/*
*  GSC3280 SoC adc Controller Driver
* 
*  Copyright (C) 2013 BLX IC Design Corp.,Ltd.
*  Author: Davied, apple_guet@126.com
*
*  This program is free software; you can redistribute it and/or modify it
*  under  the terms of the GNU General  Public License as published by the
*  Free Software Foundation;  either version 2 of the License, or (at your    
*  option) any later version.
*
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/sched.h>
#include <linux/adc-core.h>


#ifdef CONFIG_ADC_DEV_DEBUG
#define DBG(msg...) do { \
		printk(KERN_INFO msg); \
	} while (0)
#else
#define DBG(msg...)	do { } while(0)
#endif


#define ADC_DEV_MAX				16 /* 16 ADCs should be enough for everyone... */
#define ADC_DEV_BUSY				0

#define ADC_DEV_IOC_MAGIC			'a'
#define ADC_DEV_IOC_MAXNR			2
#define ADC_DEV_CON_PBAT			_IOR(ADC_DEV_IOC_MAGIC, 0, int)
#define ADC_DEV_CON_CHX			_IOWR(ADC_DEV_IOC_MAGIC, 1, int)


static dev_t adc_devt;


static int adc_dev_open(struct inode *inode, struct file *file)
{
	int err;
	struct adc_core_dev *adc = container_of(inode->i_cdev, struct adc_core_dev, char_dev);

	if (test_and_set_bit_lock(ADC_DEV_BUSY, &adc->flags))
		return -EBUSY;
	file->private_data = adc;
	err = adc->ops->open ? adc->ops->open(adc->dev.parent) : 0;
	if (err == 0) {
		return 0;
	}
	/* something has gone wrong */
	clear_bit_unlock(ADC_DEV_BUSY, &adc->flags);
	return err;
}

static long adc_dev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	int err = 0, channel = 0;
	unsigned short adc_cmd = 0;
	struct adc_core_dev *adc = file->private_data;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;

	err = mutex_lock_interruptible(&adc->ops_lock);
	if (err)
		return err;
	if ((_IOC_TYPE(cmd) != ADC_DEV_IOC_MAGIC) || (_IOC_NR(cmd) > ADC_DEV_IOC_MAXNR)) {
		err = -ENOTTY;
		goto exit;
	}
	switch(cmd) {
	case ADC_DEV_CON_PBAT:
		adc_cmd = CMD_AD_CON_PBAT;
		break;
	case ADC_DEV_CON_CHX:
		if (get_user(channel, p)) {
			err = -EFAULT;
			goto exit;
		}
		switch (channel) {
		case 0:
			adc_cmd = CMD_AD_CON_CH0;
			break;
		case 1:
			adc_cmd = CMD_AD_CON_CH1;
			break;
		case 2:
			adc_cmd = CMD_AD_CON_CH2;
			break;
		case 3:
			adc_cmd = CMD_AD_CON_CH3;
			break;
		}
		break;
	default:
		err = -ENOTTY;
		goto exit;
	}
	DBG("adc_cmd = 0x%x\n", adc_cmd);
	put_user(adc->ops->convert(adc_cmd), p);

exit:
	mutex_unlock(&adc->ops_lock);
	return err;
}

static int adc_dev_release(struct inode *inode, struct file *file)
{
	struct adc_core_dev *adc = file->private_data;

	if (adc->ops->release)
		adc->ops->release(adc->dev.parent);
	clear_bit_unlock(ADC_DEV_BUSY, &adc->flags);
	return 0;
}

static const struct file_operations adc_dev_fops = {
	.owner			= THIS_MODULE,
	.llseek			= no_llseek,
	.unlocked_ioctl	= adc_dev_ioctl,
	.open			= adc_dev_open,
	.release			= adc_dev_release,
};

void adc_dev_prepare(struct adc_core_dev *adc)
{
	if (!adc_devt) {
		DBG("!!!!!!adc_devt = 0!!!!!!\n");
		return;
	}
	if (adc->id >= ADC_DEV_MAX) {
		DBG("!!!!!!adc dev prepare error,id too many!!!!!!\n");
		pr_debug("%s: too many ADC devices\n", adc->name);
		return;
	}
	adc->dev.devt = MKDEV(MAJOR(adc_devt), adc->id);
	cdev_init(&adc->char_dev, &adc_dev_fops);
	adc->char_dev.owner = adc->owner;
}

void adc_dev_add_device(struct adc_core_dev *adc)
{
	if (cdev_add(&adc->char_dev, adc->dev.devt, 1)) {
		DBG("!!!!!!cdev add error.!!!!!!\n");
		printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
				adc->name, MAJOR(adc_devt), adc->id);
	}
	else {
		pr_debug("%s: dev (%d:%d)\n", adc->name, MAJOR(adc_devt), adc->id);
	}
}

void adc_dev_del_device(struct adc_core_dev *adc)
{
	if (adc->dev.devt)
		cdev_del(&adc->char_dev);
}

void __init adc_dev_init(void)
{
	int err;

	err = alloc_chrdev_region(&adc_devt, 0, ADC_DEV_MAX, "adc");
	if (err < 0) {
		DBG("!!!!!!alloc chrdev region error!!!!!!\n");
		printk(KERN_ERR "%s: failed to allocate char dev region\n", __FILE__);
	}
}

void __exit adc_dev_exit(void)
{
	if (adc_devt)
		unregister_chrdev_region(adc_devt, ADC_DEV_MAX);
}