1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) by Lee Revell <rlrevell@joe-job.com>
4 * Clemens Ladisch <clemens@ladisch.de>
5 * Routines for control of EMU10K1 chips
6 *
7 * BUGS:
8 * --
9 *
10 * TODO:
11 * --
12 */
13
14 #include <linux/time.h>
15 #include <sound/core.h>
16 #include <sound/emu10k1.h>
17
snd_emu10k1_timer_start(struct snd_timer * timer)18 static int snd_emu10k1_timer_start(struct snd_timer *timer)
19 {
20 struct snd_emu10k1 *emu;
21 unsigned long flags;
22 unsigned int delay;
23
24 emu = snd_timer_chip(timer);
25 delay = timer->sticks - 1;
26 if (delay < 5 ) /* minimum time is 5 ticks */
27 delay = 5;
28 spin_lock_irqsave(&emu->reg_lock, flags);
29 snd_emu10k1_intr_enable(emu, INTE_INTERVALTIMERENB);
30 outw(delay & TIMER_RATE_MASK, emu->port + TIMER);
31 spin_unlock_irqrestore(&emu->reg_lock, flags);
32 return 0;
33 }
34
snd_emu10k1_timer_stop(struct snd_timer * timer)35 static int snd_emu10k1_timer_stop(struct snd_timer *timer)
36 {
37 struct snd_emu10k1 *emu;
38 unsigned long flags;
39
40 emu = snd_timer_chip(timer);
41 spin_lock_irqsave(&emu->reg_lock, flags);
42 snd_emu10k1_intr_disable(emu, INTE_INTERVALTIMERENB);
43 spin_unlock_irqrestore(&emu->reg_lock, flags);
44 return 0;
45 }
46
snd_emu10k1_timer_precise_resolution(struct snd_timer * timer,unsigned long * num,unsigned long * den)47 static int snd_emu10k1_timer_precise_resolution(struct snd_timer *timer,
48 unsigned long *num, unsigned long *den)
49 {
50 *num = 1;
51 *den = 48000;
52 return 0;
53 }
54
55 static const struct snd_timer_hardware snd_emu10k1_timer_hw = {
56 .flags = SNDRV_TIMER_HW_AUTO,
57 .resolution = 20833, /* 1 sample @ 48KHZ = 20.833...us */
58 .ticks = 1024,
59 .start = snd_emu10k1_timer_start,
60 .stop = snd_emu10k1_timer_stop,
61 .precise_resolution = snd_emu10k1_timer_precise_resolution,
62 };
63
snd_emu10k1_timer(struct snd_emu10k1 * emu,int device)64 int snd_emu10k1_timer(struct snd_emu10k1 *emu, int device)
65 {
66 struct snd_timer *timer = NULL;
67 struct snd_timer_id tid;
68 int err;
69
70 tid.dev_class = SNDRV_TIMER_CLASS_CARD;
71 tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
72 tid.card = emu->card->number;
73 tid.device = device;
74 tid.subdevice = 0;
75 err = snd_timer_new(emu->card, "EMU10K1", &tid, &timer);
76 if (err >= 0) {
77 strcpy(timer->name, "EMU10K1 timer");
78 timer->private_data = emu;
79 timer->hw = snd_emu10k1_timer_hw;
80 }
81 emu->timer = timer;
82 return err;
83 }
84