honeybuns: ensure we are always a data UFP

The dock hub upstream port is wired to the type-C captive cable, so we
can only be a data UFP :
- ensure we reject data swap request to become a DFP
(e.g. from dual role devices preferring to be a UFP such as Ryu)
- swap to data UFP at startup (we will start as data DFP since we are a
  power source only).

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>

BRANCH=none
BUG=none
TEST=connect Honeybuns to Ryu and see Ryu becoming a power sink and a
data DFP all the time.

Change-Id: I876536451a327e04df0a81d8217ef19963d204b6
Reviewed-on: https://chromium-review.googlesource.com/300952
Commit-Ready: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Alec Berg <alecaberg@chromium.org>
Reviewed-by: Scott Collyer <scollyer@chromium.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/board/honeybuns/usb_pd_policy.c b/board/honeybuns/usb_pd_policy.c
index 65c056f102..5ba1347106 100644
--- a/board/honeybuns/usb_pd_policy.c
+++ b/board/honeybuns/usb_pd_policy.c
@@ -139,8 +139,11 @@ int pd_check_power_swap(int port)
 
 int pd_check_data_swap(int port, int data_role)
 {
-	/* Always allow data swap */
-	return 1;
+	/*
+	 * Ensure we always are a UFP :
+	 * Allow data swap if we are a DFP, otherwise don't allow.
+	 */
+	return (data_role == PD_ROLE_DFP) ? 1 : 0;
 }
 
 void pd_execute_data_swap(int port, int data_role)
@@ -154,6 +157,9 @@ void pd_check_pr_role(int port, int pr_role, int flags)
 
 void pd_check_dr_role(int port, int dr_role, int flags)
 {
+	/* if the partner is a DRP (e.g. tablet), try to switch to UFP */
+	if ((flags & PD_FLAGS_PARTNER_DR_DATA) && dr_role == PD_ROLE_DFP)
+		pd_request_data_swap(port);
 }
 
 int pd_alt_mode(int port, uint16_t svid)