Improve readability of elm327_handle_prompt()

diff --git a/module/elmcan.c b/module/elmcan.c
index 1c1465f1a570bed53d1c9ad6515315438db6c73a..c3acc07f70f5da8cb1880e86ea8eeba09827742a 100644 (file)
--- a/module/elmcan.c
+++ b/module/elmcan.c
@@ -567,7 +567,7 @@ static void elm327_handle_prompt(struct elmcan *elm)
 {
        if (elm->cmds_todo) {
                struct can_frame *frame = &elm->can_frame;
-               char txbuf[20];
+               char local_txbuf[20];
 
                if (test_bit(ELM_TODO_INIT, &elm->cmds_todo)) {
                        elm327_send(elm, *elm->next_init_cmd, strlen(*elm->next_init_cmd));
@@ -585,36 +585,54 @@ static void elm327_handle_prompt(struct elmcan *elm)
                        elm327_kick_into_cmd_mode(elm);
 
                        return;
+
                } else if (test_and_clear_bit(ELM_TODO_SILENT_MONITOR, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATCSM%i\r", !(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)));
+                       sprintf(local_txbuf, "ATCSM%i\r",
+                               !(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)));
+
                } else if (test_and_clear_bit(ELM_TODO_RESPONSES, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATR%i\r", !(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
+                       sprintf(local_txbuf, "ATR%i\r",
+                               !(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
+
                } else if (test_and_clear_bit(ELM_TODO_CAN_CONFIG, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATPB%04X\r", elm->can_config);
+                       sprintf(local_txbuf, "ATPB%04X\r",
+                               elm->can_config);
+
                } else if (test_and_clear_bit(ELM_TODO_CANID_29BIT_HIGH, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATCP%02X\r", (frame->can_id & CAN_EFF_MASK) >> 24);
+                       sprintf(local_txbuf, "ATCP%02X\r",
+                               (frame->can_id & CAN_EFF_MASK) >> 24);
+
                } else if (test_and_clear_bit(ELM_TODO_CANID_29BIT_LOW, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATSH%06X\r", frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1));
+                       sprintf(local_txbuf, "ATSH%06X\r",
+                               frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1));
+
                } else if (test_and_clear_bit(ELM_TODO_CANID_11BIT, &elm->cmds_todo)) {
-                       snprintf(txbuf, sizeof(txbuf), "ATSH%03X\r", frame->can_id & CAN_SFF_MASK);
+                       sprintf(local_txbuf, "ATSH%03X\r",
+                               frame->can_id & CAN_SFF_MASK);
+
                } else if (test_and_clear_bit(ELM_TODO_CAN_DATA, &elm->cmds_todo)) {
                        if (frame->can_id & CAN_RTR_FLAG) {
-                               snprintf(txbuf, sizeof(txbuf), "ATRTR\r");
+                               /* Send an RTR frame. Their DLC is fixed.
+                                * Some chips don't send them at all.
+                                */
+                               sprintf(local_txbuf, "ATRTR\r");
                        } else {
+                               /* Send a regular CAN data frame */
                                int i;
 
                                for (i = 0; i < frame->can_dlc; i++) {
-                                       sprintf(&txbuf[2*i], "%02X", frame->data[i]);
+                                       sprintf(&local_txbuf[2*i], "%02X",
+                                               frame->data[i]);
                                }
 
-                               sprintf(&txbuf[2*i], "\r");
+                               sprintf(&local_txbuf[2*i], "\r");
                        }
 
                        elm->drop_next_line = 1;
                        elm->state = ELM_RECEIVING;
                }
 
-               elm327_send(elm, txbuf, strlen(txbuf));
+               elm327_send(elm, local_txbuf, strlen(local_txbuf));
        } else {
                /* Enter CAN monitor mode */
                elm327_send(elm, "ATMA\r", 5);