Fix frequency function of CAN driver.

Until now, when the frequency function of CAN driver was executed, signal no output, and the frequency could not be changed.
Since there was an error in the frequency changing procedure I modified it.

Author: TomoYamanaka

targets/TARGET_RENESAS/TARGET_RZ_A1H/can_api.c

@@ -581,6 +581,7 @@ void can_free(can_t *obj) {
 }
 
 int can_frequency(can_t *obj, int f) {
+    __IO uint32_t *dmy_cfcc;
     int retval = 0;
 
     if (f <= 1000000) {
@@ -590,6 +591,12 @@ int can_frequency(can_t *obj, int f) {
         can_set_frequency(obj, f);
         /* set Channel Communication mode */
         can_set_channel_mode(obj->ch, CH_COMM);
+        /* restore  CFE bit since it is cleared */
+        /* Use send/receive FIFO buffer */
+        dmy_cfcc = CFCC_TBL[obj->ch][CAN_SEND];
+        *dmy_cfcc |= 0x01;
+        dmy_cfcc = CFCC_TBL[obj->ch][CAN_RECV];
+        *dmy_cfcc |= 0x01;
         retval = 1;
     }
 

targets/TARGET_RENESAS/TARGET_VK_RZ_A1H/can_api.c

@@ -598,6 +598,7 @@ void can_free(can_t *obj) {
 }
 
 int can_frequency(can_t *obj, int f) {
+    __IO uint32_t *dmy_cfcc;
     int retval = 0;
 
     if (f <= 1000000) {
@@ -607,6 +608,12 @@ int can_frequency(can_t *obj, int f) {
         can_set_frequency(obj, f);
         /* set Channel Communication mode */
         can_set_channel_mode(obj->ch, CH_COMM);
+        /* restore  CFE bit since it is cleared */
+        /* Use send/receive FIFO buffer */
+        dmy_cfcc = CFCC_TBL[obj->ch][CAN_SEND];
+        *dmy_cfcc |= 0x01;
+        dmy_cfcc = CFCC_TBL[obj->ch][CAN_RECV];
+        *dmy_cfcc |= 0x01;
         retval = 1;
     }