189e0445d8
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>
172 lines
6.2 KiB
C
172 lines
6.2 KiB
C
/* linux/arch/arm/plat-s3c/include/plat/gpio-cfg.h
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*
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* Copyright 2008 Openmoko, Inc.
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* Copyright 2008 Simtec Electronics
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* http://armlinux.simtec.co.uk/
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* Ben Dooks <ben@simtec.co.uk>
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*
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* S3C Platform - GPIO pin configuration
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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/* This file contains the necessary definitions to get the basic gpio
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* pin configuration done such as setting a pin to input or output or
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* changing the pull-{up,down} configurations.
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*/
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/* Note, this interface is being added to the s3c64xx arch first and will
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* be added to the s3c24xx systems later.
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*/
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#ifndef __PLAT_GPIO_CFG_H
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#define __PLAT_GPIO_CFG_H __FILE__
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typedef unsigned int __bitwise__ s3c_gpio_pull_t;
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typedef unsigned int __bitwise__ s5p_gpio_drvstr_t;
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/* forward declaration if gpio-core.h hasn't been included */
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struct s3c_gpio_chip;
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/**
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* struct s3c_gpio_cfg GPIO configuration
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* @cfg_eint: Configuration setting when used for external interrupt source
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* @get_pull: Read the current pull configuration for the GPIO
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* @set_pull: Set the current pull configuraiton for the GPIO
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* @set_config: Set the current configuration for the GPIO
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* @get_config: Read the current configuration for the GPIO
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*
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* Each chip can have more than one type of GPIO bank available and some
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* have different capabilites even when they have the same control register
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* layouts. Provide an point to vector control routine and provide any
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* per-bank configuration information that other systems such as the
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* external interrupt code will need.
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*
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* @sa s3c_gpio_cfgpin
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* @sa s3c_gpio_getcfg
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* @sa s3c_gpio_setpull
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* @sa s3c_gpio_getpull
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*/
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struct s3c_gpio_cfg {
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unsigned int cfg_eint;
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s3c_gpio_pull_t (*get_pull)(struct s3c_gpio_chip *chip, unsigned offs);
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int (*set_pull)(struct s3c_gpio_chip *chip, unsigned offs,
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s3c_gpio_pull_t pull);
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unsigned (*get_config)(struct s3c_gpio_chip *chip, unsigned offs);
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int (*set_config)(struct s3c_gpio_chip *chip, unsigned offs,
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unsigned config);
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};
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#define S3C_GPIO_SPECIAL_MARK (0xfffffff0)
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#define S3C_GPIO_SPECIAL(x) (S3C_GPIO_SPECIAL_MARK | (x))
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/* Defines for generic pin configurations */
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#define S3C_GPIO_INPUT (S3C_GPIO_SPECIAL(0))
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#define S3C_GPIO_OUTPUT (S3C_GPIO_SPECIAL(1))
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#define S3C_GPIO_SFN(x) (S3C_GPIO_SPECIAL(x))
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#define s3c_gpio_is_cfg_special(_cfg) \
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(((_cfg) & S3C_GPIO_SPECIAL_MARK) == S3C_GPIO_SPECIAL_MARK)
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/**
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* s3c_gpio_cfgpin() - Change the GPIO function of a pin.
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* @pin pin The pin number to configure.
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* @to to The configuration for the pin's function.
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*
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* Configure which function is actually connected to the external
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* pin, such as an gpio input, output or some form of special function
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* connected to an internal peripheral block.
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*
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* The @to parameter can be one of the generic S3C_GPIO_INPUT, S3C_GPIO_OUTPUT
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* or S3C_GPIO_SFN() to indicate one of the possible values that the helper
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* will then generate the correct bit mask and shift for the configuration.
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*
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* If a bank of GPIOs all needs to be set to special-function 2, then
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* the following code will work:
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*
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* for (gpio = start; gpio < end; gpio++)
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* s3c_gpio_cfgpin(gpio, S3C_GPIO_SFN(2));
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*
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* The @to parameter can also be a specific value already shifted to the
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* correct position in the control register, although these are discouraged
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* in newer kernels and are only being kept for compatibility.
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*/
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extern int s3c_gpio_cfgpin(unsigned int pin, unsigned int to);
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/**
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* s3c_gpio_getcfg - Read the current function for a GPIO pin
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* @pin: The pin to read the configuration value for.
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*
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* Read the configuration state of the given @pin, returning a value that
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* could be passed back to s3c_gpio_cfgpin().
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*
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* @sa s3c_gpio_cfgpin
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*/
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extern unsigned s3c_gpio_getcfg(unsigned int pin);
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/* Define values for the pull-{up,down} available for each gpio pin.
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*
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* These values control the state of the weak pull-{up,down} resistors
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* available on most pins on the S3C series. Not all chips support both
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* up or down settings, and it may be dependant on the chip that is being
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* used to whether the particular mode is available.
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*/
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#define S3C_GPIO_PULL_NONE ((__force s3c_gpio_pull_t)0x00)
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#define S3C_GPIO_PULL_DOWN ((__force s3c_gpio_pull_t)0x01)
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#define S3C_GPIO_PULL_UP ((__force s3c_gpio_pull_t)0x02)
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/**
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* s3c_gpio_setpull() - set the state of a gpio pin pull resistor
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* @pin: The pin number to configure the pull resistor.
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* @pull: The configuration for the pull resistor.
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*
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* This function sets the state of the pull-{up,down} resistor for the
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* specified pin. It will return 0 if successfull, or a negative error
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* code if the pin cannot support the requested pull setting.
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*
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* @pull is one of S3C_GPIO_PULL_NONE, S3C_GPIO_PULL_DOWN or S3C_GPIO_PULL_UP.
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*/
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extern int s3c_gpio_setpull(unsigned int pin, s3c_gpio_pull_t pull);
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/**
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* s3c_gpio_getpull() - get the pull resistor state of a gpio pin
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* @pin: The pin number to get the settings for
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*
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* Read the pull resistor value for the specified pin.
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*/
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extern s3c_gpio_pull_t s3c_gpio_getpull(unsigned int pin);
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/* Define values for the drvstr available for each gpio pin.
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*
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* These values control the value of the output signal driver strength,
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* configurable on most pins on the S5C series.
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*/
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#define S5P_GPIO_DRVSTR_LV1 ((__force s5p_gpio_drvstr_t)0x00)
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#define S5P_GPIO_DRVSTR_LV2 ((__force s5p_gpio_drvstr_t)0x01)
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#define S5P_GPIO_DRVSTR_LV3 ((__force s5p_gpio_drvstr_t)0x10)
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#define S5P_GPIO_DRVSTR_LV4 ((__force s5p_gpio_drvstr_t)0x11)
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/**
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* s5c_gpio_get_drvstr() - get the driver streght value of a gpio pin
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* @pin: The pin number to get the settings for
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*
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* Read the driver streght value for the specified pin.
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*/
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extern s5p_gpio_drvstr_t s5p_gpio_get_drvstr(unsigned int pin);
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/**
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* s3c_gpio_set_drvstr() - set the driver streght value of a gpio pin
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* @pin: The pin number to configure the driver streght value
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* @drvstr: The new value of the driver strength
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*
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* This function sets the driver strength value for the specified pin.
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* It will return 0 if successfull, or a negative error code if the pin
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* cannot support the requested setting.
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*/
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extern int s5p_gpio_set_drvstr(unsigned int pin, s5p_gpio_drvstr_t drvstr);
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#endif /* __PLAT_GPIO_CFG_H */
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