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23#include <linux/init.h>
24#include <linux/interrupt.h>
25#include <linux/moduleparam.h>
26#include <linux/log2.h>
27#include <sound/core.h>
28#include <sound/timer.h>
29
30#if defined(CONFIG_RTC) || defined(CONFIG_RTC_MODULE)
31
32#include <linux/mc146818rtc.h>
33
34#define RTC_FREQ 1024
35#define NANO_SEC 1000000000L
36
37
38
39
40static int rtctimer_open(struct snd_timer *t);
41static int rtctimer_close(struct snd_timer *t);
42static int rtctimer_start(struct snd_timer *t);
43static int rtctimer_stop(struct snd_timer *t);
44
45
46
47
48
49static struct snd_timer_hardware rtc_hw = {
50 .flags = SNDRV_TIMER_HW_AUTO |
51 SNDRV_TIMER_HW_FIRST |
52 SNDRV_TIMER_HW_TASKLET,
53 .ticks = 100000000L,
54 .open = rtctimer_open,
55 .close = rtctimer_close,
56 .start = rtctimer_start,
57 .stop = rtctimer_stop,
58};
59
60static int rtctimer_freq = RTC_FREQ;
61static struct snd_timer *rtctimer;
62static struct tasklet_struct rtc_tasklet;
63static rtc_task_t rtc_task;
64
65
66static int
67rtctimer_open(struct snd_timer *t)
68{
69 int err;
70
71 err = rtc_register(&rtc_task);
72 if (err < 0)
73 return err;
74 t->private_data = &rtc_task;
75 return 0;
76}
77
78static int
79rtctimer_close(struct snd_timer *t)
80{
81 rtc_task_t *rtc = t->private_data;
82 if (rtc) {
83 rtc_unregister(rtc);
84 tasklet_kill(&rtc_tasklet);
85 t->private_data = NULL;
86 }
87 return 0;
88}
89
90static int
91rtctimer_start(struct snd_timer *timer)
92{
93 rtc_task_t *rtc = timer->private_data;
94 if (snd_BUG_ON(!rtc))
95 return -EINVAL;
96 rtc_control(rtc, RTC_IRQP_SET, rtctimer_freq);
97 rtc_control(rtc, RTC_PIE_ON, 0);
98 return 0;
99}
100
101static int
102rtctimer_stop(struct snd_timer *timer)
103{
104 rtc_task_t *rtc = timer->private_data;
105 if (snd_BUG_ON(!rtc))
106 return -EINVAL;
107 rtc_control(rtc, RTC_PIE_OFF, 0);
108 return 0;
109}
110
111static void rtctimer_tasklet(unsigned long data)
112{
113 snd_timer_interrupt((struct snd_timer *)data, 1);
114}
115
116
117
118
119static void rtctimer_interrupt(void *private_data)
120{
121 tasklet_schedule(private_data);
122}
123
124
125
126
127
128static int __init rtctimer_init(void)
129{
130 int err;
131 struct snd_timer *timer;
132
133 if (rtctimer_freq < 2 || rtctimer_freq > 8192 ||
134 !is_power_of_2(rtctimer_freq)) {
135 snd_printk(KERN_ERR "rtctimer: invalid frequency %d\n",
136 rtctimer_freq);
137 return -EINVAL;
138 }
139
140
141 err = snd_timer_global_new("rtc", SNDRV_TIMER_GLOBAL_RTC, &timer);
142 if (err < 0)
143 return err;
144
145 timer->module = THIS_MODULE;
146 strcpy(timer->name, "RTC timer");
147 timer->hw = rtc_hw;
148 timer->hw.resolution = NANO_SEC / rtctimer_freq;
149
150 tasklet_init(&rtc_tasklet, rtctimer_tasklet, (unsigned long)timer);
151
152
153 rtc_task.func = rtctimer_interrupt;
154 rtc_task.private_data = &rtc_tasklet;
155
156 err = snd_timer_global_register(timer);
157 if (err < 0) {
158 snd_timer_global_free(timer);
159 return err;
160 }
161 rtctimer = timer;
162
163 return 0;
164}
165
166static void __exit rtctimer_exit(void)
167{
168 if (rtctimer) {
169 snd_timer_global_free(rtctimer);
170 rtctimer = NULL;
171 }
172}
173
174
175
176
177
178module_init(rtctimer_init)
179module_exit(rtctimer_exit)
180
181module_param(rtctimer_freq, int, 0444);
182MODULE_PARM_DESC(rtctimer_freq, "timer frequency in Hz");
183
184MODULE_LICENSE("GPL");
185
186MODULE_ALIAS("snd-timer-" __stringify(SNDRV_TIMER_GLOBAL_RTC));
187
188#endif
189