Richard Cochran | 0606f42 | 2011-02-01 13:52:35 +0000 | [diff] [blame] | 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> |
Richard Cochran | 1791f88 | 2011-03-30 15:24:21 +0200 | [diff] [blame] | 27 | #include <linux/rwsem.h> |
Richard Cochran | 0606f42 | 2011-02-01 13:52:35 +0000 | [diff] [blame] | 28 | |
| 29 | struct posix_clock; |
| 30 | |
| 31 | /** |
| 32 | * struct posix_clock_operations - functional interface to the clock |
| 33 | * |
| 34 | * Every posix clock is represented by a character device. Drivers may |
| 35 | * optionally offer extended capabilities by implementing the |
| 36 | * character device methods. The character device file operations are |
| 37 | * first handled by the clock device layer, then passed on to the |
| 38 | * driver by calling these functions. |
| 39 | * |
| 40 | * @owner: The clock driver should set to THIS_MODULE |
| 41 | * @clock_adjtime: Adjust the clock |
| 42 | * @clock_gettime: Read the current time |
| 43 | * @clock_getres: Get the clock resolution |
| 44 | * @clock_settime: Set the current time value |
| 45 | * @timer_create: Create a new timer |
| 46 | * @timer_delete: Remove a previously created timer |
| 47 | * @timer_gettime: Get remaining time and interval of a timer |
| 48 | * @timer_setttime: Set a timer's initial expiration and interval |
| 49 | * @fasync: Optional character device fasync method |
| 50 | * @mmap: Optional character device mmap method |
| 51 | * @open: Optional character device open method |
| 52 | * @release: Optional character device release method |
| 53 | * @ioctl: Optional character device ioctl method |
| 54 | * @read: Optional character device read method |
| 55 | * @poll: Optional character device poll method |
| 56 | */ |
| 57 | struct posix_clock_operations { |
| 58 | struct module *owner; |
| 59 | |
| 60 | int (*clock_adjtime)(struct posix_clock *pc, struct timex *tx); |
| 61 | |
| 62 | int (*clock_gettime)(struct posix_clock *pc, struct timespec *ts); |
| 63 | |
| 64 | int (*clock_getres) (struct posix_clock *pc, struct timespec *ts); |
| 65 | |
| 66 | int (*clock_settime)(struct posix_clock *pc, |
| 67 | const struct timespec *ts); |
| 68 | |
| 69 | int (*timer_create) (struct posix_clock *pc, struct k_itimer *kit); |
| 70 | |
| 71 | int (*timer_delete) (struct posix_clock *pc, struct k_itimer *kit); |
| 72 | |
| 73 | void (*timer_gettime)(struct posix_clock *pc, |
| 74 | struct k_itimer *kit, struct itimerspec *tsp); |
| 75 | |
| 76 | int (*timer_settime)(struct posix_clock *pc, |
| 77 | struct k_itimer *kit, int flags, |
| 78 | struct itimerspec *tsp, struct itimerspec *old); |
| 79 | /* |
| 80 | * Optional character device methods: |
| 81 | */ |
| 82 | int (*fasync) (struct posix_clock *pc, |
| 83 | int fd, struct file *file, int on); |
| 84 | |
| 85 | long (*ioctl) (struct posix_clock *pc, |
| 86 | unsigned int cmd, unsigned long arg); |
| 87 | |
| 88 | int (*mmap) (struct posix_clock *pc, |
| 89 | struct vm_area_struct *vma); |
| 90 | |
| 91 | int (*open) (struct posix_clock *pc, fmode_t f_mode); |
| 92 | |
| 93 | uint (*poll) (struct posix_clock *pc, |
| 94 | struct file *file, poll_table *wait); |
| 95 | |
| 96 | int (*release) (struct posix_clock *pc); |
| 97 | |
| 98 | ssize_t (*read) (struct posix_clock *pc, |
| 99 | uint flags, char __user *buf, size_t cnt); |
| 100 | }; |
| 101 | |
| 102 | /** |
| 103 | * struct posix_clock - represents a dynamic posix clock |
| 104 | * |
| 105 | * @ops: Functional interface to the clock |
| 106 | * @cdev: Character device instance for this clock |
| 107 | * @kref: Reference count. |
Richard Cochran | 1791f88 | 2011-03-30 15:24:21 +0200 | [diff] [blame] | 108 | * @rwsem: Protects the 'zombie' field from concurrent access. |
Richard Cochran | 0606f42 | 2011-02-01 13:52:35 +0000 | [diff] [blame] | 109 | * @zombie: If 'zombie' is true, then the hardware has disappeared. |
| 110 | * @release: A function to free the structure when the reference count reaches |
| 111 | * zero. May be NULL if structure is statically allocated. |
| 112 | * |
| 113 | * Drivers should embed their struct posix_clock within a private |
| 114 | * structure, obtaining a reference to it during callbacks using |
| 115 | * container_of(). |
| 116 | */ |
| 117 | struct posix_clock { |
| 118 | struct posix_clock_operations ops; |
| 119 | struct cdev cdev; |
| 120 | struct kref kref; |
Richard Cochran | 1791f88 | 2011-03-30 15:24:21 +0200 | [diff] [blame] | 121 | struct rw_semaphore rwsem; |
Richard Cochran | 0606f42 | 2011-02-01 13:52:35 +0000 | [diff] [blame] | 122 | bool zombie; |
| 123 | void (*release)(struct posix_clock *clk); |
| 124 | }; |
| 125 | |
| 126 | /** |
| 127 | * posix_clock_register() - register a new clock |
| 128 | * @clk: Pointer to the clock. Caller must provide 'ops' and 'release' |
| 129 | * @devid: Allocated device id |
| 130 | * |
| 131 | * A clock driver calls this function to register itself with the |
| 132 | * clock device subsystem. If 'clk' points to dynamically allocated |
| 133 | * memory, then the caller must provide a 'release' function to free |
| 134 | * that memory. |
| 135 | * |
| 136 | * Returns zero on success, non-zero otherwise. |
| 137 | */ |
| 138 | int posix_clock_register(struct posix_clock *clk, dev_t devid); |
| 139 | |
| 140 | /** |
| 141 | * posix_clock_unregister() - unregister a clock |
| 142 | * @clk: Clock instance previously registered via posix_clock_register() |
| 143 | * |
| 144 | * A clock driver calls this function to remove itself from the clock |
| 145 | * device subsystem. The posix_clock itself will remain (in an |
| 146 | * inactive state) until its reference count drops to zero, at which |
| 147 | * point it will be deallocated with its 'release' method. |
| 148 | */ |
| 149 | void posix_clock_unregister(struct posix_clock *clk); |
| 150 | |
| 151 | #endif |