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Ipod classic: disabling charging doesn't work

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torne:

--- Quote from: momom on January 09, 2012, 04:02:22 AM ---you are, of course, right :-) As said it is a problem mainly with older VIA chipsets and frankly, who cares? My desktop is 8 years old, its time for a change :-)

--- End quote ---
Well, if the problem is that it's drawing 500mA when you don't want it to, then that's not "who cares", that's "the power management logic for the Classic is missing a feature we should support". If the Classic supports USB charging power control then it should work, and if not then it shouldn't be offering the option.

dreamlayers:
Currently, the current limit is set using "GPIOCMD = 0xb060e | (on ? 1 : 0);" in usb_charging_maxcurrent_change() in firmware/target/arm/s5l8702/ipod6g/power-ipod6g.c.  Maybe it's instead necessary to use the usbdevstat bits in the MBCC7 register in the PCF50633 PMU? They're documented on page 79 of that PDF.

prof_wolfff:
Hi!, i did some tests while developing the usb_charger_detect patch for Classic, have some conclusions, not 100% sure as usual:

Charge management is done by external LTC4066 IC instead of PMU, but dont know how the power paths are routed exactly. I think (not yet verified) OF zeroes registers 0x43..0x49, anyways it doesn't matter if the charge management is enabled or disabled on PMU, the battery is always charged in the same way, seems that writing to those registers has no effect, in addition status regs (0x4b..0x4d) are not being updated while the whole charge is in progress.

I also figure USB Vbus is only connected to PMU by EXTON2 pin because cannot observe coherent activity on other (documented) registers when plugging/unplugging USB.

If i am right, 100mA/500mA current selection could be done using HPWR pin on LTC4066, the GPIOCMD register is undocumented for me but i suppose it is connected to this pin, not tested yet but will check on the next battery charge cycle, its supposed @100mA charging should take more time.

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