2.6.33+2440 led 灯 驱动程序 代码分析 （三）

yuweixian4230

代码查看：http://lxr.linux.no
我们直接看代码

1.

1. #define S3C2410_GPBCON S3C2410_GPIOREG(0x10)
   
2. #define S3C2410_GPBDAT S3C2410_GPIOREG(0x14)
3. #define S3C2410_GPBUP S3C2410_GPIOREG(0x18)

等同于：

 #define S3C2410_GPBCON (*(volatile unsigned long *)0x56000010)
 #define S3C2410_GPBDAT (*(volatile unsigned long *)0x56000014)
 #define S3C2410_GPBUP (*(volatile unsigned long *)0x56000018)

  这里，我们自己定义  3 个寄存器的地址
      S3C2410_GPIOREG定义在     arch/arm/mach-s3c2410/include/mach/regs-gpio.h

1. #define S3C2410_GPIOREG(x) ((x) + S3C24XX_VA_GPIO)
   
2. #define S3C24XX_GPIOREG2(x) ((x) + S3C24XX_VA_GPIO2)

S3C24XX_VA_GPIO：定义在linux/include/asm-arm/plat-s3c24xx/map.h

1. 72 #define S3C2410_PA_GPIO (0x56000000)
   

而在 S3C2440手册中，我们定义了

1. Register Address R/W Description Reset Value
   
2. 
   
3. GPBCON 0x56000010 R/W Configures the pins of port B 0x0
   
4. 
   
5. GPBDAT 0x56000014 R/W The data register for port B Undef.
   
6. 
   
7. GPBUP 0x56000018 R/W Pull-up disable register for port B

1. #define S3C2410_GPBCON S3C2410_GPIOREG(0x10)

等同于
  #define S3C2410_GPBCON (*volatile unsigned long *)(0x56000000+0x10)

2.设置管脚

1. #define S3C2410_GPB5 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 5)
   
2. #define S3C2410_GPB6 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 6)
   
3. #define S3C2410_GPB7 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 7)
   
4. #define S3C2410_GPB8 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 8)

S3C2410_GPIONO 定义在： arch/arm/mach-s3c2410/include/mach/gpio-nrs.h

1. 17#define S3C2410_GPIONO(bank,offset) ((bank) + (offset))
   
2. 18
   
3. 19#define S3C2410_GPIO_BANKA (32*0)
   
4. 20#define S3C2410_GPIO_BANKB (32*1)   有疑问？？
   

3. 设置输出管脚

1. #define S3C2410_GPB5_OUTP (0x01 << 10)
   
2. #define S3C2410_GPB6_OUTP (0x01 << 12)
   
3. #define S3C2410_GPB7_OUTP (0x01 << 14)
   
4. #define S3C2410_GPB8_OUTP (0x01 << 16)

在 S3C2440 手册中定义了，当为 01 时，表示输出功能

1. GPB8 [17:16] 00 = Input 01 = Output
   
2.              10 = nXDREQ1 11 = Reserved
   
3. 
   
4. GPB7 [15:14] 00 = Input 01 = Output
   
5.              10 = nXDACK1 11 = Reserved
   
6. 
   
7. GPB6 [13:12] 00 = Input 01 = Output
   
8.              10 = nXBREQ 11 = reserved
   
9. 
   
10. GPB5 [11:10] 00 = Input 01 = Output
    
11.              10 = nXBACK 11 = reserved

4.设置

1. static unsigned long gpio_table [] =
2. {
   
3.     S3C2410_GPB(5),
   
4.     S3C2410_GPB(6),
   
5.     S3C2410_GPB(7),
   
6.     S3C2410_GPB(8),
   
7. };

在哪里定义了 S3C2410_GPB(5)呢？？arch/arm/mach-s3c2410/include/mach/gpio-nrs.h

1. 60    /* S3C2410 GPIO number definitions. */
   
2. 61
   
3. 62    #define S3C2410_GPA(_nr) (S3C2410_GPIO_A_START + (_nr))
   
4. 63    #define S3C2410_GPB(_nr) (S3C2410_GPIO_B_START + (_nr))

1.      enum s3c_gpio_number {
   
2. 48   S3C2410_GPIO_A_START = 0,  ？？ 是虚拟内存，映射实现？？ 第一个地址 0
   
3. 49   S3C2410_GPIO_B_START = S3C2410_GPIO_NEXT(S3C2410_GPIO_A),  32+0吗？？
   
4. 50   S3C2410_GPIO_C_START = S3C2410_GPIO_NEXT(S3C2410_GPIO_B),

 S3C2410_GPB(5) () 0x56000010+


5 管脚设置

1. s3c2410_gpio_setpin(gpio_table[arg], 0);

::::
  s3c2410_gpio_setpin( S3C2410_GPB(5),0);

s3c2410_gpio_setpin 定义在： arch/arm/mach-s3c2410/include/mach/gpio-fns.h

1. 99   extern int s3c2410_gpio_getpull(unsigned int pin);
   
2. 100
   
3. 101  extern void s3c2410_gpio_setpin(unsigned int pin, unsigned int to);
   
4. 102
   
5. 103  extern unsigned int s3c2410_gpio_getpin(unsigned int pin);

s3c2410_gpio_setpin 代码实现在：linux/arch/arm/plat-s3c24xx/gpio.c

1.        void s3c2410_gpio_setpin(unsigned int pin, unsigned int to)
   
2.  140   {
   
3.  141      void __iomem *base = S3C24XX_GPIO_BASE(pin);
   
4.  142      unsigned long offs = S3C2410_GPIO_OFFSET(pin);
   
5.  143      unsigned long flags;
   
6.  144      unsigned long dat;
   
7.  145
   
8.  146      local_irq_save(flags);
   
9.  147
   
10.  148      dat = __raw_readl(base + 0x04);
    
11.  149      dat &= ~(1 << offs);
    
12.  150      dat |= to << offs;
    
13.  151      __raw_writel(dat, base + 0x04);
    
14.  152
    
15.  153     local_irq_restore(flags);
    
16.  154  }
    
17.  155
    
18.  156  EXPORT_SYMBOL(s3c2410_gpio_setpin);

不知道 怎么实现的 ？？？？





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