2416开发记录六： s3c2410_gpio_setpin()系列函数

依然解释LED驱动的知识点

转自：(http://blog.sina.com.cn/s/blog_7bd0d88201011ulq.html)

系列函数的定义在arch/arm/mach-s3c2410/gpio.c，相关的宏定义在include/asm-arm/arch-s3c2410/regs-gpio.h

s3c2410_gpio_cfgpin(S3C2410_GPG(0), S3C2410_GPIO_OUTPUT);

s3c2410_gpio_cfgpin()的定义在arch/arm/march-2410/include/mach/gpio-fns.h

S3C2410_GPG()的定义在arch/arm/march-2410/include/mach/gpio-nrs.h

S3C2410_GPIO_OUTPUT的定义在arch/arm/march-2410/include/mach/regs-gpio.h

我要用GPF0~6 和GPG0，则根据头文件

arch/arm/march-2410/include/mach/gpio-nrs.h中

/* GPIO bank sizes */
#define S3C2410_GPIO_A_NR (32)
#define S3C2410_GPIO_B_NR (32)
#define S3C2410_GPIO_C_NR (32)
#define S3C2410_GPIO_D_NR (32)
#define S3C2410_GPIO_E_NR (32)
#define S3C2410_GPIO_F_NR (32)
#define S3C2410_GPIO_G_NR (32)
#define S3C2410_GPIO_H_NR (32)
#define S3C2410_GPIO_J_NR (32) /* technically 16. */
#define S3C2410_GPIO_K_NR (32) /* technically 16. */
#define S3C2410_GPIO_L_NR (32) /* technically 15. */
#define S3C2410_GPIO_M_NR (32) /* technically 2. */

#if CONFIG_S3C_GPIO_SPACE != 0
#error CONFIG_S3C_GPIO_SPACE cannot be zero at the moment
#endif

#define S3C2410_GPIO_NEXT(__gpio) /
((__gpio##_START) + (__gpio##_NR) + CONFIG_S3C_GPIO_SPACE + 0)

//这里的CONFIG_S3C_GPIO_SPAC是内核配置选项，在.config中可以找到，一般配置都是：

//CONFIG_S3C_GPIO_SPACE = 0

//比如我要用GPG0，则

//S3C2410_GPIO_NEXT(S3C2410_GPIO_F) +0 =>

//(S3C2410_GPIO_F_START + S3C2410_GPIO_F_NR +  CONFIG_S3C_GPIO_SPACE + 0) + 0 =>

//这样一步一步传递，可以得出GPG0的地址

//所以才有S3C2410_GPG(0)

（1）void s3c2410_gpio_setpin(unsigned int pin, unsigned int to);

设置相应GPIO口的输出值，例如：

pin=S3C2410_GPG2(这里实际使用的是S3C2410_GPG(2))，to=0，则设置S3C2410＿GPG2的输出值为0；

pin=S3C2410_GPG2，to=1，则设置S3C2410＿GPG2的输出值为1。

函数定义：

void s3c2410_gpio_setpin(unsigned int pin, unsigned int to)
{
void __iomem *base = S3C2410_GPIO_BASE(pin);
unsigned long offs = S3C2410_GPIO_OFFSET(pin);
unsigned long flags;
unsigned long dat;

local_irq_save(flags);

dat = __raw_readl(base + 0x04);
dat &= ~(1 << offs);
dat |= to << offs;
__raw_writel(dat, base + 0x04);

local_irq_restore(flags);
}
EXPORT_SYMBOL(s3c2410_gpio_setpin);

（2）unsigned int s3c2410_gpio_getpin(unsigned int pin);

获取相应GPIO口的值。

函数定义：

unsigned int s3c2410_gpio_getpin(unsigned int pin)
{
void __iomem *base = S3C2410_GPIO_BASE(pin);
unsigned long offs = S3C2410_GPIO_OFFSET(pin);

return __raw_readl(base + 0x04) & (1<< offs);
}

EXPORT_SYMBOL(s3c2410_gpio_getpin);

（3）void s3c2410_gpio_cfgpin(unsigned int pin, unsigned int function);

设置相应GPIO口的工作模式，输入、输出、中断等。

这里我知道的定义有以下几种

S3C2410_GPIO_INPUT:

S3C2410_GPIO_OUTPUT:

S3C2410_GPIO_IRQ:(或者是类似S3C2410_GPF0_EINT0等。)

