26.05.2020 18:01, Michał Mirosław пишет: > On Sun, May 24, 2020 at 10:26:43PM +0300, Dmitry Osipenko wrote: >> This patch fixes system shutdown on a devices that use TPS65910 as a >> system's power controller. In accordance to the TPS65910 datasheet, the >> PMIC's state-machine transitions into the OFF state only when DEV_OFF >> bit of DEVCTRL_REG is set. The ON / SLEEP states also should be cleared, >> otherwise PMIC won't get into a proper state on shutdown. Devices like >> Nexus 7 tablet and Ouya game console are now shutting down properly. > > The datasheets of 65910 and 65911 say that ON and SLP bits are cleared > during OFF state. But I guess the hardware might work differently. Indeed, sounds like we can remove the SLP bit-clearing safely. IIUC, both tps65910 and tps65911 are nearly the same in regards to the power-off programming, tps65911 only supports an additional (sequential) power-off mode. I'm not sure whether we've tried to remove the SLP bit-clearing before, will be interesting to try. > [...] >> --- a/drivers/mfd/tps65910.c >> +++ b/drivers/mfd/tps65910.c >> @@ -440,8 +440,13 @@ static void tps65910_power_off(void) >> DEVCTRL_PWR_OFF_MASK) < 0) >> return; >> >> - tps65910_reg_clear_bits(tps65910, TPS65910_DEVCTRL, >> - DEVCTRL_DEV_ON_MASK); >> + if (tps65910_reg_clear_bits(tps65910, TPS65910_DEVCTRL, >> + DEVCTRL_DEV_SLP_MASK) < 0) >> + return; >> + >> + tps65910_reg_update_bits(tps65910, TPS65910_DEVCTRL, >> + DEVCTRL_DEV_OFF_MASK | DEVCTRL_DEV_ON_MASK, >> + DEVCTRL_DEV_OFF_MASK); >> } > > There is tps65910_reg_set_bits() at the start of function. I guess it > doesn't work if your changes are needed. Maybe you can remove it? It enables the "sequential power-off, reverse of power-on sequence", like datasheet says. I think it works and we actually need that PWR_OFF bit to be set separately, before setting the DEV_OFF bit. > I would also include your observations about the chip's behaviour in the > commit message so it doesn't get "fixed" later. I'll add a clarifying comment about it in v3, thank you for the suggestions.
