lkml.org 
[lkml]   [2019]   [Aug]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [v2] rtc: pcf85363/pcf85263: fix error that failed to run hwclock -w
On Fri, Aug 16, 2019 at 11:30 AM Alexandre Belloni
<alexandre.belloni@bootlin.com> wrote:
>
> On 16/08/2019 10:50:49-0500, Li Yang wrote:
> > On Fri, Aug 16, 2019 at 3:05 AM Alexandre Belloni
> > <alexandre.belloni@bootlin.com> wrote:
> > >
> > > On 16/08/2019 10:46:36+0800, Biwen Li wrote:
> > > > Issue:
> > > > - # hwclock -w
> > > > hwclock: RTC_SET_TIME: Invalid argument
> > > >
> > > > Why:
> > > > - Relative patch: https://lkml.org/lkml/2019/4/3/55 , this patch
> > > > will always check for unwritable registers, it will compare reg
> > > > with max_register in regmap_writeable.
> > > >
> > > > - In drivers/rtc/rtc-pcf85363.c, CTRL_STOP_EN is 0x2e, but DT_100THS
> > > > is 0, max_regiter is 0x2f, then reg will be equal to 0x30,
> > > > '0x30 < 0x2f' is false,so regmap_writeable will return false.
> > > >
> > > > - Root cause: the buf[] was written to a wrong place in the file
> > > > drivers/rtc/rtc-pcf85363.c
> > > >
> > >
> > > This is not true, the RTC wraps the register accesses properly and this
> >
> > This performance hack probably deserve some explanation in the code comment. :)
> >
> > > is probably something that should be handled by regmap_writable.
> >
> > The address wrapping is specific to this RTC chip. Is it also
> > commonly used by other I2C devices? I'm not sure if regmap_writable
> > should handle the wrapping case if it is too special.
> >
>
> Most of the i2c RTCs do address wrapping which is sometimes the only way
> to properly set the time.

Adding Mark and Nandor to the loop.

Regards,
Leo

\
 
 \ /
  Last update: 2019-08-16 21:45    [W:0.106 / U:2.600 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site