[PATCH v4] linux,stdout-path helper

@@ -541,26 +541,12 @@ config SERIAL_IMX
 	bool "IMX serial port support"
 	depends on ARCH_MXC
 	select SERIAL_CORE
+	select SERIAL_CORE_CONSOLE
 	select RATIONAL
 	help
 	  If you have a machine based on a Motorola IMX CPU you
 	  can enable its onboard serial port by enabling this option.
 
-config SERIAL_IMX_CONSOLE
-	bool "Console on IMX serial port"
-	depends on SERIAL_IMX
-	select SERIAL_CORE_CONSOLE
-	help
-	  If you have enabled the serial port on the Motorola IMX
-	  CPU you can make it the console by answering Y to this option.
-
-	  Even if you say Y here, the currently visible virtual console
-	  (/dev/tty0) will still be used as the system console by default, but
-	  you can alter that using a kernel command line option such as
-	  "console=ttySA0". (Try "man bootparam" or see the documentation of
-	  your boot loader (lilo or loadlin) about how to pass options to the
-	  kernel at boot time.)
-
 config SERIAL_UARTLITE
 	tristate "Xilinx uartlite serial port support"
 	depends on PPC32 || MICROBLAZE || MFD_TIMBERDALE

@@ -1192,7 +1192,6 @@ static struct uart_ops imx_pops = {
 
 static struct imx_port *imx_ports[UART_NR];
 
-#ifdef CONFIG_SERIAL_IMX_CONSOLE
 static void imx_console_putchar(struct uart_port *port, int ch)
 {
 	struct imx_port *sport = (struct imx_port *)port;

@@ -1348,11 +1347,6 @@ static struct console imx_console = {
 	.data		= &imx_reg,
 };
 
-#define IMX_CONSOLE	&imx_console
-#else
-#define IMX_CONSOLE	NULL
-#endif
-
 static struct uart_driver imx_reg = {
 	.owner          = THIS_MODULE,
 	.driver_name    = DRIVER_NAME,

@@ -1360,7 +1354,7 @@ static struct uart_driver imx_reg = {
 	.major          = SERIAL_IMX_MAJOR,
 	.minor          = MINOR_START,
 	.nr             = ARRAY_SIZE(imx_ports),
-	.cons           = IMX_CONSOLE,
+	.cons           = &imx_console,
 };
 
 static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)

@@ -1419,6 +1419,9 @@ static int serial_imx_probe_dt(struct imx_port *sport,
 
 	sport->devdata = of_id->data;
 
+	if (of_device_is_stdout_path(np))
+		add_preferred_console(imx_reg.cons->name, sport->port.line, 0);
+
 	return 0;
 }
 #else

@@ -1358,3 +1358,31 @@ const char *of_prop_next_string(struct property *prop, const char *cur)
 	return curv;
 }
 EXPORT_SYMBOL_GPL(of_prop_next_string);
+
+/**
+ * of_device_is_stdout_path - check if a device node matches the
+ *                            linux,stdout-path property
+ *
+ * Check if this device node matches the linux,stdout-path property
+ * in the chosen node. return true if yes, false otherwise.
+ */
+int of_device_is_stdout_path(struct device_node *dn)
+{
+	const char *name;
+	struct device_node *dn_stdout;
+	int is_stdout = 0;
+
+	name = of_get_property(of_chosen, "linux,stdout-path", NULL);
+	if (name == NULL)
+		return 0;
+
+	dn_stdout = of_find_node_by_path(name);
+
+	if (dn_stdout && dn_stdout == dn)
+		is_stdout = 1;
+
+	of_node_put(dn_stdout);
+
+	return is_stdout;
+}
+EXPORT_SYMBOL_GPL(of_device_is_stdout_path);

@@ -310,6 +310,8 @@ const char *of_prop_next_string(struct property *prop, const char *cur);
 		s;						\
 		s = of_prop_next_string(prop, s))
 
+int of_device_is_stdout_path(struct device_node *dn);
+
 #else /* CONFIG_OF */
 
 static inline const char* of_node_full_name(struct device_node *np)

@@ -437,6 +439,11 @@ static inline int of_machine_is_compatible(const char *compat)
 	return 0;
 }
 
+static inline int of_device_is_stdout_path(struct device_node *dn)
+{
+	return 0;
+}
+
 #define of_match_ptr(_ptr)	NULL
 #define of_match_node(_matches, _node)	NULL
 #define of_property_for_each_u32(np, propname, prop, p, u) \