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
14static 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
28static 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
37static 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
48static 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
61static 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
70int 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