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  *                   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 }