usb: typec: tcpm: Do not disconnect link for self powered devices

During HARD_RESET the data link is disconnected.
For self powered device, the spec is advising against doing that.

>From USB_PD_R3_0
7.1.5 Response to Hard Resets
Device operation during and after a Hard Reset is defined as follows:
Self-powered devices Should Not disconnect from USB during a Hard Reset
(see Section 9.1.2).
Bus powered devices will disconnect from USB during a Hard Reset due to the
loss of their power source.

Tackle this by letting TCPM know whether the device is self or bus powered.

This overcomes unnecessary port disconnections from hard reset.
Also, speeds up the enumeration time when connected to Type-A ports.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---------
Version history:
V3:
Rebase on top of usb-next

V2:
Based on feedback from heikki.krogerus@linux.intel.com
- self_powered added to the struct tcpm_port which is populated from
  a. "connector" node of the device tree in tcpm_fw_get_caps()
  b. "self_powered" node of the tcpc_config in tcpm_copy_caps

Based on feedbase from linux@roeck-us.net
- Code was refactored
- SRC_HARD_RESET_VBUS_OFF sets the link state to false based
  on self_powered flag

V1 located here:
https://lkml.org/lkml/2018/9/13/94
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
index 7e7fbfb84e8e..50c74a77db55 100644
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -89,6 +89,7 @@ struct tcpc_config {
 	enum typec_port_data data;
 	enum typec_role default_role;
 	bool try_role_hw;	/* try.{src,snk} implemented in hardware */
+	bool self_powered;	/* port belongs to a self powered device */
 
 	const struct typec_altmode_desc *alt_modes;
 };