x86, olpc: Add XO-1 RTC driver

Add a driver to configure the XO-1 RTC via CS5536 MSRs, to be used as a
system wakeup source via olpc-xo1-pm.

Device detection is based on finding the relevant device tree node.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Link: http://lkml.kernel.org/r/1309019658-1712-11-git-send-email-dsd@laptop.org
Acked-by: Andres Salomon <dilinger@queued.net>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: devicetree-discuss@lists.ozlabs.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/include/linux/cs5535.h b/include/linux/cs5535.h
index 72954c6..c077aec 100644
--- a/include/linux/cs5535.h
+++ b/include/linux/cs5535.h
@@ -40,6 +40,10 @@
 #define MSR_MFGPT_NR		0x51400029
 #define MSR_MFGPT_SETUP		0x5140002B
 
+#define MSR_RTC_DOMA_OFFSET	0x51400055
+#define MSR_RTC_MONA_OFFSET	0x51400056
+#define MSR_RTC_CEN_OFFSET	0x51400057
+
 #define MSR_LX_SPARE_MSR	0x80000011	/* DC-specific */
 
 #define MSR_GX_GLD_MSR_CONFIG	0xC0002001
@@ -95,6 +99,7 @@
 
 /* CS5536_PM1_EN bits */
 #define CS5536_PM_PWRBTN	(1 << 8)
+#define CS5536_PM_RTC		(1 << 10)
 
 /* CS5536_PM_GPE0_STS bits */
 #define CS5536_GPIOM7_PME_FLAG	(1 << 31)