ALSA: Add generic serial MIDI driver using serial bus API

Generic serial MIDI driver adding support for using serial devices compatible with the serial bus as raw MIDI devices, allowing using additional serial devices not compatible with the existing serial-u16550 driver. Supports only setting standard serial baudrates on the underlying serial device; however, the underlying serial device can be configured so that a requested 38.4 kBaud is actually the standard MIDI 31.25 kBaud. Supports DeviceTree configuration. Signed-off-by: Daniel Kaehn <kaehndan@gmail.com> Reviewed-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20220509145933.1161526-3-kaehndan@gmail.com Signed-off-by: Takashi Iwai <tiwai@suse.de>
ammarfaizi2 · May 12, 2022 · 5423505 · 5423505
1 parent 1e5a746
commit 5423505
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diff --git a/sound/drivers/Kconfig b/sound/drivers/Kconfig
@@ -165,6 +165,24 @@ config SND_SERIAL_U16550
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-serial-u16550.
 
+config SND_SERIAL_GENERIC
+	tristate "Generic serial MIDI driver"
+	depends on SERIAL_DEV_BUS
+	depends on OF
+	select SND_RAWMIDI
+	help
+	  To include support for mapping generic serial devices as raw
+	  ALSA MIDI devices, say Y here. The driver only supports setting
+	  the serial port to standard baudrates. To attain the standard MIDI
+	  baudrate of 31.25 kBaud, configure the clock of the underlying serial
+	  device so that a requested 38.4 kBaud will result in the standard speed.
+
+	  Use this devicetree binding to configure serial port mapping
+	  <file:Documentation/devicetree/bindings/sound/serial-midi.yaml>
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-serial-generic.
+
 config SND_MPU401
 	tristate "Generic MPU-401 UART driver"
 	select SND_MPU401_UART

diff --git a/sound/drivers/Makefile b/sound/drivers/Makefile
@@ -10,13 +10,15 @@ snd-mtpav-objs := mtpav.o
 snd-mts64-objs := mts64.o
 snd-portman2x4-objs := portman2x4.o
 snd-serial-u16550-objs := serial-u16550.o
+snd-serial-generic-objs := serial-generic.o
 snd-virmidi-objs := virmidi.o
 
 # Toplevel Module Dependency
 obj-$(CONFIG_SND_DUMMY) += snd-dummy.o
 obj-$(CONFIG_SND_ALOOP) += snd-aloop.o
 obj-$(CONFIG_SND_VIRMIDI) += snd-virmidi.o
 obj-$(CONFIG_SND_SERIAL_U16550) += snd-serial-u16550.o
+obj-$(CONFIG_SND_SERIAL_GENERIC) += snd-serial-generic.o
 obj-$(CONFIG_SND_MTPAV) += snd-mtpav.o
 obj-$(CONFIG_SND_MTS64) += snd-mts64.o
 obj-$(CONFIG_SND_PORTMAN2X4) += snd-portman2x4.o