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>

2 files changed, 82 insertions, 0 deletions

diff --git a/arch/x86/platform/olpc/Makefile b/arch/x86/platform/olpc/Makefile
index 1ec5ade97f44..8922b9b3cd7a 100644
--- a/arch/x86/platform/olpc/Makefile
+++ b/arch/x86/platform/olpc/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_OLPC)		+= olpc.o olpc_ofw.o olpc_dt.o
 obj-$(CONFIG_OLPC_XO1_PM)		+= olpc-xo1-pm.o xo1-wakeup.o
+obj-$(CONFIG_OLPC_XO1_RTC)	+= olpc-xo1-rtc.o
 obj-$(CONFIG_OLPC_XO1_SCI)	+= olpc-xo1-sci.o
diff --git a/arch/x86/platform/olpc/olpc-xo1-rtc.c b/arch/x86/platform/olpc/olpc-xo1-rtc.c
new file mode 100644
index 000000000000..a2b4efddd61a
--- /dev/null
+++ b/arch/x86/platform/olpc/olpc-xo1-rtc.c
@@ -0,0 +1,81 @@
+/*
+ * Support for OLPC XO-1 Real Time Clock (RTC)
+ *
+ * Copyright (C) 2011 One Laptop per Child
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/mc146818rtc.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/of.h>
+
+#include <asm/msr.h>
+#include <asm/olpc.h>
+
+static void rtc_wake_on(struct device *dev)
+{
+	olpc_xo1_pm_wakeup_set(CS5536_PM_RTC);
+}
+
+static void rtc_wake_off(struct device *dev)
+{
+	olpc_xo1_pm_wakeup_clear(CS5536_PM_RTC);
+}
+
+static struct resource rtc_platform_resource[] = {
+	[0] = {
+		.start	= RTC_PORT(0),
+		.end	= RTC_PORT(1),
+		.flags	= IORESOURCE_IO,
+	},
+	[1] = {
+		.start	= RTC_IRQ,
+		.end	= RTC_IRQ,
+		.flags	= IORESOURCE_IRQ,
+	}
+};
+
+static struct cmos_rtc_board_info rtc_info = {
+	.rtc_day_alarm = 0,
+	.rtc_mon_alarm = 0,
+	.rtc_century = 0,
+	.wake_on = rtc_wake_on,
+	.wake_off = rtc_wake_off,
+};
+
+static struct platform_device xo1_rtc_device = {
+	.name = "rtc_cmos",
+	.id = -1,
+	.num_resources = ARRAY_SIZE(rtc_platform_resource),
+	.dev.platform_data = &rtc_info,
+	.resource = rtc_platform_resource,
+};
+
+static int __init xo1_rtc_init(void)
+{
+	int r;
+	struct device_node *node;
+
+	node = of_find_compatible_node(NULL, NULL, "olpc,xo1-rtc");
+	if (!node)
+		return 0;
+	of_node_put(node);
+
+	pr_info("olpc-xo1-rtc: Initializing OLPC XO-1 RTC\n");
+	rdmsrl(MSR_RTC_DOMA_OFFSET, rtc_info.rtc_day_alarm);
+	rdmsrl(MSR_RTC_MONA_OFFSET, rtc_info.rtc_mon_alarm);
+	rdmsrl(MSR_RTC_CEN_OFFSET, rtc_info.rtc_century);
+
+	r = platform_device_register(&xo1_rtc_device);
+	if (r)
+		return r;
+
+	device_init_wakeup(&xo1_rtc_device.dev, 1);
+	return 0;
+}
+arch_initcall(xo1_rtc_init);