usb: typec: tcpm: Support non-PD mode

Even if the Type-C controller supports PD, it is doable to disable PD
capabilities with the current state machine in TCPM. Without enabling RX
in low-level drivers and with skipping the power negotiation, the port
is eligible to be a non-PD Type-C port. Use new flags whose values are
populated from the device tree to decide the port PD capability. Adding
"pd-disable" property in device tree indicates that the port does not
support PD. If PD is not supported, the device tree property
"typec-power-opmode" shall be added to specify the advertised Rp value
if the port supports SRC role.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Kyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210804081917.3390341-3-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 b9bb63d..c40e051 100644 (file)
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -316,6 +316,7 @@ struct tcpm_port {
        struct typec_partner *partner;
 
        enum typec_cc_status cc_req;
+       enum typec_cc_status src_rp;    /* work only if pd_supported == false */
 
        enum typec_cc_status cc1;
        enum typec_cc_status cc2;
@@ -323,6 +324,7 @@ struct tcpm_port {
 
        bool attached;
        bool connected;
+       bool pd_supported;
        enum typec_port_type port_type;
 
        /*
@@ -815,6 +817,9 @@ static enum typec_cc_status tcpm_rp_cc(struct tcpm_port *port)
        int nr_pdo = port->nr_src_pdo;
        int i;
 
+       if (!port->pd_supported)
+               return port->src_rp;
+
        /*
         * Search for first entry with matching voltage.
         * It should report the maximum supported current.
@@ -3568,9 +3573,11 @@ static int tcpm_src_attach(struct tcpm_port *port)
        if (ret < 0)
                return ret;
 
-       ret = port->tcpc->set_pd_rx(port->tcpc, true);
-       if (ret < 0)
-               goto out_disable_mux;
+       if (port->pd_supported) {
+               ret = port->tcpc->set_pd_rx(port->tcpc, true);
+               if (ret < 0)
+                       goto out_disable_mux;
+       }
 
        /*
         * USB Type-C specification, version 1.2,
@@ -3600,7 +3607,8 @@ static int tcpm_src_attach(struct tcpm_port *port)
 out_disable_vconn:
        tcpm_set_vconn(port, false);
 out_disable_pd:
-       port->tcpc->set_pd_rx(port->tcpc, false);
+       if (port->pd_supported)
+               port->tcpc->set_pd_rx(port->tcpc, false);
 out_disable_mux:
        tcpm_mux_set(port, TYPEC_STATE_SAFE, USB_ROLE_NONE,
                     TYPEC_ORIENTATION_NONE);
@@ -3804,6 +3812,20 @@ static enum typec_pwr_opmode tcpm_get_pwr_opmode(enum typec_cc_status cc)
        }
 }
 
+static enum typec_cc_status tcpm_pwr_opmode_to_rp(enum typec_pwr_opmode opmode)
+{
+       switch (opmode) {
+       case TYPEC_PWR_MODE_USB:
+               return TYPEC_CC_RP_DEF;
+       case TYPEC_PWR_MODE_1_5A:
+               return TYPEC_CC_RP_1_5;
+       case TYPEC_PWR_MODE_3_0A:
+       case TYPEC_PWR_MODE_PD:
+       default:
+               return TYPEC_CC_RP_3_0;
+       }
+}
+
 static void run_state_machine(struct tcpm_port *port)
 {
        int ret;
@@ -3914,6 +3936,10 @@ static void run_state_machine(struct tcpm_port *port)
                if (port->ams == POWER_ROLE_SWAP ||
                    port->ams == FAST_ROLE_SWAP)
                        tcpm_ams_finish(port);
+               if (!port->pd_supported) {
+                       tcpm_set_state(port, SRC_READY, 0);
+                       break;
+               }
                port->upcoming_state = SRC_SEND_CAPABILITIES;
                tcpm_ams_start(port, POWER_NEGOTIATION);
                break;
@@ -4161,7 +4187,10 @@ static void run_state_machine(struct tcpm_port *port)
                                current_lim = PD_P_SNK_STDBY_MW / 5;
                        tcpm_set_current_limit(port, current_lim, 5000);
                        tcpm_set_charge(port, true);
-                       tcpm_set_state(port, SNK_WAIT_CAPABILITIES, 0);
+                       if (!port->pd_supported)
+                               tcpm_set_state(port, SNK_READY, 0);
+                       else
+                               tcpm_set_state(port, SNK_WAIT_CAPABILITIES, 0);
                        break;
                }
                /*
@@ -4389,7 +4418,8 @@ static void run_state_machine(struct tcpm_port *port)
                tcpm_set_vbus(port, true);
                if (port->ams == HARD_RESET)
                        tcpm_ams_finish(port);
-               port->tcpc->set_pd_rx(port->tcpc, true);
+               if (port->pd_supported)
+                       port->tcpc->set_pd_rx(port->tcpc, true);
                tcpm_set_attached_state(port, true);
                tcpm_set_state(port, SRC_UNATTACHED, PD_T_PS_SOURCE_ON);
                break;
@@ -5898,6 +5928,7 @@ EXPORT_SYMBOL_GPL(tcpm_tcpc_reset);
 static int tcpm_fw_get_caps(struct tcpm_port *port,
                            struct fwnode_handle *fwnode)
 {
+       const char *opmode_str;
        const char *cap_str;
        int ret;
        u32 mw, frs_current;
@@ -5932,22 +5963,37 @@ static int tcpm_fw_get_caps(struct tcpm_port *port,
                return ret;
        port->typec_caps.type = ret;
        port->port_type = port->typec_caps.type;
+       port->pd_supported = !fwnode_property_read_bool(fwnode, "pd-disable");
 
