Tim Chen has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/48195 )
Change subject: mb/google/dedede/var/metaknight: Add LTE power on/off sequence ......................................................................
Patch Set 1:
(1 comment)
https://review.coreboot.org/c/coreboot/+/48195/1//COMMIT_MSG Commit Message:
https://review.coreboot.org/c/coreboot/+/48195/1//COMMIT_MSG@15 PS1, Line 15: Warm reset: Power off -> 500ms -> Power on
LTE module vendor recently has been telling us not to power off the module during warm reset. […]
Below is the answer we get from vendor in issue tracker 173671094
charles.chen@fibocom.corp-partner.google.com added comment #20: I have clarified this issue as below
GPP_A10 connect to LTE FCPO(Pin 6) GPP_H17 connect to LTE RESET(Pin 67) Actually, there are two reset timing control suggestion as page27 and 28 in the HW User manual. One is GPP_A10 always keep high and GPP_H17 goes to low at least 2ms, the other is both of GPP_A10 and GPP_H17 go to low but need to meet t_off2(2ms), t_off(500ms) and t_on1(8ms) describe in the page 28.