kernel-fxtec-pro1x/arch/arm/plat-samsung/include/plat/gpio-cfg.h
Ben Dooks 189e0445d8 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>
2010-05-28 19:31:32 +09:00

172 lines
6.2 KiB
C

/* linux/arch/arm/plat-s3c/include/plat/gpio-cfg.h
*
* Copyright 2008 Openmoko, Inc.
* Copyright 2008 Simtec Electronics
* http://armlinux.simtec.co.uk/
* Ben Dooks <ben@simtec.co.uk>
*
* S3C Platform - GPIO pin configuration
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/* This file contains the necessary definitions to get the basic gpio
* pin configuration done such as setting a pin to input or output or
* changing the pull-{up,down} configurations.
*/
/* Note, this interface is being added to the s3c64xx arch first and will
* be added to the s3c24xx systems later.
*/
#ifndef __PLAT_GPIO_CFG_H
#define __PLAT_GPIO_CFG_H __FILE__
typedef unsigned int __bitwise__ s3c_gpio_pull_t;
typedef unsigned int __bitwise__ s5p_gpio_drvstr_t;
/* forward declaration if gpio-core.h hasn't been included */
struct s3c_gpio_chip;
/**
* struct s3c_gpio_cfg GPIO configuration
* @cfg_eint: Configuration setting when used for external interrupt source
* @get_pull: Read the current pull configuration for the GPIO
* @set_pull: Set the current pull configuraiton for the GPIO
* @set_config: Set the current configuration for the GPIO
* @get_config: Read the current configuration for the GPIO
*
* Each chip can have more than one type of GPIO bank available and some
* have different capabilites even when they have the same control register
* 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;
s3c_gpio_pull_t (*get_pull)(struct s3c_gpio_chip *chip, unsigned offs);
int (*set_pull)(struct s3c_gpio_chip *chip, unsigned offs,
s3c_gpio_pull_t pull);
unsigned (*get_config)(struct s3c_gpio_chip *chip, unsigned offs);
int (*set_config)(struct s3c_gpio_chip *chip, unsigned offs,
unsigned config);
};
#define S3C_GPIO_SPECIAL_MARK (0xfffffff0)
#define S3C_GPIO_SPECIAL(x) (S3C_GPIO_SPECIAL_MARK | (x))
/* Defines for generic pin configurations */
#define S3C_GPIO_INPUT (S3C_GPIO_SPECIAL(0))
#define S3C_GPIO_OUTPUT (S3C_GPIO_SPECIAL(1))
#define S3C_GPIO_SFN(x) (S3C_GPIO_SPECIAL(x))
#define s3c_gpio_is_cfg_special(_cfg) \
(((_cfg) & S3C_GPIO_SPECIAL_MARK) == S3C_GPIO_SPECIAL_MARK)
/**
* s3c_gpio_cfgpin() - Change the GPIO function of a pin.
* @pin pin The pin number to configure.
* @to to The configuration for the pin's function.
*
* 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);
/**
* s3c_gpio_getcfg - Read the current function for a GPIO pin
* @pin: The pin to read the configuration value for.
*
* Read the configuration state of the given @pin, returning a value that
* could be passed back to s3c_gpio_cfgpin().
*
* @sa s3c_gpio_cfgpin
*/
extern unsigned s3c_gpio_getcfg(unsigned int pin);
/* Define values for the pull-{up,down} available for each gpio pin.
*
* These values control the state of the weak pull-{up,down} resistors
* available on most pins on the S3C series. Not all chips support both
* up or down settings, and it may be dependant on the chip that is being
* used to whether the particular mode is available.
*/
#define S3C_GPIO_PULL_NONE ((__force s3c_gpio_pull_t)0x00)
#define S3C_GPIO_PULL_DOWN ((__force s3c_gpio_pull_t)0x01)
#define S3C_GPIO_PULL_UP ((__force s3c_gpio_pull_t)0x02)
/**
* s3c_gpio_setpull() - set the state of a gpio pin pull resistor
* @pin: The pin number to configure the pull resistor.
* @pull: The configuration for the pull resistor.
*
* 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);
/**
* s3c_gpio_getpull() - get the pull resistor state of a gpio pin
* @pin: The pin number to get the settings for
*
* Read the pull resistor value for the specified pin.
*/
extern s3c_gpio_pull_t s3c_gpio_getpull(unsigned int pin);
/* Define values for the drvstr available for each gpio pin.
*
* These values control the value of the output signal driver strength,
* configurable on most pins on the S5C series.
*/
#define S5P_GPIO_DRVSTR_LV1 ((__force s5p_gpio_drvstr_t)0x00)
#define S5P_GPIO_DRVSTR_LV2 ((__force s5p_gpio_drvstr_t)0x01)
#define S5P_GPIO_DRVSTR_LV3 ((__force s5p_gpio_drvstr_t)0x10)
#define S5P_GPIO_DRVSTR_LV4 ((__force s5p_gpio_drvstr_t)0x11)
/**
* s5c_gpio_get_drvstr() - get the driver streght value of a gpio pin
* @pin: The pin number to get the settings for
*
* Read the driver streght value for the specified pin.
*/
extern s5p_gpio_drvstr_t s5p_gpio_get_drvstr(unsigned int pin);
/**
* s3c_gpio_set_drvstr() - set the driver streght value of a gpio pin
* @pin: The pin number to configure the driver streght value
* @drvstr: The new value of the driver strength
*
* This function sets the driver strength value for the specified pin.
* It will return 0 if successfull, or a negative error code if the pin
* cannot support the requested setting.
*/
extern int s5p_gpio_set_drvstr(unsigned int pin, s5p_gpio_drvstr_t drvstr);
#endif /* __PLAT_GPIO_CFG_H */