Implemented power support in the command shell

This commit adds the `set_p` command for setting power, and the `p`
configuration field for reading it back.  There is no support for making
requests based on power yet (the field is still interpreted as a current
unconditionally).

lib/include/pd.h

  * PRV: Programmable RDO voltage unit (20 mV)
  * PDV: Power Delivery voltage unit (50 mV)
  * PAV: PPS APDO voltage unit (100 mV)
+ *
  * A: ampere
  * CA: centiampere
  * MA: milliampere
  * PDI: Power Delivery current unit (10 mA)
  * PAI: PPS APDO current unit (50 mA)
+ *
+ * W: watt
+ * CW: centiwatt
+ * MW: milliwatt
  */
 #define PD_MV2PRV(mv) ((mv) / 20)
 #define PD_MV2PDV(mv) ((mv) / 50)
 #define PD_PRV2MV(prv) ((prv) * 20)
 #define PD_PDV2MV(pdv) ((pdv) * 50)
 #define PD_PAV2MV(pav) ((pav) * 100)
+
 #define PD_MA2PDI(ma) ((ma) / 10)
 #define PD_MA2PAI(ma) ((ma) / 50)
 #define PD_CA2PAI(ca) ((ca) / 5)
 #define PD_PAI2MA(pai) ((pai) * 50)
 #define PD_PAI2CA(pai) ((pai) * 5)
 
+#define PD_MW2CW(mw) ((mw) / 10)
+
 /* Get portions of a voltage in more normal units */
 #define PD_MV_V(mv) ((mv) / 1000)
 #define PD_MV_MV(mv) ((mv) % 1000)
 #define PD_PAI_A(pai) ((pai) / 20)
 #define PD_PAI_CA(pai) (5 * ((pai) % 20))
 
+/* Get portions of a power in more normal units */
+#define PD_CW_W(cw) ((cw) / 100)
+#define PD_CW_CW(cw) ((cw) % 100)
+
 /*
  * Unit constants
  */
 #define PD_MV_MAX 21000
 #define PD_PDV_MIN PD_MV2PDV(PD_MV_MIN)
 #define PD_PDV_MAX PD_MV2PDV(PD_MV_MAX)
+
 #define PD_MA_MIN 0
 #define PD_MA_MAX 5000
 #define PD_PDI_MIN PD_MA2PDI(PD_MA_MIN)
 #define PD_PDI_MAX PD_MA2PDI(PD_MA_MAX)
 
+#define PD_MW_MIN 0
+#define PD_MW_MAX 100000
+
 
 #endif /* PDB_PD_H */

src/config.c

         case PDBS_CONFIG_FLAGS_CURRENT_DEFN_I:
             chprintf(chp, "i: %d.%02d A\r\n", PD_PDI_A(cfg->i), PD_PDI_CA(cfg->i));
             break;
+        case PDBS_CONFIG_FLAGS_CURRENT_DEFN_P:
+            chprintf(chp, "p: %d.%02d W\r\n", PD_CW_W(cfg->p), PD_CW_CW(cfg->p));
+            break;
     }
 }
 

src/shell.c

     }
 }
 
+static void cmd_set_p(BaseSequentialStream *chp, int argc, char *argv[])
+{
+    if (argc != 1) {
+        chprintf(chp, "Usage: set_p power_in_mW\r\n");
+        return;
+    }
+
+    char *endptr;
+    long i = strtol(argv[0], &endptr, 0);
+    if (i >= PD_MW_MIN && i <= PD_MW_MAX && endptr > argv[0]) {
+        /* Convert mW to the unit used in the configuration object */
+        tmpcfg.p = PD_MW2CW(i);
+        /* Set the flags to say we're storing a power */
+        tmpcfg.flags &= ~PDBS_CONFIG_FLAGS_CURRENT_DEFN;
+        tmpcfg.flags |= PDBS_CONFIG_FLAGS_CURRENT_DEFN_P;
+    } else {
+        chprintf(chp, "Invalid power\r\n");
+        return;
+    }
+}
+
 static void cmd_output(BaseSequentialStream *chp, int argc, char *argv[])
 {
     if (argc == 0) {
     {"set_v", cmd_set_v, "Set the voltage in millivolts"},
     {"set_vrange", cmd_set_vrange, "Set the minimum and maximum voltage in millivolts"},
     {"set_i", cmd_set_i, "Set the current in milliamps"},
+    {"set_p", cmd_set_p, "Set the power in milliwatts"},
     {"output", cmd_output, "Get or set the output status"},
     {"get_source_cap", cmd_get_source_cap, "Print the capabilities of the PD source"},
     {NULL, NULL, NULL}