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usb: musb: dsps: fix otg state machine 

Due to lack of ID pin interrupt event on AM335x devices, the musb dsps
driver uses polling to detect usb device attach for dual-role port.

But in the case if a micro-A cable adapter is attached without a USB device
attached to the cable, the musb state machine gets stuck in a_wait_vrise
state waiting for the MUSB_CONNECT interrupt which won't happen due to the
usb device is not attached. The state is stuck in a_wait_vrise even after
the micro-A cable is detached, which could cause VBUS retention if then the
dual-role port is attached to a host port.

To fix the problem, make a_wait_vrise as a transient state, then move the
state to either a_wait_bcon for host port or a_idle state for dual-role
port, if no usb device is attached to the port.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Bin Liu 2018-12-18 07:58:04 -06:00 committed by Greg Kroah-Hartman
parent 1d6e81a288
commit 6010abf2c2
1 changed files with 7 additions and 2 deletions
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9
drivers/usb/musb/musb_dsps.c
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@ -227,8 +227,13 @@ static int dsps_check_status(struct musb *musb, void *unused)
switch (musb->xceiv->otg->state) {
case OTG_STATE_A_WAIT_VRISE:
dsps_mod_timer_optional(glue);
break;
if (musb->port_mode == MUSB_HOST) {
musb->xceiv->otg->state = OTG_STATE_A_WAIT_BCON;
dsps_mod_timer_optional(glue);
break;
}
/* fall through */
case OTG_STATE_A_WAIT_BCON:
/* keep VBUS on for host-only mode */
if (musb->port_mode == MUSB_HOST) {