usb: typec: tcpm: Create legacy PDOs for PD2 connection

If the port partner is PD2, the PDOs of the local port should follow the
format defined in PD2 Spec. Dynamically modify the pre-defined PD3 PDOs
and transform them into PD2 format before sending them to the PD2 port
partner.

Reviewed-by: Guenter Roeck <linux@roeckus.net>
Signed-off-by: Kyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210115163311.391332-1-kyletso@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 0dd932f..0afd8ef 100644 (file)
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -1023,13 +1023,47 @@ static int tcpm_set_pwr_role(struct tcpm_port *port, enum typec_role role)
        return 0;
 }
 
+/*
+ * Transform the PDO to be compliant to PD rev2.0.
+ * Return 0 if the PDO type is not defined in PD rev2.0.
+ * Otherwise, return the converted PDO.
+ */
+static u32 tcpm_forge_legacy_pdo(struct tcpm_port *port, u32 pdo, enum typec_role role)
+{
+       switch (pdo_type(pdo)) {
+       case PDO_TYPE_FIXED:
+               if (role == TYPEC_SINK)
+                       return pdo & ~PDO_FIXED_FRS_CURR_MASK;
+               else
+                       return pdo & ~PDO_FIXED_UNCHUNK_EXT;
+       case PDO_TYPE_VAR:
+       case PDO_TYPE_BATT:
+               return pdo;
+       case PDO_TYPE_APDO:
+       default:
+               return 0;
+       }
+}
+
 static int tcpm_pd_send_source_caps(struct tcpm_port *port)
 {
        struct pd_message msg;
-       int i;
+       u32 pdo;
+       unsigned int i, nr_pdo = 0;
 
        memset(&msg, 0, sizeof(msg));
-       if (!port->nr_src_pdo) {
+
+       for (i = 0; i < port->nr_src_pdo; i++) {
+               if (port->negotiated_rev >= PD_REV30) {
+                       msg.payload[nr_pdo++] = cpu_to_le32(port->src_pdo[i]);
+               } else {
+                       pdo = tcpm_forge_legacy_pdo(port, port->src_pdo[i], TYPEC_SOURCE);
+                       if (pdo)
+                               msg.payload[nr_pdo++] = cpu_to_le32(pdo);
+               }
+       }
+
+       if (!nr_pdo) {
                /* No source capabilities defined, sink only */
                msg.header = PD_HEADER_LE(PD_CTRL_REJECT,
                                          port->pwr_role,
@@ -1042,10 +1076,8 @@ static int tcpm_pd_send_source_caps(struct tcpm_port *port)
                                          port->data_role,
                                          port->negotiated_rev,
                                          port->message_id,
-                                         port->nr_src_pdo);
+                                         nr_pdo);
        }
-       for (i = 0; i < port->nr_src_pdo; i++)
-               msg.payload[i] = cpu_to_le32(port->src_pdo[i]);
 
        return tcpm_pd_transmit(port, TCPC_TX_SOP, &msg);
 }
@@ -1053,10 +1085,22 @@ static int tcpm_pd_send_source_caps(struct tcpm_port *port)
 static int tcpm_pd_send_sink_caps(struct tcpm_port *port)
 {
        struct pd_message msg;
-       int i;
+       u32 pdo;
+       unsigned int i, nr_pdo = 0;
 
        memset(&msg, 0, sizeof(msg));
-       if (!port->nr_snk_pdo) {
+
+       for (i = 0; i < port->nr_snk_pdo; i++) {
+               if (port->negotiated_rev >= PD_REV30) {
+                       msg.payload[nr_pdo++] = cpu_to_le32(port->snk_pdo[i]);
+               } else {
+                       pdo = tcpm_forge_legacy_pdo(port, port->snk_pdo[i], TYPEC_SINK);
+                       if (pdo)
+                               msg.payload[nr_pdo++] = cpu_to_le32(pdo);
+               }
+       }
+
+       if (!nr_pdo) {
                /* No sink capabilities defined, source only */
                msg.header = PD_HEADER_LE(PD_CTRL_REJECT,
                                          port->pwr_role,
@@ -1069,10 +1113,8 @@ static int tcpm_pd_send_sink_caps(struct tcpm_port *port)
                                          port->data_role,
                                          port->negotiated_rev,
                                          port->message_id,
-                                         port->nr_snk_pdo);
+                                         nr_pdo);
        }
-       for (i = 0; i < port->nr_snk_pdo; i++)
-               msg.payload[i] = cpu_to_le32(port->snk_pdo[i]);
 
        return tcpm_pd_transmit(port, TCPC_TX_SOP, &msg);
 }

diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h
index 272454f..70d6819 100644 (file)
--- a/include/linux/usb/pd.h
+++ b/include/linux/usb/pd.h
@@ -225,6 +225,7 @@ enum pd_pdo_type {
 #define PDO_FIXED_EXTPOWER             BIT(27) /* Externally powered */
 #define PDO_FIXED_USB_COMM             BIT(26) /* USB communications capable */
 #define PDO_FIXED_DATA_SWAP            BIT(25) /* Data role swap supported */
+#define PDO_FIXED_UNCHUNK_EXT          BIT(24) /* Unchunked Extended Message supported (Source) */
 #define PDO_FIXED_FRS_CURR_MASK                (BIT(24) | BIT(23)) /* FR_Swap Current (Sink) */
 #define PDO_FIXED_FRS_CURR_SHIFT       23
 #define PDO_FIXED_VOLT_SHIFT           10      /* 50mV units */