drivers: lora: sx126x: add low energy support

Add optional low-power sequencing for SX126x (GPIO and SUBGHZ radio
control) so the host can turn the radio off between operations.
Remove debug helpers dump_gpio() and dump_rf_ctrl().
Drop gridpoint_stm32wl_subghz_radio compat; use st,stm32wl-subghz-radio
only.

Signed-off-by: Jon Ringle <jringle@gridpoint.com>

Author: ringlej

drivers/lora/loramac_node/sx126x.c

@@ -50,8 +50,15 @@ static const struct sx126x_config dev_config = {
 #if HAVE_GPIO_RX_ENABLE
 	.rx_enable = GPIO_DT_SPEC_INST_GET(0, rx_enable_gpios),
 #endif
+#if HAVE_GPIO_FE_CTRL
+	.fe_ctrl1_enable = GPIO_DT_SPEC_INST_GET(0, fe_ctrl1_enable_gpios),
+	.fe_ctrl2_enable = GPIO_DT_SPEC_INST_GET(0, fe_ctrl2_enable_gpios),
+	.fe_ctrl3_enable = GPIO_DT_SPEC_INST_GET(0, fe_ctrl3_enable_gpios),
+#endif
+
 };
 
+
 static struct sx126x_data dev_data;
 
 void SX126xWaitOnBusy(void);
@@ -253,29 +260,57 @@ void SX126xAntSwOff(void)
 #endif
 }
 
+#if HAVE_GPIO_TX_ENABLE
 static void sx126x_set_tx_enable(int value)
 {
-#if HAVE_GPIO_TX_ENABLE
 	gpio_pin_set_dt(&dev_config.tx_enable, value);
-#endif
 }
+#endif
 
+#if HAVE_GPIO_RX_ENABLE
 static void sx126x_set_rx_enable(int value)
 {
-#if HAVE_GPIO_RX_ENABLE
 	gpio_pin_set_dt(&dev_config.rx_enable, value);
+}
+#endif
+
+
+static void sx126x_set_fe_ctrl(int ctrl1, int ctrl2, int ctrl3)
+{
+#if HAVE_GPIO_FE_CTRL
+	gpio_pin_set_dt(&dev_config.fe_ctrl1_enable, ctrl1);
+	gpio_pin_set_dt(&dev_config.fe_ctrl2_enable, ctrl2);
+	gpio_pin_set_dt(&dev_config.fe_ctrl3_enable, ctrl3);
 #endif
 }
 
+
 RadioOperatingModes_t SX126xGetOperatingMode(void)
 {
 	return dev_data.mode;
 }
 
+#if HAVE_GPIO_FE_CTRL
+static const enum {
+	RFO_LP,
+	RFO_HP,
+} pa_output = DT_INST_STRING_UPPER_TOKEN(0, power_amplifier_output);
+#endif
+
+#define LORA_NODE DT_NODELABEL(lora)
+
+
 void SX126xSetOperatingMode(RadioOperatingModes_t mode)
 {
 	LOG_DBG("SetOperatingMode: %s (%i)", sx126x_mode_name(mode), mode);
 
+#if HAVE_GPIO_FE_CTRL
+	const int off_fe_ctrl_lines[]  = DT_PROP(LORA_NODE, off_fe_ctrl_lines);
+	const int rx_fe_ctrl_lines[]   = DT_PROP(LORA_NODE, rx_fe_ctrl_lines);
+	const int txhp_fe_ctrl_lines[] = DT_PROP(LORA_NODE, txhp_fe_ctrl_lines);
+	const int txlp_fe_ctrl_lines[] = DT_PROP(LORA_NODE, txlp_fe_ctrl_lines);
+#endif
+
 	dev_data.mode = mode;
 
 	/* To avoid inadvertently putting the RF switch in an
@@ -284,24 +319,43 @@ void SX126xSetOperatingMode(RadioOperatingModes_t mode)
 	 */
 	switch (mode) {
 	case MODE_TX:
+#if HAVE_GPIO_TX_ENABLE
 		sx126x_set_rx_enable(0);
 		sx126x_set_tx_enable(1);
+#endif
+#if HAVE_GPIO_FE_CTRL
+		if (pa_output == RFO_LP) {
+			sx126x_set_fe_ctrl(txlp_fe_ctrl_lines[0], txlp_fe_ctrl_lines[1], txlp_fe_ctrl_lines[2]);
+		} else {
+			sx126x_set_fe_ctrl(txhp_fe_ctrl_lines[0], txhp_fe_ctrl_lines[1], txhp_fe_ctrl_lines[2]);
+		}
+#endif
 		break;
 
 	case MODE_RX:
 	case MODE_RX_DC:
 	case MODE_CAD:
+#if HAVE_GPIO_TX_ENABLE
 		sx126x_set_tx_enable(0);
 		sx126x_set_rx_enable(1);
+#endif
+#if HAVE_GPIO_FE_CTRL
+		sx126x_set_fe_ctrl(rx_fe_ctrl_lines[0], rx_fe_ctrl_lines[1], rx_fe_ctrl_lines[2]);
+#endif
 		break;
 
