ALSA: mpu401: clean up interrupt specification
The semantics of snd_mpu401_uart_new()'s interrupt parameters are
somewhat counterintuitive: To prevent the function from allocating its
own interrupt, either the irq number must be invalid, or the irq_flags
parameter must be zero. At the same time, the irq parameter being
invalid specifies that the mpu401 code has to work without an interrupt
allocated by the caller. This implies that, if there is an interrupt
and it is allocated by the caller, the irq parameter must be set to
a valid-looking number which then isn't actually used.
With the removal of IRQF_DISABLED, zero becomes a valid irq_flags value,
which forces us to handle the parameters differently.
This patch introduces a new flag MPU401_INFO_IRQ_HOOK for when the
device interrupt is handled by the caller, and makes the allocation of
the interrupt to depend only on the irq parameter. As suggested by
Takashi, the irq_flags parameter was dropped because, when used, it had
the constant value IRQF_DISABLED.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/drivers/mpu401/mpu401_uart.c b/sound/drivers/mpu401/mpu401_uart.c
index 2af0999..9d01c18 100644
--- a/sound/drivers/mpu401/mpu401_uart.c
+++ b/sound/drivers/mpu401/mpu401_uart.c
@@ -3,7 +3,7 @@
* Routines for control of MPU-401 in UART mode
*
* MPU-401 supports UART mode which is not capable generate transmit
- * interrupts thus output is done via polling. Also, if irq < 0, then
+ * interrupts thus output is done via polling. Without interrupt,
* input is done also via polling. Do not expect good performance.
*
*
@@ -374,7 +374,7 @@
/* first time - flush FIFO */
while (max-- > 0)
mpu->read(mpu, MPU401D(mpu));
- if (mpu->irq < 0)
+ if (mpu->info_flags & MPU401_INFO_USE_TIMER)
snd_mpu401_uart_add_timer(mpu, 1);
}
@@ -383,7 +383,7 @@
snd_mpu401_uart_input_read(mpu);
spin_unlock_irqrestore(&mpu->input_lock, flags);
} else {
- if (mpu->irq < 0)
+ if (mpu->info_flags & MPU401_INFO_USE_TIMER)
snd_mpu401_uart_remove_timer(mpu, 1);
clear_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode);
}
@@ -496,7 +496,7 @@
static void snd_mpu401_uart_free(struct snd_rawmidi *rmidi)
{
struct snd_mpu401 *mpu = rmidi->private_data;
- if (mpu->irq_flags && mpu->irq >= 0)
+ if (mpu->irq >= 0)
free_irq(mpu->irq, (void *) mpu);
release_and_free_resource(mpu->res);
kfree(mpu);
@@ -509,8 +509,7 @@
* @hardware: the hardware type, MPU401_HW_XXXX
* @port: the base address of MPU401 port
* @info_flags: bitflags MPU401_INFO_XXX
- * @irq: the irq number, -1 if no interrupt for mpu
- * @irq_flags: the irq request flags (SA_XXX), 0 if irq was already reserved.
+ * @irq: the ISA irq number, -1 if not to be allocated
* @rrawmidi: the pointer to store the new rawmidi instance
*
* Creates a new MPU-401 instance.
@@ -525,7 +524,7 @@
unsigned short hardware,
unsigned long port,
unsigned int info_flags,
- int irq, int irq_flags,
+ int irq,
struct snd_rawmidi ** rrawmidi)
{
struct snd_mpu401 *mpu;
@@ -577,8 +576,8 @@
mpu->cport = port + 2;
else
mpu->cport = port + 1;
- if (irq >= 0 && irq_flags) {
- if (request_irq(irq, snd_mpu401_uart_interrupt, irq_flags,
+ if (irq >= 0) {
+ if (request_irq(irq, snd_mpu401_uart_interrupt, IRQF_DISABLED,
"MPU401 UART", (void *) mpu)) {
snd_printk(KERN_ERR "mpu401_uart: "
"unable to grab IRQ %d\n", irq);
@@ -586,9 +585,10 @@
return -EBUSY;
}
}
+ if (irq < 0 && !(info_flags & MPU401_INFO_IRQ_HOOK))
+ info_flags |= MPU401_INFO_USE_TIMER;
mpu->info_flags = info_flags;
mpu->irq = irq;
- mpu->irq_flags = irq_flags;
if (card->shortname[0])
snprintf(rmidi->name, sizeof(rmidi->name), "%s MIDI",
card->shortname);