samus: automatically recover from charge circuit failuresstabilize-6752.B

Occasionally the charge circuit on samus gets wedged and will not
charge. This change detects when the charge circuit has failed
and automatically recovers from it. It uses the BQ PROCHOT warning
to detect the failure by setting PROCHOT to trigger when the BQ
thinks input current is higher than the input current limit. When
the failure is detected, the EC disables charging and tells PD MCU
to disable CHARGE_EN, then a couple seconds later, it re-enables
charging.

This CL also adds more communication between EC and PD for the EC
to be able to set the charge state for the PD. Valid charge states
are: No charging allowed, 5V charging only, and max charging. The
EC uses this as such:
- When the EC gets AC present interrupt, it sets off a deferred
function to change charge state to max charging after some delay
to give time for the charge circuit to settle down.
- When the EC gets AC disconnect interrupt, it disables charging
briefly, enables learn mode, and then sets 5V charging allowed.
This allows for the same starting conditions in the charge circuit
for every AC attach.
- When the EC detects a wedged charge circuit, it disables charging
and waits a few seconds before re-enabling 5V only charging.

Additionally, this change moves the charging cutoff in S3/S5/G3 when
the battery is full to the EC. With the added control for the EC
to set the PD charging state, it is more convenient for the EC to
manage cutting off charging when battery is full.

BUG=chrome-os-partner:36081
BRANCH=samus
TEST=test the basics:
- connect/disconnect zinger a bunch of times
- connect and disconnect two zingers in different order
- connect two zingers and charge override between the two

test the automatic charge wedge recover:
- wedge the charge circuit by setting charger voltage under battery
voltage: "charger voltage 7000"
- wait a few seconds for the system to recover and check it is charging
with "battery" command

test full battery charge cutoff:
- added console command to change battery soc in board/samus/extpower.c:
static int cmd_battfake(int argc, char **argv)
{
	char *e;

	battery_soc = strtoi(argv[1], &e, 10);
	batt_soc_change();
	return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(battfake, cmd_battfake, "", "", NULL);
- in S0, tested "battfake 100" does not disable charging.
- in G3, tested "battfake 100" disables charging and "battfake 99"
re-enables charging.
- set "battfake 100" and tested transitioning to S0 enables charging and
transitioning to S5 disables charging.
- attached two chargers and used charge override to select active port.
then toggled "battfake 100" to "battfake 99" back and forth and verified
charge override port is still the same.

test third-party 12V charger:
- plug in a bunch of times and make sure we stay at 5V for 500ms and then
transition to 12V

test with no battery:
- tested five different units with no battery and just zinger. 3/5 boot,
while the other 2 don't. But, the 2 that don't boot without battery also
can't boot w/o battery when this CL is reverted, so I don't think this
change is causing the problem, I think there is an electrical limitation.

test with EVT zinger:
- EVT zingers (P2 - C2) negotiate very quickly after connection, which
can cause INA problems w/o this CL. Tested an EVT zinger with samus and
did a bunch of connections and disconnections and verified that we always
wait at 5V for 500ms and that we don't wedge the INA circuit on connect.

test backwards compatibility:
- test new PD with old EC and make sure we can charge with zinger.
(note that if the charge circuit wedges, we won't be able to unwedge it).
- test old PD with new EC and make sure we can charge with zinger.

Change-Id: I7703b7a2ab1209d7f559b265b03517e79c74b16a
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/245253
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index 0bad095dd5..8d168e1f1c 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -917,14 +917,25 @@ static void pd_send_request_msg(int port, int always_send_request)
 #else
 	const int charging = 1;
 #endif
+
+#ifdef CONFIG_USB_PD_CHECK_MAX_REQUEST_ALLOWED
+	int max_request_allowed = pd_is_max_request_allowed();
+#else
+	const int max_request_allowed = 1;
+#endif
+
 	/* Clear new power request */
 	pd[port].new_power_request = 0;
 
 	/* Build and send request RDO */
-	/* If this port is not actively charging, select vSafe5V */
+	/*
+	 * If this port is not actively charging or we are not allowed to
+	 * request the max voltage, then select vSafe5V
+	 */
 	res = pd_build_request(pd_src_cap_cnt[port], pd_src_caps[port],
 			       &rdo, &curr_limit, &supply_voltage,
-			       charging ? PD_REQUEST_MAX : PD_REQUEST_VSAFE5V);
+			       charging && max_request_allowed ?
+					PD_REQUEST_MAX : PD_REQUEST_VSAFE5V);
 
 	if (res != EC_SUCCESS)
 		/*