diff options
| -rw-r--r-- | Documentation/devicetree/bindings/rtc/rtc-cmos.txt | 28 | ||||
| -rw-r--r-- | arch/x86/kernel/rtc.c | 3 | ||||
| -rw-r--r-- | drivers/rtc/rtc-cmos.c | 45 | ||||
| -rw-r--r-- | include/linux/of.h | 12 |
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 */ |