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>

2 files changed, 30 insertions, 4 deletions

diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h
index 5a98983195cb..337a5485af7c 100644
--- a/include/linux/usb/pd.h
+++ b/include/linux/usb/pd.h
@@ -398,9 +398,30 @@ enum pd_apdo_type {
 #define PDO_SPR_AVS_APDO_15V_TO_20V_MAX_CURR	GENMASK(9, 0)	/* 10mA unit */
 
 /* SPR AVS has two different current ranges 9V - 15V, 15V - 20V */
-#define SPR_AVS_TIER1_MIN_VOLT_MV		9000
-#define SPR_AVS_TIER1_MAX_VOLT_MV		15000
-#define SPR_AVS_TIER2_MAX_VOLT_MV		20000
+#define SPR_AVS_TIER1_MIN_VOLT_MV              9000
+#define SPR_AVS_TIER1_MAX_VOLT_MV              15000
+#define SPR_AVS_TIER2_MAX_VOLT_MV              20000
+
+#define SPR_AVS_AVS_SMALL_STEP_V	1
+/* vAvsStep - 100mv */
+#define SPR_AVS_VOLT_MV_STEP		100
+/* SPR AVS RDO Operating Current is in 50mA step */
+#define RDO_SPR_AVS_CURR_MA_STEP	50
+/* SPR AVS RDO Output voltage is in 25mV step */
+#define RDO_SPR_AVS_OUT_VOLT_MV_STEP	25
+
+#define RDO_SPR_AVS_VOLT	GENMASK(20, 9)
+#define RDO_SPR_AVS_CURR	GENMASK(6, 0)
+
+#define RDO_SPR_AVS_OUT_VOLT(mv)					\
+	FIELD_PREP(RDO_SPR_AVS_VOLT, ((mv) / RDO_SPR_AVS_OUT_VOLT_MV_STEP))
+
+#define RDO_SPR_AVS_OP_CURR(ma)						\
+	FIELD_PREP(RDO_SPR_AVS_CURR, ((ma) / RDO_SPR_AVS_CURR_MA_STEP))
+
+#define RDO_AVS(idx, out_mv, op_ma, flags)				\
+	(RDO_OBJ(idx) | (flags) |					\
+	 RDO_SPR_AVS_OUT_VOLT(out_mv) | RDO_SPR_AVS_OP_CURR(op_ma))
 
 static inline enum pd_pdo_type pdo_type(u32 pdo)
 {
@@ -660,6 +681,11 @@ static inline unsigned int rdo_max_power(u32 rdo)
 
 #define PD_P_SNK_STDBY_MW	2500	/* 2500 mW */
 
+#define PD_I_SNK_STBY_MA		500	/* 500 mA */
+
+#define PD_T_AVS_SRC_TRANS_SMALL	50	/* 50 ms */
+#define PD_T_AVS_SRC_TRANS_LARGE	700	/* 700 ms */
+
 #if IS_ENABLED(CONFIG_TYPEC)
 
 struct usb_power_delivery;
diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
index b22e659f81ba..93079450bba0 100644
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -31,7 +31,7 @@ enum typec_cc_polarity {
 /* Time to wait for TCPC to complete transmit */
 #define PD_T_TCPC_TX_TIMEOUT	100		/* in ms	*/
 #define PD_ROLE_SWAP_TIMEOUT	(MSEC_PER_SEC * 10)
-#define PD_PPS_CTRL_TIMEOUT	(MSEC_PER_SEC * 10)
+#define PD_AUG_PSY_CTRL_TIMEOUT	(MSEC_PER_SEC * 10)
 
 enum tcpm_transmit_status {
 	TCPC_TX_SUCCESS = 0,