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[ Upstream commit 50c8aec4212a966817e868056efc9bfbb73337c0 ] (RTC,ALM)YEAR registers of Exynos built-in RTC device contains 3 BCD characters. s3c-rtc driver uses only 2 lower of them and supports years from 2000..2099 range. The third BCD value is typically set to 0, but it looks that handling of it is broken in the hardware. It sometimes defaults to a random (even non-BCD) value. This is not an issue for handling RTCYEAR register, because bcd2bin() properly handles only 8bit values (2 BCD characters, the third one is skipped). The problem is however with ALMYEAR register and proper RTC alarm operation. When YEAREN bit is set for the configured alarm, RTC hardware triggers alarm only when ALMYEAR and RTCYEAR matches. This usually doesn't happen because of the random noise on the third BCD character. Fix this by simply skipping setting ALMYEAR register in alarm configuration. This workaround fixes broken alarm operation on Exynos built-in rtc device. My tests revealed that the issue happens on the following Exynos series: 3250, 4210, 4412, 5250 and 5410. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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