tcpm: Implement sink support for PD SPR AVS negotiation
Add support to enable TCPM to negotiate with
USB PD Standard Power Range Adjustable Voltage Supply (SPR AVS) when
acting as a power sink.
* Added support to the tcpm power supply properties, allowing userspace
to enable and control the dynamic limits (voltage and current)
specific to the SPR AVS contract.
* Implemented tcpm_pd_select_spr_avs_apdo() to select the appropriate
APDO and validate the requested voltage/current against both the
Source and Sink capabilities.
* Implemented tcpm_pd_build_spr_avs_request() to construct the
Request Data Object (RDO) for SPR AVS.
* Added SNK_NEGOTIATE_SPR_AVS_CAPABILITIES state to the state machine to
handle negotiation for SPR AVS.
* Updated the SNK_TRANSITION_SINK state to implement the SPR
AVS-specific VBUS transition rules, including reducing current draw to
PD_I_SNK_STBY_MA for large voltage changes, as required by USB PD spec.
Log stub captured when enabling AVS:
$ echo 3 > /sys/class/power_supply/tcpm-source-psy-1-0025/online
$ cat /d/usb/tcpm-1-0025/log
[ 358.895775] request to set AVS online
[ 358.895792] AMS POWER_NEGOTIATION start
[ 358.895806] state change SNK_READY -> AMS_START [rev3 POWER_NEGOTIATION]
[ 358.895850] state change AMS_START -> SNK_NEGOTIATE_SPR_AVS_CAPABILITIES [rev3 POWER_NEGOTIATION]
[ 358.895866] SPR AVS src_pdo_index:4 snk_pdo_index:2 req_op_curr_ma roundup:2200 req_out_volt_mv roundup:9000
[ 358.895880] Requesting APDO SPR AVS 4: 9000 mV, 2200 mA
[ 358.896405] set_auto_vbus_discharge_threshold mode:0 pps_active:n vbus:0 pps_apdo_min_volt:0 ret:0
[ 358.896422] PD TX, header: 0x1a82
[ 358.900158] PD TX complete, status: 0
[ 358.900205] pending state change SNK_NEGOTIATE_SPR_AVS_CAPABILITIES -> HARD_RESET_SEND @ 60 ms [rev3 POWER_NEGOTIATION]
[ 358.904832] PD RX, header: 0x1a3 [1]
[ 358.904854] state change SNK_NEGOTIATE_SPR_AVS_CAPABILITIES -> SNK_TRANSITION_SINK [rev3 POWER_NEGOTIATION]
[ 358.904888] pending state change SNK_TRANSITION_SINK -> HARD_RESET_SEND @ 700 ms [rev3 POWER_NEGOTIATION]
[ 359.021530] PD RX, header: 0x3a6 [1]
[ 359.021546] Setting voltage/current limit 9000 mV 2200 mA
[ 359.023035] set_auto_vbus_discharge_threshold mode:3 pps_active:n vbus:9000 pps_apdo_min_volt:0 ret:0
[ 359.023053] state change SNK_TRANSITION_SINK -> SNK_READY [rev3 POWER_NEGOTIATION]
[ 359.023090] AMS POWER_NEGOTIATION finished
$ cat /sys/class/power_supply/tcpm-source-psy-1-0025/online
3
Log stub captured when increasing voltage:
$ echo 9100000 > /sys/class/power_supply/tcpm-source-psy-1-0025/voltage_now
$ cat /d/usb/tcpm-1-0025/log
[ 632.116714] AMS POWER_NEGOTIATION start
[ 632.116728] state change SNK_READY -> AMS_START [rev3 POWER_NEGOTIATION]
[ 632.116779] state change AMS_START -> SNK_NEGOTIATE_SPR_AVS_CAPABILITIES [rev3 POWER_NEGOTIATION]
[ 632.116798] SPR AVS src_pdo_index:4 snk_pdo_index:2 req_op_curr_ma roundup:2200 req_out_volt_mv roundup:9100
[ 632.116811] Requesting APDO SPR AVS 4: 9100 mV, 2200 mA
[ 632.117315] set_auto_vbus_discharge_threshold mode:0 pps_active:n vbus:0 pps_apdo_min_volt:0 ret:0
[ 632.117328] PD TX, header: 0x1c82
[ 632.121007] PD TX complete, status: 0
[ 632.121052] pending state change SNK_NEGOTIATE_SPR_AVS_CAPABILITIES -> HARD_RESET_SEND @ 60 ms [rev3 POWER_NEGOTIATION]
[ 632.124572] PD RX, header: 0x5a3 [1]
[ 632.124594] state change SNK_NEGOTIATE_SPR_AVS_CAPABILITIES -> SNK_TRANSITION_SINK [rev3 POWER_NEGOTIATION]
[ 632.124623] pending state change SNK_TRANSITION_SINK -> HARD_RESET_SEND @ 700 ms [rev3 POWER_NEGOTIATION]
[ 632.149256] PD RX, header: 0x7a6 [1]
[ 632.149271] Setting voltage/current limit 9100 mV 2200 mA
[ 632.150770] set_auto_vbus_discharge_threshold mode:3 pps_active:n vbus:9100 pps_apdo_min_volt:0 ret:0
[ 632.150787] state change SNK_TRANSITION_SINK -> SNK_READY [rev3 POWER_NEGOTIATION]
[ 632.150823] AMS POWER_NEGOTIATION finished
$ cat /sys/class/power_supply/tcpm-source-psy-1-0025/voltage_now
9100000
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Amit Sunil Dhamne <amitsd@google.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/20260316150301.3892223-4-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
d3d959404e