#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <asm/current.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/err.h>
//#include <stdint.h>
#include "gpio.h"
#include "./../../stm32f429xx.h"
#include "asm/uaccess.h"


static int major = 100;
static int minor = 0;
static dev_t devno;
static struct cdev *gpio_cdev = NULL;
static int count = 3;
#define DEVNAME "gpio"

static int gpio_open(struct inode *inode, struct file *filep);
static int gpio_close(struct inode *inode, struct file *filep);
static ssize_t gpio_read(struct file *filep, char __user *buf, size_t size, loff_t *offset);
static ssize_t gpio_write(struct file *filep, const char __user *buf, size_t size, loff_t *offset);
static int gpio_ioctl(struct inode *inode, struct file *filep, unsigned int cmd, unsigned long arg);
static struct file_operations gpio_ops = 
{
	.owner = THIS_MODULE,
	.open = gpio_open,
	.release = gpio_close,
	.ioctl = gpio_ioctl,
	.read = gpio_read,
	.write = gpio_write,
	
};

static int gpio_open(struct inode *inode, struct file *filep)
{
	return 0;
}

static int gpio_close(struct inode *inode, struct file *filep)
{
	return 0;
}

static int enable_gpio_clock(gpio_data_t *gpin_data)
{
	RCC_TypeDef *rcc_dev = RCC;
	
	switch((int)gpin_data->port)
	{
	//AHB1
	case (int)GPIOA:	rcc_dev->AHB1ENR |= 0x001; break;
	case (int)GPIOB:	rcc_dev->AHB1ENR |= 0x002; break;
	case (int)GPIOC:	rcc_dev->AHB1ENR |= 0x004; break;
	case (int)GPIOD:	rcc_dev->AHB1ENR |= 0x008; break;
	case (int)GPIOE:	rcc_dev->AHB1ENR |= 0x010; break;
	case (int)GPIOF:	rcc_dev->AHB1ENR |= 0x020; break;
	case (int)GPIOG:	rcc_dev->AHB1ENR |= 0x040; break;
	case (int)GPIOH:	rcc_dev->AHB1ENR |= 0x080; break;
	case (int)GPIOI:	rcc_dev->AHB1ENR |= 0x100; break;
	case (int)GPIOJ:	rcc_dev->AHB1ENR |= 0x200; break;
	case (int)GPIOK:	rcc_dev->AHB1ENR |= 0x400; break;
	default: printk("---> invalid gpio port!\n");break;
	}
	return 0;
}

static int gpio_ioctl(struct inode *inode, struct file *filep, unsigned int cmd, unsigned long arg)
{
	uint8_t position;
	gpio_data_t gpin_data;
	GPIO_TypeDef *gpio_dev;	
	if ( copy_from_user(&gpin_data, (void*)arg, sizeof(gpio_data_t)) )
		return -EFAULT;

	gpio_dev = (GPIO_TypeDef*)gpin_data.port;

	//get gpio pin position
	for(position=0;position<16;position++)
	{
		if(gpin_data.pin == 0x01<<position)
			break;
	}
	
	switch(cmd)
	{
	case SET_GPIO_INPUT:
		enable_gpio_clock(&gpin_data);
		gpio_dev->MODER &= ~((0x03) << (position<<1));
		break;
	case SET_GPIO_PUSH_PULL_OUTPUT:
		enable_gpio_clock(&gpin_data);
		gpio_dev->MODER &= ~((0x03) << (position<<1));
		gpio_dev->MODER |= ((0x01) << (position<<1));
		gpio_dev->OTYPER &= (~gpin_data.pin);
		break;
	case SET_GPIO_OPEN_DRAIN_OUTPUT:
		enable_gpio_clock(&gpin_data);
		gpio_dev->MODER &= ~((0x03) << (position<<1));
		gpio_dev->MODER |= ((0x01) << (position<<1));
		gpio_dev->OTYPER |= gpin_data.pin;
		break;
	case SET_GPIO_PULL_UP:
		gpio_dev->PUPDR &= ~((0x03) << (position<<1));
		gpio_dev->PUPDR |= ((0x01) << (position<<1));
		break;
	case SET_GPIO_PULL_DOWN:
		gpio_dev->PUPDR &= ~((0x03) << (position<<1));
		gpio_dev->PUPDR |= ((0x02) << (position<<1));
		break;
	case SET_GPIO_NO_PULL:
		gpio_dev->PUPDR &= ~((0x03) << (position<<1));
		break;
	case SET_GPIO_SPEED:
		switch(gpin_data.data)
		{
		case GPIO_LOW_SPEED: 
			gpio_dev->OSPEEDR &= ~((0x03) << (position<<1));
			break;
		case GPIO_MEDIUM_SPEED:
			gpio_dev->OSPEEDR &= ~((0x03) << (position<<1));
			gpio_dev->OSPEEDR |= ((0x01) << (position<<1));
			break;
		case GPIO_FAST_SPEED:			
			gpio_dev->OSPEEDR &= ~((0x03) << (position<<1));
			gpio_dev->OSPEEDR |= ((0x02) << (position<<1));
			break;
		case GPIO_HIGH_SPEED:
			gpio_dev->OSPEEDR |= ((0x03) << (position<<1));
			break;
		default:break;
		}
		break;
	case SET_GPIO_VALUE:
		if(gpin_data.data)
			gpio_dev->ODR |= gpin_data.pin;
		else
			gpio_dev->ODR &= ~gpin_data.pin;
		break;
	case GET_GPIO_VALUE:
		if(gpio_dev->IDR & gpin_data.pin)
			gpin_data.data = 0x01;
		else
			gpin_data.data = 0x00;
		break;
	default:
		printk("---> Invalid action\n");
		return -EINVAL;
		break;		

	}
	return 0;
}

static ssize_t gpio_read(struct file *filep, char __user *buf, size_t size, loff_t *offset)
{
	return 0;
}

static ssize_t gpio_write(struct file *filep, const char __user *buf, size_t size, loff_t *offset)
{
	return 0;
}



static int __init gpio_init(void)
{
	int ret;
	gpio_cdev = cdev_alloc();
	if(gpio_cdev == NULL){
		return -ENOMEM;
	}

	cdev_init(gpio_cdev,&gpio_ops);
	devno = MKDEV(major,minor);
	ret = register_chrdev_region(devno, count, DEVNAME);
	if(ret){
		goto ERR_STEP;
	}
	
	ret = cdev_add(gpio_cdev, devno, count);
	if(ret){
		goto ERR_STEP1;
	}
	return 0;

ERR_STEP1:
	unregister_chrdev_region(devno,count);
ERR_STEP:
	cdev_del(gpio_cdev);
	return ret;
}

static void __exit gpio_exit(void)
{
	unregister_chrdev_region(MKDEV(major,minor),count);
	cdev_del(gpio_cdev);
}

module_init(gpio_init);
module_exit(gpio_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jimbo");
MODULE_DESCRIPTION("this is gpio module");