sound/pci/emu10k1/timer.c

   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         if ((err = snd_timer_new(emu->card, "EMU10K1", &tid, &timer)) >= 0) {
  76                 strcpy(timer->name, "EMU10K1 timer");
  77                 timer->private_data = emu;
  78                 timer->hw = snd_emu10k1_timer_hw;
  79         }
  80         emu->timer = timer;
  81         return err;
  82 }