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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2026-02-23 16:29:37 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2026-02-26 18:46:04 +0100
commit1ae2f435350ec05224a39995c3a680aa6fdae5a5 (patch)
tree3ddebdc85937a2d4240bea7a5e368d14d5f0609b
parent6cee29ad9d7e400d39ae0b1a54447fedcb62eecd (diff)
ACPI: x86: cmos_rtc: Create a CMOS RTC platform device
Make the CMOS RTC ACPI scan handler create a platform device that will be used subsequently by rtc-cmos for driver binding on x86 systems with ACPI and update add_rtc_cmos() to skip registering a fallback platform device for the CMOS RTC when the above one has been registered. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> # x86 Link: https://patch.msgid.link/1962427.tdWV9SEqCh@rafael.j.wysocki
-rw-r--r--arch/x86/kernel/rtc.c4
-rw-r--r--drivers/acpi/x86/cmos_rtc.c8
-rw-r--r--include/linux/acpi.h4
3 files changed, 16 insertions, 0 deletions
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index 51a849a79c98..b112178e8185 100644
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -2,6 +2,7 @@
/*
* RTC related functions
*/
+#include <linux/acpi.h>
#include <linux/platform_device.h>
#include <linux/mc146818rtc.h>
#include <linux/export.h>
@@ -146,6 +147,9 @@ static __init int add_rtc_cmos(void)
}
}
#endif
+ if (cmos_rtc_platform_device_present)
+ return 0;
+
if (!x86_platform.legacy.rtc)
return -ENODEV;
diff --git a/drivers/acpi/x86/cmos_rtc.c b/drivers/acpi/x86/cmos_rtc.c
index 45db7e51cbe6..bdd66dfd4a44 100644
--- a/drivers/acpi/x86/cmos_rtc.c
+++ b/drivers/acpi/x86/cmos_rtc.c
@@ -24,6 +24,8 @@ static const struct acpi_device_id acpi_cmos_rtc_ids[] = {
{}
};
+bool cmos_rtc_platform_device_present;
+
static bool cmos_rtc_space_handler_present __read_mostly;
static acpi_status acpi_cmos_rtc_space_handler(u32 function,
@@ -103,6 +105,12 @@ static int acpi_cmos_rtc_attach(struct acpi_device *adev,
if (ret < 0)
return ret;
+ if (IS_ERR_OR_NULL(acpi_create_platform_device(adev, NULL))) {
+ pr_err("Failed to create CMOS-RTC platform device\n");
+ return 0;
+ } else {
+ cmos_rtc_platform_device_present = true;
+ }
return 1;
}
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 4d2f0bed7a06..2bdb801cee01 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -791,6 +791,8 @@ const char *acpi_get_subsystem_id(acpi_handle handle);
int acpi_mrrm_max_mem_region(void);
#endif
+extern bool cmos_rtc_platform_device_present;
+
#else /* !CONFIG_ACPI */
#define acpi_disabled 1
@@ -1116,6 +1118,8 @@ static inline int acpi_mrrm_max_mem_region(void)
return 1;
}
+#define cmos_rtc_platform_device_present false
+
#endif /* !CONFIG_ACPI */
#ifdef CONFIG_ACPI_HMAT