I got a powered USB 2.0 hub (ET-UP900). As power source I am using the phones charger. But if I connect the hub with my phone (SM-C115) it does not charge. If I connect the charger directly it works.
My first thought was the hub does not provide enough power. But if I do the same thing with a tablet (SM-P905), which requires more power, it does work.
Also strange: If the hub is powered it does not work. If the hub is not powered it works just fine.
As I am using a custom build kernel I am looking a dmesg and fiddling with kernel options and driver to find the correct setting.
Maybe someone can give me a hint what might work?
Alternative: Any cable I can plugin in between to charge the phone and use the USB hub? I got a OTG charging cable but it would power the USB hub instead of the phone.
I found something about a special cable with a resistor to get into a special AUDIODOCK mode. I did found this AUDIODOCK in the source code of a related driver I saw in dmesg
drivers/misc/max77803-muic.c. Maybe I can change the driver to force this mode all the time or something like this...
drivers/misc/max77803-muic.c I saw the CONFIG_MUIC_MAX77803_SUPPORT_OTG_AUDIO_DOCK option needs to be set and the driver I got here does not support this anyway. I guess I try to use a updated driver. With AUDIO_DOCK support implemented.