[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>

Documentation/sound/alsa/ALSA-Configuration.txt

@@ -1278,6 +1278,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
     port	- port number or -1 (disable)
     irq		- IRQ number or -1 (disable)
     pnp		- PnP detection - 0 = disable, 1 = enable (default)
+    uart_enter	- Issue UART_ENTER command at open - bool, default = on
 
     This module supports multiple devices and PnP.
     

include/sound/mpu401.h

@@ -50,6 +50,7 @@
 #define MPU401_INFO_INTEGRATED	(1 << 2)	/* integrated h/w port */
 #define MPU401_INFO_MMIO	(1 << 3)	/* MMIO access */
 #define MPU401_INFO_TX_IRQ	(1 << 4)	/* independent TX irq */
+#define MPU401_INFO_UART_ONLY	(1 << 5)	/* No ENTER_UART cmd needed */
 
 #define MPU401_MODE_BIT_INPUT		0
 #define MPU401_MODE_BIT_OUTPUT		1

sound/drivers/mpu401/mpu401.c

@@ -42,6 +42,7 @@ static int pnp[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
 #endif
 static long port[SNDRV_CARDS] = SNDRV_DEFAULT_PORT;	/* MPU-401 port number */
 static int irq[SNDRV_CARDS] = SNDRV_DEFAULT_IRQ;	/* MPU-401 IRQ */
+static int uart_enter[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
 
 module_param_array(index, int, NULL, 0444);
 MODULE_PARM_DESC(index, "Index value for MPU-401 device.");
@@ -57,6 +58,8 @@ module_param_array(port, long, NULL, 0444);
 MODULE_PARM_DESC(port, "Port # for MPU-401 device.");
 module_param_array(irq, int, NULL, 0444);
 MODULE_PARM_DESC(irq, "IRQ # for MPU-401 device.");
+module_param_array(uart_enter, bool, NULL, 0444);
+MODULE_PARM_DESC(uart_enter, "Issue UART_ENTER command at open.");
 
 static struct platform_device *platform_devices[SNDRV_CARDS];
 static int pnp_registered;
@@ -80,10 +83,11 @@ static int snd_mpu401_create(int dev, struct snd_card **rcard)
 		strcat(card->longname, "polled");
 	}
 
-	if ((err = snd_mpu401_uart_new(card, 0,
-				       MPU401_HW_MPU401,
-				       port[dev], 0,
-				       irq[dev], irq[dev] >= 0 ? IRQF_DISABLED : 0, NULL)) < 0) {
+	err = snd_mpu401_uart_new(card, 0, MPU401_HW_MPU401, port[dev],
+				  uart_enter[dev] ? 0 : MPU401_INFO_UART_ONLY,
+				  irq[dev], irq[dev] >= 0 ? IRQF_DISABLED : 0,
+				  NULL);
+	if (err < 0) {
 		printk(KERN_ERR "MPU401 not detected at 0x%lx\n", port[dev]);
 		goto _err;
 	}

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;