servo_v4: Disable CCD (monitoring SBU) when DTS-mode disabled by a user

The SBU monitoring logic is used for muxing the correct polarity for
CCD. If the DTS-mode is disabled by a user, meaning that CCD is supposed
not being used, the SBU monitoring logic can be disabled.

For DP alt-mode, the SBU lines are used for AUX channel. This SBU
monitoring logic affects the AUX channel, due to the strong pull-up
on the USB D+ line. It should be disabled.

Remove the original calls of ccd_enable(), which is called when
supplying power and detecting DUT Rd/Rd or Rp/Rp. This requires PD
comm. We don't want CCD depends on PD comm.

BRANCH=servo
BUG=b:137219603
TEST=The default role "cc srcdts", CCD works on both phyical polarity.
TEST=Called "cc src", checked GPIO SBU_MUX_EN 0.

Change-Id: I8f2f7bda88426e6097f0f4efd811114b7a1135c3
Signed-off-by: Wai-Hong Tam <waihong@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1815557
Reviewed-by: Nick Sanders <nsanders@chromium.org>

2 files changed, 14 insertions, 11 deletions

diff --git a/board/servo_v4/board.c b/board/servo_v4/board.c
index 0d5abc58e2..bf1c51e267 100644
--- a/board/servo_v4/board.c
+++ b/board/servo_v4/board.c
@@ -383,13 +383,14 @@ static void ccd_measure_sbu(void)
 	hook_call_deferred(&ccd_measure_sbu_data, 100 * MSEC);
 }
 
-
 void ccd_enable(int enable)
 {
-	/*
-	 * We may use this if displayport is ever enabled.
-	 * For now, CCD is always enabled on SBU.
-	 */
+	if (enable) {
+		hook_call_deferred(&ccd_measure_sbu_data, 0);
+	} else {
+		gpio_set_level(GPIO_SBU_MUX_EN, 0);
+		hook_call_deferred(&ccd_measure_sbu_data, -1);
+	}
 }
 
 int board_get_version(void)
diff --git a/board/servo_v4/usb_pd_policy.c b/board/servo_v4/usb_pd_policy.c
index 07008c0cca..138f53a4a7 100644
--- a/board/servo_v4/usb_pd_policy.c
+++ b/board/servo_v4/usb_pd_policy.c
@@ -658,10 +658,6 @@ int pd_set_power_supply_ready(int port)
 		return EC_ERROR_NOT_POWERED;
 	}
 
-	/* Enable CCD, if debuggable TS attached */
-	if (pd_ts_dts_plugged(DUT))
-		ccd_enable(1);
-
 	return EC_SUCCESS; /* we are ready */
 }
 
@@ -671,8 +667,6 @@ void pd_power_supply_reset(int port)
 	if (port == CHG)
 		return;
 
-	ccd_enable(0);
-
 	/* Disable VBUS */
 	gpio_set_level(GPIO_DUT_CHG_EN, 0);
 
@@ -827,6 +821,14 @@ static void do_cc(int cc_config_new)
 				usleep(PD_T_ERROR_RECOVERY);
 		}
 
+		if ((cc_config & ~cc_config_new) & CC_DISABLE_DTS) {
+			/* DTS-disabled -> DTS-enabled */
+			ccd_enable(1);
+		} else if ((cc_config_new & ~cc_config) & CC_DISABLE_DTS) {
+			/* DTS-enabled -> DTS-disabled */
+			ccd_enable(0);
+		}
+
 		/* Accept new cc_config value */
 		cc_config = cc_config_new;