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 Michael Wu <[email protected]>

---
 drivers/usb/typec/tcpm/tcpm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

drivers/usb/typec/tcpm/tcpm.c +0 -0

index d962f67c95ae6..beb7143128667 100644

Quoted 35 lines · Michael Wu

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 Michael Wu <[email protected]>

---
  drivers/usb/typec/tcpm/tcpm.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

drivers/usb/typec/tcpm/tcpm.c +2 -1

index d962f67c95ae6..beb7143128667 100644
@@ -519,7 +519,8 @@ static const char * const pd_rev[] = {
 
  #define tcpm_port_is_sink(port) \
  	((tcpm_cc_is_sink((port)->cc1) && !tcpm_cc_is_sink((port)->cc2)) || \
-	 (tcpm_cc_is_sink((port)->cc2) && !tcpm_cc_is_sink((port)->cc1)))
+	 (tcpm_cc_is_sink((port)->cc2) && !tcpm_cc_is_sink((port)->cc1)) || \
+	 (tcpm_cc_is_sink((port)->cc1) && tcpm_cc_is_sink((port)->cc2)))
 

drivers/usb/typec/tcpm/tcpm.c static const char * const pd_rev[] = { · line 526

Quoted 2 lines

drivers/usb/typec/tcpm/tcpm.c +0 -0

  #define tcpm_cc_is_source(cc) ((cc) == TYPEC_CC_RD)
  #define tcpm_cc_is_audio(cc) ((cc) == TYPEC_CC_RA)

This look OK to me, but I would still like to wait for comments from Guenter - just in case.

thanks,

Quoted 24 lines · Heikki Krogerus

Quoted 23 lines · Michael Wu

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 Michael Wu <[email protected]>

---
  drivers/usb/typec/tcpm/tcpm.c | 3 ++-

  1 file changed, 2 insertions(+), 1 deletion(-)

Quoted 17 lines

drivers/usb/typec/tcpm/tcpm.c static const char * const pd_rev[] = { · line 525

Quoted 13 lines

drivers/usb/typec/tcpm/tcpm.c +2 -1

index d962f67c95ae6..beb7143128667 100644
@@ -519,7 +519,8 @@ static const char * const pd_rev[] = {
   #define tcpm_port_is_sink(port) \
       ((tcpm_cc_is_sink((port)->cc1) && !tcpm_cc_is_sink((port)->cc2)) || \
-     (tcpm_cc_is_sink((port)->cc2) && !tcpm_cc_is_sink((port)->cc1)))
+     (tcpm_cc_is_sink((port)->cc2) && !tcpm_cc_is_sink((port)->cc1)) 
 || \
+     (tcpm_cc_is_sink((port)->cc1) && tcpm_cc_is_sink((port)->cc2)))
   #define tcpm_cc_is_source(cc) ((cc) == TYPEC_CC_RD)
   #define tcpm_cc_is_audio(cc) ((cc) == TYPEC_CC_RA)

This look OK to me, but I would still like to wait for comments from Guenter - just in case.

Look at the conditions. Reordered, we end up with
    (tcpm_cc_is_sink((port)->cc1) && !tcpm_cc_is_sink((port)->cc2)) || (tcpm_cc_is_sink((port)->cc1) && tcpm_cc_is_sink((port)->cc2))
which simplifies to
    tcpm_cc_is_sink((port)->cc1)
making the complete expression
    tcpm_cc_is_sink((port)->cc1) || (tcpm_cc_is_sink((port)->cc2) && !tcpm_cc_is_sink((port)->cc1))
which simplifies further to
    tcpm_cc_is_sink((port)->cc1) || tcpm_cc_is_sink((port)->cc2)

The simplified expression doesn't conflict with other detections, so I am ok with it. It might be worthwhile adding a comment to the code, though, explaining the reason
Guenter

Quoted 2 lines

thanks,