diff options
| author | Johan Hovold <johan+linaro@kernel.org> | 2025-02-19 16:41:14 +0300 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2025-03-17 13:52:25 +0300 |
| commit | bba38b874886b227283d56ecb2f7ebbaa01a781d (patch) | |
| tree | 6b00af2e4decd7c7417aece985547c25c74d3450 /include/linux/rtc.h | |
| parent | 931a88914ad6da6731c0510aa11c15d297567616 (diff) | |
| download | linux-bba38b874886b227283d56ecb2f7ebbaa01a781d.tar.xz | |
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 <jens.glathe@oldschoolsolutions.biz>
Tested-by: Steev Klimaszewski <steev@kali.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Tested-by: Sebastian Reichel <sre@kernel.org> # Lenovo T14s Gen6
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20250219134118.31017-3-johan+linaro@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'include/linux/rtc.h')
| -rw-r--r-- | include/linux/rtc.h | 1 |
1 files changed, 1 insertions, 0 deletions
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 */ |