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 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 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 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 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 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