Hello Linus,
Here is the RTC subsystem pull request for v5.15 which is very late.
I'll try to not make that a habit. The broken down time conversion is
similar to what is done in the time subsystem since v5.14. The rest is
fairly straightforward.
The following changes since commit e73f0f0ee7541171d89f2e2491130c7771ba58d3:
Linux 5.14-rc1 (2021-07-11 15:07:40 -0700)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git tags/rtc-5.15
for you to fetch changes up to 0c45d3e24ef3d3d87c5e0077b8f38d1372af7176:
rtc: rx8010: select REGMAP_I2C (2021-09-09 10:18:40 +0200)
----------------------------------------------------------------
RTC for 5.15
Subsystem:
- Switch to Neri and Schneider time conversion algorithm
Drivers:
- rx8025: add rx8035 support
- s5m: modernize driver and set range
----------------------------------------------------------------
Alexandre Belloni (6):
rtc: s5m: switch to devm_rtc_allocate_device
rtc: s5m: signal the core when alarm are not available
rtc: s5m: enable wakeup only when available
rtc: s5m: set range
rtc: lib_test: add MODULE_LICENSE
rtc: move RTC_LIB_KUNIT_TEST to proper location
Cassio Neri (1):
rtc: Improve performance of rtc_time64_to_tm(). Add tests.
Dmitry Osipenko (1):
rtc: tps65910: Correct driver module alias
Mateusz Jończyk (1):
rtc: cmos: remove stale REVISIT comments
Mathew McBride (2):
rtc: rx8025: implement RX-8035 support
dt-bindings: rtc: add Epson RX-8025 and RX-8035
Yu-Tung Chang (1):
rtc: rx8010: select REGMAP_I2C
.../devicetree/bindings/rtc/trivial-rtc.yaml | 3 +
drivers/rtc/Kconfig | 10 ++
drivers/rtc/Makefile | 2 +
drivers/rtc/lib.c | 107 +++++++++++++++------
drivers/rtc/lib_test.c | 81 ++++++++++++++++
drivers/rtc/rtc-cmos.c | 8 +-
drivers/rtc/rtc-rx8025.c | 46 ++++++++-
drivers/rtc/rtc-s5m.c | 48 ++++-----
drivers/rtc/rtc-tps65910.c | 2 +-
9 files changed, 243 insertions(+), 64 deletions(-)
create mode 100644 drivers/rtc/lib_test.c
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
On Sat, Sep 11, 2021 at 8:59 AM Alexandre Belloni
<[email protected]> wrote:
>
> The broken down time conversion is similar to what is done
> in the time subsystem since v5.14.
By "similar" you mean "identical", no?
Why is the rtc subsystem not just using the generic time64_to_tm()?
Yes, yes, I realize that due to historical mistakes, there's a
duplicate 'struct rtc_time' struct, but it turns out that that is
_identical_ to 'struct tm' except it also has a 'int tm_isdst' at the
end.
So you could literally make a union of the two, pass the 'struct tm'
part down to the generic code, and just do
rtc_tm->tm_isdst = 0;
at the end.
Rather than have a duplicate copy of that admittedly clever Neri and
Schneider algorithm.
Hmm?
Linus
The pull request you sent on Sat, 11 Sep 2021 17:59:18 +0200:
> git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git tags/rtc-5.15
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/107ccc45bb25c7fdc7a744496caa4d8a52af4812
Thank you!
--
Deet-doot-dot, I am a bot.
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On 11/09/2021 10:05:02-0700, Linus Torvalds wrote:
> On Sat, Sep 11, 2021 at 8:59 AM Alexandre Belloni
> <[email protected]> wrote:
> >
> > The broken down time conversion is similar to what is done
> > in the time subsystem since v5.14.
>
> By "similar" you mean "identical", no?
>
> Why is the rtc subsystem not just using the generic time64_to_tm()?
>
> Yes, yes, I realize that due to historical mistakes, there's a
> duplicate 'struct rtc_time' struct, but it turns out that that is
> _identical_ to 'struct tm' except it also has a 'int tm_isdst' at the
> end.
>
> So you could literally make a union of the two, pass the 'struct tm'
> part down to the generic code, and just do
>
> rtc_tm->tm_isdst = 0;
>
> at the end.
>
> Rather than have a duplicate copy of that admittedly clever Neri and
> Schneider algorithm.
>
> Hmm?
>
Yes, most of it is historical, I did have a look at removing the copy
but at the time, rtc_time64_to_tm was slightly more efficient because
it knew the time was positive.
The other issue is that struct rtc_time is exposed to userspace while
the kernel struct tm is not and this would tie both struct and if you
look close enough, struct tm has long tm_year and struct rtc_time has
int tm_year which on 32-bit ARM has a different size.
I've been reluctant to change struct tm because I didn't take the time
to check the impact on all the users (IIRC, mainly in filesystems).
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com