Revert "BB retimer: Set 'DP CONNECTION' bit only when mux_state gets HPD event"

This reverts commit 4dfe7f2a385d9ad3ca10064b29e4acb0f68c30a3.

Reason for revert: In VESA DisplayPortAltMode v2.0 chapter 3.9.2.2,
the HPD will be sent after SBU isolation switches have been close to
connect the AUX_CH.

In this behavior, it will only enable AUX_CH when received HPD and
cause type-c devices couldn't output display.

So we need revert this CL to meet the VSEA DisplayPortAltMode spec.

Original change's description:
> BB retimer: Set 'DP CONNECTION' bit only when mux_state gets HPD event
>
> For some chromebooks design, there are expanssion card (typeC
> to HDMI) communicate with TCPC through CC line, when the HDMI
> card connect to chromebook the DP CONNECTION bit would be enable
> even no connect HDMI moinitor.
>
> It will increase BBR power consumption, so set 'DP CONNECTION'
> bit only when mux_state gets HPD event.
>
> BUG=b:233975818
> BRANCH=None
> TEST=Test on Banshee, measure BBR power consumption reduce from
> 143mW to 7mW. And the HDMI monitor can be output.
>
> Signed-off-by: johnwc_yeh <johnwc_yeh@compal.corp-partner.google.com>
> Change-Id: I8a80235992cfa1bac28f03c3b6a7ec378e07ecf3
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3726600
> Reviewed-by: Diana Z <dzigterman@chromium.org>
> Tested-by: Enzo Hong <enzo.hong@intel.corp-partner.google.com>
> Commit-Queue: Diana Z <dzigterman@chromium.org>

Bug: b:233975818, b:240896516
Change-Id: I48f2818d2eaee921bc0374976f6eddcdc152ac36
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3995963
Reviewed-by: caveh jalali <caveh@chromium.org>
Commit-Queue: Peter Chi <peter_chi@wistron.corp-partner.google.com>
Tested-by: Peter Chi <peter_chi@wistron.corp-partner.google.com>
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>

2 files changed, 16 insertions, 17 deletions

diff --git a/driver/retimer/bb_retimer.c b/driver/retimer/bb_retimer.c
index f7a4ce6164..cb7c58c058 100644
--- a/driver/retimer/bb_retimer.c
+++ b/driver/retimer/bb_retimer.c
@@ -428,7 +428,14 @@ static int retimer_set_state(const struct usb_mux *me, mux_state_t mux_state,
 			set_retimer_con |= BB_RETIMER_USB_3_SPEED;
 	}
 
+	/*
+	 * Bit 8: DP_CONNECTION
+	 * 0 – No DP connection
+	 * 1 – DP connected
+	 */
 	if (mux_state & USB_PD_MUX_DP_ENABLED) {
+		set_retimer_con |= BB_RETIMER_DP_CONNECTION;
+
 		/*
 		 * Bit 11-10: DP_PIN_ASSIGNMENT (ignored if BIT8 = 0)
 		 * 00 – Pin assignments E/E’
@@ -545,26 +552,15 @@ void bb_retimer_hpd_update(const struct usb_mux *me, mux_state_t hpd_state,
 		retimer_con_reg &= ~BB_RETIMER_IRQ_HPD;
 
 	/*
-	 * Bit 8: DP_CONNECTION
-	 * 0 - No DP connection
-	 * 1 - DP connected
-	 *
 	 * Bit 15: HPD_LVL (ignored if BIT8 = 0)
 	 * 0 - HPD_State Low
 	 * 1 - HPD_State High
-	 *
-	 * HDMI card connect to chromebook the DP_CONNECTION bit
-	 * would be enable.
-	 * It will increase BBR power consumption, so enable the DP bit
-	 * only when the HPD bit is set so that the retimer stays in
-	 * low power mode until the external monitor is connected.
 	 */
+
 	if (hpd_state & USB_PD_MUX_HPD_LVL)
-		retimer_con_reg |=
-			(BB_RETIMER_HPD_LVL | BB_RETIMER_DP_CONNECTION);
+		retimer_con_reg |= BB_RETIMER_HPD_LVL;
 	else
-		retimer_con_reg &=
-			~(BB_RETIMER_HPD_LVL | BB_RETIMER_DP_CONNECTION);
+		retimer_con_reg &= ~BB_RETIMER_HPD_LVL;
 
 	/* Writing the register4 */
 	bb_retimer_write(me, BB_RETIMER_REG_CONNECTION_STATE, retimer_con_reg);
diff --git a/zephyr/test/drivers/default/src/bb_retimer.c b/zephyr/test/drivers/default/src/bb_retimer.c
index 5edd0a7cc8..5cfedc789e 100644
--- a/zephyr/test/drivers/default/src/bb_retimer.c
+++ b/zephyr/test/drivers/default/src/bb_retimer.c
@@ -162,7 +162,8 @@ ZTEST_USER(bb_retimer_no_tasks, test_bb_set_state)
 	zassert_false(ack_required, "ACK is never required for BB retimer");
 	conn = bb_emul_get_reg(emul, BB_RETIMER_REG_CONNECTION_STATE);
 	exp_conn = BB_RETIMER_USB_DATA_ROLE |
-		   BB_RETIMER_DATA_CONNECTION_PRESENT;
+		   BB_RETIMER_DATA_CONNECTION_PRESENT |
+		   BB_RETIMER_DP_CONNECTION;
 	zassert_equal(exp_conn, conn, "Expected state 0x%lx, got 0x%lx",
 		      exp_conn, conn);
 
@@ -175,7 +176,8 @@ ZTEST_USER(bb_retimer_no_tasks, test_bb_set_state)
 	zassert_false(ack_required, "ACK is never required for BB retimer");
 	conn = bb_emul_get_reg(emul, BB_RETIMER_REG_CONNECTION_STATE);
 	exp_conn = BB_RETIMER_USB_DATA_ROLE |
-		   BB_RETIMER_DATA_CONNECTION_PRESENT | BB_RETIMER_IRQ_HPD;
+		   BB_RETIMER_DATA_CONNECTION_PRESENT |
+		   BB_RETIMER_DP_CONNECTION | BB_RETIMER_IRQ_HPD;
 	zassert_equal(exp_conn, conn, "Expected state 0x%lx, got 0x%lx",
 		      exp_conn, conn);
 
@@ -188,7 +190,8 @@ ZTEST_USER(bb_retimer_no_tasks, test_bb_set_state)
 	zassert_false(ack_required, "ACK is never required for BB retimer");
 	conn = bb_emul_get_reg(emul, BB_RETIMER_REG_CONNECTION_STATE);
 	exp_conn = BB_RETIMER_USB_DATA_ROLE |
-		   BB_RETIMER_DATA_CONNECTION_PRESENT | BB_RETIMER_HPD_LVL;
+		   BB_RETIMER_DATA_CONNECTION_PRESENT |
+		   BB_RETIMER_DP_CONNECTION | BB_RETIMER_HPD_LVL;
 	zassert_equal(exp_conn, conn, "Expected state 0x%lx, got 0x%lx",
 		      exp_conn, conn);
 }