linux-toradex.git/drivers/rtc/lib_test.c, branch v6.0-rc1 Linux kernel for Apalis and Colibri modules rtc: lib_test: add MODULE_LICENSE 2021-08-10T21:21:46+00:00 Alexandre Belloni alexandre.belloni@bootlin.com 2021-08-10T21:20:06+00:00 5546e3dfb65a4389e747766ac455a50c3675fb0f As the documentation states, "The exact license information can only be determined via the license information in the corresponding source files." and the SPDX identifier has the proper information. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210810212008.631359-1-alexandre.belloni@bootlin.com 
As the documentation states, "The exact license information can only be
determined via the license information in the corresponding source files."
and the SPDX identifier has the proper information.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210810212008.631359-1-alexandre.belloni@bootlin.com
rtc: Improve performance of rtc_time64_to_tm(). Add tests. 2021-08-09T22:09:21+00:00 Cassio Neri cassio.neri@gmail.com 2021-06-24T20:13:43+00:00 1d1bb12a8b1805ddeef9793ebeb920179fb0fa38 The current implementation of rtc_time64_to_tm() contains unnecessary loops, branches and look-up tables. The new one uses an arithmetic-based algorithm appeared in [1] and is approximately 4.3 times faster (YMMV). The drawback is that the new code isn't intuitive and contains many 'magic numbers' (not unusual for this type of algorithm). However, [1] justifies all those numbers and, given this function's history, the code is unlikely to need much maintenance, if any at all. Add a KUnit test case that checks every day in a 160,000 years interval starting on 1970-01-01 against the expected result. Add a new config RTC_LIB_KUNIT_TEST symbol to give the option to run this test suite. [1] Neri, Schneider, "Euclidean Affine Functions and Applications to Calendar Algorithms". https://arxiv.org/abs/2102.06959 Signed-off-by: Cassio Neri <cassio.neri@gmail.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210624201343.85441-1-cassio.neri@gmail.com 
The current implementation of rtc_time64_to_tm() contains unnecessary
loops, branches and look-up tables. The new one uses an arithmetic-based
algorithm appeared in [1] and is approximately 4.3 times faster (YMMV).

The drawback is that the new code isn't intuitive and contains many 'magic
numbers' (not unusual for this type of algorithm). However, [1] justifies
all those numbers and, given this function's history, the code is unlikely
to need much maintenance, if any at all.

Add a KUnit test case that checks every day in a 160,000 years interval
starting on 1970-01-01 against the expected result. Add a new config
RTC_LIB_KUNIT_TEST symbol to give the option to run this test suite.

[1] Neri, Schneider, "Euclidean Affine Functions and Applications to
Calendar Algorithms". https://arxiv.org/abs/2102.06959

Signed-off-by: Cassio Neri <cassio.neri@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210624201343.85441-1-cassio.neri@gmail.com