Re: [PATCH v4 4/4] drivers/rtc/rtc-s5m.c: add support for S2MPS15 RTC

[Alim Akhtar]

On 10/29/2015 04:33 PM, Krzysztof Kozlowski wrote:
> 2015-10-29 16:47 GMT+09:00 Alim Akhtar <alim.akhtar@xxxxxxxxxxx>:
> > Hello Krzysztof,
> >
> >
> > On 10/29/2015 11:24 AM, Krzysztof Kozlowski wrote:
> > > On 29.10.2015 13:58, Alim Akhtar wrote:
> > > > RTC found in s2mps15 is almost same as one found on s2mps14/13
> > > > with few differences in RTC_UPDATE register fields, like
> > > > bit fields are changed for WUDR and AUDR.
> > > > This patch add required changes to enable s2mps15 rtc timer.
> > > >
> > > > Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
> > > > Signed-off-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx>
> > > > ---
> > > >    drivers/rtc/rtc-s5m.c           |   20 ++++++++++++++++++--
> > > >    include/linux/mfd/samsung/rtc.h |    4 ++++
> > > >    2 files changed, 22 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/rtc/rtc-s5m.c b/drivers/rtc/rtc-s5m.c
> > > > index f2504b4eef34..0d106a99958f 100644
> > > > --- a/drivers/rtc/rtc-s5m.c
> > > > +++ b/drivers/rtc/rtc-s5m.c
> > > > @@ -188,6 +188,7 @@ static inline int
> > > > s5m_check_peding_alarm_interrupt(struct s5m_rtc_info *info,
> > > >                  ret = regmap_read(info->regmap, S5M_RTC_STATUS, &val);
> > > >                  val &= S5M_ALARM0_STATUS;
> > > >                  break;
> > > > +       case S2MPS15X:
> > > >          case S2MPS14X:
> > > >          case S2MPS13X:
> > > >                  ret = regmap_read(info->s5m87xx->regmap_pmic,
> > > > S2MPS14_REG_ST2,
> > > > @@ -223,6 +224,9 @@ static inline int s5m8767_rtc_set_time_reg(struct
> > > > s5m_rtc_info *info)
> > > >          if (info->device_type == S5M8763X || info->device_type ==
> > > > S5M8767X)
> > > >                  data |= S5M_RTC_TIME_EN_MASK;
> > > >
> > > > +       if (info->device_type == S2MPS15X)
> > > > +               data |= S2MPS15_RTC_WUDR_MASK;
> > > > +
> > >
> > >
> > >
> > > You are setting here bit 1 and bit 4. However vendor code sets only bit
> > > 4 (called WUDR there). That's confusing. Why the difference? Or maybe I
> > > am looking at wrong vendor tree (SM-G920F)?
> > Sorry, I don't have access to vendor code that you are looking into, so
> > won't be able to comment on that.
>
> Everyone have the access. It is on opensource.samsung.com, as required by GPL.
Ok, I didn't check there.
> > I am testing this patch before sending them, what I have found is if you
> > don't update WUDR the time does not changes in rtc.
> > e.g.
> > if you don't do above changes then you will see below:
> > -----
> > # date --set="Oct 29 14:10:40 2015" <update the a new date>
> > Thu Oct 29 14:10:40 UTC 2015
> > #
> > # hwclock --systohc <copy system clock to hardware clock/rtc>
> > # hwclock <read back hwclock>
> > Thu Oct 29 12:52:32 2015  .922889 seconds
> > ----
> > which is not excepted.
> >
> > And with the above change I see:
> >
> > ----
> >   # date --set="Oct 29 14:30:10 2015" <update the a new date>
> > Thu Oct 29 14:30:10 UTC 2015
> > # date
> > Thu Oct 29 14:30:12 UTC 2015
> > # hwclock --systohc <copy system clock to hardware clock/rtc>
> > # hwclock <read back hwclock>
> > Thu Oct 29 14:30:21 2015  .333006 seconds
> > ----
> >
> > Which is as expected.
>
> Okay, but I said that vendor is setting only WUDR which is bit 4. You
bit:4 is AUDR (for alarm). not WUDR and bit: 1 is WDUR(for timer)
> are setting bit 1 and bit 4. Your reply - about the need of setting
> WUDR (bit 4 I guess) - does not explain my concerns. Do you have to
> set bit 1?
Yes, I think we need to set both for timer and alarm.
I have send you a snapshot of the rtc_update register in UM via internal 
email. PTAL.
> > > >          ret = regmap_write(info->regmap, info->regs->rtc_udr_update,
> > > > data);
> > > >          if (ret < 0) {
> > > >                  dev_err(info->dev, "failed to write update reg(%d)\n",
> > > > ret);
> > > > @@ -252,6 +256,9 @@ static inline int s5m8767_rtc_set_alarm_reg(struct
> > > > s5m_rtc_info *info)
> > > >          case S5M8767X:
> > > >                  data &= ~S5M_RTC_TIME_EN_MASK;
> > > >                  break;
> > > > +       case S2MPS15X:
> > > > +               data |= S2MPS15_RTC_AUDR_MASK;
> > > > +               break;
> > > >          case S2MPS14X:
> > > >                  data |= S2MPS_RTC_RUDR_MASK;
> > > >                  break;
> > >
> > >
> > > Another difference: you are setting here exactly the same values as
> > > S2MPS13 - bit 1 and bit 4. However vendor code sets only bit 4 (called
> > > WUDR there)?
> > No they are not, AUDR on s2mps13 is bit:1 where as it is bit:4 on s2mps15.
> > > What exactly is necessary to update alarm and time registers on S2MPS15?
> > As explained above in example, it is required to update the 'write alarm
> > buffer(AUDR)' and 'write time buffer(WUDR)' bits in-order to get rtc
> > working.
>
> For updating time and alarm registers? Or only for updating alarm registers?
example was only for the timer register.

> Best regards,
> Krzysztof
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