Read the Type-C Current in the PE, not the DPM

Now the call to fusb_get_typec_current is made in the policy engine,
then passed to pdb_dpm_evaluate_typec_current.  This is more consistent
with pdb_dpm_evaluate_capability, improving the PD Buddy DPM API.
That's right, I'm thinking about API design now for when I split the
code into a library and application.

src/device_policy_manager.c

@@ -185,15 +185,16 @@ bool pdb_dpm_giveback_enabled(void)
     return cfg->flags & PDB_CONFIG_FLAGS_GIVEBACK;
 }
 
-bool pdb_dpm_evaluate_typec_current(void)
+bool pdb_dpm_evaluate_typec_current(enum fusb_typec_current tcc)
 {
     struct pdb_config *cfg = pdb_config_flash_read();
 
     /* We don't control the voltage anymore; it will always be 5 V. */
     dpm_requested_voltage = PD_MV2PDV(5000);
 
-    /* Get the present Type-C Current advertisement */
-    pdb_dpm_typec_current = fusb_get_typec_current();
+    /* Make the present Type-C Current advertisement available to the rest of
+     * the DPM */
+    pdb_dpm_typec_current = tcc;
 
     /* If we have no configuration or don't want 5 V, Type-C Current can't
      * possibly satisfy our needs */
@@ -202,11 +203,11 @@ bool pdb_dpm_evaluate_typec_current(void)
     }
 
     /* If 1.5 A is available and we want no more than that, great. */
-    if (pdb_dpm_typec_current == OnePointFiveAmps && cfg->i <= 150) {
+    if (tcc == OnePointFiveAmps && cfg->i <= 150) {
         return true;
     }
     /* If 3 A is available and we want no more than that, that's great too. */
-    if (pdb_dpm_typec_current == ThreePointZeroAmps && cfg->i <= 300) {
+    if (tcc == ThreePointZeroAmps && cfg->i <= 300) {
         return true;
     }
     /* We're overly cautious if USB default current is available, since that

src/device_policy_manager.h

@@ -66,7 +66,7 @@ bool pdb_dpm_giveback_enabled(void);
  *
  * Returns true if sufficient power is available, false otherwise.
  */
-bool pdb_dpm_evaluate_typec_current(void);
+bool pdb_dpm_evaluate_typec_current(enum fusb_typec_current tcc);
 
 /*
  * Indicate that power negotiations are starting.

src/policy_engine.c

@@ -25,6 +25,7 @@
 #include "device_policy_manager.h"
 #include "protocol_tx.h"
 #include "hard_reset.h"
+#include "fusb302b.h"
 #include "pd.h"
 
 
@@ -637,7 +638,7 @@ static enum policy_engine_state pe_sink_send_reject(void)
 static enum policy_engine_state pe_sink_source_unresponsive(void)
 {
     static int old_tcc_match = -1;
-    int tcc_match = pdb_dpm_evaluate_typec_current();
+    int tcc_match = pdb_dpm_evaluate_typec_current(fusb_get_typec_current());
 
     /* If the last two readings are the same, set the output */
     if (old_tcc_match == tcc_match) {