Messages in this thread | | | Subject | Re: Zaurus suspend saga | From | Stanislav Brabec <> | Date | Mon, 07 Sep 2009 15:10:25 +0200 |
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Pavel Machek wrote: > > > Sadly lack of time means I've lost track of the Zaurus kernels but this > > sounds like all accesses to the SSP buses now go through the SPI layer > > and when it was converted nobody thought about the impact this would > > have on the Zaurus charger code. > >Unfortunately... Do you have any idea when this conversion took place?
In past, MAX1111 driver was embedded in the Zaurus specific code. Now MAX1111 is a generic SPI driver and spitz_pm.c calls it.
Maybe it will still work with CONFIG_CORGI_SSP_DEPRECATED.
> > c) We rip the whole thing out and stop supporting "offline" charging. > > How much faster is offline charge, compared to online charging? I have > impression that online charging basically does not charge anything...
I think that online charging works, but it seems to be slower. I am not sure, whether it is a hardware or software issue. You can control charging speed by software, but the final word has the charging chip.
Here are control wires: SPITZ_SCP_JK_A: output = turns dummy load to 1 kOhm resistor SPITZ_SCP_JK_B: output = high charging current SPITZ_SCP_CHRG_ON: output = charging on SPITZ_SCP_ADC_TEMP_ON: output = turns battery sensor on/off SPITZ_GPIO_CHRG_FULL input = charging complete SPITZ_GPIO_AC_IN input = AC adapter is present
MAX1111 inputs: MAX1111_ACIN_VOLT: Voltage in AC input (after pass of input circuit, before tha final diode) MAX1111_BATT_TEMP: Battery temperature sensor MAX1111_BATT_VOLT: Battery voltage
Here are notes from the design: Pre-charge = 102mA Fast charge = 680mA Fast charge set ON = 105mA Iterm = 55mA
Thresholds: SPITZ_GPIO_AC_IN: 4.2V (IC charging circuit) SPITZ_GPIO_FATAL_BAT: 3.0V (voltage detector IC on battery) PXA270 batt fault: 2.8V (voltage on the main non-regulated power) CF/SD: 2.8V (voltage required for CF/SD activation, I am not sure, why it is done, because 2.8V is outside of spec anyway)
When I measured my battery, Linux 2.6.26 went to emergency sleep at 3.4V.
Note that battery thresholds probably should not be hardwired in spitz_pm.c but read from the NAND configuration instead (Andrea Adami knows, how it can be done).
Here is the datasheet of the charging circuit: http://www.penguin.cz/~utx/zaurus/datasheets/power/charging/sc801.pdf
There were more problems in the charging code even before:
- The measurement code should work without turning LED on (bootloader can do it). SPITZ_SCP_JK_A should connect dummy load. I guess it should be enough for measurement. But comments in the source tree say that is did not work. I am not sure why.
- It would be nice to have "small travel charger heuristic": Turn fast charging on, charger "disappears", switch to slow charging, charger "appears" => stay in slow charging mode, and retry after some time, or after going to suspend, reset the flag when charger is removed.
- sysfs interface for charging would be nice. For example: Cyril has an external battery pack and he wants to disable charging of internal battery from the external battery.
-- Best Regards / S pozdravem,
Stanislav Brabec software developer --------------------------------------------------------------------- SUSE LINUX, s. r. o. e-mail: sbrabec@suse.cz Lihovarská 1060/12 tel: +420 284 028 966, +49 911 740538747 190 00 Praha 9 fax: +420 284 028 951 Czech Republic http://www.suse.cz/
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