fix the custom commands support

modbus/mb_controller/common/esp_modbus_master.c

@@ -8,7 +8,8 @@
 #include "esp_modbus_master.h" // for public interface defines
 
 // Helper macro to set custom command
-#define SET_CMD(mode, rd_cmd, wr_cmd) ((mode == MB_PARAM_WRITE) ? wr_cmd : (mode == MB_PARAM_READ) ? rd_cmd : 0)
+#define GET_CMD(mode, access, rd_cmd, wr_cmd) (((mode == MB_PARAM_WRITE) && (access & PAR_PERMS_WRITE)) ? wr_cmd : \
+                                               ((mode == MB_PARAM_READ) && (access & PAR_PERMS_READ)) ? rd_cmd : 0)
 
 static const char TAG[] __attribute__((unused)) = "MB_CONTROLLER_MASTER";
 
@@ -737,6 +738,8 @@ esp_err_t mbc_master_set_param_data(void* dest, void* src, mb_descr_type_t param
 
 // Helper function to get configured Modbus command for each type of Modbus register area.
 // Supports custom command options using the PAR_PERMS_CUST_CMD permission.
+// The MB_PARAM_CUSTOM register type mimics the custom commands specificly handled with
+// custom command handlers which have to be defined in command handling table.
 uint8_t mbc_master_get_command(const mb_parameter_descriptor_t *pdescr, mb_param_mode_t mode)
 {
     MB_RETURN_ON_FALSE((pdescr), 0, TAG, "incorrect data pointer.");
@@ -744,31 +747,23 @@ uint8_t mbc_master_get_command(const mb_parameter_descriptor_t *pdescr, mb_param
     switch(pdescr->mb_param_type)
     {
         case MB_PARAM_HOLDING:
-            if (pdescr->access & PAR_PERMS_CUST_CMD) {
-                command = SET_CMD(mode, (uint8_t)pdescr->param_opts.cust_cmd_read, (uint8_t)pdescr->param_opts.cust_cmd_write);
-            } else {
-                command = SET_CMD(mode, MB_FUNC_READ_HOLDING_REGISTER, MB_FUNC_WRITE_MULTIPLE_REGISTERS);
-            }
+            command = GET_CMD(mode, pdescr->access, MB_FUNC_READ_HOLDING_REGISTER, MB_FUNC_WRITE_MULTIPLE_REGISTERS);
             break;
         case MB_PARAM_INPUT:
-            if (pdescr->access & PAR_PERMS_CUST_CMD) {
-                command = SET_CMD(mode, (uint8_t)pdescr->param_opts.cust_cmd_read, 0);
-            } else {
-                command = SET_CMD(mode, MB_FUNC_READ_INPUT_REGISTER, 0);
-            }
+            command = GET_CMD(mode, pdescr->access, MB_FUNC_READ_INPUT_REGISTER, 0);
             break;
         case MB_PARAM_COIL:
-            if (pdescr->access & PAR_PERMS_CUST_CMD) {
-                command = SET_CMD(mode, (uint8_t)pdescr->param_opts.cust_cmd_read, (uint8_t)pdescr->param_opts.cust_cmd_write);
-            } else {
-                command = SET_CMD(mode, MB_FUNC_READ_COILS, MB_FUNC_WRITE_MULTIPLE_COILS);
-            }
+            command = GET_CMD(mode, pdescr->access, MB_FUNC_READ_COILS, MB_FUNC_WRITE_MULTIPLE_COILS);
             break;
         case MB_PARAM_DISCRETE:
+            command = GET_CMD(mode, pdescr->access, MB_FUNC_READ_DISCRETE_INPUTS, 0);
+            break;
+        case MB_PARAM_CUSTOM:
             if (pdescr->access & PAR_PERMS_CUST_CMD) {
-                command = SET_CMD(mode, (uint8_t)pdescr->param_opts.cust_cmd_read, 0);
+                // Use custom command in the request for read or write
+                command = GET_CMD(mode, pdescr->access, (uint8_t)pdescr->param_opts.cust_cmd_read, (uint8_t)pdescr->param_opts.cust_cmd_write);
             } else {
-                command = SET_CMD(mode, MB_FUNC_READ_DISCRETE_INPUTS, 0);
+                command = 0;
             }
             break;
         default:

modbus/mb_controller/common/include/esp_modbus_common.h

@@ -150,11 +150,12 @@ typedef enum
  * @brief Type of Modbus parameter
  */
 typedef enum {
-    MB_PARAM_HOLDING = 0x00,         /*!< Modbus Holding register. */
-    MB_PARAM_INPUT,                  /*!< Modbus Input register. */
-    MB_PARAM_COIL,                   /*!< Modbus Coils. */
-    MB_PARAM_DISCRETE,               /*!< Modbus Discrete bits. */
+    MB_PARAM_HOLDING = 0x00,            /*!< Modbus Holding register. */
+    MB_PARAM_INPUT,                     /*!< Modbus Input register. */
+    MB_PARAM_COIL,                      /*!< Modbus Coils. */
+    MB_PARAM_DISCRETE,                  /*!< Modbus Discrete bits. */
     MB_PARAM_COUNT,
+    MB_PARAM_CUSTOM,                    /*!< Modbus custom commands (is not counted in area descriptors). */
     MB_PARAM_UNKNOWN = 0xFF
 } mb_param_type_t;
 

modbus/mb_controller/common/include/esp_modbus_master.h

@@ -71,7 +71,7 @@ typedef union {
     struct {
         int cust_cmd_read;          /*!< Parameter custom read request command */
         int cust_cmd_write;         /*!< Parameter custom write request command */
-        int cust_cmd_not_used;      /*!< Not used option for custom request */
+        int cust_cmd_other;         /*!< Optional field for custom request */
     };
 } mb_parameter_opt_t;
 
@@ -179,7 +179,7 @@ typedef struct {
  */
 typedef struct {
     uint8_t slave_addr;             /*!< Modbus slave address */
-    uint8_t command;    /*!< Modbus command to send */
+    uint8_t command;                /*!< Modbus command to send */
     uint16_t reg_start;             /*!< Modbus start register */
     uint16_t reg_size;              /*!< Modbus number of registers */
 } mb_param_request_t;
@@ -482,6 +482,20 @@ mb_err_enum_t mbc_reg_coils_master_cb(mb_base_t *inst, uint8_t *reg_buffer, uint
 */
 esp_err_t mbc_master_set_param_data(void* dest, void* src, mb_descr_type_t param_type, size_t param_size);
 
+
+/**
+ * @brief The helper function to get supported modbus function code (command) according to parameter type
+ *
+ * @param[in] pdescr the pointer to the characteristic descriptor in data dictionary
+ * @param[in] mode access mode for characteristic
+ *
+ * @return
+ *     - modbus function code, if the command is correctly configured
+ *     - 0 - invalid argument or command not found
+*/
+uint8_t mbc_master_get_command(const mb_parameter_descriptor_t *pdescr, mb_param_mode_t mode);
+
+
 #ifdef __cplusplus
 }
 #endif