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>

5 files changed, 99 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/rtc/olpc-xo1-rtc.txt b/Documentation/devicetree/bindings/rtc/olpc-xo1-rtc.txt
new file mode 100644
index 000000000000..a2891ceb6344
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/olpc-xo1-rtc.txt
@@ -0,0 +1,5 @@
+OLPC XO-1 RTC
+~~~~~~~~~~~~~
+
+Required properties:
+ - compatible : "olpc,xo1-rtc"
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a6aefbbc5cbf..0a9d573a2f9d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2080,6 +2080,13 @@ config OLPC_XO1_PM
         ---help---
           Add support for poweroff and suspend of the OLPC XO-1 laptop.
 
+config OLPC_XO1_RTC
+        bool "OLPC XO-1 Real Time Clock"
+        depends on OLPC_XO1_PM && RTC_DRV_CMOS
+        ---help---
+          Add support for the XO-1 real time clock, which can be used as a
+          programmable wakeup source.
+
 config OLPC_XO1_SCI
         bool "OLPC XO-1 SCI extras"
         depends on OLPC && OLPC_XO1_PM && POWER_SUPPLY
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);
diff --git a/include/linux/cs5535.h b/include/linux/cs5535.h
index 72954c6bf5d6..c077aec3a6ff 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 @@ static inline int cs5535_pic_unreqz_select_high(unsigned int group,
 
 /* 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)