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 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 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 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 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