Messages in this thread | | | From | David Abdurachmanov <> | Date | Thu, 30 Sep 2021 10:51:14 +0300 | Subject | Re: [PATCH] drivers: mfd: da9063: Add restart notifier implementation |
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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 } [..]
> > 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
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