nrf: boards: nordic: nrf7120pdk: Enable prng for zephyr,entropy

Add nRF7120 to FAKE_ENTROPY_NRF_PRNG config
Enabled prng for zephyr,entropy on nRF7120

Signed-off-by: Robert Robinson <[email protected]>

Author: rob-robinson-14

boards/nordic/nrf7120pdk/nrf7120pdk_nrf7120_cpuapp.dts

@@ -14,5 +14,11 @@
 
 	chosen {
 		zephyr,sram = &cpuapp_sram;
+		zephyr,entropy = &prng;
+	};
+
+	prng: prng {
+		compatible = "nordic,entropy-prng";
+		status = "okay";
 	};
 };

boards/nordic/nrf7120pdk/nrf7120pdk_nrf7120_cpuapp_emu.dts

@@ -17,6 +17,12 @@
 		zephyr,sram = &cpuapp_sram;
 		zephyr,console = &uart00;
 		zephyr,shell-uart = &uart00;
+		zephyr,entropy = &prng;
+	};
+
+	prng: prng {
+		compatible = "nordic,entropy-prng";
+		status = "okay";
 	};
 };
 

drivers/entropy/Kconfig

@@ -4,6 +4,8 @@
 #
 # SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 
+rsource "Kconfig.nrf_prng"
+
 config ENTROPY_CC3XX
 	bool "Arm CC3XX RNG driver for Nordic devices"
 	depends on HAS_HW_NRF_CC3XX && !BUILD_WITH_TFM

drivers/entropy/Kconfig.nrf_prng

@@ -0,0 +1,20 @@
+# nRF fake entropy prng generator driver configuration
+#
+# Copyright (c) 2025 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+
+if ENTROPY_GENERATOR
+
+config FAKE_ENTROPY_NRF_PRNG
+	bool "A fake nRF entropy driver"
+	default y
+	depends on DT_HAS_NORDIC_ENTROPY_PRNG_ENABLED
+	depends on (SOC_SERIES_NRF54HX || SOC_SERIES_NRF92X || SOC_SERIES_NRF54LX || SOC_SERIES_NRF71X)
+	select ENTROPY_HAS_DRIVER
+	help
+	  This is a super simple PRNG driver that can be used on nRF platforms that
+	  do not have an entropy source.
+	  This is NOT SAFE to use for cryptographic operations!
+
+endif