这都是在/arch/arm/mach-s3c2410/include/mach/regs-gpio.h文件中定义的

函数定义：

void s3c2410_gpio_cfgpin(unsigned int pin, unsigned int function)
{
void __iomem *base = S3C2410_GPIO_BASE(pin);
unsigned long mask;
unsigned long con;
unsigned long flags;

if (pin < S3C2410_GPIO_BANKB) {
mask = 1 << S3C2410_GPIO_OFFSET(pin);
} else {
mask = 3 << S3C2410_GPIO_OFFSET(pin)*2;
}

local_irq_save(flags);

con  = __raw_readl(base + 0x00);
con &= ~mask;
con |= function;

__raw_writel(con, base + 0x00);

local_irq_restore(flags);
}

EXPORT_SYMBOL(s3c2410_gpio_cfgpin);

（4）unsigned int s3c2410_gpio_getcfg(unsigned int pin);

获取相应GPIO口的工作模式，输入、输出、中断等。

函数定义：

unsigned int s3c2410_gpio_getcfg(unsigned int pin)
{
void __iomem *base = S3C2410_GPIO_BASE(pin);
unsigned long mask;

if (pin < S3C2410_GPIO_BANKB) {
mask = 1 << S3C2410_GPIO_OFFSET(pin);
} else {
mask = 3 << S3C2410_GPIO_OFFSET(pin)*2;
}

return __raw_readl(base) & mask;
}

EXPORT_SYMBOL(s3c2410_gpio_getcfg);

（5）void s3c2410_gpio_pullup(unsigned int pin, unsigned int to);

设置相应的GPIO口的电平，例如：

pin=S3C2410_GPG2，to=0，则拉低S3C2410_GPG2，也就是设置S3C2410＿GPG2的值为0；

pin=S3C2410_GPG2，to=1，则拉高S3C2410_GPG2，也就是设置S3C2410＿GPG2的值为1。

函数定义：

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void s3c2410_gpio_pullup(unsigned int pin, unsigned int to)
{
void __iomem *base = S3C2410_GPIO_BASE(pin);
unsigned long offs = S3C2410_GPIO_OFFSET(pin);
unsigned long flags;
unsigned long up;

if (pin < S3C2410_GPIO_BANKB)
return;

local_irq_save(flags);

up = __raw_readl(base + 0x08);
up &= ~(1L << offs);
up |= to << offs;
__raw_writel(up, base + 0x08);

local_irq_restore(flags);
}

EXPORT_SYMBOL(s3c2410_gpio_pullup);

（6）unsigned int s3c2410_modify_misccr(unsigned int clear, unsigned int change);

杂项设置，设置寄存器MISCCR，具体看函数定义。

函数定义：

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unsigned int s3c2410_modify_misccr(unsigned int clear, unsigned int change)
{
unsigned long flags;
unsigned long misccr;

local_irq_save(flags);
misccr = __raw_readl(S3C2410_MISCCR);
misccr &= ~clear;
misccr ^= change;
__raw_writel(misccr, S3C2410_MISCCR);
local_irq_restore(flags);

return misccr;
}

EXPORT_SYMBOL(s3c2410_modify_misccr);

（7）int s3c2410_gpio_getirq(unsigned int pin);

获取相应的GPIO口所对应的中断号。

函数定义：

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int s3c2410_gpio_getirq(unsigned int pin)
{
if (pin < S3C2410_GPF0 || pin > S3C2410_GPG15_EINT23)
return -1;

if (pin < S3C2410_GPG0 && pin > S3C2410_GPF7)
return -1;

if (pin < S3C2410_GPF4)
return (pin - S3C2410_GPF0) + IRQ_EINT0;

if (pin < S3C2410_GPG0)
return (pin - S3C2410_GPF4) + IRQ_EINT4;

return (pin - S3C2410_GPG0) + IRQ_EINT8;
}

EXPORT_SYMBOL(s3c2410_gpio_getirq);

（8）int s3c2410_gpio_irqfilter(unsigned int pin, unsigned int on, unsigned int config);

中断过滤配置，具体看函数定义。

函数定义：

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int s3c2410_gpio_irqfilter(unsigned int pin, unsigned int on,
unsigned int config)
{
void __iomem *reg = S3C2410_EINFLT0;
unsigned long flags;
unsigned long val;

if (pin < S3C2410_GPG8 || pin > S3C2410_GPG15)
return -1;

config &= 0xff;

pin -= S3C2410_GPG8_EINT16;
reg += pin & ~3;

local_irq_save(flags);

val = __raw_readl(reg);
val &= ~(0xff << ((pin & 3) * 8));
val |= config << ((pin & 3) * 8);
__raw_writel(val, reg);

val = __raw_readl(S3C2410_EXTINT2);
val &= ~(1 << ((pin * 4) + 3));
val |= on << ((pin * 4) + 3);
__raw_writel(val, S3C2410_EXTINT2);

local_irq_restore(flags);

return 0;
}

EXPORT_SYMBOL(s3c2410_gpio_irqfilter);