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ARM: SAMSUNG: gpio-cfg.h: update documentation 

Update the documentation on the gpio configuration calls to add more
references to useful information and also to document the values that
are passed.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Ben Dooks 2010-05-24 12:21:40 +09:00
parent d192baeaa7
commit 189e0445d8
1 changed files with 21 additions and 0 deletions
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21
arch/arm/plat-samsung/include/plat/gpio-cfg.h
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@ -43,6 +43,11 @@ struct s3c_gpio_chip;
* layouts. Provide an point to vector control routine and provide any
* per-bank configuration information that other systems such as the
* external interrupt code will need.
*
* @sa s3c_gpio_cfgpin
* @sa s3c_gpio_getcfg
* @sa s3c_gpio_setpull
* @sa s3c_gpio_getpull
*/
struct s3c_gpio_cfg {
unsigned int cfg_eint;
@ -75,6 +80,20 @@ struct s3c_gpio_cfg {
* Configure which function is actually connected to the external
* pin, such as an gpio input, output or some form of special function
* connected to an internal peripheral block.
*
* The @to parameter can be one of the generic S3C_GPIO_INPUT, S3C_GPIO_OUTPUT
* or S3C_GPIO_SFN() to indicate one of the possible values that the helper
* will then generate the correct bit mask and shift for the configuration.
*
* If a bank of GPIOs all needs to be set to special-function 2, then
* the following code will work:
*
* for (gpio = start; gpio < end; gpio++)
* s3c_gpio_cfgpin(gpio, S3C_GPIO_SFN(2));
*
* The @to parameter can also be a specific value already shifted to the
* correct position in the control register, although these are discouraged
* in newer kernels and are only being kept for compatibility.
*/
extern int s3c_gpio_cfgpin(unsigned int pin, unsigned int to);
@ -108,6 +127,8 @@ extern unsigned s3c_gpio_getcfg(unsigned int pin);
* This function sets the state of the pull-{up,down} resistor for the
* specified pin. It will return 0 if successfull, or a negative error
* code if the pin cannot support the requested pull setting.
*
* @pull is one of S3C_GPIO_PULL_NONE, S3C_GPIO_PULL_DOWN or S3C_GPIO_PULL_UP.
*/
extern int s3c_gpio_setpull(unsigned int pin, s3c_gpio_pull_t pull);