MIPS: Malta: Add back RTC support

With the conversion of MIPS to RTC_LIB the old RTC driver CONFIG_RTC became
unselectable.  Fix by setting up a platform device.  Also enable
RTC_CLASS so system time gets set from RTC on kernel initialization.

[Ralf: Original patch by Tiejun; polished nice and shiny by me]
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/configs/malta_defconfig

@@ -1126,7 +1126,6 @@ CONFIG_LEGACY_PTY_COUNT=256
 # CONFIG_IPMI_HANDLER is not set
 # CONFIG_WATCHDOG is not set
 CONFIG_HW_RANDOM=m
-CONFIG_RTC=y
 # CONFIG_R3964 is not set
 # CONFIG_APPLICOM is not set
 # CONFIG_DRM is not set
@@ -1199,7 +1198,43 @@ CONFIG_USB_ARCH_HAS_EHCI=y
 # CONFIG_MMC is not set
 # CONFIG_NEW_LEDS is not set
 # CONFIG_INFINIBAND is not set
-# CONFIG_RTC_CLASS is not set
+CONFIG_RTC_LIB=y
+CONFIG_RTC_CLASS=y
+CONFIG_RTC_HCTOSYS=y
+CONFIG_RTC_HCTOSYS_DEVICE="rtc0"
+# CONFIG_RTC_DEBUG is not set
+
+#
+# RTC interfaces
+#
+CONFIG_RTC_INTF_SYSFS=y
+CONFIG_RTC_INTF_PROC=y
+CONFIG_RTC_INTF_DEV=y
+# CONFIG_RTC_INTF_DEV_UIE_EMUL is not set
+# CONFIG_RTC_DRV_TEST is not set
+
+#
+# SPI RTC drivers
+#
+
+#
+# Platform RTC drivers
+#
+CONFIG_RTC_DRV_CMOS=y
+# CONFIG_RTC_DRV_DS1286 is not set
+# CONFIG_RTC_DRV_DS1511 is not set
+# CONFIG_RTC_DRV_DS1553 is not set
+# CONFIG_RTC_DRV_DS1742 is not set
+# CONFIG_RTC_DRV_STK17TA8 is not set
+# CONFIG_RTC_DRV_M48T86 is not set
+# CONFIG_RTC_DRV_M48T35 is not set
+# CONFIG_RTC_DRV_M48T59 is not set
+# CONFIG_RTC_DRV_BQ4802 is not set
+# CONFIG_RTC_DRV_V3020 is not set
+
+#
+# on-CPU RTC drivers
+#
 
 #
 # DMA Engine support

arch/mips/mti-malta/malta-platform.c

@@ -6,7 +6,10 @@
  * Copyright (C) 2007 MIPS Technologies, Inc.
  *   written by Ralf Baechle (ralf@linux-mips.org)
  *
- * Probe driver for the Malta's UART ports:
+ * Copyright (C) 2008 Wind River Systems, Inc.
+ *   updated by Tiejun Chen <tiejun.chen@windriver.com>
+ *
+ * 1. Probe driver for the Malta's UART ports:
  *
  *   o 2 ports in the SMC SuperIO
  *   o 1 port in the CBUS UART, a discrete 16550 which normally is only used
@@ -14,10 +17,14 @@
  *
  * We don't use 8250_platform.c on Malta as it would result in the CBUS
  * UART becoming ttyS0.
+ *
+ * 2. Register RTC-CMOS platform device on Malta.
  */
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/serial_8250.h>
+#include <linux/mc146818rtc.h>
+#include <linux/platform_device.h>
 
 #define SMC_PORT(base, int)						\
 {									\
@@ -45,7 +52,7 @@ static struct plat_serial8250_port uart8250_data[] = {
 	{ },
 };
 
-static struct platform_device uart8250_device = {
+static struct platform_device malta_uart8250_device = {
 	.name			= "serial8250",
 	.id			= PLAT8250_DEV_PLATFORM2,
 	.dev			= {
@@ -53,13 +60,44 @@ static struct platform_device uart8250_device = {
 	},
 };
 
-static int __init uart8250_init(void)
+struct resource malta_rtc_resources[] = {
+	{
+		.start	= RTC_PORT(0),
+		.end	= RTC_PORT(7),
+		.flags	= IORESOURCE_IO,
+	}, {
+		.start	= RTC_IRQ,
+		.end	= RTC_IRQ,
+		.flags	= IORESOURCE_IRQ,
+	}
+};
+
+static struct platform_device malta_rtc_device = {
+	.name		= "rtc_cmos",
+	.id		= -1,
+	.resource	= malta_rtc_resources,
+	.num_resources	= ARRAY_SIZE(malta_rtc_resources),
+};
+
+static struct platform_device *malta_devices[] __initdata = {
+	&malta_uart8250_device,
+	&malta_rtc_device,
+};
+
+static int __init malta_add_devices(void)
 {
-	return platform_device_register(&uart8250_device);
-}
+	int err;
 
-module_init(uart8250_init);
+	err = platform_add_devices(malta_devices, ARRAY_SIZE(malta_devices));
+	if (err)
+		return err;
+
+	/*
+	 * Set RTC to BCD mode to support current alarm code.
+	 */
+	CMOS_WRITE(CMOS_READ(RTC_CONTROL) & ~RTC_DM_BINARY, RTC_CONTROL);
+
+	return 0;
+}
 
-MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("8250 UART probe driver for the Malta CBUS UART");
+device_initcall(malta_add_devices);