1、arch/arm/plat-s3c64xx/gpiolib.c文件中有如下：

arch_initcall(s3c64xx_gpiolib_init);这个应该实在系统初始化时调用。

static __init int s3c64xx_gpiolib_init(void)
{
s3c64xx_gpiolib_add(gpio_4bit, ARRAY_SIZE(gpio_4bit),
s3c64xx_gpiolib_add_4bit);


s3c64xx_gpiolib_add(gpio_4bit2, ARRAY_SIZE(gpio_4bit2),
s3c64xx_gpiolib_add_4bit2);


s3c64xx_gpiolib_add(gpio_2bit, ARRAY_SIZE(gpio_2bit), NULL);


return 0;
}

这三的蓝色部分是什么呢 看下面的源码，应该知道其是个struct s3c_gpio_chip *chips结构体，在同一个文件中定义，现在原始的结构体：

/**
* struct s3c_gpio_chip - wrapper for specific implementation of gpio对具体GPIO的包装
* @chip: The chip structure to be exported via gpiolib. 芯片的结构，配置通过gpiolib向外输出
* @base: The base pointer to the gpio configuration registers.
* @config: special function and pull-resistor control information.
*
* This wrapper provides the necessary information for the Samsung
* specific gpios being registered with gpiolib.
*/
struct s3c_gpio_chip {
struct gpio_chip chip;
struct s3c_gpio_cfg*config;
void __iomem*base;
};

struct gpio_chip源码如下：

/**
* struct gpio_chip - abstract a GPIO controller 对GPIO控制器的抽象
* @label: for diagnostics为判断而设
* @dev: optional device providing the GPIOs
* @owner: helps prevent removal of modules exporting active GPIOs
* @request: optional hook for chip-specific activation, such as
*enabling module power and clock; may sleep
* @free: optional hook for chip-specific deactivation, such as
*disabling module power and clock; may sleep
* @direction_input: configures signal "offset" as input, or returns error
* @get: returns value for signal "offset"; for output signals this
*returns either the value actually sensed, or zero
* @direction_output: configures signal "offset" as output, or returns error
* @set: assigns output value for signal "offset"
* @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
*implementation may not sleep
* @dbg_show: optional routine to show contents in debugfs; default code
*will be used when this is omitted, but custom code can show extra
*state (such as pullup/pulldown configuration).
* @base: identifies the first GPIO number handled by this chip; or, if
*negative during registration, requests dynamic ID allocation.
* @ngpio: the number of GPIOs handled by this controller; the last GPIO
*handled is (base + ngpio - 1).
* @can_sleep: flag must be set iff get()/set() methods sleep, as they
*must while accessing GPIO expander chips over I2C or SPI
*
* A gpio_chip can help platforms abstract various sources of GPIOs so
* they can all be accessed through a common programing interface.