forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
119 lines
3.9 KiB
119 lines
3.9 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */ |
|
/* |
|
* posix-clock.h - support for dynamic clock devices |
|
* |
|
* Copyright (C) 2010 OMICRON electronics GmbH |
|
*/ |
|
#ifndef _LINUX_POSIX_CLOCK_H_ |
|
#define _LINUX_POSIX_CLOCK_H_ |
|
|
|
#include <linux/cdev.h> |
|
#include <linux/fs.h> |
|
#include <linux/poll.h> |
|
#include <linux/posix-timers.h> |
|
#include <linux/rwsem.h> |
|
|
|
struct posix_clock; |
|
|
|
/** |
|
* struct posix_clock_operations - functional interface to the clock |
|
* |
|
* Every posix clock is represented by a character device. Drivers may |
|
* optionally offer extended capabilities by implementing the |
|
* character device methods. The character device file operations are |
|
* first handled by the clock device layer, then passed on to the |
|
* driver by calling these functions. |
|
* |
|
* @owner: The clock driver should set to THIS_MODULE |
|
* @clock_adjtime: Adjust the clock |
|
* @clock_gettime: Read the current time |
|
* @clock_getres: Get the clock resolution |
|
* @clock_settime: Set the current time value |
|
* @open: Optional character device open method |
|
* @release: Optional character device release method |
|
* @ioctl: Optional character device ioctl method |
|
* @read: Optional character device read method |
|
* @poll: Optional character device poll method |
|
*/ |
|
struct posix_clock_operations { |
|
struct module *owner; |
|
|
|
int (*clock_adjtime)(struct posix_clock *pc, struct __kernel_timex *tx); |
|
|
|
int (*clock_gettime)(struct posix_clock *pc, struct timespec64 *ts); |
|
|
|
int (*clock_getres) (struct posix_clock *pc, struct timespec64 *ts); |
|
|
|
int (*clock_settime)(struct posix_clock *pc, |
|
const struct timespec64 *ts); |
|
|
|
/* |
|
* Optional character device methods: |
|
*/ |
|
long (*ioctl) (struct posix_clock *pc, |
|
unsigned int cmd, unsigned long arg); |
|
|
|
int (*open) (struct posix_clock *pc, fmode_t f_mode); |
|
|
|
__poll_t (*poll) (struct posix_clock *pc, |
|
struct file *file, poll_table *wait); |
|
|
|
int (*release) (struct posix_clock *pc); |
|
|
|
ssize_t (*read) (struct posix_clock *pc, |
|
uint flags, char __user *buf, size_t cnt); |
|
}; |
|
|
|
/** |
|
* struct posix_clock - represents a dynamic posix clock |
|
* |
|
* @ops: Functional interface to the clock |
|
* @cdev: Character device instance for this clock |
|
* @dev: Pointer to the clock's device. |
|
* @rwsem: Protects the 'zombie' field from concurrent access. |
|
* @zombie: If 'zombie' is true, then the hardware has disappeared. |
|
* |
|
* Drivers should embed their struct posix_clock within a private |
|
* structure, obtaining a reference to it during callbacks using |
|
* container_of(). |
|
* |
|
* Drivers should supply an initialized but not exposed struct device |
|
* to posix_clock_register(). It is used to manage lifetime of the |
|
* driver's private structure. It's 'release' field should be set to |
|
* a release function for this private structure. |
|
*/ |
|
struct posix_clock { |
|
struct posix_clock_operations ops; |
|
struct cdev cdev; |
|
struct device *dev; |
|
struct rw_semaphore rwsem; |
|
bool zombie; |
|
}; |
|
|
|
/** |
|
* posix_clock_register() - register a new clock |
|
* @clk: Pointer to the clock. Caller must provide 'ops' field |
|
* @dev: Pointer to the initialized device. Caller must provide |
|
* 'release' field |
|
* |
|
* A clock driver calls this function to register itself with the |
|
* clock device subsystem. If 'clk' points to dynamically allocated |
|
* memory, then the caller must provide a 'release' function to free |
|
* that memory. |
|
* |
|
* Returns zero on success, non-zero otherwise. |
|
*/ |
|
int posix_clock_register(struct posix_clock *clk, struct device *dev); |
|
|
|
/** |
|
* posix_clock_unregister() - unregister a clock |
|
* @clk: Clock instance previously registered via posix_clock_register() |
|
* |
|
* A clock driver calls this function to remove itself from the clock |
|
* device subsystem. The posix_clock itself will remain (in an |
|
* inactive state) until its reference count drops to zero, at which |
|
* point it will be deallocated with its 'release' method. |
|
*/ |
|
void posix_clock_unregister(struct posix_clock *clk); |
|
|
|
#endif
|
|
|