drivers: modem: ublox-sara-r4: Support SARA-U2 modems, sense VINT

This adds support for SARA-U2 modems. They have different timings on
the PWR_ON pin, don't support AT+CESQ and require a manual GPRS
connection setup.

The VINT pin is used as a more reliable and faster way to power on the
modem.

Based on work by Göran Weinholt <goran.weinholt@endian.se>

Signed-off-by: Michael Scott <mike@foundries.io>

boards/arm/particle_boron/Kconfig.defconfig

@@ -58,9 +58,13 @@ config UART_1_NRF_UARTE
 config UART_1_NRF_FLOW_CONTROL
 	default y
 
-config MODEM_UBLOX_SARA_R4
+config MODEM_UBLOX_SARA
 	default y
 
+choice MODEM_UBLOX_SARA_VARIANT
+	default MODEM_UBLOX_SARA_R4
+endchoice
+
 config UART_INTERRUPT_DRIVEN
 	default y
 

boards/arm/particle_boron/board.c

@@ -39,7 +39,7 @@ static int board_particle_boron_init(struct device *dev)
 
 	external_antenna(false);
 
-#if defined(CONFIG_MODEM_UBLOX_SARA_R4)
+#if defined(CONFIG_MODEM_UBLOX_SARA)
 	struct device *gpio_dev;
 
 	/* Enable the serial buffer for SARA-R4 modem */
@@ -52,6 +52,7 @@ static int board_particle_boron_init(struct device *dev)
 
 	gpio_pin_configure(gpio_dev, SERIAL_BUFFER_ENABLE_GPIO_PIN,
 			   GPIO_DIR_OUT);
+	gpio_pin_write(gpio_dev, SERIAL_BUFFER_ENABLE_GPIO_PIN, 0);
 #endif
 
 	return 0;

boards/arm/particle_boron/particle_boron.dts

@@ -48,5 +48,6 @@
 
 		mdm-power-gpios = <&gpio0 16 0>;
 		mdm-reset-gpios = <&gpio0 12 0>;
+		mdm-vint-gpios = <&gpio0 2 0>;
 	};
 };

boards/shields/sparkfun_sara_r4/sparkfun_sara_r4.conf

@@ -1,6 +1,7 @@
 # Enable u-blox SARA-R4 modem
 CONFIG_MODEM=y
 CONFIG_MODEM_SHELL=y
+CONFIG_MODEM_UBLOX_SARA=y
 CONFIG_MODEM_UBLOX_SARA_R4=y
 CONFIG_UART_INTERRUPT_DRIVEN=y
 

drivers/modem/CMakeLists.txt

@@ -12,7 +12,7 @@ zephyr_sources_ifdef(CONFIG_MODEM_IFACE_UART modem_iface_uart.c)
 zephyr_sources_ifdef(CONFIG_MODEM_CMD_HANDLER modem_cmd_handler.c)
 zephyr_sources_ifdef(CONFIG_MODEM_SOCKET modem_socket.c)
 
-if(CONFIG_MODEM_UBLOX_SARA_R4)
+if(CONFIG_MODEM_UBLOX_SARA)
 	zephyr_library_include_directories(${ZEPHYR_BASE}/subsys/net/ip)
 	zephyr_library_sources(ublox-sara-r4.c)
 endif()

drivers/modem/Kconfig.ublox-sara-r4

@@ -6,8 +6,8 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
-config MODEM_UBLOX_SARA_R4
+config MODEM_UBLOX_SARA
-	bool "Enable u-blox SARA-R4 LTE-CatM1/NB-IoT modem driver"
+	bool "Enable u-blox SARA modem driver"
 	select MODEM_CONTEXT
 	select MODEM_CMD_HANDLER
 	select MODEM_IFACE_UART
@@ -19,7 +19,23 @@ config MODEM_UBLOX_SARA_R4
 	  Choose this setting to enable u-blox SARA-R4 LTE-CatM1/NB-IoT modem
 	  driver.
 
-if MODEM_UBLOX_SARA_R4
+if MODEM_UBLOX_SARA
+
+choice MODEM_UBLOX_SARA_VARIANT
+	bool "u-blox SARA variant selection"
+	default MODEM_UBLOX_SARA_R4
+
+config MODEM_UBLOX_SARA_R4
+	bool "u-blox SARA-R4"
+	help
+	  Enable support for SARA-R4 modem
+
+config MODEM_UBLOX_SARA_U2
+	bool "u-blox SARA-U2"
+	help
+	  Enable support for SARA-U2 modem
+
+endchoice
 
 config MODEM_UBLOX_SARA_R4_NAME
 	string "Driver name"
@@ -64,4 +80,4 @@ config MODEM_UBLOX_SARA_R4_INIT_PRIORITY
 	  Note that the priority needs to be lower than the net stack
 	  so that it can start before the networking sub-system.
 
