[PATCH 3/4] usb: chipidea: pull down dp for possible charger detection operation

[Peter Chen <peter.chen@kernel.org>]

From: Peter Chen <peter.chen@nxp.com>

The bootloader may use device mode, and keep dp up. We need dp
to be pulled down before possbile charger detection operation.

Signed-off-by: Peter Chen <peter.chen@nxp.com>
---
 drivers/usb/chipidea/core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index ea8ac4a54a8d..804c0a5a213b 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -1123,8 +1123,11 @@ static int ci_hdrc_probe(struct platform_device *pdev)
 
 	if (!ci_otg_is_fsm_mode(ci)) {
 		/* only update vbus status for peripheral */
-		if (ci->role == CI_ROLE_GADGET)
+		if (ci->role == CI_ROLE_GADGET) {
+			/* Pull down DP for possible charger detection */
+			hw_write(ci, OP_USBCMD, USBCMD_RS, 0);
 			ci_handle_vbus_change(ci);
+		}
 
 		ret = ci_role_start(ci, ci->role);
 		if (ret) {
-- 
2.17.1