[diag] add gpio diag command support (#8316)

examples/platforms/simulation/radio.c

@@ -166,6 +166,13 @@ static otMacKeyMaterial sCurrKey;
 static otMacKeyMaterial sNextKey;
 static otRadioKeyType   sKeyType;
 
+enum
+{
+    SIM_GPIO = 0,
+};
+
+static bool sGpioValue = false;
+
 static int8_t GetRssi(uint16_t aChannel);
 
 #if OPENTHREAD_SIMULATION_VIRTUAL_TIME == 0
@@ -1399,3 +1406,25 @@ void parseFromEnvAsUint16(const char *aEnvName, uint16_t *aValue)
         }
     }
 }
+
+otError otPlatDiagGpioSet(uint32_t aGpio, bool aValue)
+{
+    otError error = OT_ERROR_NONE;
+
+    otEXPECT_ACTION(aGpio == SIM_GPIO, error = OT_ERROR_INVALID_ARGS);
+    sGpioValue = aValue;
+
+exit:
+    return error;
+}
+
+otError otPlatDiagGpioGet(uint32_t aGpio, bool *aValue)
+{
+    otError error = OT_ERROR_NONE;
+
+    otEXPECT_ACTION((aGpio == SIM_GPIO) && (aValue != NULL), error = OT_ERROR_INVALID_ARGS);
+    *aValue = sGpioValue;
+
+exit:
+    return error;
+}