linux-kernel - [PATCH v3 0/2] TCPM non-pd mode

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Date:   Wed, 28 Jul 2021 17:29:28 +0800
From:   Kyle Tso <kyletso@...gle.com>
To:     linux@...ck-us.net, heikki.krogerus@...ux.intel.com,
        gregkh@...uxfoundation.org, robh+dt@...nel.org
Cc:     badhri@...gle.com, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        Kyle Tso <kyletso@...gle.com>
Subject: [PATCH v3 0/2] TCPM non-pd mode

The reason for this patch is to let the device/system policy decide
whether PD is going to be supported using devicetree properties.

A new dt property "pd-unsupported" is introduced and TCPM uses this
property as a flag to decide whether PD is supported. If the flag is
false (the dt property is not present), the RX functionality of the
low-level driver will not be enabled. The power negotiation related
states will be skipped as well. If the flag is true, everything is as
what it was before.                                                  

If "pd-unsupported" is present, and the port is SRC or DRP, another                               
existing dt property "typec-power-opmode" needs to be specified to                                  
indicate which Rp value should be used when the port is SRC.                                        

changes since v2:
- Negated the meaning and the name of the dt property. Now the name is
  "pd-unsupported"
- Changed the control flow if the port is SNK or DRP. Return directly if
  the flag is false (PD not supported). Read "self-powered" before that.

---
cover-letter in v2:
---
The reason for this patch is to let the device/system policy decide                                 
whether PD is going to be supported using devicetree properties.                                    

A new dt property "pd-supported" is introduced and TCPM uses this                                   
property as a flag to decide whether PD is supported. If the flag is                                
false, the RX functionality of the low-level driver will not be enabled.                            
The power negotiation related states will be skipped as well. If the                                
flag is true, everything is as what it was before.                                                  

If "pd-supported" is not present, and the port is SRC or DRP, another                               
existing dt property "typec-power-opmode" needs to be specified to                                  
indicate which Rp value should be used when the port is SRC.                                        

changes since v1:                                                                                   
- revise the patch to use dt properties

Kyle Tso (2):
  dt-bindings: connector: Add pd-supported property
  usb: typec: tcpm: Support non-PD mode

 .../bindings/connector/usb-connector.yaml     |  4 +
 drivers/usb/typec/tcpm/tcpm.c                 | 88 +++++++++++++++----
 2 files changed, 74 insertions(+), 18 deletions(-)

-- 
2.32.0.432.gabb21c7263-goog