misc: Add simple driver to enable the legacy UART on Winbond Super IO chips

On most x86 boards, the legacy serial ports (io address 0x3f8/0x2f8)
are provided by a superio chip connected to the LPC bus. We must
program the superio chip so that serial ports are available for us.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/winbond_w83627.h b/include/winbond_w83627.h
new file mode 100644
index 0000000..ac3bec6
--- /dev/null
+++ b/include/winbond_w83627.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2016 Stefan Roese <sr@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _WINBOND_W83627_H_
+#define _WINBOND_W83627_H_
+
+/* I/O address of Winbond Super IO chip */
+#define WINBOND_IO_PORT		0x2e
+
+/* Logical device number */
+#define W83627DHG_FDC		0	/* Floppy */
+#define W83627DHG_PP		1	/* Parallel port */
+#define W83627DHG_SP1		2	/* Com1 */
+#define W83627DHG_SP2		3	/* Com2 */
+#define W83627DHG_KBC		5	/* PS/2 keyboard & mouse */
+#define W83627DHG_SPI		6	/* Serial peripheral interface */
+#define W83627DHG_WDTO_PLED	8	/* WDTO#, PLED */
+#define W83627DHG_ACPI		10	/* ACPI */
+#define W83627DHG_HWM		11	/* Hardware monitor */
+#define W83627DHG_PECI_SST	12	/* PECI, SST */
+
+/**
+ * Configure the base I/O port of the specified serial device and enable the
+ * serial device.
+ *
+ * @dev: high 8 bits = super I/O port, low 8 bits = logical device number
+ * @iobase: processor I/O port address to assign to this serial device
+ * @irq: processor IRQ number to assign to this serial device
+ */
+void winbond_enable_serial(uint dev, uint iobase, uint irq);
+
+#endif /* _WINBOND_W83627_H_ */