dm: Allow stdio registration to be dropped

Provide a CONFIG_DM_STDIO option to enable registering a serial device
with the stdio library. This is seldom useful in SPL, so disable it by
default when building for SPL.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@ti.com>

drivers/serial/serial-uclass.c

@@ -163,10 +163,12 @@ void serial_stdio_init(void)
 {
 }
 
+#ifdef CONFIG_DM_STDIO
 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
 {
 	_serial_putc(sdev->priv, ch);
 }
+#endif
 
 void serial_stub_puts(struct stdio_dev *sdev, const char *str)
 {
@@ -246,9 +248,11 @@ U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
 
 static int serial_post_probe(struct udevice *dev)
 {
-	struct stdio_dev sdev;
 	struct dm_serial_ops *ops = serial_get_ops(dev);
+#ifdef CONFIG_DM_STDIO
 	struct serial_dev_priv *upriv = dev->uclass_priv;
+	struct stdio_dev sdev;
+#endif
 	int ret;
 
 	/* Set the baud rate */
@@ -258,9 +262,9 @@ static int serial_post_probe(struct udevice *dev)
 			return ret;
 	}
 
+#ifdef CONFIG_DM_STDIO
 	if (!(gd->flags & GD_FLG_RELOC))
 		return 0;
-
 	memset(&sdev, '\0', sizeof(sdev));
 
 	strncpy(sdev.name, dev->name, sizeof(sdev.name));
@@ -271,7 +275,7 @@ static int serial_post_probe(struct udevice *dev)
 	sdev.getc = serial_stub_getc;
 	sdev.tstc = serial_stub_tstc;
 	stdio_register_dev(&sdev, &upriv->sdev);
-
+#endif
 	return 0;
 }
 

include/config_defaults.h

@@ -22,6 +22,7 @@
 
 #ifndef CONFIG_SPL_BUILD
 #define CONFIG_DM_DEVICE_REMOVE
+#define CONFIG_DM_STDIO
 #endif
 
 #endif