ALSA: mpu401: Allocate resources with device-managed APIs

This patch converts the card object management with devres as a clean
up. The remove callback gets reduced by that.

This should give no user-visible functional changes.

Note that this converts only the mpu401 card driver. The mpu401_uart
component is still managed with snd_device. It's for the case where
the mpu401_uart component may be removed dynamically without the
actual device unbind.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/drivers/mpu401/mpu401.c

···
 		snd_printk(KERN_ERR "the uart_enter option is obsolete; remove it\n");
 
 	*rcard = NULL;
-	err = snd_card_new(devptr, index[dev], id[dev], THIS_MODULE,
-			   0, &card);
+	err = snd_devm_card_new(devptr, index[dev], id[dev], THIS_MODULE,
+				0, &card);
 	if (err < 0)
 		return err;
 	strcpy(card->driver, "MPU-401 UART");
···
 				  irq[dev], NULL);
 	if (err < 0) {
 		printk(KERN_ERR "MPU401 not detected at 0x%lx\n", port[dev]);
-		goto _err;
+		return err;
 	}
 
 	*rcard = card;
 	return 0;
-
- _err:
-	snd_card_free(card);
-	return err;
 }
 
 static int snd_mpu401_probe(struct platform_device *devptr)
···
 	if (err < 0)
 		return err;
 	err = snd_card_register(card);
-	if (err < 0) {
-		snd_card_free(card);
+	if (err < 0)
 		return err;
-	}
 	platform_set_drvdata(devptr, card);
-	return 0;
-}
-
-static int snd_mpu401_remove(struct platform_device *devptr)
-{
-	snd_card_free(platform_get_drvdata(devptr));
 	return 0;
 }
 
···
 
 static struct platform_driver snd_mpu401_driver = {
 	.probe		= snd_mpu401_probe,
-	.remove		= snd_mpu401_remove,
 	.driver		= {
 		.name	= SND_MPU401_DRIVER,
 	},
···
 		if (err < 0)
 			return err;
 		err = snd_card_register(card);
-		if (err < 0) {
-			snd_card_free(card);
+		if (err < 0)
 			return err;
-		}
 		pnp_set_drvdata(pnp_dev, card);
 		snd_mpu401_devices++;
 		++dev;
···
 	return -ENODEV;
 }
 
-static void snd_mpu401_pnp_remove(struct pnp_dev *dev)
-{
-	struct snd_card *card = (struct snd_card *) pnp_get_drvdata(dev);
-
-	snd_card_disconnect(card);
-	snd_card_free_when_closed(card);
-}
-
 static struct pnp_driver snd_mpu401_pnp_driver = {
 	.name = "mpu401",
 	.id_table = snd_mpu401_pnpids,
 	.probe = snd_mpu401_pnp_probe,
-	.remove = snd_mpu401_pnp_remove,
 };
 #else
 static struct pnp_driver snd_mpu401_pnp_driver;