tcpm: anx74xx: Improvements to low power mode for S3/G3 chipset state

Before entering standby mode, bit 7 (cable_det) or analog_ctrl_0 is
cleared. This allows a new cable detect event to trigger the EC to
put the ANX4329 into normal mode. However, in some cases such as when
in S3/S5/G3 chipset power states a port will be in sink only mode and
therefore won't attach when a sink only adapter is connected to the
port. This results in the an indefinite toggle of standby<->normal
mode transitions. This constant toggle floods the EC console and more
importantly prevents the ANX4329 from remaining in standby mode and
the power consumption remains at ~9.5 mW instead of ~1.2 mW when no
adapter is connected.

This CL adds logic around clearing the cable_det bit so that it's only
cleared if both CC lines are open or if an Emark cable is
attached. Emark cable is determined from the presence of Ra on one CC
line and no Rd on the other CC line. The special consideration for an
Emark cable is reqiured because when an Emark cable is connected, the
USB PD auto toggle state may require some number of iterations until
the attach event is recognized.

In order to support handle cases where the drp mode is changed via
either the EC console command or host command, added a call to
tcpm_set_drp_toggle whenever the drp state is updated. Since the drp
mode is updated upon chipset resume events, the chipset resume hook in
board.c for anx74xx_cable_det_handler() became redundant and hence it
was removed.

BUG=b:35775019,b:35586188
BRANCH=reef
TEST=Tested the following cases:
- Sink, source adapters in chipset S0. Verified that adapters
connected as expected. Also, used Emark cable to connect to both USB
PD chargers (source)  and Pixel phone (sink).

- Run 'lidclose' on EC console then connect Type C -> A adatper
[3490.370125 TCPC p0 reset!]
[3490.389588 TCPC p0 Low Power Mode]
It no longer toggles indefintely and after running 'lidopen' verified
that port 0 is now in SRC_DISCOVERY.

- In S3/G3 connected USB PD charger with regular and Emark typeC
  cable. Verified that port 0 is in SNK_READY state.

- use 'pd dualrole sink' and test with Type C -> A adatper. Verified
  that tcpc wakes up, but goes into standby mode until entering 'pd
  dualrole on'.

- When sink only adapter is connected in S3/G3, measure power level
  ~1.2 mW as opposed to ~10 mW in S0.

- Repeated similar tests on port 1 (parade tcpc) to verify that
  adapters connected as expected.

Change-Id: Ib8de666f72723934186fee7869f9dda01381c7a8
Signed-off-by: Scott <scollyer@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/463991
Commit-Ready: Scott Collyer <scollyer@chromium.org>
Tested-by: Scott Collyer <scollyer@chromium.org>
Reviewed-by: S Wang <swang@analogix.corp-partner.google.com>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index b92641e5c8..ee4ae31ab0 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -1428,6 +1428,12 @@ void pd_update_dual_role_config(int port)
 		set_state(port, PD_STATE_SRC_DISCONNECTED);
 		tcpm_set_cc(port, TYPEC_CC_RP);
 	}
+
+#if defined(CONFIG_USB_PD_DUAL_ROLE_AUTO_TOGGLE) && \
+	defined(CONFIG_USB_PD_TCPC_LOW_POWER)
+	/* When switching drp mode, make sure tcpc is out of standby mode */
+	tcpm_set_drp_toggle(port, 0);
+#endif
 }
 
 int pd_get_role(int port)