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Commit dbc1defe authored by Michael Wu's avatar Michael Wu Committed by Greg Kroah-Hartman
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usb:typec:tcpm:support double Rp to Vbus cable as sink



The USB Type-C Cable and Connector Specification defines the wire
connections for the USB Type-C to USB 2.0 Standard-A cable assembly
(Release 2.2, Chapter 3.5.2).
The Notes says that Pin A5 (CC) of the USB Type-C plug shall be connected
to Vbus through a resister Rp.
However, there is a large amount of such double Rp connected to Vbus
non-standard cables which produced by UGREEN circulating on the market, and
it can affects the normal operations of the state machine easily,
especially to CC1 and CC2 be pulled up at the same time.
In fact, we can regard those cables as sink to avoid abnormal state.

Message as follow:
[   58.900212] VBUS on
[   59.265433] CC1: 0 -> 3, CC2: 0 -> 3 [state TOGGLING, polarity 0, connected]
[   62.623308] CC1: 3 -> 0, CC2: 3 -> 0 [state TOGGLING, polarity 0, disconnected]
[   62.625006] VBUS off
[   62.625012] VBUS VSAFE0V

Signed-off-by: default avatarMichael Wu <michael@allwinnertech.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Reviewed-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230920063030.66312-1-michael@allwinnertech.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5c954e03
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