/*
 * AD7606 SPI ADC driver
 *
 * Copyright 2011 Analog Devices Inc.
 *
 * Licensed under the GPL-2.
 */

#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/list.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/sched.h>

#include "../iio.h"
#include "../sysfs.h"
#include "../ring_generic.h"
#include "adc.h"

#include "ad7606.h"

int ad7606_reset(struct ad7606_state *st)
{
	if (st->have_reset) {
		gpio_set_value(st->pdata->gpio_reset, 1);
		ndelay(100); /* t_reset >= 100ns */
		gpio_set_value(st->pdata->gpio_reset, 0);
		return 0;
	}

	return -ENODEV;
}

static int ad7606_scan_direct(struct ad7606_state *st, unsigned ch)
{
	int ret;

	st->done = false;
	gpio_set_value(st->pdata->gpio_convst, 1);

	ret = wait_event_interruptible(st->wq_data_avail, st->done);
	if (ret)
		goto error_ret;

	if (st->have_frstdata) {
		ret = st->bops->read_block(st->dev, 1, st->data);
		if (ret)
			goto error_ret;
		if (!gpio_get_value(st->pdata->gpio_frstdata)) {
			/* This should never happen */
			ad7606_reset(st);
			ret = -EIO;
			goto error_ret;
		}
		ret = st->bops->read_block(st->dev,
			st->chip_info->num_channels - 1, &st->data[1]);
		if (ret)
			goto error_ret;
	} else {
		ret = st->bops->read_block(st->dev,
			st->chip_info->num_channels, st->data);
		if (ret)
			goto error_ret;
	}

	ret = st->data[ch];

error_ret:
	gpio_set_value(st->pdata->gpio_convst, 0);

	return ret;
}

static ssize_t ad7606_scan(struct device *dev,
			    struct device_attribute *attr,
			    char *buf)
{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad7606_state *st = dev_info->dev_data;
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	int ret;

	mutex_lock(&dev_info->mlock);
	if (iio_ring_enabled(dev_info))
		ret = ad7606_scan_from_ring(st, this_attr->address);
	else
		ret = ad7606_scan_direct(st, this_attr->address);
	mutex_unlock(&dev_info->mlock);

	if (ret < 0)
		return ret;

	return sprintf(buf, "%d\n", (short) ret);
}

static IIO_DEV_ATTR_IN_RAW(0, ad7606_scan, 0);
static IIO_DEV_ATTR_IN_RAW(1, ad7606_scan, 1);
static IIO_DEV_ATTR_IN_RAW(2, ad7606_scan, 2);
static IIO_DEV_ATTR_IN_RAW(3, ad7606_scan, 3);
static IIO_DEV_ATTR_IN_RAW(4, ad7606_scan, 4);
static IIO_DEV_ATTR_IN_RAW(5, ad7606_scan, 5);
static IIO_DEV_ATTR_IN_RAW(6, ad7606_scan, 6);
static IIO_DEV_ATTR_IN_RAW(7, ad7606_scan, 7);

static ssize_t ad7606_show_scale(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	/* Driver currently only support internal vref */
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
	unsigned int scale_uv = (st->range * 1000 * 2) >> st->chip_info->bits;

	return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
}
static IIO_DEVICE_ATTR(in_scale, S_IRUGO, ad7606_show_scale, NULL, 0);

static ssize_t ad7606_show_name(struct device *dev,
				 struct device_attribute *attr,
				 char *buf)
{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad7606_state *st = iio_dev_get_devdata(dev_info);

	return sprintf(buf, "%s\n", st->chip_info->name);
}

static IIO_DEVICE_ATTR(name, S_IRUGO, ad7606_show_name, NULL, 0);

static ssize_t ad7606_show_range(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad7606_state *st = iio_dev_get_devdata(dev_info);

	return sprintf(buf, "%u\n", st->range);
}

static ssize_t ad7606_store_range(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
	unsigned long lval;

