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Subject[PATCH v2] rtc/cmos: add OF bindings
This allows to load the OF driver based informations from the device
tree. Systems without BIOS may need to perform some initialization.
PowerPC creates a PNP device from the OF information and performs this
kind of initialization in their private PCI quirk. This looks more
generic.

Cc: rtc-linux@googlegroups.com
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: devicetree-discuss@lists.ozlabs.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
---

* Grant Likely | 2011-01-11 17:04:42 [-0700]:

>It's usually cleaner to break the of-specific probe stuff into a
>separate function that can be #ifdef'ed out as a whole instead of
>having #ifdef blocks inside the probe functions. Aside from that this
>patch looks good to me.

Done.

Documentation/powerpc/dts-bindings/rtc-cmos.txt | 28 ++++++++++++++
drivers/rtc/rtc-cmos.c | 46 +++++++++++++++++++++++
2 files changed, 74 insertions(+), 0 deletions(-)
create mode 100644 Documentation/powerpc/dts-bindings/rtc-cmos.txt

diff --git a/Documentation/powerpc/dts-bindings/rtc-cmos.txt b/Documentation/powerpc/dts-bindings/rtc-cmos.txt
new file mode 100644
index 0000000..7382989
--- /dev/null
+++ b/Documentation/powerpc/dts-bindings/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/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index 5856167..95a08dd 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -36,6 +36,8 @@
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/log2.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>
@@ -1121,6 +1123,46 @@ 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) {}
+#endif
/*----------------------------------------------------------------*/

/* Platform setup should have set up an RTC device, when PNP is
@@ -1129,6 +1171,7 @@ 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),
@@ -1157,6 +1200,9 @@ static struct platform_driver cmos_platform_driver = {
.shutdown = cmos_platform_shutdown,
.driver = {
.name = (char *) driver_name,
+#if defined(CONFIG_OF)
+ .of_match_table = of_cmos_match,
+#endif
.suspend = cmos_suspend,
.resume = cmos_resume,
}
--
1.7.3.2


Sebastian


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