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 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 }