	if (strict_strtoul(buf, 10, &lval))
		return -EINVAL;
	if (!(lval == 5000 || lval == 10000)) {
		dev_err(dev, "range is not supported\n");
		return -EINVAL;
	}
	mutex_lock(&dev_info->mlock);
	gpio_set_value(st->pdata->gpio_range, lval == 10000);
	st->range = lval;
	mutex_unlock(&dev_info->mlock);

	return count;
}

static IIO_DEVICE_ATTR(range, S_IRUGO | S_IWUSR, \
		       ad7606_show_range, ad7606_store_range, 0);
static IIO_CONST_ATTR(range_available, "5000 10000");

static ssize_t ad7606_show_oversampling_ratio(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad7606_state *st = iio_dev_get_devdata(dev_info);

	return sprintf(buf, "%u\n", st->oversampling);
}

static int ad7606_oversampling_get_index(unsigned val)
{
	unsigned char supported[] = {0, 2, 4, 8, 16, 32, 64};
	int i;

	for (i = 0; i < ARRAY_SIZE(supported); i++)
		if (val == supported[i])
			return i;

	return -EINVAL;
}

static ssize_t ad7606_store_oversampling_ratio(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
	unsigned long lval;
	int ret;

	if (strict_strtoul(buf, 10, &lval))
		return -EINVAL;

	ret = ad7606_oversampling_get_index(lval);
	if (ret < 0) {
		dev_err(dev, "oversampling %lu is not supported\n", lval);
		return ret;
	}

	mutex_lock(&dev_info->mlock);
	gpio_set_value(st->pdata->gpio_os0, (ret >> 0) & 1);
	gpio_set_value(st->pdata->gpio_os1, (ret >> 1) & 1);
	gpio_set_value(st->pdata->gpio_os1, (ret >> 2) & 1);
	st->oversampling = lval;
	mutex_unlock(&dev_info->mlock);

	return count;
}

static IIO_DEVICE_ATTR(oversampling_ratio, S_IRUGO | S_IWUSR,
		       ad7606_show_oversampling_ratio,
		       ad7606_store_oversampling_ratio, 0);
static IIO_CONST_ATTR(oversampling_ratio_available, "0 2 4 8 16 32 64");

static struct attribute *ad7606_attributes[] = {
	&iio_dev_attr_in0_raw.dev_attr.attr,
	&iio_dev_attr_in1_raw.dev_attr.attr,
	&iio_dev_attr_in2_raw.dev_attr.attr,
	&iio_dev_attr_in3_raw.dev_attr.attr,
	&iio_dev_attr_in4_raw.dev_attr.attr,
	&iio_dev_attr_in5_raw.dev_attr.attr,
	&iio_dev_attr_in6_raw.dev_attr.attr,
	&iio_dev_attr_in7_raw.dev_attr.attr,
	&iio_dev_attr_in_scale.dev_attr.attr,
	&iio_dev_attr_name.dev_attr.attr,
	&iio_dev_attr_range.dev_attr.attr,
	&iio_const_attr_range_available.dev_attr.attr,
	&iio_dev_attr_oversampling_ratio.dev_attr.attr,
	&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
	NULL,
};

static mode_t ad7606_attr_is_visible(struct kobject *kobj,
				     struct attribute *attr, int n)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad7606_state *st = iio_dev_get_devdata(dev_info);

	mode_t mode = attr->mode;

	if (st->chip_info->num_channels <= 6 &&
		(attr == &iio_dev_attr_in7_raw.dev_attr.attr ||
		attr == &iio_dev_attr_in6_raw.dev_attr.attr))
		mode = 0;
	else if (st->chip_info->num_channels <= 4 &&
		(attr == &iio_dev_attr_in5_raw.dev_attr.attr ||
		attr == &iio_dev_attr_in4_raw.dev_attr.attr))
		mode = 0;
	else if (!st->have_os &&
		(attr == &iio_dev_attr_oversampling_ratio.dev_attr.attr ||
		attr ==
		&iio_const_attr_oversampling_ratio_available.dev_attr.attr))
		mode = 0;
	else if (!st->have_range &&
		(attr == &iio_dev_attr_range.dev_attr.attr ||
		attr == &iio_const_attr_range_available.dev_attr.attr))
			mode = 0;

