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[2003:f6:5f13:c804::1b9]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3a53229de0csm11340604f8f.1.2025.06.10.00.35.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Jun 2025 00:35:23 -0700 (PDT) From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= To: Alessandro Zummo , Alexandre Belloni Cc: Alexandre Mergnat , Cassio Neri , stable@vger.kernel.org, linux-rtc@vger.kernel.org Subject: [PATCH 5.10.y 0/3] rtc: backport support for handling dates before 1970 Date: Tue, 10 Jun 2025 09:34:57 +0200 Message-ID: X-Mailer: git-send-email 2.49.0 Precedence: bulk X-Mailing-List: linux-rtc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Developer-Signature: v=1; a=openpgp-sha256; l=1574; i=u.kleine-koenig@baylibre.com; h=from:subject:message-id; bh=71kPFbeIHYmPXRrsapFjJ64rErsVjsccg2t4mfNpiEM=; b=owEBbQGS/pANAwAKAY+A+1h9Ev5OAcsmYgBoR+AimG2JUFGxzNyMnxXuTqUnbHEaEpsW4FXrB 2PwIf+nkaqJATMEAAEKAB0WIQQ/gaxpOnoeWYmt/tOPgPtYfRL+TgUCaEfgIgAKCRCPgPtYfRL+ TgjDB/91AsfWdd/8uhhcXzbfmNtuQ6RvC731jWw73QR5/rwcdreCaKfHog6g1KSTSp9WhuSe5S1 Mv9F/RW23lj7vyPKz5JIkPjCU3EAI0MNyCLu5Y4SfvTzEF0vMpTat8bAlHZaTfQ6ulCpgR6HKfq n4LxGhMQYI7OCUt2UOpPofHDAdMdTL2DeyjmMJDw7XKyNoKO05dFFzGC68PlGqe8bLYYTmGTtdF U38unQADW5/7+wha7eEhQTRnsyYBg1iOIl7EcZzj4JAx9oOGiqSkhmULtcoO8llRtzxNk9RG8bd kiQL9oNKV6gIAEKNvXOmriWpw872xna05QDPkDQ4W6qhQAOz X-Developer-Key: i=u.kleine-koenig@baylibre.com; a=openpgp; fpr=0D2511F322BFAB1C1580266BE2DCDD9132669BD6 Content-Transfer-Encoding: 8bit Hello, this is a followup to https://lore.kernel.org/stable/cover.1749223334.git.u.kleine-koenig@baylibre.com that handled backporting the two patches by Alexandre to the active stable kernels between 6.15 and 5.15. Here comes a backport to 5.10.y, git am handles application to 5.4.y just fine. Compared to the backport for later kernels I included a major rework of rtc_time64_to_tm() by Cassio Neri. (FTR: I checked, that commit by Cassio Neri isn't the reason we need to fix rtc_time64_to_tm(), the actual problem is older.) Now that I completed the backport and did some final checks on it I noticed that the problem fixed here is (TTBOMK) a theoretic one because only drivers with .start_secs < 0 are known to have issues and in 5.10 and before there is no such driver. I'm uncertain if this should result in not backporting the changes. I would tend to pick them anyhow, but I won't argue on a veto. Best regards Uwe Alexandre Mergnat (2): rtc: Make rtc_time64_to_tm() support dates before 1970 rtc: Fix offset calculation for .start_secs < 0 Cassio Neri (1): rtc: Improve performance of rtc_time64_to_tm(). Add tests. drivers/rtc/Kconfig | 10 ++++ drivers/rtc/Makefile | 1 + drivers/rtc/class.c | 2 +- drivers/rtc/lib.c | 121 ++++++++++++++++++++++++++++++++--------- drivers/rtc/lib_test.c | 79 +++++++++++++++++++++++++++ 5 files changed, 185 insertions(+), 28 deletions(-) create mode 100644 drivers/rtc/lib_test.c base-commit: 01e7e36b8606e5d4fddf795938010f7bfa3aa277 -- 2.49.0