-endif # MODEM_UBLOX_SARA_R4
+endif # MODEM_UBLOX_SARA

drivers/modem/ublox-sara-r4.c

@@ -33,6 +33,9 @@ LOG_MODULE_REGISTER(modem_ublox_sara_r4, CONFIG_MODEM_LOG_LEVEL);
 enum mdm_control_pins {
 	MDM_POWER = 0,
 	MDM_RESET,
+#if defined(DT_UBLOX_SARA_R4_0_MDM_VINT_GPIOS_CONTROLLER)
+	MDM_VINT,
+#endif
 };
 
 static struct modem_pin modem_pins[] = {
@@ -44,6 +47,11 @@ static struct modem_pin modem_pins[] = {
 	MODEM_PIN(DT_INST_0_UBLOX_SARA_R4_MDM_RESET_GPIOS_CONTROLLER,
 		  DT_INST_0_UBLOX_SARA_R4_MDM_RESET_GPIOS_PIN, GPIO_DIR_OUT),
 
+#if defined(DT_UBLOX_SARA_R4_0_MDM_VINT_GPIOS_CONTROLLER)
+	/* MDM_VINT */
+	MODEM_PIN(DT_INST_0_UBLOX_SARA_R4_MDM_VINT_GPIOS_CONTROLLER,
+		  DT_INST_0_UBLOX_SARA_R4_MDM_VINT_GPIOS_PIN, GPIO_DIR_IN),
+#endif
 };
 
 #define MDM_UART_DEV_NAME		DT_INST_0_UBLOX_SARA_R4_BUS_NAME
@@ -52,10 +60,14 @@ static struct modem_pin modem_pins[] = {
 #define MDM_POWER_DISABLE		0
 #define MDM_RESET_NOT_ASSERTED		1
 #define MDM_RESET_ASSERTED		0
+#if defined(DT_UBLOX_SARA_R4_0_MDM_VINT_GPIOS_CONTROLLER)
+#define MDM_VINT_ENABLE			1
+#define MDM_VINT_DISABLE		0
+#endif
 
 #define MDM_CMD_TIMEOUT			K_SECONDS(10)
 #define MDM_REGISTRATION_TIMEOUT	K_SECONDS(180)
-#define MDM_PROMPT_CMD_DELAY		K_MSEC(10)
+#define MDM_PROMPT_CMD_DELAY		K_MSEC(75)
 
 #define MDM_MAX_DATA_LENGTH		1024
 #define MDM_RECV_MAX_BUF		30
@@ -255,7 +267,7 @@ static int send_socket_data(struct modem_socket *sock,
 
 	/* slight pause per spec so that @ prompt is received */
 	k_sleep(MDM_PROMPT_CMD_DELAY);
-
+#if defined(CONFIG_MODEM_UBLOX_SARA_R4)
 	/*
 	 * HACK: Apparently, enabling HEX transmit mode also
 	 * affects the BINARY send method.  We need to encode
@@ -266,6 +278,9 @@ static int send_socket_data(struct modem_socket *sock,
 		snprintk(send_buf, sizeof(send_buf), "%02x", buf[i]);
 		mctx.iface.write(&mctx.iface, send_buf, 2U);
 	}
+#else
+	mctx.iface.write(&mctx.iface, buf, buf_len);
+#endif
 
 	if (timeout == K_NO_WAIT) {
 		ret = 0;
@@ -367,6 +382,7 @@ MODEM_CMD_DEFINE(on_cmd_atcmdinfo_imei)
 	LOG_INF("IMEI: %s", log_strdup(mdata.mdm_imei));
 }
 
+#if !defined(CONFIG_MODEM_UBLOX_SARA_U2)
 /*
  * Handler: +CESQ: <rxlev>[0],<ber>[1],<rscp>[2],<ecn0>[3],<rsrq>[4],<rsrp>[5]
  */
@@ -383,6 +399,27 @@ MODEM_CMD_DEFINE(on_cmd_atcmdinfo_rssi_cesq)
 
 	LOG_INF("RSRP: %d", mctx.data_rssi);
 }
+#endif
+
+#if defined(CONFIG_MODEM_UBLOX_SARA_U2)
+/* Handler: +CSQ: <signal_power>[0],<qual>[1] */
+MODEM_CMD_DEFINE(on_cmd_atcmdinfo_rssi_csq)
+{
+	int rssi;
+
+	rssi = ATOI(argv[1], 0, "qual");
+	if (rssi == 31) {
+		mctx.data_rssi = -46;
+	} else if (rssi >= 0 && rssi <= 31) {
+		/* FIXME: This value depends on the RAT */
+		mctx.data_rssi = -110 + ((rssi * 2) + 1);
+	} else {
+		mctx.data_rssi = -1000;
+	}
+
+	LOG_INF("QUAL: %d", mctx.data_rssi);
+}
+#endif
 
 /*
  * Modem Socket Command Handlers
@@ -595,21 +632,53 @@ static int pin_init(void)
 
