misc: Add simple driver for some Nuvoton NCT6102D devices

This simple driver provides some functions to control some of the
integrated devices. The watchdog is enabled per default. This driver
adds a function to disable the watchdog. Also the internal legacy
UART (io address 0x3f8/0x2f8) is enabled per default.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Cc: Simon Glass <sjg@chromium.org>

drivers/misc/Kconfig

@@ -90,6 +90,14 @@ config MXC_OCOTP
 	  Programmable memory pages that are stored on the some
 	  Freescale i.MX processors.
 
+config NUVOTON_NCT6102D
+	bool "Enable Nuvoton NCT6102D Super I/O driver"
+	help
+	  If you say Y here, you will get support for the Nuvoton
+	  NCT6102D Super I/O driver. This can be used to enable or
+	  disable the legacy UART, the watchdog or other devices
+	  in the Nuvoton Super IO chips on X86 platforms.
+
 config PWRSEQ
 	bool "Enable power-sequencing drivers"
 	depends on DM

drivers/misc/Makefile

@@ -24,6 +24,7 @@ obj-$(CONFIG_I2C_EEPROM) += i2c_eeprom.o
 obj-$(CONFIG_FSL_MC9SDZ60) += mc9sdz60.o
 obj-$(CONFIG_MXC_OCOTP) += mxc_ocotp.o
 obj-$(CONFIG_MXS_OCOTP) += mxs_ocotp.o
+obj-$(CONFIG_NUVOTON_NCT6102D) += nuvoton_nct6102d.o
 obj-$(CONFIG_NS87308) += ns87308.o
 obj-$(CONFIG_PDSP188x) += pdsp188x.o
 obj-$(CONFIG_$(SPL_)PWRSEQ) += pwrseq-uclass.o

drivers/misc/nuvoton_nct6102d.c

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2016 Stefan Roese <sr@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <nuvoton_nct6102d.h>
+#include <asm/io.h>
+#include <asm/pnp_def.h>
+
+static void superio_outb(int reg, int val)
+{
+	outb(reg, NCT_EFER);
+	outb(val, NCT_EFDR);
+}
+
+static inline int superio_inb(int reg)
+{
+	outb(reg, NCT_EFER);
+	return inb(NCT_EFDR);
+}
+
+static int superio_enter(void)
+{
+	outb(NCT_ENTRY_KEY, NCT_EFER); /* Enter extended function mode */
+	outb(NCT_ENTRY_KEY, NCT_EFER); /* Again according to manual */
+
+	return 0;
+}
+
+static void superio_select(int ld)
+{
+	superio_outb(NCT_LD_SELECT_REG, ld);
+}
+
+static void superio_exit(void)
+{
+	outb(NCT_EXIT_KEY, NCT_EFER); /* Leave extended function mode */
+}
+
+/*
+ * The Nuvoton NCT6102D starts per default after reset with both,
+ * the internal watchdog and the internal legacy UART enabled. This
+ * code provides a function to disable the watchdog.
+ */
+int nct6102d_wdt_disable(void)
+{
+	superio_enter();
+	/* Select logical device for WDT */
+	superio_select(NCT6102D_LD_WDT);
+	superio_outb(NCT6102D_WDT_TIMEOUT, 0x00);
+	superio_exit();
+
+	return 0;
+}

include/nuvoton_nct6102d.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2016 Stefan Roese <sr@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _NUVOTON_NCT6102D_H_
+#define _NUVOTON_NCT6102D_H_
+
+/* I/O address of Nuvoton Super IO chip */
+#define NCT6102D_IO_PORT	0x4e
+
+/* Extended Function Enable Registers */
+#define NCT_EFER (NCT6102D_IO_PORT + 0)
+/* Extended Function Index Register (same as EFER) */
+#define NCT_EFIR (NCT6102D_IO_PORT + 0)
+/* Extended Function Data Register */
+#define NCT_EFDR (NCT_EFIR + 1)
+
+#define NCT_LD_SELECT_REG	0x07
+
+/* Logical device number */
+#define NCT6102D_LD_UARTA	0x02
+#define NCT6102D_LD_WDT		0x08
+
+#define NCT6102D_UARTA_ENABLE	0x30
+#define NCT6102D_WDT_TIMEOUT	0xf1
+
+#define NCT_ENTRY_KEY		0x87
+#define NCT_EXIT_KEY		0xaa
+
+int nct6102d_wdt_disable(void);
+
+#endif /* _NUVOTON_NCT6102D_H_ */