 	case MODE_SLEEP:
 		/* Additionally disable the DIO1 interrupt to save power */
 		sx126x_dio1_irq_disable(&dev_data);
 		__fallthrough;
 	default:
+#if HAVE_GPIO_TX_ENABLE
 		sx126x_set_rx_enable(0);
 		sx126x_set_tx_enable(0);
+#endif
+#if HAVE_GPIO_FE_CTRL
+		sx126x_set_fe_ctrl(off_fe_ctrl_lines[0], off_fe_ctrl_lines[1], off_fe_ctrl_lines[2]);
+#endif
 		break;
 	}
 }
@@ -437,7 +491,14 @@ static int sx126x_lora_init(const struct device *dev)
 
 	if (sx12xx_configure_pin(antenna_enable, GPIO_OUTPUT_INACTIVE) ||
 	    sx12xx_configure_pin(rx_enable, GPIO_OUTPUT_INACTIVE) ||
-	    sx12xx_configure_pin(tx_enable, GPIO_OUTPUT_INACTIVE)) {
+	    sx12xx_configure_pin(tx_enable, GPIO_OUTPUT_INACTIVE)
+#if HAVE_GPIO_FE_CTRL
+		|| sx12xx_configure_pin(fe_ctrl1_enable, GPIO_OUTPUT_INACTIVE)
+		|| sx12xx_configure_pin(fe_ctrl2_enable, GPIO_OUTPUT_INACTIVE)
+		|| sx12xx_configure_pin(fe_ctrl3_enable, GPIO_OUTPUT_INACTIVE)
+#endif
+	)
+	{
 		return -EIO;
 	}
 

drivers/lora/loramac_node/sx126x_common.h

@@ -34,6 +34,7 @@
 	DT_INST_NODE_HAS_PROP(0, antenna_enable_gpios)
 #define HAVE_GPIO_TX_ENABLE	DT_INST_NODE_HAS_PROP(0, tx_enable_gpios)
 #define HAVE_GPIO_RX_ENABLE	DT_INST_NODE_HAS_PROP(0, rx_enable_gpios)
+#define HAVE_GPIO_FE_CTRL  (DT_INST_NODE_HAS_PROP(0, fe_ctrl1_enable_gpios) && !DT_INST_NODE_HAS_PROP(0, tx_enable_gpios))
 
 struct sx126x_config {
 	struct spi_dt_spec bus;
@@ -46,6 +47,12 @@ struct sx126x_config {
 #if HAVE_GPIO_RX_ENABLE
 	struct gpio_dt_spec rx_enable;
 #endif
+#if HAVE_GPIO_FE_CTRL
+	struct gpio_dt_spec fe_ctrl3_enable;
+	struct gpio_dt_spec fe_ctrl2_enable;
+	struct gpio_dt_spec fe_ctrl1_enable;
+#endif
+
 };
 
 struct sx126x_data {

dts/bindings/lora/semtech,sx126x-base.yaml

@@ -35,6 +35,45 @@ properties:
       Antenna switch RX enable GPIO. If set, the driver tracks the
       state of the radio and controls the RF switch.
 
+  txlp-fe-ctrl-lines:
+    type: array
+    description: |
+      RF front-end GPIO bit values to enable transmit low-power. Array
+      of 3 binary values corresponding to FE_CTRL1, FE_CTRL2, FE_CTRL3
+
+  txhp-fe-ctrl-lines:
+    type: array
+    description: |
+      RF front-end GPIO bit values to enable transmit high-power.  Array
+      of 3 binary values corresponding to FE_CTRL1, FE_CTRL2, FE_CTRL3
+
+  rx-fe-ctrl-lines:
+    type: array
+    description: |
+      RF front-end GPIO bit values to enable receive.  Array
+      of 3 binary values corresponding to FE_CTRL1, FE_CTRL2, FE_CTRL3
+
+  off-fe-ctrl-lines:
+    type: array
+    description: |
+      RF front-end GPIO bit values to switch off antenna.  Array
+      of 3 binary values corresponding to FE_CTRL1, FE_CTRL2, FE_CTRL3
+
+  fe-ctrl1-enable-gpios:
+    type: phandle-array
+    description: |
+      FE_CTRL1 signal GPIO controlling RF switch.
+
+  fe-ctrl2-enable-gpios:
+    type: phandle-array
+    description: |
+      FE_CTRL2 signal GPIO controlling RF switch.
+
+  fe-ctrl3-enable-gpios:
+    type: phandle-array
+    description: |
+      FE_CTRL3 signal GPIO controlling RF switch.
+
   dio1-gpios:
     type: phandle-array
     description: |