 | AD7887_DUAL |
				    AD7887_REF_DIS | AD7887_PM_MODE4;

		st->xfer[1].rx_buf = &st->data[0];
		st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
		st->xfer[1].len = 2;

		st->xfer[2].rx_buf = &st->data[2];
		st->xfer[2].tx_buf = &st->tx_cmd_buf[4];
		st->xfer[2].len = 2;

		spi_message_init(&st->msg[AD7887_CH0_CH1]);
		spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
		spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);

		st->xfer[3].rx_buf = &st->data[0];
		st->xfer[3].tx_buf = &st->tx_cmd_buf[6];
		st->xfer[3].len = 2;

		spi_message_init(&st->msg[AD7887_CH1]);
		spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);

		if (pdata && pdata->vref_mv)
			st->int_vref_mv = pdata->vref_mv;
		else if (voltage_uv)
			st->int_vref_mv = voltage_uv / 1000;
		else
			dev_warn(&spi->dev, "reference voltage unspecified\n");

		indio_dev->channels = st->chip_info->channel;
		indio_dev->num_channels = 3;
	} else {
		if (pdata && pdata->vref_mv)
			st->int_vref_mv = pdata->vref_mv;
		else if (pdata && pdata->use_onchip_ref)
			st->int_vref_mv = st->chip_info->int_vref_mv;
		else
			dev_warn(&spi->dev, "reference voltage unspecified\n");

		indio_dev->channels = &st->chip_info->channel[1];
		indio_dev->num_channels = 2;
	}

	ret = ad7887_register_ring_funcs_and_init(indio_dev);
	if (ret)
		goto error_disable_reg;

	ret = iio_device_register(indio_dev);
	if (ret)
		goto error_unregister_ring;

	return 0;
error_unregister_ring:
	ad7887_ring_cleanup(indio_dev);
error_disable_reg:
	if (!IS_ERR(st->reg))
		regulator_disable(st->reg);
error_put_reg:
	if (!IS_ERR(st->reg))
		regulator_put(st->reg);
	iio_device_free(indio_dev);

	return ret;
}

static int __devexit ad7887_remove(struct spi_device *spi)
{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad7887_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	ad7887_ring_cleanup(indio_dev);
	if (!IS_ERR(st->reg)) {
		regulator_disable(st->reg);
		regulator_put(st->reg);
	}
	iio_device_free(indio_dev);

	return 0;
}

static const struct spi_device_id ad7887_id[] = {
	{"ad7887", ID_AD7887},
	{}
};
MODULE_DEVICE_TABLE(spi, ad7887_id);

static struct spi_driver ad7887_driver = {
	.driver = {
		.name	= "ad7887",
		.owner	= THIS_MODULE,
	},
	.probe		= ad7887_probe,
	.remove		= __devexit_p(ad7887_remove),
	.id_table	= ad7887_id,
};
module_spi_driver(ad7887_driver);

MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
MODULE_LICENSE("GPL v2");