	return mode;
}

static const struct attribute_group ad7606_attribute_group = {
	.attrs = ad7606_attributes,
	.is_visible = ad7606_attr_is_visible,
};

static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {
	/*
	 * More devices added in future
	 */
	[ID_AD7606_8] = {
		.name = "ad7606",
		.bits = 16,
		.sign = IIO_SCAN_EL_TYPE_SIGNED,
		.int_vref_mv = 2500,
		.num_channels = 8,
	},
	[ID_AD7606_6] = {
		.name = "ad7606-6",
		.bits = 16,
		.sign = IIO_SCAN_EL_TYPE_SIGNED,
		.int_vref_mv = 2500,
		.num_channels = 6,
	},
	[ID_AD7606_4] = {
		.name = "ad7606-4",
		.bits = 16,
		.sign = IIO_SCAN_EL_TYPE_SIGNED,
		.int_vref_mv = 2500,
		.num_channels = 4,
	},
};

static int ad7606_request_gpios(struct ad7606_state *st)
{
	struct gpio gpio_array[3] = {
		[0] = {
			.gpio =  st->pdata->gpio_os0,
			.flags = GPIOF_DIR_OUT | ((st->oversampling & 1) ?
				 GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
			.label = "AD7606_OS0",
		},
		[1] = {
			.gpio =  st->pdata->gpio_os1,
			.flags = GPIOF_DIR_OUT | ((st->oversampling & 2) ?
				 GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
			.label = "AD7606_OS1",
		},
		[2] = {
			.gpio =  st->pdata->gpio_os2,
			.flags = GPIOF_DIR_OUT | ((st->oversampling & 4) ?
				 GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
			.label = "AD7606_OS2",
		},
	};
	int ret;

	ret = gpio_request_one(st->pdata->gpio_convst, GPIOF_OUT_INIT_LOW,
			       "AD7606_CONVST");
	if (ret) {
		dev_err(st->dev, "failed to request GPIO CONVST\n");
		return ret;
	}

	ret = gpio_request_array(gpio_array, ARRAY_SIZE(gpio_array));
	if (!ret) {
		st->have_os = true;
	}

	ret = gpio_request_one(st->pdata->gpio_reset, GPIOF_OUT_INIT_LOW,
			       "AD7606_RESET");
	if (!ret)
		st->have_reset = true;

	ret = gpio_request_one(st->pdata->gpio_range, GPIOF_DIR_OUT |
			       ((st->range == 10000) ? GPIOF_INIT_HIGH :
			       	GPIOF_INIT_LOW), "AD7606_RANGE");
	if (!ret)
		st->have_range = true;

	ret = gpio_request_one(st->pdata->gpio_stby, GPIOF_OUT_INIT_HIGH,
			       "AD7606_STBY");
	if (!ret)
		st->have_stby = true;

	if (gpio_is_valid(st->pdata->gpio_frstdata)) {
		ret = gpio_request_one(st->pdata->gpio_frstdata, GPIOF_IN,
				       "AD7606_FRSTDATA");
		if (!ret)
			st->have_frstdata = true;
	}

	return 0;
}

static void ad7606_free_gpios(struct ad7606_state *st)
{
	if (st->have_range)
		gpio_free(st->pdata->gpio_range);

	if (st->have_stby)
		gpio_free(st->pdata->gpio_stby);

	if (st->have_os) {
		gpio_free(st->pdata->gpio_os0);
		gpio_free(st->pdata->gpio_os1);
		gpio_free(st->pdata->gpio_os2);
	}

	if (st->have_reset)
		gpio_free(st->pdata->gpio_reset);

	if (st->have_frstdata)
		gpio_free(st->pdata->gpio_frstdata);

	gpio_free(st->pdata->gpio_convst);
}

/**
 *  Interrupt handler
 */
static irqreturn_t ad7606_interrupt(int irq, void *dev_id)
{
	struct ad7606_state *st = dev_id;

