Re: Regarding backporting RTC PCF85263 driver to cip 4.4 kernel


Nobuhiro Iwamatsu
 

Hi,

-----Original Message-----
From: cip-dev-bounces@...
[mailto:cip-dev-bounces@...] On Behalf Of Pavel
Machek
Sent: Monday, July 15, 2019 6:46 AM
To: Biju Das <biju.das@...>
Cc: Christopher Feghali <christopher.feghali.xb@...>;
cip-dev@...
Subject: Re: [cip-dev] Regarding backporting RTC PCF85263 driver to cip
4.4 kernel

Hi!

RTC PCF85263 is used by iWave RZ/G1C SBC( iwg23s) platform. We have
upstreamed this driver support on 4.19 kernel [1] [1].
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/c
om
mit/drivers/rtc/rtc-pcf85363.c?h=v5.2&id=fc979933bcf162595b6004d0de4
ef
fb64c323152

This driver is based on RTC PCF 85363 driver which has rtc
nvmem/alarm support [2] . Rtc nvmem framework is introduced in 4.13
[2].
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/c
om
mit/drivers/rtc/rtc-pcf85363.c?h=v5.2&id=a9687aa2764dd2669602bd19dc6
36
cbeef5293d5

We are seeing the following options for backporting this driver to
4.4 kernel
First, you did a lot of work there...

Option 1:
Backport this driver[1] to 4.4 kernel along with nvmem/alarm support.
we have already done this work and patches are available at [3] [3].
https://gitlab.com/bijud/pcf85263/tree/master
Ok, this is rather long/big series, and some parts are quite scary:
https://gitlab.com/bijud/pcf85263/blob/master/0013-rtc-nvmem-allow-r
egistering-the-nvmem-device-before-.patch

Option 2:
Backport RTC PCF85263 driver, removing Alarm/nvmem functionality from
[2] .
So we basically get this one, and few patches on top, local to the new
files.
https://gitlab.com/bijud/pcf85263/blob/master/0015-rtc-add-support-f
or-NXP-PCF85363-real-time-clock.patch

I think I prefer option 2.

Option 3:
Don't backport RTC support at all.
Applying patch #15 is easy. We can do option 2 I believe.
I think that option 2 is good.

Best regards,
Nobuhiro

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