drivers: lora: sx1276: select PA output by dts property

PA selection mainly depends on board design. So it looks like
device-tree is a better mechanism than Kconfig in this case. Use string
property with two possible values: "rfo" and "pa-boost".

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>

boards/arm/96b_wistrio/96b_wistrio.dts

@@ -73,6 +73,7 @@
 			<&gpioh 0 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>,
 			<&gpioc 13 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>;
 		spi-max-frequency = <1000000>;
+		power-amplifier-output = "pa-boost";
 	};
 };
 

drivers/lora/Kconfig.sx1276

@@ -4,7 +4,7 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
-menuconfig LORA_SX1276
+config LORA_SX1276
 	bool "Semtech SX1276 driver"
 	select HAS_SEMTECH_RADIO_DRIVERS
 	select HAS_SEMTECH_LORAMAC
@@ -12,22 +12,3 @@ menuconfig LORA_SX1276
 	depends on SPI
 	help
 	  Enable LoRa driver for Semtech SX1276.
-
-choice
-	prompt "SX1276 PA Output pin"
-	default PA_BOOST_PIN
-	depends on LORA_SX1276
-	help
-	  Antenna connection type.
-
-config PA_RFO_PIN
-	bool "PA_RFO_PIN"
-	help
-	  Antenna connected to PA_RFO pin.
-
-config PA_BOOST_PIN
-	bool "PA_BOOST_PIN"
-	help
-	  Antenna connected to PA_BOOST pin.
-
-endchoice

drivers/lora/sx1276.c

@@ -23,6 +23,15 @@ LOG_MODULE_REGISTER(sx1276);
 #define GPIO_RESET_FLAGS	DT_INST_GPIO_FLAGS(0, reset_gpios)
 #define GPIO_CS_PIN		DT_INST_SPI_DEV_CS_GPIOS_PIN(0)
 
+#define PA_PIN			DT_ENUM_IDX(DT_DRV_INST(0),	\
+					    power_amplifier_output)
+
+/*
+ * Those macros must be in sync with 'power-amplifier-output' dts property.
+ */
+#define SX1276_PA_RFO				0
+#define SX1276_PA_BOOST				1
+
 #define SX1276_REG_PA_CONFIG			0x09
 #define SX1276_REG_PA_DAC			0x4d
 #define SX1276_REG_VERSION			0x42
@@ -239,7 +248,7 @@ void SX1276SetRfTxPower(int8_t power)
 
 	pa_dac &= RF_PADAC_20DBM_MASK;
 
-#if defined CONFIG_PA_BOOST_PIN
+#if PA_PIN == SX1276_PA_BOOST
 	power = clamp_int8(power, 2, 20);
 
 	pa_config |= RF_PACONFIG_PASELECT_PABOOST;
@@ -250,7 +259,7 @@ void SX1276SetRfTxPower(int8_t power)
 		pa_dac |= RF_PADAC_20DBM_OFF;
 		pa_config |= (power - 2) & 0x0F;
 	}
-#elif CONFIG_PA_RFO_PIN
+#elif PA_PIN == SX1276_PA_RFO
 	power = clamp_int8(power, -4, 15);
 
 	pa_dac |= RF_PADAC_20DBM_OFF;

dts/bindings/lora/semtech,sx1276.yaml

@@ -1,4 +1,5 @@
 # Copyright (c) 2019, Manivannan Sadhasivam
+# Copyright (c) 2020, Grinn
 # SPDX-License-Identifier: Apache-2.0
 
 description: Semtech SX1276 LoRa Modem
@@ -24,3 +25,12 @@ properties:
         Up to six pins that produce service interrupts from the modem.
 
         These signals are normally active-high.
+
+    power-amplifier-output:
+      type: string
+      required: true
+      description: |
+        Selects power amplifier output pin.
+      enum:
+         - "rfo"
+         - "pa-boost"

tests/drivers/build_all/spi.dtsi

@@ -208,6 +208,7 @@ test_spi_sx1276: sx1276@13 {
 	spi-max-frequency = <0>;
 	reset-gpios = <&test_gpio 0 0>;
 	dio-gpios = <&test_gpio 0 0>;
+	power-amplifier-output = "rfo";
 };
 
 test_spi_st7789v: st7789v@14 {