Hi Andrew, This series adds support for Abracon AB-RTCMC-32.768kHz-B5ZE-S3 I2C RTC chip. Unlike many RTC chips, it includes an internal oscillator which spares room on the PCB. It also has some interesting features, like battery low detection (which the driver in this series supports). The only small "limitation" (mainly due to what RTC subsystem expects from RTC chips) is the fact that its alarm is accurate to the second. This series provides a solution (described below) for that limitation using another mechanism of the chip. I decided to split support between three different patches for this v0: - Patch 1/3: it simply references Abracon Corporation in vendor-prefixes documentation file. As Abracon has no NASDAQ ticker symbol; I have decided to use "abcn" (I initially started my work w/ "ab" but later changed for "abcn" which looked more meaningful) - Patch 2/3: it adds initial support for the chip and provides the ability to read/write time and also read/write alarm. As the alarm the chip provides is accurate to the minute, the support provided by this patch also has this limitation (e.g. UIE mode is not supported). - Patch 3/3: the chip supports a watchdog timer which can be used to extend the alarm mechanism in patch 2/3 in order to provide support for alarms under one minute (e.g. support UIE mode). In practice, the logic I implemented is to use the watchdog timer for alarms which are at most 4 minutes in the future and use the common alarm mechanism for alarms which are set to larger values. With that additional patch the device fully passes the rtctest.c program. I decided to split the driver between two patches (2 and 3 of 3) in order to ease review: patch 2 should be pretty straightforward to read for someone familiar w/ RTC subsystem. Patch 3 only extends what is in patch 2 regarding alarms. If you prefer a single patch in a v1, do not hesitate to ask. The set currently applies on top of 3.19-rc4 but I can rebase it against something else if you prefer. Cheers, a+ Arnaud Ebalard (3): of: add vendor prefix for Abracon Corporation rtc: add support for Abracon AB-RTCMC-32.768kHz-B5ZE-S3 I2C RTC chip rtc: rtc-ab-b5ze-s3: Add sub-minute alarm support .../devicetree/bindings/i2c/trivial-devices.txt | 1 + .../devicetree/bindings/vendor-prefixes.txt | 1 + drivers/rtc/Kconfig | 11 + drivers/rtc/Makefile | 1 + drivers/rtc/rtc-ab-b5ze-s3.c | 1031 ++++++++++++++++++++ 5 files changed, 1045 insertions(+) create mode 100644 drivers/rtc/rtc-ab-b5ze-s3.c -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
