path: root/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
diff options
Diffstat (limited to 'Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl')
1 files changed, 25 insertions, 4 deletions
diff --git a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
index 23c6c7cde4e6..635cbb94357c 100644
--- a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
+++ b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
@@ -4215,7 +4215,7 @@ struct _snd_pcm_runtime {
struct snd_rawmidi *rmidi;
- snd_mpu401_uart_new(card, 0, MPU401_HW_MPU401, port, integrated,
+ snd_mpu401_uart_new(card, 0, MPU401_HW_MPU401, port, info_flags,
irq, irq_flags, &rmidi);
@@ -4242,15 +4242,36 @@ struct _snd_pcm_runtime {
+ The 5th argument is bitflags for additional information.
When the i/o port address above is a part of the PCI i/o
region, the MPU401 i/o port might have been already allocated
- (reserved) by the driver itself. In such a case, pass non-zero
- to the 5th argument
- (<parameter>integrated</parameter>). Otherwise, pass 0 to it,
+ (reserved) by the driver itself. In such a case, pass a bit flag
+ <constant>MPU401_INFO_INTEGRATED</constant>,
the mpu401-uart layer will allocate the i/o ports by itself.
+ <para>
+ When the controller supports only the input or output MIDI stream,
+ pass <constant>MPU401_INFO_INPUT</constant> or
+ <constant>MPU401_INFO_OUTPUT</constant> bitflag, respectively.
+ Then the rawmidi instance is created as a single stream.
+ </para>
+ <para>
+ <constant>MPU401_INFO_MMIO</constant> bitflag is used to change
+ the access method to MMIO (via readb and writeb) instead of
+ iob and outb. In this case, you have to pass the iomapped address
+ to <function>snd_mpu401_uart_new()</function>.
+ </para>
+ <para>
+ When <constant>MPU401_INFO_TX_IRQ</constant> is set, the output
+ stream isn't checked in the default interrupt handler. The driver
+ needs to call <function>snd_mpu401_uart_interrupt_tx()</function>
+ by itself to start processing the output stream in irq handler.
+ </para>
Usually, the port address corresponds to the command port and
port + 1 corresponds to the data port. If not, you may change