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lcd_dev.c

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  • lcd_dev.c 4.05 KiB
    //#include "bcm2835.h"
    #include <linux/init.h>
    #include <linux/kernel.h>
    #include <linux/module.h>
    #include <linux/fs.h>
    #include <linux/uaccess.h>
    #include <linux/slab.h>
    #include <linux/delay.h>
    
    #include <asm/mach/map.h>
    #include <asm/uaccess.h>
    
    #define   IR_MAJOR_NUMBER      504
    #define IR_DEV_NAME         "lcd_dev"
    #define I2C_BASE_ADDR      0x3F804000
    
    #define DLEN 0x08
    #define FIFO 0x10
    #define S   0x04
    #define C   0x00
    #define DIV 0x14
    #define BSC_A 0x0C
    
    static void __iomem *i2c_base;
    
    volatile unsigned int *i2c, paddr;
    
    int lcd_open(struct inode *inode, struct file *filp){
       printk(KERN_ALERT "LCD sensor driver open!!\n");
       i2c_base = ioremap(I2C_BASE_ADDR, 0xFF);
       i2c=(volatile unsigned int*)(i2c_base);
       return 0;
    }
       
    int lcd_release(struct inode *inode, struct file *filp){
       printk(KERN_ALERT "Infrared distance sensor driver closed!!\n");
       return 1;
    }
    
    ssize_t lcd_write(struct file* flip, const char* buf, size_t count, loff_t* f_pos){
       char* kbuf;
       kbuf=kmalloc(count, GFP_KERNEL);
       copy_from_user(kbuf, buf, 1);
       //printk(KERN_ALERT "SEX: %x\n", *kbuf);
       //char buffer[1];
       //buffer[0]=0x01;
       
       unsigned int len=1; 
       volatile unsigned int* dlen = (volatile unsigned int*)(i2c_base +  DLEN);
       volatile unsigned int* fifo = (volatile unsigned int*)(i2c_base + FIFO);
       volatile unsigned int* status = (volatile unsigned int*)(i2c_base + S);
       volatile unsigned int* control = (volatile unsigned int*)(i2c_base + C);
       volatile unsigned int* bsc_a = (volatile unsigned int*)(i2c_base + BSC_A);
       
       *bsc_a = 0x3F;
       
       unsigned int remaining=len;
       unsigned int i=0;
       unsigned int reason = 0;
       
       *control |= 0x20;
       *status = (0x200 | 0x100 | 0x02);
       *dlen = len;
       while(remaining &&(i<16)){
             *fifo = kbuf[i];
             i++;
             remaining--;
       }
       
       *control = (0x8000|0x80);
       
       while(!(*status & 0x02)){
          while(remaining && (*status & 0x10)){
                *fifo = kbuf[i];
                i++;
                remaining--;
          }
       }
       
       if(*status & 0x100)
          reason = 1;
       else if(*status & 0x200)
          reason = 2;
       else if(remaining)
          reason = 4;
          
       *control |= 0x02;
       printk(KERN_ALERT "reason: %d\n", reason);
       //copy_to_user(buf, &reason, sizeof(int));
       return 0;
    }
    /*
    ssize_t lcd_read(struct file *filp, char *buf, size_t size, loff_t *f_pos){
       int
       char buffer[1];
       buffer[0]=0x01;
       unsigned int len=1; 
       volatile unsigned int* dlen = (volatile unsigned int*)(i2c_base +  DLEN);
       volatile unsigned int* fifo = (volatile unsigned int*)(i2c_base + FIFO);
       volatile unsigned int* status = (volatile unsigned int*)(i2c_base + S);
       volatile unsigned int* control = (volatile unsigned int*)(i2c_base + C);
       
       unsigned int remaining=len;
       unsigned int i=0;
       unsigned int reason = 0;
       
       *control |= 0x20;
       *status = (0x200 | 0x100 | 0x02);
       *dlen = len;
       while(remaining &&(i<16)){
             *fifo = buffer[i];
             i++;
             remaining--;
       }
       
       *control = (0x8000|0x80);
       
       while(!(*status & 0x02)){
          while(remaining && (*status & 0x10)){
                *fifo = buffer[i];
                i++;
                remaining--;
          }
       }
       
       if(*status & 0x100)
          reason = 1;
       else if(*status & 0x200)
          reason = 2;
       else if(remaining)
          reason = 4;
          
       *control |= 0x02;
       printk(KERN_ALERT "reason: %d\n", reason);
       copy_to_user(buf, &reason, sizeof(int));
       return 0;
       return size;
    }
    */
    
    static struct file_operations ir_fops = {
       .owner = THIS_MODULE,
       .open = lcd_open,
       .release = lcd_release,
       .write = lcd_write
    };
    
    int __init lcd_init(void){
       if(register_chrdev(IR_MAJOR_NUMBER, IR_DEV_NAME, &ir_fops) < 0)
          printk(KERN_ALERT "LCD initialization failed\n");
       else
          printk(KERN_ALERT "LCD initialization success\n");
       return 0;
    }
    
    void __exit lcd_exit(void){
       unregister_chrdev(IR_MAJOR_NUMBER, IR_DEV_NAME);
       printk(KERN_ALERT "LCD driver exit done");
    }
    
    module_init(lcd_init);
    module_exit(lcd_exit);
    
    MODULE_LICENSE("GPL");
    MODULE_AUTHOR("MW");
    MODULE_DESCRIPTION("joreka");