Part Number: BEAGLEBK
Tool/software: Linux
Hello,
I am using Beaglebone which has the TPS65217 PMIC and using it's battery charging capability. AC power is used and battery is charging correctly. From my reading of Section 8 of the datasheet, I expected the switch between AC and battery power to work without any special setting.
I checked the SYS_5V pin coming on the expansion header of Beaglebone on Pin 7/8. It shows 5V when connected to AC and 4.1V when connected to battery. The Beaglebone powers off somehow when I shut off AC power. Perhaps it receives a power down signal.
The hardware I have connected on the expansion header basically has two CAN transceivers, IO expander and is what provides me the provision for connecting the battery and NTC to those battery access points. I am using 4.4.110 kernel on Beaglebone.
I have modified the device tree node for tps and removed the "ti,pmic-shutdown-controller" and added the property "ti,system-power-controller" to the rtc node which is the omap RTC. Looking at the dmesg logs, I see "PM: bootloader does not support rtc-only". This seems to come from pm33xx.c in drivers/soc/ti since the check for boot magic value fails. The boot magic value is not written to the RTC scratch pad area since it seems the call to pm_ops->check_off_mode_enable fails which seems to be actually a call to am33xx_check_off_enable in arch/arm/mach-omaps2/pm33xx-core.c and which always returns 0.
I also had raised a query in TPS65217 forum but it seems the problem is not with TPS65217 but with the Beaglebone. I also saw the below two Linux kernel mailing lists discussion.
https://www.spinics.net/lists/linux-omap/msg118585.html
https://www.spinics.net/lists/linux-omap/msg118615.html
Can someone help me on how to have dynamic switching between AC/USB and battery power on Beaglebone and what else other than the above has to be done in Linux to enable this?
Thanks & Regards,
Sanchayan Maity.
