plankton: reset USB hub on cable plug

If USB hub is connected to the type-C port, we need to reset the hub
whenever a cable plugs in. Otherwise, USB3.0 may fail to enumerate.

BRANCH=None
BUG=None
TEST=Plug/unplug cable and measure hub reset signal.

Change-Id: I60f67c83653d532971ee156914fe6ae0ecdb8d3a
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/229490
Reviewed-by: Pin-chih Lin <johnylin@chromium.org>
Reviewed-by: Alec Berg <alecaberg@chromium.org>

board/plankton/board.c

@@ -225,6 +225,21 @@ static int board_usb_hub_reset(void)
 	return pca9534_set_level(I2C_PORT_MASTER, 0x40, 7, 1);
 }
 
+void board_maybe_reset_usb_hub(void)
+{
+	int ret;
+	int level;
+
+	ret = pca9534_config_pin(I2C_PORT_MASTER, 0x40, 6, PCA9534_INPUT);
+	if (ret)
+		return;
+	ret = pca9534_get_level(I2C_PORT_MASTER, 0x40, 6, &level);
+	if (ret)
+		return;
+	if (level == 1)
+		board_usb_hub_reset();
+}
+
 static int cmd_usb_hub_reset(int argc, char *argv[])
 {
 	return board_usb_hub_reset();

board/plankton/board.h

@@ -64,6 +64,9 @@ enum board_src_cap {
 /* Set USB PD source capability */
 void board_set_source_cap(enum board_src_cap cap);
 
+/* Reset USB hub if USB hub is switched to type-C port */
+void board_maybe_reset_usb_hub(void);
+
 #endif /* !__ASSEMBLER__ */
 
 #endif /* __BOARD_H */

board/plankton/usb_pd_policy.c

@@ -167,6 +167,10 @@ void pd_power_supply_reset(int port)
 
 int pd_board_checks(void)
 {
+	static int was_connected = -1;
+	if (was_connected != 1 && pd_is_connected(0))
+		board_maybe_reset_usb_hub();
+	was_connected = pd_is_connected(0);
 	return EC_SUCCESS;
 }