	if (iio_ring_enabled(st->indio_dev)) {
		if (!work_pending(&st->poll_work))
			schedule_work(&st->poll_work);
	} else {
		st->done = true;
		wake_up_interruptible(&st->wq_data_avail);
	}

	return IRQ_HANDLED;
};

struct ad7606_state *ad7606_probe(struct device *dev, int irq,
			      void __iomem *base_address,
			      unsigned id,
			      const struct ad7606_bus_ops *bops)
{
	struct ad7606_platform_data *pdata = dev->platform_data;
	struct ad7606_state *st;
	int ret;

	st = kzalloc(sizeof(*st), GFP_KERNEL);
	if (st == NULL) {
		ret = -ENOMEM;
		goto error_ret;
	}

	st->dev = dev;
	st->id = id;
	st->irq = irq;
	st->bops = bops;
	st->base_address = base_address;
	st->range = pdata->default_range == 10000 ? 10000 : 5000;

	ret = ad7606_oversampling_get_index(pdata->default_os);
	if (ret < 0) {
		dev_warn(dev, "oversampling %d is not supported\n",
			 pdata->default_os);
		st->oversampling = 0;
	} else {
		st->oversampling = pdata->default_os;
	}

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

	st->pdata = pdata;
	st->chip_info = &ad7606_chip_info_tbl[id];

	atomic_set(&st->protect_ring, 0);

	st->indio_dev = iio_allocate_device();
	if (st->indio_dev == NULL) {
		ret = -ENOMEM;
		goto error_disable_reg;
	}

	st->indio_dev->dev.parent = dev;
	st->indio_dev->attrs = &ad7606_attribute_group;
	st->indio_dev->dev_data = (void *)(st);
	st->indio_dev->driver_module = THIS_MODULE;
	st->indio_dev->modes = INDIO_DIRECT_MODE;

	init_waitqueue_head(&st->wq_data_avail);

	ret = ad7606_request_gpios(st);
	if (ret)
		goto error_free_device;

	ret = ad7606_reset(st);
	if (ret)
		dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");

	ret = request_irq(st->irq, ad7606_interrupt,
		IRQF_TRIGGER_FALLING, st->chip_info->name, st);
	if (ret)
		goto error_free_gpios;

	ret = ad7606_register_ring_funcs_and_init(st->indio_dev);
	if (ret)
		goto error_free_irq;

	ret = iio_device_register(st->indio_dev);
	if (ret)
		goto error_free_irq;

	ret = iio_ring_buffer_register(st->indio_dev->ring, 0);
	if (ret)
		goto error_cleanup_ring;

	return st;

error_cleanup_ring:
	ad7606_ring_cleanup(st->indio_dev);
	iio_device_unregister(st->indio_dev);

error_free_irq:
	free_irq(st->irq, st);

error_free_gpios:
	ad7606_free_gpios(st);

error_free_device:
	iio_free_device(st->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);
	kfree(st);
error_ret:
	return ERR_PTR(ret);
}

int ad7606_remove(struct ad7606_state *st)
{
	struct iio_dev *indio_dev = st->indio_dev;
	iio_ring_buffer_unregister(indio_dev->ring);
	ad7606_ring_cleanup(indio_dev);
	iio_device_unregister(indio_dev);
	free_irq(st->irq, st);
	if (!IS_ERR(st->reg)) {
		regulator_disable(st->reg);
		regulator_put(st->reg);
	}

	ad7606_free_gpios(st);

	kfree(st);
	return 0;
}

void ad7606_suspend(struct ad7606_state *st)
{
	if (st->have_stby) {
		if (st->have_range)
			gpio_set_value(st->pdata->gpio_range, 1);
		gpio_set_value(st->pdata->gpio_stby, 0);
	}
}

void ad7606_resume(struct ad7606_state *st)
{
	if (st->have_stby) {
		if (st->have_range)
			gpio_set_value(st->pdata->gpio_range,
					st->range == 10000);

		gpio_set_value(st->pdata->gpio_stby, 1);
		ad7606_reset(st);
	}
}

MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
MODULE_LICENSE("GPL v2");