Added LED status code for default USB power

It's useful to know when only default USB power is available, as opposed
to when some mechanism for negotiating higher power is available but it
isn't possible to get high enough power.  This can let users know e.g.
using a USB A to C cable can't provide high power, potentially reducing
confusion.

The blink code for this is 1 7/8 s on, 1/8 s off.  I think this is
sufficiently unlike other blink patterns that it won't cause any
confusion.

(cherry picked from commit b4680ab723)

README.md

 
 ### Status LED descriptions
 
-LED State            | Mode  | Meaning
----------------------|-------|---------------------------------------------------
-Fast blink (4/sec)   | Sink  | Negotiating USB Power Delivery contract
-Medium blink (2/sec) | Sink  | USB Power Delivery contract established, output on
-Off                  | Sink  | Output on
-On                   | Sink  | Unable to get configured power from source
-Slow blink (1/sec)   | Setup | Running in setup mode
-Fast blink (4/sec)   | Setup | `identify` command run
+LED State                  | Mode  | Meaning
+---------------------------|-------|---------------------------------------------------
+Fast blink (4 blink/sec)   | Sink  | Negotiating USB Power Delivery contract
+Medium blink (2 blink/sec) | Sink  | USB Power Delivery contract established, output on
+Off                        | Sink  | Output on
+On                         | Sink  | Unable to get configured power from source
+Long blink (1 blink/2 sec) | Sink  | Only default USB power is available (e.g. powered with USB A to C cable)
+Slow blink (1 blink/sec)   | Setup | Running in setup mode
+Fast blink (4 blink/sec)   | Setup | `identify` command run

src/device_policy_manager.c

 /*
  * Set the output state, with LED indication.
  */
-static void dpm_output_set(struct pdbs_dpm_data *dpm_data, bool state)
+static void dpm_output_set(struct pdbs_dpm_data *dpm_data, bool state, bool led)
 {
     /* Update the present voltage */
     dpm_data->_present_voltage = dpm_data->_requested_voltage;
     /* Set the power output */
     if (state && dpm_data->output_enabled) {
         /* Turn the output on */
-        if (dpm_data->led_pd_status) {
+        if (dpm_data->led_pd_status && led) {
             chEvtSignal(pdbs_led_thread, PDBS_EVT_LED_OUTPUT_ON);
         }
         palSetLine(LINE_OUT_CTRL);
     } else {
         /* Turn the output off */
-        if (dpm_data->led_pd_status) {
+        if (dpm_data->led_pd_status && led) {
             chEvtSignal(pdbs_led_thread, PDBS_EVT_LED_OUTPUT_OFF);
         }
         palClearLine(LINE_OUT_CTRL);
     /* Pretend we requested 5 V */
     dpm_data->_requested_voltage = 5000;
     /* Turn the output off */
-    dpm_output_set(cfg->dpm_data, false);
+    dpm_output_set(cfg->dpm_data, false, true);
 }
 
 void pdbs_dpm_transition_min(struct pdb_config *cfg)
 {
-    dpm_output_set(cfg->dpm_data, false);
+    dpm_output_set(cfg->dpm_data, false, true);
 }
 
 void pdbs_dpm_transition_standby(struct pdb_config *cfg)
     /* Cast the dpm_data to the right type */
     struct pdbs_dpm_data *dpm_data = cfg->dpm_data;
 
-    dpm_output_set(cfg->dpm_data, dpm_data->_capability_match);
+    dpm_output_set(cfg->dpm_data, dpm_data->_capability_match, true);
+}
+
+void pdbs_dpm_transition_typec(struct pdb_config *cfg)
+{
+    /* Cast the dpm_data to the right type */
+    struct pdbs_dpm_data *dpm_data = cfg->dpm_data;
+
+    /* If we only have default Type-C Current, set a special LED status */
+    if (dpm_data->led_pd_status
+            && dpm_data->typec_current == fusb_tcc_default) {
+        chEvtSignal(pdbs_led_thread, PDBS_EVT_LED_OUTPUT_OFF_NO_TYPEC);
+    }
+
+    /* Set the output, only setting the LED status if it wasn't set above */
+    dpm_output_set(cfg->dpm_data, dpm_data->_capability_match,
+            dpm_data->typec_current != fusb_tcc_default);
 }

src/device_policy_manager.h

  */
 void pdbs_dpm_transition_requested(struct pdb_config *cfg);
 
+/*
+ * Transition to the Type-C Current power level
+ */
+void pdbs_dpm_transition_typec(struct pdb_config *cfg);
+
 
 #endif /* PDBS_DEVICE_POLICY_MANAGER_H */

src/led.c

                     palToggleLine(LINE_LED);
                 }
                 break;
+            case PDBS_EVT_LED_LONG_BLINK:
+                timeout = LED_FAST;
+                if (i % 16 == 0) {
+                    palClearLine(LINE_LED);
+                } else {
+                    palSetLine(LINE_LED);
+                }
+                break;
             case PDBS_EVT_LED_FAST_BLINK_SLOW:
                 timeout = LED_FAST;
                 if (i == 0) {

src/led.h

 #define PDBS_EVT_LED_MEDIUM_BLINK_OFF EVENT_MASK(3)
 #define PDBS_EVT_LED_SLOW_BLINK EVENT_MASK(4)
 #define PDBS_EVT_LED_FAST_BLINK_SLOW EVENT_MASK(5)
+#define PDBS_EVT_LED_LONG_BLINK EVENT_MASK(6)
 
 /* Semantic LED event names */
 #define PDBS_EVT_LED_CONFIG PDBS_EVT_LED_SLOW_BLINK
 #define PDBS_EVT_LED_NEGOTIATING PDBS_EVT_LED_FAST_BLINK
 #define PDBS_EVT_LED_OUTPUT_ON PDBS_EVT_LED_MEDIUM_BLINK_OFF
 #define PDBS_EVT_LED_OUTPUT_OFF PDBS_EVT_LED_ON
+#define PDBS_EVT_LED_OUTPUT_OFF_NO_TYPEC PDBS_EVT_LED_LONG_BLINK
 
 /* The LED thread object */
 extern thread_t *pdbs_led_thread;

src/main.c

         pdbs_dpm_transition_min,
         pdbs_dpm_transition_standby,
         pdbs_dpm_transition_requested,
-        pdbs_dpm_transition_requested, /* transition_typec */
+        pdbs_dpm_transition_typec,
         NULL /* not_supported_received */
     },
     .dpm_data = &dpm_data