[POWERPC] Create add_rtc() function to enable the RTC CMOS driver

In order to use the RTC CMOS driver, each architecture must register a
platform device for the RTC.

This creates a function to register the platform device based on the RTC
device node and verifies that the RTC port against the hard-coded value
in asm/mc146818rtc.h.

Signed-off-by: Wade Farnsworth <wfarnsworth@mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/sysdev/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_TSI108_BRIDGE)	+= tsi108_pci.o tsi108_dev.o
 obj-$(CONFIG_QUICC_ENGINE)	+= qe_lib/
 mv64x60-$(CONFIG_PCI)		+= mv64x60_pci.o
 obj-$(CONFIG_MV64X60)		+= $(mv64x60-y) mv64x60_pic.o mv64x60_dev.o
+obj-$(CONFIG_RTC_DRV_CMOS)	+= rtc_cmos_setup.o
 
 # contains only the suspend handler for time
 ifeq ($(CONFIG_RTC_CLASS),)

arch/powerpc/sysdev/rtc_cmos_setup.c

@@ -0,0 +1,49 @@
+/*
+ * Setup code for PC-style Real-Time Clock.
+ *
+ * Author: Wade Farnsworth <wfarnsworth@mvista.com>
+ *
+ * 2007 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/mc146818rtc.h>
+
+#include <asm/prom.h>
+
+static int  __init add_rtc(void)
+{
+	struct device_node *np;
+	struct platform_device *pd;
+	struct resource res;
+	int ret;
+
+	np = of_find_compatible_node(NULL, NULL, "pnpPNP,b00");
+	if (!np)
+		return -ENODEV;
+
+	ret = of_address_to_resource(np, 0, &res);
+	of_node_put(np);
+	if (ret)
+		return ret;
+
+	/*
+	 * RTC_PORT(x) is hardcoded in asm/mc146818rtc.h.  Verify that the
+	 * address provided by the device node matches.
+	 */
+	if (res.start != RTC_PORT(0))
+		return -EINVAL;
+
+	pd = platform_device_register_simple("rtc_cmos", -1,
+					     &res, 1);
+	if (IS_ERR(pd))
+		return PTR_ERR(pd);
+
+	return 0;
+}
+fs_initcall(add_rtc);