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linux-next/drivers/gpio/gpiolib.h
Johan Hovold ebbeba120a gpio: sysfs: fix gpio attribute-creation race
Fix attribute-creation race with userspace by using the default group
to create also the contingent gpio device attributes.

Fixes: d8f388d8dc ("gpio: sysfs interface")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-15 17:20:56 +01:00

156 lines
4.7 KiB
C

/*
* Internal GPIO functions.
*
* Copyright (C) 2013, Intel Corporation
* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
*
* 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.
*/
#ifndef GPIOLIB_H
#define GPIOLIB_H
#include <linux/err.h>
#include <linux/device.h>
enum of_gpio_flags;
/**
* struct acpi_gpio_info - ACPI GPIO specific information
* @gpioint: if %true this GPIO is of type GpioInt otherwise type is GpioIo
* @active_low: in case of @gpioint, the pin is active low
*/
struct acpi_gpio_info {
bool gpioint;
bool active_low;
};
#ifdef CONFIG_ACPI
void acpi_gpiochip_add(struct gpio_chip *chip);
void acpi_gpiochip_remove(struct gpio_chip *chip);
void acpi_gpiochip_request_interrupts(struct gpio_chip *chip);
void acpi_gpiochip_free_interrupts(struct gpio_chip *chip);
struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
const char *propname, int index,
struct acpi_gpio_info *info);
#else
static inline void acpi_gpiochip_add(struct gpio_chip *chip) { }
static inline void acpi_gpiochip_remove(struct gpio_chip *chip) { }
static inline void
acpi_gpiochip_request_interrupts(struct gpio_chip *chip) { }
static inline void
acpi_gpiochip_free_interrupts(struct gpio_chip *chip) { }
static inline struct gpio_desc *
acpi_get_gpiod_by_index(struct acpi_device *adev, const char *propname,
int index, struct acpi_gpio_info *info)
{
return ERR_PTR(-ENOSYS);
}
#endif
struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
const char *list_name, int index, enum of_gpio_flags *flags);
struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip, u16 hwnum);
extern struct spinlock gpio_lock;
extern struct list_head gpio_chips;
struct gpio_desc {
struct gpio_chip *chip;
unsigned long flags;
/* flag symbols are bit numbers */
#define FLAG_REQUESTED 0
#define FLAG_IS_OUT 1
#define FLAG_EXPORT 2 /* protected by sysfs_lock */
#define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */
#define FLAG_TRIG_FALL 4 /* trigger on falling edge */
#define FLAG_TRIG_RISE 5 /* trigger on rising edge */
#define FLAG_ACTIVE_LOW 6 /* value has active low */
#define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */
#define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */
#define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
#define FLAG_SYSFS_DIR 10 /* show sysfs direction attribute */
#define ID_SHIFT 16 /* add new flags before this one */
#define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1)
#define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
const char *label;
};
int gpiod_request(struct gpio_desc *desc, const char *label);
void gpiod_free(struct gpio_desc *desc);
/*
* Return the GPIO number of the passed descriptor relative to its chip
*/
static int __maybe_unused gpio_chip_hwgpio(const struct gpio_desc *desc)
{
return desc - &desc->chip->desc[0];
}
/* With descriptor prefix */
#define gpiod_emerg(desc, fmt, ...) \
pr_emerg("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\
##__VA_ARGS__)
#define gpiod_crit(desc, fmt, ...) \
pr_crit("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \
##__VA_ARGS__)
#define gpiod_err(desc, fmt, ...) \
pr_err("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \
##__VA_ARGS__)
#define gpiod_warn(desc, fmt, ...) \
pr_warn("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \
##__VA_ARGS__)
#define gpiod_info(desc, fmt, ...) \
pr_info("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \
##__VA_ARGS__)
#define gpiod_dbg(desc, fmt, ...) \
pr_debug("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\
##__VA_ARGS__)
/* With chip prefix */
#define chip_emerg(chip, fmt, ...) \
pr_emerg("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
#define chip_crit(chip, fmt, ...) \
pr_crit("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
#define chip_err(chip, fmt, ...) \
pr_err("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
#define chip_warn(chip, fmt, ...) \
pr_warn("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
#define chip_info(chip, fmt, ...) \
pr_info("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
#define chip_dbg(chip, fmt, ...) \
pr_debug("GPIO chip %s: " fmt, chip->label, ##__VA_ARGS__)
#ifdef CONFIG_GPIO_SYSFS
int gpiochip_export(struct gpio_chip *chip);
void gpiochip_unexport(struct gpio_chip *chip);
#else
static inline int gpiochip_export(struct gpio_chip *chip)
{
return 0;
}
static inline void gpiochip_unexport(struct gpio_chip *chip)
{
}
#endif /* CONFIG_GPIO_SYSFS */
#endif /* GPIOLIB_H */