Add os.urandom module to ports/analog for MAX32690_apard

I added a port-specific module, os.urandom() to ports/analog. Now
users can generate random numbers from the TRNG hardware. The following
code generates 3 random numbers and prints them in hex:

import os
print(os.urandom(3).hex())

Files I modiied:
* ports/analog/Makefile: added INC and SRC for TRNG
* ports/mpconfigport.mk: enabled CIRCUITPY_RANDOM
* ports/analog/common-hal/os/__init__.c: implemented common_hal_os_urandom()
* ports/analog/supervisor/port.c: initialized the TRNG object

Author: PaggieZ

ports/analog/Makefile

@@ -83,7 +83,8 @@ INC += \
 	-I$(PERIPH_SRC)/ICC \
 	-I$(PERIPH_SRC)/TMR \
 	-I$(PERIPH_SRC)/RTC \
-	-I$(PERIPH_SRC)/UART
+	-I$(PERIPH_SRC)/UART \
+	-I$(PERIPH_SRC)/TRNG
 
 INC += -I$(CMSIS_ROOT)/Device/Maxim/$(MCU_VARIANT_UPPER)/Source/GCC
 
@@ -116,7 +117,9 @@ SRC_MAX32 += \
 	$(PERIPH_SRC)/TMR/tmr_$(DIE_TYPE).c \
 	$(PERIPH_SRC)/UART/uart_common.c \
 	$(PERIPH_SRC)/UART/uart_$(DIE_TYPE).c \
-	$(PERIPH_SRC)/UART/uart_revb.c
+	$(PERIPH_SRC)/UART/uart_revb.c \
+	$(PERIPH_SRC)/TRNG/trng_revb.c \
+	$(PERIPH_SRC)/TRNG/trng_$(DIE_TYPE).c
 
 SRC_C += $(SRC_MAX32) \
 			boards/$(BOARD)/board.c \

ports/analog/common-hal/os/__init__.c

@@ -15,9 +15,14 @@
 
 // #include "peripherals/periph.h"
 
+// true random number generator, TRNG
+#include "trng.h"
+
 bool common_hal_os_urandom(uint8_t *buffer, uint32_t length) {
     #if (HAS_TRNG)
-    // todo (low prior): implement
+    // get a random number of "length" number of bytes
+    MXC_TRNG_Random(buffer, length);
+    return true;
     #else
     #endif
     return false;

ports/analog/mpconfigport.mk

@@ -51,7 +51,7 @@ CIRCUITPY_BITBANGIO ?= 1
 # Requires Microcontroller
 CIRCUITPY_TOUCHIO ?= 1
 # Requires OS
-CIRCUITPY_RANDOM ?= 0
+CIRCUITPY_RANDOM ?= 1
 # Requires busio.UART
 CIRCUITPY_CONSOLE_UART ?= 0
 # Does nothing without I2C

ports/analog/supervisor/port.c

@@ -44,6 +44,9 @@
 #include "mxc_delay.h"
 #include "rtc.h"
 
+// true random number generator, TRNG
+#include "trng.h"
+
 // msec to RTC subsec ticks (4 kHz)
 /* Converts a time in milleseconds to equivalent RSSA register value */
 #define MSEC_TO_SS_ALARM(x) (0 - ((x * 4096) / 1000))
@@ -112,9 +115,18 @@ safe_mode_t port_init(void) {
     }
     ;
 
+    // enable TRNG (true random number generator)
+    #ifdef CIRCUITPY_RANDOM
+    MXC_TRNG_Init();
+    #endif
+
     return SAFE_MODE_NONE;
 }
 
+void TRNG_IRQHandler(void) {
+    MXC_TRNG_Handler();
+}
+
 void RTC_IRQHandler(void) {
     // Read flags to clear
     int flags = MXC_RTC_GetFlags();