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-rw-r--r--Documentation/devicetree/bindings/rtc/rtc-cmos.txt28
-rw-r--r--arch/x86/kernel/rtc.c3
-rw-r--r--drivers/rtc/rtc-cmos.c45
-rw-r--r--include/linux/of.h12
4 files changed, 88 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/rtc/rtc-cmos.txt b/Documentation/devicetree/bindings/rtc/rtc-cmos.txt
new file mode 100644
index 000000000000..7382989b3052
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/rtc-cmos.txt
@@ -0,0 +1,28 @@
+ Motorola mc146818 compatible RTC
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Required properties:
+ - compatible : "motorola,mc146818"
+ - reg : should contain registers location and length.
+
+Optional properties:
+ - interrupts : should contain interrupt.
+ - interrupt-parent : interrupt source phandle.
+ - ctrl-reg : Contains the initial value of the control register also
+ called "Register B".
+ - freq-reg : Contains the initial value of the frequency register also
+ called "Regsiter A".
+
+"Register A" and "B" are usually initialized by the firmware (BIOS for
+instance). If this is not done, it can be performed by the driver.
+
+ISA Example:
+
+ rtc@70 {
+ compatible = "motorola,mc146818";
+ interrupts = <8 3>;
+ interrupt-parent = <&ioapic1>;
+ ctrl-reg = <2>;
+ freq-reg = <0x26>;
+ reg = <1 0x70 2>;
+ };
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index 6f39cab052d5..3f2ad2640d85 100644
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -6,6 +6,7 @@
#include <linux/acpi.h>
#include <linux/bcd.h>
#include <linux/pnp.h>
+#include <linux/of.h>
#include <asm/vsyscall.h>
#include <asm/x86_init.h>
@@ -236,6 +237,8 @@ static __init int add_rtc_cmos(void)
}
}
#endif
+ if (of_have_populated_dt())
+ return 0;
platform_device_register(&rtc_device);
dev_info(&rtc_device.dev,
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index c7ff8df347e7..159b95e4b420 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -37,6 +37,8 @@
#include <linux/mod_devicetable.h>
#include <linux/log2.h>
#include <linux/pm.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
#include <asm-generic/rtc.h>
@@ -1123,6 +1125,47 @@ static struct pnp_driver cmos_pnp_driver = {
#endif /* CONFIG_PNP */
+#ifdef CONFIG_OF
+static const struct of_device_id of_cmos_match[] = {
+ {
+ .compatible = "motorola,mc146818",
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, of_cmos_match);
+
+static __init void cmos_of_init(struct platform_device *pdev)
+{
+ struct device_node *node = pdev->dev.of_node;
+ struct rtc_time time;
+ int ret;
+ const __be32 *val;
+
+ if (!node)
+ return;
+
+ val = of_get_property(node, "ctrl-reg", NULL);
+ if (val)
+ CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
+
+ val = of_get_property(node, "freq-reg", NULL);
+ if (val)
+ CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
+
+ get_rtc_time(&time);
+ ret = rtc_valid_tm(&time);
+ if (ret) {
+ struct rtc_time def_time = {
+ .tm_year = 1,
+ .tm_mday = 1,
+ };
+ set_rtc_time(&def_time);
+ }
+}
+#else
+static inline void cmos_of_init(struct platform_device *pdev) {}
+#define of_cmos_match NULL
+#endif
/*----------------------------------------------------------------*/
/* Platform setup should have set up an RTC device, when PNP is
@@ -1131,6 +1174,7 @@ static struct pnp_driver cmos_pnp_driver = {
static int __init cmos_platform_probe(struct platform_device *pdev)
{
+ cmos_of_init(pdev);
cmos_wake_setup(&pdev->dev);
return cmos_do_probe(&pdev->dev,
platform_get_resource(pdev, IORESOURCE_IO, 0),
@@ -1162,6 +1206,7 @@ static struct platform_driver cmos_platform_driver = {
#ifdef CONFIG_PM
.pm = &cmos_pm_ops,
#endif
+ .of_match_table = of_cmos_match,
}
};
diff --git a/include/linux/of.h b/include/linux/of.h
index d9dd664a6a9c..266db1d0baa9 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -70,6 +70,11 @@ extern struct device_node *allnodes;
extern struct device_node *of_chosen;
extern rwlock_t devtree_lock;
+static inline bool of_have_populated_dt(void)
+{
+ return allnodes != NULL;
+}
+
static inline bool of_node_is_root(const struct device_node *node)
{
return node && (node->parent == NULL);
@@ -222,5 +227,12 @@ extern void of_attach_node(struct device_node *);
extern void of_detach_node(struct device_node *);
#endif
+#else
+
+static inline bool of_have_populated_dt(void)
+{
+ return false;
+}
+
#endif /* CONFIG_OF */
#endif /* _LINUX_OF_H */