On 26/04/2016 at 16:31:46 +0200, Jeppe Ledet-Pedersen wrote : > > Good catch, I didn't look at this patch but it includes a lot of code > > that should be going to the RTC driver. > > If trickle charging is not enabled, I guess the RTC will not charge its > > backup battery. > > Thank you for the comments. > > Alexandre is correct. If the "cypress,charge-enabled" property is > present, the internal 80 uA trickle charger is enabled to charge a > backup capacitor on the VBAK pin. > > Do you want more code than the trickle charger setup moved to the RTC > driver? > I guess the 32k oscillator could go in the rtc driver too. > >>> +- cypress,charge-fast: enable fast (1 mA) charging > >> > >> What does fast mean? > >> > > Fast charging means charging with 1 mA instead of 80 uA. The wording is > from the datasheet, but I agree it should be renamed to something that > better explains what the difference is. > > >> I think it is time for a common binding here. There's all sorts of > >> variations on setting the charge current in bindings. Add something like > >> "charge-current-microamp" in power_supply.txt and use it here. Then > >> 1000uA implies "fast charge". > > > > Well, this is not a power supply, it is an RTC. > > > > I think both properties should got to the RTC subdevice and be parsed in > > the RTC driver. > > The backup capacitor is primarily used to supply current to the RTC, but > a couple of other registers are also battery-backed (watchdog reset > cause, event counter), so I put the charger setup in the main MFD file. > > If you prefer, I can move them both to the RTC driver? I would prefer unless you think that many people are not using the RTC while still using the watchdog (I'd say that is not the case). > > > Note that for trickle charging, we currently have the following > > properties: > > - trickle-resistor-ohms > > - trickle-diode-disable > > - abracon,tc-diode > > - abracon,tc-resistor > > > > abracon,tc-resistor can be replaced by trickle-resistor-ohms, I'll make > > a patch but abracon,tc-diode allows to select a diode type (and in > > particular a voltage drop). > > > > I think we could add a trickle-current-microamp like you suggested and > > trickle-diode-disable can be reused. > > So replace "cypress,charge-enabled/charge-fast" with > "trickle-current-microamp" and a check for 0/80/1000 uA? > Yeah, seems fine. -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
