[ALSA] mpu401 - Add MPU401_INFO_UART_ONLY bitflag

Added MPU401_INFO_UART_ONLY bitflag to avoid issueing UART_ENTER command
at opening streams.  Some devices support only UART mode and give errors
to UART_ENTER.
A new module option, uart_enter, is added to snd-mpu401 driver.
For UART-only devices, set uart_enter=0.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 12 insertions, 6 deletions

diff --git a/sound/drivers/mpu401/mpu401_uart.c b/sound/drivers/mpu401/mpu401_uart.c
index 3daa9fa56c0b..85aedc348e2d 100644
--- a/sound/drivers/mpu401/mpu401_uart.c
+++ b/sound/drivers/mpu401/mpu401_uart.c
@@ -266,6 +266,16 @@ static int snd_mpu401_uart_cmd(struct snd_mpu401 * mpu, unsigned char cmd,
         return 0;
 }
 
+static int snd_mpu401_do_reset(struct snd_mpu401 *mpu)
+{
+        if (snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1))
+                return -EIO;
+        if (!(mpu->info_flags & MPU401_INFO_UART_ONLY) &&
+            snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1))
+                return -EIO;
+        return 0;
+}
+
 /*
  * input/output open/close - protected by open_mutex in rawmidi.c
  */
@@ -278,9 +288,7 @@ static int snd_mpu401_uart_input_open(struct snd_rawmidi_substream *substream)
         if (mpu->open_input && (err = mpu->open_input(mpu)) < 0)
                 return err;
         if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode)) {
-                if (snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1))
-                        goto error_out;
-                if (snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1))
+                if (snd_mpu401_do_reset(mpu) < 0)
                         goto error_out;
         }
         mpu->substream_input = substream;
@@ -302,9 +310,7 @@ static int snd_mpu401_uart_output_open(struct snd_rawmidi_substream *substream)
         if (mpu->open_output && (err = mpu->open_output(mpu)) < 0)
                 return err;
         if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode)) {
-                if (snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1))
-                        goto error_out;
-                if (snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1))
+                if (snd_mpu401_do_reset(mpu) < 0)
                         goto error_out;
         }
         mpu->substream_output = substream;