ALSA: oxygen: add UART I/O functions

Add functions to allow model drivers to communicate with external chips
by doing I/O with the not-used-for-MIDI UART.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

1 files changed, 21 insertions, 0 deletions

diff --git a/sound/pci/oxygen/oxygen_io.c b/sound/pci/oxygen/oxygen_io.c
index 83f135f80df4..deba7389aec3 100644
--- a/sound/pci/oxygen/oxygen_io.c
+++ b/sound/pci/oxygen/oxygen_io.c
@@ -20,6 +20,7 @@
 #include <linux/delay.h>
 #include <linux/sched.h>
 #include <sound/core.h>
+#include <sound/mpu401.h>
 #include <asm/io.h>
 #include "oxygen.h"
 
@@ -232,3 +233,23 @@ void oxygen_write_i2c(struct oxygen *chip, u8 device, u8 map, u8 data)
                       device | OXYGEN_2WIRE_DIR_WRITE);
 }
 EXPORT_SYMBOL(oxygen_write_i2c);
+
+static void _write_uart(struct oxygen *chip, unsigned int port, u8 data)
+{
+        if (oxygen_read8(chip, OXYGEN_MPU401 + 1) & MPU401_TX_FULL)
+                msleep(1);
+        oxygen_write8(chip, OXYGEN_MPU401 + port, data);
+}
+
+void oxygen_reset_uart(struct oxygen *chip)
+{
+        _write_uart(chip, 1, MPU401_RESET);
+        _write_uart(chip, 1, MPU401_ENTER_UART);
+}
+EXPORT_SYMBOL(oxygen_reset_uart);
+
+void oxygen_write_uart(struct oxygen *chip, u8 data)
+{
+        _write_uart(chip, 0, data);
+}
+EXPORT_SYMBOL(oxygen_write_uart);