dm: serial: Add ->getconfig() callback

In some cases it would be good to know the settings, such as parity,
of current serial console. One example might be an ACPI SPCR table
to generate using these parameters.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
index 3ded627..51ae176 100644
--- a/drivers/serial/serial-uclass.c
+++ b/drivers/serial/serial-uclass.c
@@ -294,6 +294,20 @@
 		ops->setbrg(gd->cur_serial_dev, gd->baudrate);
 }
 
+int serial_getconfig(uint *config)
+{
+	struct dm_serial_ops *ops;
+
+	if (!gd->cur_serial_dev)
+		return 0;
+
+	ops = serial_get_ops(gd->cur_serial_dev);
+	if (ops->getconfig)
+		return ops->getconfig(gd->cur_serial_dev, config);
+
+	return 0;
+}
+
 int serial_setconfig(uint config)
 {
 	struct dm_serial_ops *ops;
@@ -419,6 +433,8 @@
 		ops->pending += gd->reloc_off;
 	if (ops->clear)
 		ops->clear += gd->reloc_off;
+	if (ops->getconfig)
+		ops->getconfig += gd->reloc_off;
 	if (ops->setconfig)
 		ops->setconfig += gd->reloc_off;
 #if CONFIG_POST & CONFIG_SYS_POST_UART