        port->slow_charger_loop = fwnode_property_read_bool(fwnode, "slow-charger-loop");
        if (port->port_type == TYPEC_PORT_SNK)
                goto sink;
 
-       /* Get source pdos */
-       ret = fwnode_property_count_u32(fwnode, "source-pdos");
-       if (ret <= 0)
-               return -EINVAL;
+       /* Get Source PDOs for the PD port or Source Rp value for the non-PD port */
+       if (port->pd_supported) {
+               ret = fwnode_property_count_u32(fwnode, "source-pdos");
+               if (ret == 0)
+                       return -EINVAL;
+               else if (ret < 0)
+                       return ret;
 
-       port->nr_src_pdo = min(ret, PDO_MAX_OBJECTS);
-       ret = fwnode_property_read_u32_array(fwnode, "source-pdos",
-                                            port->src_pdo, port->nr_src_pdo);
-       if ((ret < 0) || tcpm_validate_caps(port, port->src_pdo,
-                                           port->nr_src_pdo))
-               return -EINVAL;
+               port->nr_src_pdo = min(ret, PDO_MAX_OBJECTS);
+               ret = fwnode_property_read_u32_array(fwnode, "source-pdos",
+                                                    port->src_pdo, port->nr_src_pdo);
+               if (ret)
+                       return ret;
+               ret = tcpm_validate_caps(port, port->src_pdo, port->nr_src_pdo);
+               if (ret)
+                       return ret;
+       } else {
+               ret = fwnode_property_read_string(fwnode, "typec-power-opmode", &opmode_str);
+               if (ret)
+                       return ret;
+               ret = typec_find_pwr_opmode(opmode_str);
+               if (ret < 0)
+                       return ret;
+               port->src_rp = tcpm_pwr_opmode_to_rp(ret);
+       }
 
        if (port->port_type == TYPEC_PORT_SRC)
                return 0;
@@ -5961,6 +6007,11 @@ static int tcpm_fw_get_caps(struct tcpm_port *port,
        if (port->typec_caps.prefer_role < 0)
                return -EINVAL;
 sink:
+       port->self_powered = fwnode_property_read_bool(fwnode, "self-powered");
+
+       if (!port->pd_supported)
+               return 0;
+
        /* Get sink pdos */
        ret = fwnode_property_count_u32(fwnode, "sink-pdos");
        if (ret <= 0)
@@ -5977,9 +6028,7 @@ sink:
                return -EINVAL;
        port->operating_snk_mw = mw / 1000;
 
-       port->self_powered = fwnode_property_read_bool(fwnode, "self-powered");
-
-       /* FRS can only be supported byb DRP ports */
+       /* FRS can only be supported by DRP ports */
        if (port->port_type == TYPEC_PORT_DRP) {
                ret = fwnode_property_read_u32(fwnode, "new-source-frs-typec-current",
                                               &frs_current);