Exynos 4412用于Linux内核的GPIO配置函数

Exynos 4412 SoC暴露给Linux内核的GPIO配置函数定义在Linux内核代码仓库的arch/arm/plat-samsung/include/plat/gpio-cfg.h中:

/* 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;
typedef unsigned int __bitwise__ s5p_gpio_pd_cfg_t;
typedef unsigned int __bitwise__ s5p_gpio_pd_pull_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);
 
/**
 * s3c_gpio_cfgpin_range() - Change the GPIO function for configuring pin range
 * @start: The pin number to start at
 * @nr: The number of pins to configure from @start.
 * @cfg: The configuration for the pin's function
 *
 * Call s3c_gpio_cfgpin() for the @nr pins starting at @start.
 *
 * @sa s3c_gpio_cfgpin.
 */
extern int s3c_gpio_cfgpin_range(unsigned int start, unsigned int nr,
                 unsigned int cfg);
 
/* 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 dependent 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 successful, 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);
 
/* configure `all` aspects of an gpio */
 
/**
 * s3c_gpio_cfgall_range() - configure range of gpio functtion and pull.
 * @start: The gpio number to start at.
 * @nr: The number of gpio to configure from @start.
 * @cfg: The configuration to use
 * @pull: The pull setting to use.
 *
 * Run s3c_gpio_cfgpin() and s3c_gpio_setpull() over the gpio range starting
 * @gpio and running for @size.
 *
 * @sa s3c_gpio_cfgpin
 * @sa s3c_gpio_setpull
 * @sa s3c_gpio_cfgpin_range
 */
extern int s3c_gpio_cfgall_range(unsigned int start, unsigned int nr,
                 unsigned int cfg, s3c_gpio_pull_t pull);
 
static inline int s3c_gpio_cfgrange_nopull(unsigned int pin, unsigned int size,
                       unsigned int cfg)
{
    return s3c_gpio_cfgall_range(pin, size, cfg, S3C_GPIO_PULL_NONE);
}
 
/* 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 S5P series.
 */
#define S5P_GPIO_DRVSTR_LV1    ((__force s5p_gpio_drvstr_t)0x0)
#define S5P_GPIO_DRVSTR_LV2    ((__force s5p_gpio_drvstr_t)0x2)
#define S5P_GPIO_DRVSTR_LV3    ((__force s5p_gpio_drvstr_t)0x1)
#define S5P_GPIO_DRVSTR_LV4    ((__force s5p_gpio_drvstr_t)0x3)
 
/**
 * 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 successful, 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);
 
/* Define values for the power down configuration available for each gpio pin.
 *
 * These values control the state of the power down configuration resistors
 * available on most pins on the S5P series.
 */
#define S5P_GPIO_PD_OUTPUT0    ((__force s5p_gpio_pd_cfg_t)0x00)
#define S5P_GPIO_PD_OUTPUT1    ((__force s5p_gpio_pd_cfg_t)0x01)
#define S5P_GPIO_PD_INPUT    ((__force s5p_gpio_pd_cfg_t)0x02)
#define S5P_GPIO_PD_PREV_STATE    ((__force s5p_gpio_pd_cfg_t)0x03)
 
/**
 * s5p_gpio_set_pd_cfg() - set the configuration of a gpio power down mode
 * @pin: The pin number to configure the pull resistor.
 * @pd_cfg: The configuration for the pwer down mode configuration register.
 *
 * This function sets the configuration of the power down mode resistor for the
 * specified pin. It will return 0 if successful, or a negative error
 * code if the pin cannot support the requested power down mode.
 *
*/
extern int s5p_gpio_set_pd_cfg(unsigned int pin, s5p_gpio_pd_cfg_t pd_cfg);
 
/**
 * s5p_gpio_get_pd_cfg() - get the power down mode configuration of a gpio pin
 * @pin: The pin number to get the settings for
 *
 * Read the power down mode resistor value for the specified pin.
*/
extern s5p_gpio_pd_cfg_t s5p_gpio_get_pd_cfg(unsigned int pin);
 
/* Define values for the power down pull-{up,down} available for each gpio pin.
 *
 * These values control the state of the power down mode pull-{up,down}
 * resistors available on most pins on the S5P series.
 */
#define S5P_GPIO_PD_UPDOWN_DISABLE    ((__force s5p_gpio_pd_pull_t)0x00)
#define S5P_GPIO_PD_DOWN_ENABLE        ((__force s5p_gpio_pd_pull_t)0x01)
#define S5P_GPIO_PD_UP_ENABLE        ((__force s5p_gpio_pd_pull_t)0x03)
 
/**
 * s5p_gpio_set_pd_pull() - set the pull-{up,down} of a gpio pin power down mode
 * @pin: The pin number to configure the pull resistor.
 * @pd_pull: The configuration for the power down mode pull resistor.
 *
 * This function sets the configuration of the pull-{up,down} resistor for the
 * specified pin. It will return 0 if successful, or a negative error
 * code if the pin cannot support the requested pull setting.
 *
*/
extern int s5p_gpio_set_pd_pull(unsigned int pin, s5p_gpio_pd_pull_t pd_pull);
 
/**
 * s5p_gpio_get_pd_pull() - get the power down pull resistor config of gpio pin
 * @pin: The pin number to get the settings for
 *
 * Read the power mode pull resistor value for the specified pin.
*/
extern s5p_gpio_pd_pull_t s5p_gpio_get_pd_pull(unsigned int pin);
 
/**
 * s5p_register_gpio_interrupt() - register interrupt support for a gpio group
 * @pin: The pin number from the group to be registered
 *
 * This function registers gpio interrupt support for the group that the
 * specified pin belongs to.
 *
 * The total number of gpio pins is quite large ob s5p series. Registering
 * irq support for all of them would be a resource waste. Because of that the
 * interrupt support for standard gpio pins is registered dynamically.
 *
 * It will return the irq number of the interrupt that has been registered
 * or -ENOMEM if no more gpio interrupts can be registered. It is allowed
 * to call this function more than once for the same gpio group (the group
 * will be registered only once).
 */
extern int s5p_register_gpio_interrupt(int pin);
 
/** s5p_register_gpioint_bank() - add gpio bank for further gpio interrupt
 * registration (see s5p_register_gpio_interrupt function)
 * @chain_irq: chained irq number for the gpio int handler for this bank
 * @start: start gpio group number of this bank
 * @nr_groups: number of gpio groups handled by this bank
 *
 * This functions registers initial information about gpio banks that
 * can be later used by the s5p_register_gpio_interrupt() function to
 * enable support for gpio interrupt for particular gpio group.
 */
#ifdef CONFIG_S5P_GPIO_INT
extern int s5p_register_gpioint_bank(int chain_irq, int start, int nr_groups);
#else
#define s5p_register_gpioint_bank(chain_irq, start, nr_groups) do { } while (0)
#endif
 
#endif /* __PLAT_GPIO_CFG_H */

Linux内核标准GPIO库linux/gpio.h同样可用,参考 https://blog.csdn.net/qq_37596943/article/details/103672254

  • int gpio_request(unsigned gpio, const char *label);
  • void gpio_free(unsigned gpio);
  • int gpio_direction_output(unsigned gpio, int value);
  • int gpio_direction_input(unsigned gpio);
  • int gpio_set_value(unsigned gpio, int value);
  • int gpio_get_value(unsigned gpio);
it
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