From: Alexandre Ghiti <alexandre.ghiti@canonical.com>
To: David Abdurachmanov <david.abdurachmanov@gmail.com>
Cc: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>,
Support Opensource <Support.Opensource@diasemi.com>,
Lee Jones <lee.jones@linaro.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drivers: mfd: da9063: Add restart notifier implementation
Date: Thu, 30 Sep 2021 12:25:22 +0200 [thread overview]
Message-ID: <CA+zEjCtQN6c8bikg620PQwoPzJ6T4wGLvzQ413iPs1tCeHif0Q@mail.gmail.com> (raw)
In-Reply-To: <CAEn-LTqVd8z=kpCtWjiPbKuw24NuHLTQxWzw7g34fEJgDYrp8w@mail.gmail.com>
Hi David,
On Thu, Sep 30, 2021 at 9:51 AM David Abdurachmanov
<david.abdurachmanov@gmail.com> wrote:
>
> On Wed, Sep 29, 2021 at 4:36 PM Adam Thomson
> <Adam.Thomson.Opensource@diasemi.com> wrote:
> >
> > On 24 September 2021 17:17, Alexandre Ghiti wrote:
> >
> > > > > +static int da9063_restart_notify(struct notifier_block *this,
> > > > > + unsigned long mode, void *cmd)
> > > > > +{
> > > > > + struct da9063 *da9063 = container_of(this, struct da9063,
> > > > > restart_handler);
> > > > > +
> > > > > + regmap_write(da9063->regmap, DA9063_REG_PAGE_CON, 0x00);
> > > > > + regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 0x04);
> > > > > + regmap_write(da9063->regmap, DA9063_REG_CONTROL_A, 0x68);
> > > > > +
> > > > > + return NOTIFY_DONE;
> > > > > +}
> > > >
> > > > I will talk with our HW team to clarify, but this sequence looks to be very
> > > > specific to the needs of the platform in question which doesn't feel right to
> > > > me. As was mentioned on another thread as well, the watchdog driver already
> > > has
> > > > a restart function to reset the device (and thus the system), so I don't believe
> > > > we should have multiple of these.
> > >
> > > From the discussion that happened here
> > > https://www.dialog-semiconductor.com/products/pmics?post_id=10052#tab-
> > > support_tab_content,
> > > it does not seem possible to use the watchdog on a chip whose OTP does
> > > not set AUTOBOOT. But anyway, I'm looking forward to hearing from the
> > > HW team :)
> >
> > So I've discussed this internally and so far it's not completely clear how the
> > sequence you provided actually performs the reset as you suggest. It certainly
> > doesn't look like it should, so maybe this relates to an external pin somehow
> > triggering the restart in this particular scenario? I'd be interested to
> > understand which event bits are set when the board does restart to understand
> > what did actually trigger the boot-up.
> >
> > Regardless of this though, the consensus right now would be to use the RTC as a
> > wake event to restart the platform. An alarm can be set for a couple of seconds
> > into the future (or longer if required) and that would provide the event
> > required to come up from powerdown/shutdown, in the absence of AUTOBOOT being
> > set in OTP. I believe this would be the safest route to take in this case. You
> > can then just use the SHUTDOWN bit on CONTROL_F to take down the board.
>
> Today I was looking into OpenBSD DA9063 drivers and they might be
> doing what you described for the reset.
>
> dev/fdt/dapmic.c
>
> [..]
> 241 void
> 242 dapmic_reset(void)
> 243 {
> 244 struct dapmic_softc *sc = dapmic_cd.cd_devs[0];
> 245 uint8_t reg;
> 246
> 247 /* Enable tick alarm wakeup with a one second interval. */
> 248 reg = dapmic_reg_read(sc, ALARM_MO);
> 249 reg &= ~ALARM_MO_TICK_TYPE;
> 250 reg |= ALARM_MO_TICK_WAKE;
> 251 dapmic_reg_write(sc, ALARM_MO, reg);
> 252
> 253 /* Enable tick function. */
> 254 reg = dapmic_reg_read(sc, ALARM_Y);
> 255 reg |= ALARM_Y_TICK_ON;
> 256 dapmic_reg_write(sc, ALARM_Y, reg);
> 257
> 258 /* Clear events such that we wake up again. */
> 259 dapmic_reg_write(sc, EVENT_A, dapmic_reg_read(sc, EVENT_A));
> 260 dapmic_reg_write(sc, CONTROL_F, CONTROL_F_SHUTDOWN);
> 261 }
> [..]
>
Thanks for the pointer! I have just tested this sequence from the
u-boot shell, it resets the board correctly. But then if we try to
power down the board by a long press to the corresponding button on
the board within 16 seconds, it resets the board: so we cannot
shutdown the board in the next 16 seconds that follow this sequence.
Maybe that can be resolved by using the one-shot alarm as described by
Adam, I'll try to find that in the datasheet.
Thanks
Alex
> >
> > To reiterate, I believe this should be made a board specific quirk, rather than
> > as part of the generic MFD core of DA9063, as the timings may vary for other
> > platforms.
>
> Agree. Currently it seems Linux drivers expect DA9063 boards to have
> AUTOBOOT ON set in OTP, which is not the case for SiFive Unmatched
> (thus issues with reset and WDT).
>
> david
>
> > _______________________________________________
> > linux-riscv mailing list
> > linux-riscv@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2021-09-30 10:25 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-21 5:33 [PATCH] drivers: mfd: da9063: Add restart notifier implementation Alexandre Ghiti
2021-09-21 10:16 ` Anup Patel
2021-09-21 11:20 ` Alexandre Ghiti
2021-09-21 10:25 ` Ben Dooks
2021-09-21 11:33 ` Alexandre Ghiti
2021-09-23 13:16 ` Alexandre Ghiti
2021-09-24 15:04 ` Adam Thomson
2021-09-24 16:17 ` Alexandre Ghiti
2021-09-29 13:33 ` Adam Thomson
2021-09-30 7:51 ` David Abdurachmanov
2021-09-30 9:28 ` Adam Thomson
2021-09-30 10:25 ` Alexandre Ghiti [this message]
2021-10-04 12:05 ` Alexandre Ghiti
2021-10-04 15:11 ` Adam Thomson
2021-10-05 13:43 ` Alexandre Ghiti
2021-10-06 9:30 ` Adam Thomson
2021-10-06 11:35 ` Alexandre Ghiti
2021-10-08 9:46 ` Adam Thomson
2021-10-12 10:32 ` Adam Thomson
2021-10-14 15:51 ` Alexandre Ghiti
2021-10-15 8:47 ` Adam Thomson
2021-09-30 9:37 ` Alexandre Ghiti
2021-09-30 10:47 ` Adam Thomson
2021-09-30 9:55 ` Alexandre Ghiti
2021-10-04 15:29 ` Adam Thomson
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