We are using imx6 interfaced EC25, LTE module over usb, our observation is that on certain boards device stucks when reboot is issued after shutdown gets processed, we have also checked that reboot trigger gets asserted as expected but imx6 does not reboot, but when we remove power to EC25, able to reset device using switch otherwise reset switch does not work, I would like to know shutdown sequence of EC25, what would cause EC25 not allowing host to reboot, whether its usb or something else, help would be appreciated.
Btw, you cannot shutdown the IMX6 with the EC25 connected?
Thanks for reply, I am able to shutdown but when I issue reboot command device does complete shutdown/reboot process, but does not reboot again it stucks need power cycle to boot it again.
I did probed reset triggered from IMX (POR_B), which looks fine,
Another observation is that reset from u-boot works just fine, which does not trigger watchdog external reset.
But to probe problem in reboot command from linux console, when reboot is issued from linux console it stucks, when probed pmic chip triggers reset as expected, so looks fine. yet device doesn’t get reboot, if you could provide more information about shutdown sequence that needs to follow for grace full shutdown that would help. In u-boot doesn’t configures lte chip, so looking into lte chip shutdown.
Another point is that this issue does not appear on all device, observed on few devices, on such devices reboot from u-boot works fine and if ec25 module is removed from device reboot from linux which was not working now works fine on that device as well.
Whether it is related to the driving ability of PMIC of imx？