 	LOG_DBG("MDM_POWER_PIN -> DISABLE");
 	modem_pin_write(&mctx, MDM_POWER, MDM_POWER_DISABLE);
+#if defined(CONFIG_MODEM_UBLOX_SARA_U2)
+	k_sleep(K_SECONDS(1));
+#else
 	k_sleep(K_SECONDS(4));
+#endif
 	LOG_DBG("MDM_POWER_PIN -> ENABLE");
 	modem_pin_write(&mctx, MDM_POWER, MDM_POWER_ENABLE);
 	k_sleep(K_SECONDS(1));
 
 	/* make sure module is powered off */
+#if defined(DT_UBLOX_SARA_R4_0_MDM_VINT_GPIOS_CONTROLLER)
+	LOG_DBG("Waiting for MDM_VINT_PIN = 0");
+
+	do {
+		k_sleep(K_MSEC(100));
+	} while (modem_pin_read(&mctx, MDM_VINT) != MDM_VINT_DISABLE);
+#else
 	k_sleep(K_SECONDS(8));
+#endif
+
 	LOG_DBG("MDM_POWER_PIN -> DISABLE");
+
+	unsigned int irq_lock_key = irq_lock();
+
 	modem_pin_write(&mctx, MDM_POWER, MDM_POWER_DISABLE);
+#if defined(CONFIG_MODEM_UBLOX_SARA_U2)
+	k_usleep(50);		/* 50-80 microseconds */
+#else
 	k_sleep(K_SECONDS(1));
-	LOG_DBG("MDM_POWER_PIN -> ENABLE");
+#endif
 	modem_pin_write(&mctx, MDM_POWER, MDM_POWER_ENABLE);
+
+	irq_unlock(irq_lock_key);
+
+	LOG_DBG("MDM_POWER_PIN -> ENABLE");
+
+#if defined(DT_UBLOX_SARA_R4_0_MDM_VINT_GPIOS_CONTROLLER)
+	LOG_DBG("Waiting for MDM_VINT_PIN = 1");
+	do {
+		k_sleep(K_MSEC(100));
+	} while (modem_pin_read(&mctx, MDM_VINT) != MDM_VINT_ENABLE);
+#else
 	k_sleep(K_SECONDS(10));
+#endif
 
 	modem_pin_config(&mctx, MDM_POWER, GPIO_DIR_IN);
+
 	LOG_INF("... Done!");
 
 	return 0;
@@ -617,9 +686,14 @@ static int pin_init(void)
 
 static void modem_rssi_query_work(struct k_work *work)
 {
-	struct modem_cmd cmd = MODEM_CMD("+CESQ: ", on_cmd_atcmdinfo_rssi_cesq,
+	struct modem_cmd cmd =
-					 6U, ",");
+#if defined(CONFIG_MODEM_UBLOX_SARA_U2)
+		MODEM_CMD("+CSQ: ", on_cmd_atcmdinfo_rssi_csq, 2U, ",");
+	static char *send_cmd = "AT+CSQ";
+#else
+		MODEM_CMD("+CESQ: ", on_cmd_atcmdinfo_rssi_cesq, 6U, ",");
 	static char *send_cmd = "AT+CESQ";
+#endif
 	int ret;
 
 	/* query modem RSSI */
@@ -668,6 +742,18 @@ static void modem_reset(void)
 		SETUP_CMD_NOHANDLE("AT+CFUN=1"),
 	};
 
+#if defined(CONFIG_MODEM_UBLOX_SARA_U2)
+	static struct setup_cmd u2_setup_cmds[] = {
+		/* set the APN */
+		SETUP_CMD_NOHANDLE("AT+UPSD=0,1,\""
+				CONFIG_MODEM_UBLOX_SARA_R4_MANUAL_MCCMNO "\""),
+		/* set dynamic IP */
+		SETUP_CMD_NOHANDLE("AT+UPSD=0,7,\"0.0.0.0\""),
+		/* activate the GPRS connection */
+		SETUP_CMD_NOHANDLE("AT+UPSDA=0,3"),
+	};
+#endif
+
 	/* bring down network interface */
 	atomic_clear_bit(mdata.net_iface->if_dev->flags, NET_IF_UP);
 
@@ -767,6 +853,17 @@ restart:
 		goto restart;
 	}
 
+#if defined(CONFIG_MODEM_UBLOX_SARA_U2)
+	ret = modem_cmd_handler_setup_cmds(&mctx.iface, &mctx.cmd_handler,
+					   u2_setup_cmds,
+					   ARRAY_SIZE(u2_setup_cmds),
+					   &mdata.sem_response,
+					   MDM_REGISTRATION_TIMEOUT);
+	if (ret < 0) {
+		goto error;
+	}
+#endif
+
 	LOG_INF("Network is ready.");
 
 	/* Set iface up */

dts/bindings/modem/ublox,sara-r4.yaml

@@ -26,3 +26,7 @@ properties:
     mdm-reset-gpios:
       type: compound
       category: required
+
+    mdm-vint-gpios:
+      type: compound
+      category: optional