Allow the DPM to not control the LED

The DPM used to always set the LED to indicate the PD status.  This
caused fighting when the PD threads were run simultaneously with the
shell, making the LED show different things depending on what commands
the user ran.  Not cool!

This commit adds a bool pdb_dpm_led_pd_status, which prevents the DPM
from setting the LED when set to false.  This commit also sets it to
false before starting the PD threads in Setup mode, allowing the shell
to be in full control of the LED.  Right on!

src/device_policy_manager.c

 #include "fusb302b.h"
 
 
+bool pdb_dpm_led_pd_status = true;
+
+
 /* The current draw when the output is disabled */
 #define DPM_MIN_CURRENT PD_MA2PDI(100)
 
     uint8_t numobj = PD_NUMOBJ_GET(capabilities);
 
     /* Make the LED blink to indicate ongoing power negotiations */
-    chEvtSignal(pdb_led_thread, PDB_EVT_LED_NEGOTIATING);
+    if (pdb_dpm_led_pd_status) {
+        chEvtSignal(pdb_led_thread, PDB_EVT_LED_NEGOTIATING);
+    }
 
     /* Get whether or not the power supply is constrained */
     dpm_unconstrained_power = capabilities->obj[0] & PD_PDO_SRC_FIXED_UNCONSTRAINED;
 
 void pdb_dpm_pd_start(void)
 {
-    chEvtSignal(pdb_led_thread, PDB_EVT_LED_NEGOTIATING);
+    if (pdb_dpm_led_pd_status) {
+        chEvtSignal(pdb_led_thread, PDB_EVT_LED_NEGOTIATING);
+    }
 }
 
 void pdb_dpm_sink_standby(void)
     /* Set the power output */
     if (state) {
         /* Turn the output on */
-        chEvtSignal(pdb_led_thread, PDB_EVT_LED_OUTPUT_ON);
+        if (pdb_dpm_led_pd_status) {
+            chEvtSignal(pdb_led_thread, PDB_EVT_LED_OUTPUT_ON);
+        }
         palSetLine(LINE_OUT_CTRL);
     } else {
         /* Turn the output off */
-        chEvtSignal(pdb_led_thread, PDB_EVT_LED_OUTPUT_OFF);
+        if (pdb_dpm_led_pd_status) {
+            chEvtSignal(pdb_led_thread, PDB_EVT_LED_OUTPUT_OFF);
+        }
         palClearLine(LINE_OUT_CTRL);
     }
 }

src/device_policy_manager.h

 #include "messages.h"
 
 
+/* Whether the DPM sets the LED to indicate the PD status */
+extern bool pdb_dpm_led_pd_status;
+
+
 /*
  * Create a Request message based on the given Source_Capabilities message.
  *

src/main.c

 
 #include "priorities.h"
 #include "led.h"
+#include "device_policy_manager.h"
 #include "policy_engine.h"
 #include "protocol_tx.h"
 #include "protocol_rx.h"
  */
 static void setup(void)
 {
+    /* Set the DPM to not set the LED to show PD status */
+    pdb_dpm_led_pd_status = false;
+
     /* Start the USB Power Delivery threads */
     start_pd();