drivers: entropy: gecko_trng: Fully initialize on read

If the TRNG has been unretained, it's not sufficient to enable
the clock, it must be fully reinitialized.

This is a minimal fix to ensure entropy is accumulated after sleep.
Long term, this driver should be made to use device power
management with power domain awareness.

Signed-off-by: Aksel Skauge Mellbye <[email protected]>

Author: asmellby

drivers/entropy/entropy_gecko_trng.c

@@ -44,6 +44,8 @@
 #endif	/* _SILICON_LABS_32B_SERIES_2_CONFIG_* */
 #endif	/* CONFIG_CRYPTO_ACC_GECKO_TRNG */
 
+static int entropy_gecko_trng_init(const struct device *dev);
+
 static void entropy_gecko_trng_read(uint8_t *output, size_t len)
 {
 #ifndef CONFIG_CRYPTO_ACC_GECKO_TRNG
@@ -77,7 +79,7 @@ static int entropy_gecko_trng_get_entropy(const struct device *dev,
 	ARG_UNUSED(dev);
 
 #ifdef CONFIG_CRYPTO_ACC_GECKO_TRNG
-	CMU_ClockEnable(cmuClock_CRYPTOACC, true);
+	entropy_gecko_trng_init(dev);
 #endif
 
 	while (length) {