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 18 static int snd_emu10k1_timer_start(struct snd_timer *timer) 19 { 20 struct snd_emu10k1 *emu; 21 unsigned int delay; 22 23 emu = snd_timer_chip(timer); 24 delay = timer->sticks - 1; 25 if (delay < 5 ) /* minimum time is 5 ticks */ 26 delay = 5; 27 snd_emu10k1_intr_enable(emu, INTE_INTERVALTIMERENB); 28 outw(delay & TIMER_RATE_MASK, emu->port + TIMER); 29 return 0; 30 } 31 32 static int snd_emu10k1_timer_stop(struct snd_timer *timer) 33 { 34 struct snd_emu10k1 *emu; 35 36 emu = snd_timer_chip(timer); 37 snd_emu10k1_intr_disable(emu, INTE_INTERVALTIMERENB); 38 return 0; 39 } 40 41 static unsigned long snd_emu10k1_timer_c_resolution(struct snd_timer *timer) 42 { 43 struct snd_emu10k1 *emu = snd_timer_chip(timer); 44 45 if (emu->card_capabilities->emu_model && 46 emu->emu1010.word_clock == 44100) 47 return 22676; // 1 sample @ 44.1 kHz = 22.675736...us 48 else 49 return 20833; // 1 sample @ 48 kHz = 20.833...us 50 } 51 52 static int snd_emu10k1_timer_precise_resolution(struct snd_timer *timer, 53 unsigned long *num, unsigned long *den) 54 { 55 struct snd_emu10k1 *emu = snd_timer_chip(timer); 56 57 *num = 1; 58 if (emu->card_capabilities->emu_model) 59 *den = emu->emu1010.word_clock; 60 else 61 *den = 48000; 62 return 0; 63 } 64 65 static const struct snd_timer_hardware snd_emu10k1_timer_hw = { 66 .flags = SNDRV_TIMER_HW_AUTO, 67 .ticks = 1024, 68 .start = snd_emu10k1_timer_start, 69 .stop = snd_emu10k1_timer_stop, 70 .c_resolution = snd_emu10k1_timer_c_resolution, 71 .precise_resolution = snd_emu10k1_timer_precise_resolution, 72 }; 73 74 int snd_emu10k1_timer(struct snd_emu10k1 *emu, int device) 75 { 76 struct snd_timer *timer = NULL; 77 struct snd_timer_id tid; 78 int err; 79 80 tid.dev_class = SNDRV_TIMER_CLASS_CARD; 81 tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE; 82 tid.card = emu->card->number; 83 tid.device = device; 84 tid.subdevice = 0; 85 err = snd_timer_new(emu->card, "EMU10K1", &tid, &timer); 86 if (err >= 0) { 87 strcpy(timer->name, "EMU10K1 timer"); 88 timer->private_data = emu; 89 timer->hw = snd_emu10k1_timer_hw; 90 } 91 emu->timer = timer; 92 return err; 93 } 94