xref: /linux/sound/pci/emu10k1/timer.c (revision a1c613ae4c322ddd58d5a8539dbfba2a0380a8c0)
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  *                   Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
6  *
7  *  Routines for control of EMU10K1 chips
8  */
9 
10 #include <linux/time.h>
11 #include <sound/core.h>
12 #include <sound/emu10k1.h>
13 
snd_emu10k1_timer_start(struct snd_timer * timer)14 static int snd_emu10k1_timer_start(struct snd_timer *timer)
15 {
16 	struct snd_emu10k1 *emu;
17 	unsigned int delay;
18 
19 	emu = snd_timer_chip(timer);
20 	delay = timer->sticks - 1;
21 	if (delay < 5 ) /* minimum time is 5 ticks */
22 		delay = 5;
23 	snd_emu10k1_intr_enable(emu, INTE_INTERVALTIMERENB);
24 	outw(delay & TIMER_RATE_MASK, emu->port + TIMER);
25 	return 0;
26 }
27 
snd_emu10k1_timer_stop(struct snd_timer * timer)28 static int snd_emu10k1_timer_stop(struct snd_timer *timer)
29 {
30 	struct snd_emu10k1 *emu;
31 
32 	emu = snd_timer_chip(timer);
33 	snd_emu10k1_intr_disable(emu, INTE_INTERVALTIMERENB);
34 	return 0;
35 }
36 
snd_emu10k1_timer_c_resolution(struct snd_timer * timer)37 static unsigned long snd_emu10k1_timer_c_resolution(struct snd_timer *timer)
38 {
39 	struct snd_emu10k1 *emu = snd_timer_chip(timer);
40 
41 	if (emu->card_capabilities->emu_model &&
42 	    emu->emu1010.word_clock == 44100)
43 		return 22676;  // 1 sample @ 44.1 kHz = 22.675736...us
44 	else
45 		return 20833;  // 1 sample @ 48 kHz = 20.833...us
46 }
47 
snd_emu10k1_timer_precise_resolution(struct snd_timer * timer,unsigned long * num,unsigned long * den)48 static int snd_emu10k1_timer_precise_resolution(struct snd_timer *timer,
49 					       unsigned long *num, unsigned long *den)
50 {
51 	struct snd_emu10k1 *emu = snd_timer_chip(timer);
52 
53 	*num = 1;
54 	if (emu->card_capabilities->emu_model)
55 		*den = emu->emu1010.word_clock;
56 	else
57 		*den = 48000;
58 	return 0;
59 }
60 
61 static const struct snd_timer_hardware snd_emu10k1_timer_hw = {
62 	.flags = SNDRV_TIMER_HW_AUTO,
63 	.ticks = 1024,
64 	.start = snd_emu10k1_timer_start,
65 	.stop = snd_emu10k1_timer_stop,
66 	.c_resolution = snd_emu10k1_timer_c_resolution,
67 	.precise_resolution = snd_emu10k1_timer_precise_resolution,
68 };
69 
snd_emu10k1_timer(struct snd_emu10k1 * emu,int device)70 int snd_emu10k1_timer(struct snd_emu10k1 *emu, int device)
71 {
72 	struct snd_timer *timer = NULL;
73 	struct snd_timer_id tid;
74 	int err;
75 
76 	tid.dev_class = SNDRV_TIMER_CLASS_CARD;
77 	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
78 	tid.card = emu->card->number;
79 	tid.device = device;
80 	tid.subdevice = 0;
81 	err = snd_timer_new(emu->card, "EMU10K1", &tid, &timer);
82 	if (err >= 0) {
83 		strcpy(timer->name, "EMU10K1 timer");
84 		timer->private_data = emu;
85 		timer->hw = snd_emu10k1_timer_hw;
86 	}
87 	emu->timer = timer;
88 	return err;
89 }
90