+/******************************************************************/
+
+/*** NOTE: the physical timer resolution actually is 1024000 ticks per second,
+ *** but announcing those attributes to user-space would make programs
+ *** configure the timer to a 1 tick value, resulting in an absolutely fatal
+ *** timer IRQ storm.
+ *** Thus I chose to announce a down-scaled virtual timer to the outside and
+ *** calculate real timer countdown values internally.
+ *** (the scale factor can be set via module parameter "seqtimer_scaling").
+ ***/
+
+static int
+snd_azf3328_timer_start(struct snd_timer *timer)
+{
+ struct snd_azf3328 *chip;
+ unsigned long flags;
+ unsigned int delay;
+
+ snd_azf3328_dbgcallenter();
+ chip = snd_timer_chip(timer);
+ delay = ((timer->sticks * seqtimer_scaling) - 1) & TIMER_VALUE_MASK;
+ if (delay < 49) {
+ /* uhoh, that's not good, since user-space won't know about
+ * this timing tweak
+ * (we need to do it to avoid a lockup, though) */
+
+ snd_azf3328_dbgtimer("delay was too low (%d)!\n", delay);
+ delay = 49; /* minimum time is 49 ticks */
+ }
+ snd_azf3328_dbgtimer("setting timer countdown value %d, add COUNTDOWN|IRQ\n", delay);
+ delay |= TIMER_ENABLE_COUNTDOWN | TIMER_ENABLE_IRQ;
+ spin_lock_irqsave(&chip->reg_lock, flags);
+ snd_azf3328_codec_outl(chip, IDX_IO_TIMER_VALUE, delay);
+ spin_unlock_irqrestore(&chip->reg_lock, flags);
+ snd_azf3328_dbgcallleave();
+ return 0;
+}
+
+static int
+snd_azf3328_timer_stop(struct snd_timer *timer)
+{
+ struct snd_azf3328 *chip;
+ unsigned long flags;
+
+ snd_azf3328_dbgcallenter();
+ chip = snd_timer_chip(timer);
+ spin_lock_irqsave(&chip->reg_lock, flags);
+ /* disable timer countdown and interrupt */
+ /* FIXME: should we write TIMER_ACK_IRQ here? */
+ snd_azf3328_codec_outb(chip, IDX_IO_TIMER_VALUE + 3, 0);
+ spin_unlock_irqrestore(&chip->reg_lock, flags);
+ snd_azf3328_dbgcallleave();
+ return 0;
+}
+
+
+static int
+snd_azf3328_timer_precise_resolution(struct snd_timer *timer,
+ unsigned long *num, unsigned long *den)
+{
+ snd_azf3328_dbgcallenter();
+ *num = 1;
+ *den = 1024000 / seqtimer_scaling;
+ snd_azf3328_dbgcallleave();
+ return 0;
+}
+
+static struct snd_timer_hardware snd_azf3328_timer_hw = {
+ .flags = SNDRV_TIMER_HW_AUTO,
+ .resolution = 977, /* 1000000/1024000 = 0.9765625us */
+ .ticks = 1024000, /* max tick count, defined by the value register; actually it's not 1024000, but 1048576, but we don't care */
+ .start = snd_azf3328_timer_start,
+ .stop = snd_azf3328_timer_stop,
+ .precise_resolution = snd_azf3328_timer_precise_resolution,
+};
+
+static int __devinit
+snd_azf3328_timer(struct snd_azf3328 *chip, int device)
+{
+ struct snd_timer *timer = NULL;
+ struct snd_timer_id tid;
+ int err;
+
+ snd_azf3328_dbgcallenter();
+ tid.dev_class = SNDRV_TIMER_CLASS_CARD;
+ tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
+ tid.card = chip->card->number;
+ tid.device = device;
+ tid.subdevice = 0;
+
+ snd_azf3328_timer_hw.resolution *= seqtimer_scaling;
+ snd_azf3328_timer_hw.ticks /= seqtimer_scaling;
+ if ((err = snd_timer_new(chip->card, "AZF3328", &tid, &timer)) < 0) {
+ goto out;
+ }
+
+ strcpy(timer->name, "AZF3328 timer");
+ timer->private_data = chip;
+ timer->hw = snd_azf3328_timer_hw;
+
+ chip->timer = timer;
+
+ err = 0;
+
+out:
+ snd_azf3328_dbgcallleave();
+ return err;
+}
+
+/******************************************************************/
+