From bba38b874886b227283d56ecb2f7ebbaa01a781d Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 19 Feb 2025 14:41:14 +0100 Subject: rtc: pm8xxx: add support for uefi offset On many Qualcomm platforms the PMIC RTC control and time registers are read-only so that the RTC time can not be updated. Instead an offset needs be stored in some machine-specific non-volatile memory, which the driver can take into account. Add support for storing a 32-bit offset from the GPS time epoch in a UEFI variable so that the RTC time can be set on such platforms. The UEFI variable is 882f8c2b-9646-435f-8de5-f208ff80c1bd-RTCInfo and holds a 12-byte structure where the first four bytes is a GPS time offset in little-endian byte order. Note that this format is not arbitrary as the variable is shared with the UEFI firmware (and Windows). Tested-by: Jens Glathe Tested-by: Steev Klimaszewski Tested-by: Joel Stanley Tested-by: Sebastian Reichel # Lenovo T14s Gen6 Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20250219134118.31017-3-johan+linaro@kernel.org Signed-off-by: Alexandre Belloni --- include/linux/rtc.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 3f4d315aaec9..95da051fb155 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -170,6 +170,7 @@ struct rtc_device { /* useful timestamps */ #define RTC_TIMESTAMP_BEGIN_0000 -62167219200ULL /* 0000-01-01 00:00:00 */ #define RTC_TIMESTAMP_BEGIN_1900 -2208988800LL /* 1900-01-01 00:00:00 */ +#define RTC_TIMESTAMP_EPOCH_GPS 315964800LL /* 1980-01-06 00:00:00 */ #define RTC_TIMESTAMP_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */ #define RTC_TIMESTAMP_END_2063 2966371199LL /* 2063-12-31 23:59:59 */ #define RTC_TIMESTAMP_END_2079 3471292799LL /* 2079-12-31 23:59:59 */ -- cgit v1.2.3