Messages in this thread | | | From | Sebastian Krzyszkowiak <> | Subject | Re: [PATCH 1/2] power: supply: max17042_battery: Clear status bits in interrupt handler | Date | Mon, 13 Sep 2021 20:32:52 +0200 |
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On poniedziałek, 13 września 2021 15:02:34 CEST Krzysztof Kozlowski wrote: > On 12/09/2021 22:54, Sebastian Krzyszkowiak wrote: > > The gauge requires us to clear the status bits manually for some alerts > > to be properly dismissed. Previously the IRQ was configured to react only > > on falling edge, which wasn't technically correct (the ALRT line is active > > low), but it had a happy side-effect of preventing interrupt storms > > on uncleared alerts from happening. > > > > Fixes: 7fbf6b731bca ("power: supply: max17042: Do not enforce (incorrect) > > interrupt trigger type") Cc: <stable@vger.kernel.org> > > Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm> > > --- > > > > drivers/power/supply/max17042_battery.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/power/supply/max17042_battery.c > > b/drivers/power/supply/max17042_battery.c index > > 8dffae76b6a3..c53980c8432a 100644 > > --- a/drivers/power/supply/max17042_battery.c > > +++ b/drivers/power/supply/max17042_battery.c > > @@ -876,6 +876,9 @@ static irqreturn_t max17042_thread_handler(int id, > > void *dev)> > > max17042_set_soc_threshold(chip, 1); > > > > } > > > > + regmap_clear_bits(chip->regmap, MAX17042_STATUS, > > + 0xFFFF & ~(STATUS_POR_BIT | STATUS_BST_BIT)); > > + > > Are you sure that this was the reason of interrupt storm? Not incorrect > SoC value (read from register for ModelGauge m3 while not configuring > fuel gauge model).
Yes, I am sure. I have observed this on a fully configured max17055 with ModelGauge m5. It also makes sense to me based on what I read in the code and datasheets.
There were two kinds of storms - the short ones happening on each SOC change caused by SOC threshold alerts set by max17042_set_soc_threshold which eventually got cleared by reconfiguring the thresholds; and a huge one happening when SOC got down to 0% that did not get away until the battery got charged to at least 1% at which point the thresholds got reconfigured again (which is how I noticed the underflow fixed by the second patch).
Besides, I also have patches for configuring m5 gauge via DT that I'll send once I clean them up.
> You should only clear bits which you are awaken for... Have in mind that > in DT-configuration the fuel gauge is most likely broken by missing > configuration. With alert enabled, several other config fields should be > cleared.
I have checked all the bits in the Status register and aside of Bst, POR and bunch of "don't-care" bits they're all alert indicators that we either handle explicitly in the interrupt handler (Smn/Smx) or implicitly via power_supply_changed (Imn/Imx, Vmn/Vmx, Tmn/Tmx, dSOCi, Bi/Br). The driver unconditionally enables alerts for SOC thresholds and all the rest stays effectively disabled at POR; however, a bootloader or firmware may configure it differently, which may be wanted for things like resuming from suspend when a bad condition happens. Therefore we need to clear all the bits anyway and I'm not sure whether iterating through them in a "if set then clear" loop gains us anything aside of additional lines of code.
> Best regards, > Krzysztof
Cheers, Sebastian[unhandled content-type:application/pgp-signature] | |