From d38bf3ff2dbb75f0ad8bf4b9abcdce40cda0c07d Mon Sep 17 00:00:00 2001
From: raiden00pl <raiden00@railab.me>
Date: Thu, 16 Nov 2023 14:16:14 +0100
Subject: [PATCH] nrf91/nrf91_modem.c: configure system mode

---
 arch/arm/src/nrf91/Kconfig       | 27 +++++++++++++++++++
 arch/arm/src/nrf91/nrf91_modem.c | 46 ++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/arch/arm/src/nrf91/Kconfig b/arch/arm/src/nrf91/Kconfig
index 902d71babd..ed57c976fa 100644
--- a/arch/arm/src/nrf91/Kconfig
+++ b/arch/arm/src/nrf91/Kconfig
@@ -742,4 +742,31 @@ config NRF91_MODEM_AT
 	bool "Modem AT interface support"
 	default y
 
+config NRF91_MODEM_LTEM
+	bool "Modem LTE-M mode support"
+	default y
+
+config NRF91_MODEM_NBIOT
+	bool "Modem NB-IoT mode support"
+	default n
+
+config NRF91_MODEM_GNSS
+	bool "Modem GNSS support"
+	depends on SENSORS_GPS
+	default y
+
+config NRF91_MODEM_PREFERENCE
+	int "Modem mode preference"
+	default 0
+	range 0 4
+	---help---
+		0 - No preference. Initial system selection is based on history data and USIM
+		1 - LTE-M preferred
+		2 - NB-IoT preferred
+		3 - Network selection priorities override system priority, but LTE-M is prefered
+		4 - Network selection priorities override system priority, but NB-IoT is prefered
+
+		For details look at "nRF9160 AT Commands Command Reference Guid" from Nordic,
+		section "5.27 System mode"
+
 endif # NRF91_MODEM
diff --git a/arch/arm/src/nrf91/nrf91_modem.c b/arch/arm/src/nrf91/nrf91_modem.c
index c18e2adac9..59d97e7b32 100644
--- a/arch/arm/src/nrf91/nrf91_modem.c
+++ b/arch/arm/src/nrf91/nrf91_modem.c
@@ -32,6 +32,7 @@
 #include "chip.h"
 
 #include "nrf_modem.h"
+#include "nrf_modem_at.h"
 
 #include "nrf91_modem.h"
 
@@ -47,6 +48,18 @@
 #  error NRF91 modem requires using LFXO as the LFCLK source
 #endif
 
+#ifndef CONFIG_NRF91_MODEM_LTEM
+#  define CONFIG_NRF91_MODEM_LTEM 0
+#endif
+
+#ifndef CONFIG_NRF91_MODEM_NBIOT
+#  define CONFIG_NRF91_MODEM_NBIOT 0
+#endif
+
+#ifndef CONFIG_NRF91_MODEM_GNSS
+#  define CONFIG_NRF91_MODEM_GNSS 0
+#endif
+
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
@@ -102,6 +115,30 @@ static void nrf91_modem_fault_handler(struct nrf_modem_fault_info *info)
   ASSERT(0);
 }
 
+/****************************************************************************
+ * Name: nrf91_modem_config
+ ****************************************************************************/
+
+static int nrf91_modem_config(void)
+{
+  int ret;
+
+  /* Configure modem system mode */
+
+  ret = nrf_modem_at_printf("AT%%XSYSTEMMODE=%d,%d,%d,%d",
+                            CONFIG_NRF91_MODEM_LTEM,
+                            CONFIG_NRF91_MODEM_NBIOT,
+                            CONFIG_NRF91_MODEM_GNSS,
+                            CONFIG_NRF91_MODEM_PREFERENCE);
+  if (ret < 0)
+    {
+      goto errout;
+    }
+
+errout:
+  return ret;
+}
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -125,6 +162,15 @@ int nrf91_modem_initialize(void)
 
   /* Initial modem configuration */
 
+  ret = nrf91_modem_config();
+  if (ret < 0)
+    {
+      nerr("nrf91_modem_config failed %d\n", ret);
+      goto errout;
+    }
+
+  /* Initial modem configuration */
+
   ret = nrf91_modem_config();
   if (ret < 0)
     {