serial: Implement CONFIG_SERIAL_MULTI into max3100 serial driver

Implement support for CONFIG_SERIAL_MULTI into max3100 serial driver.
This driver was so far only usable directly, but this patch also adds
support for the multi method. This allows using more than one serial
driver alongside the max3100 driver. Also, add a weak implementation
of default_serial_console() returning this driver.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Tom Rini <trini@ti.com>
diff --git a/drivers/serial/serial_max3100.c b/drivers/serial/serial_max3100.c
index 4abc271..b21fba0 100644
--- a/drivers/serial/serial_max3100.c
+++ b/drivers/serial/serial_max3100.c
@@ -25,6 +25,8 @@
 
 #include <common.h>
 #include <watchdog.h>
+#include <serial.h>
+#include <linux/compiler.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -149,7 +151,7 @@
 static int rxfifo_out;
 static unsigned char rxfifo_buf[16];
 
-static void max3100_putc(int c)
+static void max3100_serial_putc_raw(int c)
 {
 	unsigned int rx;
 
@@ -164,7 +166,7 @@
 	}
 }
 
-static int max3100_getc(void)
+static int max3100_serial_getc(void)
 {
 	int c;
 	unsigned int rx;
@@ -190,7 +192,7 @@
 	return c;
 }
 
-static int max3100_tstc(void)
+static int max3100_serial_tstc(void)
 {
 	unsigned int rx;
 
@@ -213,7 +215,7 @@
 	return 1;
 }
 
-int serial_init(void)
+static int max3100_serial_init(void)
 {
 	unsigned int wconf, rconf;
 	int i;
@@ -268,31 +270,73 @@
 	return (0);
 }
 
-void serial_putc(const char c)
+static void max3100_serial_putc(const char c)
 {
 	if (c == '\n')
-		max3100_putc('\r');
+		max3100_serial_putc_raw('\r');
 
-	max3100_putc(c);
+	max3100_serial_putc_raw(c);
+}
+
+static void max3100_serial_puts(const char *s)
+{
+	while (*s)
+		max3100_serial_putc_raw(*s++);
+}
+
+static void max3100_serial_setbrg(void)
+{
+}
+
+#ifdef CONFIG_SERIAL_MULTI
+static struct serial_device max3100_serial_drv = {
+	.name	= "max3100_serial",
+	.start	= max3100_serial_init,
+	.stop	= NULL,
+	.setbrg	= max3100_serial_setbrg,
+	.putc	= max3100_serial_putc,
+	.puts	= max3100_serial_puts,
+	.getc	= max3100_serial_getc,
+	.tstc	= max3100_serial_tstc,
+};
+
+void max3100_serial_initialize(void)
+{
+	serial_register(&max3100_serial_drv);
+}
+
+__weak struct serial_device *default_serial_console(void)
+{
+	return &max3100_serial_drv;
+}
+#else
+int serial_init(void)
+{
+	return max3100_serial_init();
+}
+
+void serial_setbrg(void)
+{
+	max3100_serial_setbrg();
+}
+
+void serial_putc(const char c)
+{
+	max3100_serial_putc(c);
 }
 
 void serial_puts(const char *s)
 {
-	while (*s)
-		serial_putc (*s++);
+	max3100_serial_puts(s);
 }
 
 int serial_getc(void)
 {
-	return max3100_getc();
+	return max3100_serial_getc();
 }
 
 int serial_tstc(void)
 {
-	return max3100_tstc();
+	return max3100_serial_tstc();
 }
-
-/* XXX WTF? */
-void serial_setbrg(void)
-{
-}
+#endif