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0606f422 RC |
1 | /* |
2 | * posix-clock.h - support for dynamic clock devices | |
3 | * | |
4 | * Copyright (C) 2010 OMICRON electronics GmbH | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | #ifndef _LINUX_POSIX_CLOCK_H_ | |
21 | #define _LINUX_POSIX_CLOCK_H_ | |
22 | ||
23 | #include <linux/cdev.h> | |
24 | #include <linux/fs.h> | |
25 | #include <linux/poll.h> | |
26 | #include <linux/posix-timers.h> | |
27 | ||
28 | struct posix_clock; | |
29 | ||
30 | /** | |
31 | * struct posix_clock_operations - functional interface to the clock | |
32 | * | |
33 | * Every posix clock is represented by a character device. Drivers may | |
34 | * optionally offer extended capabilities by implementing the | |
35 | * character device methods. The character device file operations are | |
36 | * first handled by the clock device layer, then passed on to the | |
37 | * driver by calling these functions. | |
38 | * | |
39 | * @owner: The clock driver should set to THIS_MODULE | |
40 | * @clock_adjtime: Adjust the clock | |
41 | * @clock_gettime: Read the current time | |
42 | * @clock_getres: Get the clock resolution | |
43 | * @clock_settime: Set the current time value | |
44 | * @timer_create: Create a new timer | |
45 | * @timer_delete: Remove a previously created timer | |
46 | * @timer_gettime: Get remaining time and interval of a timer | |
47 | * @timer_setttime: Set a timer's initial expiration and interval | |
48 | * @fasync: Optional character device fasync method | |
49 | * @mmap: Optional character device mmap method | |
50 | * @open: Optional character device open method | |
51 | * @release: Optional character device release method | |
52 | * @ioctl: Optional character device ioctl method | |
53 | * @read: Optional character device read method | |
54 | * @poll: Optional character device poll method | |
55 | */ | |
56 | struct posix_clock_operations { | |
57 | struct module *owner; | |
58 | ||
59 | int (*clock_adjtime)(struct posix_clock *pc, struct timex *tx); | |
60 | ||
61 | int (*clock_gettime)(struct posix_clock *pc, struct timespec *ts); | |
62 | ||
63 | int (*clock_getres) (struct posix_clock *pc, struct timespec *ts); | |
64 | ||
65 | int (*clock_settime)(struct posix_clock *pc, | |
66 | const struct timespec *ts); | |
67 | ||
68 | int (*timer_create) (struct posix_clock *pc, struct k_itimer *kit); | |
69 | ||
70 | int (*timer_delete) (struct posix_clock *pc, struct k_itimer *kit); | |
71 | ||
72 | void (*timer_gettime)(struct posix_clock *pc, | |
73 | struct k_itimer *kit, struct itimerspec *tsp); | |
74 | ||
75 | int (*timer_settime)(struct posix_clock *pc, | |
76 | struct k_itimer *kit, int flags, | |
77 | struct itimerspec *tsp, struct itimerspec *old); | |
78 | /* | |
79 | * Optional character device methods: | |
80 | */ | |
81 | int (*fasync) (struct posix_clock *pc, | |
82 | int fd, struct file *file, int on); | |
83 | ||
84 | long (*ioctl) (struct posix_clock *pc, | |
85 | unsigned int cmd, unsigned long arg); | |
86 | ||
87 | int (*mmap) (struct posix_clock *pc, | |
88 | struct vm_area_struct *vma); | |
89 | ||
90 | int (*open) (struct posix_clock *pc, fmode_t f_mode); | |
91 | ||
92 | uint (*poll) (struct posix_clock *pc, | |
93 | struct file *file, poll_table *wait); | |
94 | ||
95 | int (*release) (struct posix_clock *pc); | |
96 | ||
97 | ssize_t (*read) (struct posix_clock *pc, | |
98 | uint flags, char __user *buf, size_t cnt); | |
99 | }; | |
100 | ||
101 | /** | |
102 | * struct posix_clock - represents a dynamic posix clock | |
103 | * | |
104 | * @ops: Functional interface to the clock | |
105 | * @cdev: Character device instance for this clock | |
106 | * @kref: Reference count. | |
107 | * @mutex: Protects the 'zombie' field from concurrent access. | |
108 | * @zombie: If 'zombie' is true, then the hardware has disappeared. | |
109 | * @release: A function to free the structure when the reference count reaches | |
110 | * zero. May be NULL if structure is statically allocated. | |
111 | * | |
112 | * Drivers should embed their struct posix_clock within a private | |
113 | * structure, obtaining a reference to it during callbacks using | |
114 | * container_of(). | |
115 | */ | |
116 | struct posix_clock { | |
117 | struct posix_clock_operations ops; | |
118 | struct cdev cdev; | |
119 | struct kref kref; | |
120 | struct mutex mutex; | |
121 | bool zombie; | |
122 | void (*release)(struct posix_clock *clk); | |
123 | }; | |
124 | ||
125 | /** | |
126 | * posix_clock_register() - register a new clock | |
127 | * @clk: Pointer to the clock. Caller must provide 'ops' and 'release' | |
128 | * @devid: Allocated device id | |
129 | * | |
130 | * A clock driver calls this function to register itself with the | |
131 | * clock device subsystem. If 'clk' points to dynamically allocated | |
132 | * memory, then the caller must provide a 'release' function to free | |
133 | * that memory. | |
134 | * | |
135 | * Returns zero on success, non-zero otherwise. | |
136 | */ | |
137 | int posix_clock_register(struct posix_clock *clk, dev_t devid); | |
138 | ||
139 | /** | |
140 | * posix_clock_unregister() - unregister a clock | |
141 | * @clk: Clock instance previously registered via posix_clock_register() | |
142 | * | |
143 | * A clock driver calls this function to remove itself from the clock | |
144 | * device subsystem. The posix_clock itself will remain (in an | |
145 | * inactive state) until its reference count drops to zero, at which | |
146 | * point it will be deallocated with its 'release' method. | |
147 | */ | |
148 | void posix_clock_unregister(struct posix_clock *clk); | |
149 | ||
150 | #endif |