GTA02 charging with 1000mA using wall-outlet charger

[laforge@…]

by using the ADC of the PCF50633, we can detect if the 48kOhms resistor in our
wall-outlet power supply is present. If we detect this case, we can allow
1000mA charge current (fast charge)

[mickey@…]

Awesome news!

[willie_chen@…]

done

[laforge@…]

Please don't close the but unless the code has ended up in our kernel patchset
and is available in the builds from buildhost.

[andy@…]

What is the status of this functionality wrt "our kernel patchset", did it
make it in okay?

[willie_chen@…]

Now it can be divided three cases here

• USB Device Mode : R > 100k
  • charging with 100mA
• USB Host Mode: R < 10
  • no charging
• Charger Mode: R = 48k 1%
  • charging with 1000mA

[laforge@…]

Please show me the code. Where and how are those cases differentiated? when was
the patch sent to the openmoko-kernel list? Or is it attached to bugzilla?

[msmakela@…]

Is it possible to charge the GTA02 when it is in host mode? I'd like to use the
OpenMoko? as a fancy data logger for my bicycle, and the dynamo hub could easily
provide at least 580 mA. It'd be much simpler to implement USB HID in the
sensor/charger circuit than a full USB host.

Could the charging current perhaps be overridden from the user space?
Furthermore, would the 1000 mA mode adjust to a smaller charge current when the
input voltage drops?

[msmakela@…]

Is there any update on this bug? Will the GTA02 follow the OMTP spec for
charging that may have been available at
<​http://www.omtp.org/docs/OMTP_Local_Data_Connectivity_v1_0.pdf> but I sadly
have not come across?

The Battery Charging Specification of the USB Implementers Forum
<​http://www.usb.org/developers/devclass_docs/batt_charging_1_0.zip>
does not mention any 48k resistor as in the bug description. Instead, it says
that dedicated chargers must identify themselves by shorting D+ and D- with at
most 200 ohms resistance. Unfortunately for me, this means that the only USB
port on the GTA02 can't be used for charging and talking to a USB device at the
same time. I hope you can implement some user-space hook that makes the GTA02
believe that an attached USB device (not host) also is a dedicated charger.

[msmakela@…]

The "OMTP Local Data Connectivity" specification appears to be available here:
<​http://www.omtp.org/recommendations_papers/publications_local_connect.html>,
<​http://www.omtp.org/pdf/OMTP_Local_Data_Connectivity_v1_0.pdf>. It refers to
the Battery Charging Specification of the USB Implementers Forum
<​http://www.usb.org/developers/devclass_docs/batt_charging_1_0.zip> that I
mentioned in my previous comment.

[andy]

This is solved for some time in kernel and U-Boot (badly, you have to have it in there already when you start up) and charges at 1A limit by detecting ID resistor. Closing as fixed.