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From: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
To: David Abdurachmanov <david.abdurachmanov@gmail.com>,
	Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Cc: Alexandre Ghiti <alexandre.ghiti@canonical.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 09:28:37 +0000	[thread overview]
Message-ID: <DB9PR10MB4652444644C8ECF3C729A8C680AA9@DB9PR10MB4652.EURPRD10.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <CAEn-LTqVd8z=kpCtWjiPbKuw24NuHLTQxWzw7g34fEJgDYrp8w@mail.gmail.com>

On 30 September 2021 08:51, David Abdurachmanov wrote:

> > 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 }
> [..]

This is using the tick alarm which is repeating. That is one option or
alternatively there's a one-shot alarm option which can be used which might be
preferable as you won't see continues events from the RTC when the system boots
up again.

  reply	other threads:[~2021-09-30  9:28 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-21  5:33 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 [this message]
2021-09-30 10:25         ` Alexandre Ghiti
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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