provide rtc_cmos platform device

Recently (around 2.6.25) I've noticed that RTC no longer works for me. It
turned out this is because I use pnpacpi=off kernel option to work around
the parport_pc bugs. I always did so, but RTC used to work fine in the
past, and now it have regressed.

The patch fixes the problem by creating the platform device for the RTC
when PNP is disabled. This may also help running the PNP-enabled kernel
on an older PCs.

Signed-off-by: Stas Sergeev <[e-mail]>
Cc: David Brownell <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Bjorn Helgaas <[e-mail]>
Cc: Adam Belay <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/x86/kernel/rtc.c

···
 #include <linux/acpi.h>
 #include <linux/bcd.h>
 #include <linux/mc146818rtc.h>
+#include <linux/platform_device.h>
+#include <linux/pnp.h>
 
 #include <asm/time.h>
 #include <asm/vsyscall.h>
···
 }
 EXPORT_SYMBOL(native_read_tsc);
 
+
+static struct resource rtc_resources[] = {
+	[0] = {
+		.start	= RTC_PORT(0),
+		.end	= RTC_PORT(1),
+		.flags	= IORESOURCE_IO,
+	},
+	[1] = {
+		.start	= RTC_IRQ,
+		.end	= RTC_IRQ,
+		.flags	= IORESOURCE_IRQ,
+	}
+};
+
+static struct platform_device rtc_device = {
+	.name		= "rtc_cmos",
+	.id		= -1,
+	.resource	= rtc_resources,
+	.num_resources	= ARRAY_SIZE(rtc_resources),
+};
+
+static __init int add_rtc_cmos(void)
+{
+#ifdef CONFIG_PNP
+	if (!pnp_platform_devices)
+		platform_device_register(&rtc_device);
+#else
+	platform_device_register(&rtc_device);
+#endif /* CONFIG_PNP */
+	return 0;
+}
+device_initcall(add_rtc_cmos);

drivers/rtc/rtc-cmos.c

···
 	.resume		= cmos_pnp_resume,
 };
 
-static int __init cmos_init(void)
-{
-	return pnp_register_driver(&cmos_pnp_driver);
-}
-module_init(cmos_init);
-
-static void __exit cmos_exit(void)
-{
-	pnp_unregister_driver(&cmos_pnp_driver);
-}
-module_exit(cmos_exit);
-
-#else	/* no PNP */
+#endif	/* CONFIG_PNP */
 
 /*----------------------------------------------------------------*/
 
···
 
 static int __init cmos_init(void)
 {
+#ifdef	CONFIG_PNP
+	if (pnp_platform_devices)
+		return pnp_register_driver(&cmos_pnp_driver);
+	else
+		return platform_driver_probe(&cmos_platform_driver,
+			cmos_platform_probe);
+#else
 	return platform_driver_probe(&cmos_platform_driver,
 			cmos_platform_probe);
+#endif /* CONFIG_PNP */
 }
 module_init(cmos_init);
 
 static void __exit cmos_exit(void)
 {
+#ifdef	CONFIG_PNP
+	if (pnp_platform_devices)
+		pnp_unregister_driver(&cmos_pnp_driver);
+	else
+		platform_driver_unregister(&cmos_platform_driver);
+#else
 	platform_driver_unregister(&cmos_platform_driver);
+#endif /* CONFIG_PNP */
 }
 module_exit(cmos_exit);
 
-
-#endif	/* !PNP */
 
 MODULE_AUTHOR("David Brownell");
 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");