Introduce new generic ADC driver for ADS1115 chip (#14437)

boards/px4/fmu-v3/default.cmake

@@ -19,6 +19,7 @@ px4_add_board(
 		TEL4:/dev/ttyS6
 	DRIVERS
 		adc/board_adc
+		adc/ads1115
 		barometer # all available barometer drivers
 		batt_smbus
 		camera_capture

boards/px4/fmu-v4/default.cmake

@@ -15,6 +15,7 @@ px4_add_board(
 		TEL2:/dev/ttyS2
 	DRIVERS
 		adc/board_adc
+		adc/ads1115
 		barometer # all available barometer drivers
 		batt_smbus
 		camera_capture

boards/px4/fmu-v4pro/default.cmake

@@ -18,6 +18,7 @@ px4_add_board(
 		TEL4:/dev/ttyS6
 	DRIVERS
 		adc/board_adc
+		adc/ads1115
 		barometer # all available barometer drivers
 		batt_smbus
 		camera_capture

boards/px4/fmu-v5/default.cmake

@@ -17,6 +17,7 @@ px4_add_board(
 		TEL4:/dev/ttyS3
 	DRIVERS
 		adc/board_adc
+		adc/ads1115
 		barometer # all available barometer drivers
 		batt_smbus
 		camera_capture

boards/px4/fmu-v5x/default.cmake

@@ -18,6 +18,7 @@ px4_add_board(
 		GPS2:/dev/ttyS7
 	DRIVERS
 		adc/board_adc
+		adc/ads1115
 		barometer # all available barometer drivers
 		batt_smbus
 		camera_capture

boards/px4/raspberrypi/default.cmake

@@ -11,6 +11,7 @@ px4_add_board(
 	TOOLCHAIN arm-linux-gnueabihf
 	TESTING
 	DRIVERS
+		adc/ads1115
 		#barometer # all available barometer drivers
 		barometer/ms5611
 		batt_smbus

src/drivers/adc/ads1115/ADS1115.cpp

@@ -0,0 +1,197 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2020 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#include "ADS1115.h"
+#include <cassert>
+
+int ADS1115::init()
+{
+	int ret = I2C::init();
+
+	if (ret != PX4_OK) {
+		PX4_ERR("I2C init failed");
+		return ret;
+	}
+
+	uint8_t config[2] = {};
+	config[0] = CONFIG_HIGH_OS_NOACT | CONFIG_HIGH_MUX_P0NG | CONFIG_HIGH_PGA_6144 | CONFIG_HIGH_MODE_SS;
+	config[1] = CONFIG_LOW_DR_250SPS | CONFIG_LOW_COMP_MODE_TRADITIONAL | CONFIG_LOW_COMP_POL_RESET |
+		    CONFIG_LOW_COMP_LAT_NONE | CONFIG_LOW_COMP_QU_DISABLE;
+	return writeReg(ADDRESSPOINTER_REG_CONFIG, config, 2);
+}
+
+int ADS1115::setChannel(ADS1115::ChannelSelection ch)
+{
+	uint8_t buf[2] = {};
+	uint8_t next_mux_reg = CONFIG_HIGH_MUX_P0NG;
+
+	switch (ch) {
+	case A0:
+		next_mux_reg = CONFIG_HIGH_MUX_P0NG;
+		break;
+
+	case A1:
+		next_mux_reg = CONFIG_HIGH_MUX_P1NG;
+		break;
+
+	case A2:
+		next_mux_reg = CONFIG_HIGH_MUX_P2NG;
+		break;
+
+	case A3:
+		next_mux_reg = CONFIG_HIGH_MUX_P3NG;
+		break;
+
+	default:
+		assert(false);
+		break;
+	}
+
+	buf[0] = CONFIG_HIGH_OS_START_SINGLE | next_mux_reg | CONFIG_HIGH_PGA_6144 | CONFIG_HIGH_MODE_SS;
+	buf[1] = CONFIG_LOW_DR_250SPS | CONFIG_LOW_COMP_MODE_TRADITIONAL | CONFIG_LOW_COMP_POL_RESET |
+		 CONFIG_LOW_COMP_LAT_NONE | CONFIG_LOW_COMP_QU_DISABLE;
+	return writeReg(ADDRESSPOINTER_REG_CONFIG, buf, 2);    // must write whole register to take effect
+}
+
+bool ADS1115::isSampleReady()
+{
+	uint8_t buf[1] = {0x00};
+
+	if (readReg(ADDRESSPOINTER_REG_CONFIG, buf, 1) != 0) { return false; } // Pull config register
+
+	return (buf[0] & (uint8_t) 0x80);
+}
+
+ADS1115::ChannelSelection ADS1115::getMeasurement(int16_t *value)
+{
+	uint8_t buf[2] = {0x00};
+	readReg(ADDRESSPOINTER_REG_CONFIG, buf, 1); // Pull config register
+	ChannelSelection channel;
+
+	switch ((buf[0] & (uint8_t) 0x70) >> 4) {
+	case 0x04:
+		channel = A0;
+		break;
+
+	case 0x05:
+		channel = A1;
+		break;
+
+	case 0x06:
+		channel = A2;
+		break;
+
+	case 0x07:
+		channel = A3;
+		break;
+
+	default:
+		return Invalid;
+	}
+
+	readReg(ADDRESSPOINTER_REG_CONVERSATION, buf, 2);
+	uint16_t raw_adc_val = buf[0] * 256 + buf[1];
+
+	if (raw_adc_val & (uint16_t) 0x8000) {     // Negetive value
+		raw_adc_val = ~raw_adc_val + 1;     // 2's complement
+		*value = -raw_adc_val;
+
+	} else {
+		*value = raw_adc_val;
+	}
+
+	return channel;
+}
+
+ADS1115::ChannelSelection ADS1115::cycleMeasure(int16_t *value)
+{
+	uint8_t buf[2] = {0x00};
+	readReg(ADDRESSPOINTER_REG_CONFIG, buf, 1); // Pull config register
+	ChannelSelection channel;
+	uint8_t next_mux_reg = CONFIG_HIGH_MUX_P0NG;
+
+	switch ((buf[0] & (uint8_t) 0x70) >> 4) {
+	case 0x04:
+		channel = A0;
+		next_mux_reg = CONFIG_HIGH_MUX_P1NG;
+		break;
+
+	case 0x05:
+		channel = A1;
+		next_mux_reg = CONFIG_HIGH_MUX_P2NG;
+		break;
+
+	case 0x06:
+		channel = A2;
+		next_mux_reg = CONFIG_HIGH_MUX_P3NG;
+		break;
+
+	case 0x07:
+		channel = A3;
+		next_mux_reg = CONFIG_HIGH_MUX_P0NG;
+		break;
+
+	default:
+		return Invalid;
+	}
+
+	readReg(ADDRESSPOINTER_REG_CONVERSATION, buf, 2);
+	uint16_t raw_adc_val = buf[0] * 256 + buf[1];
+
+	if (raw_adc_val & (uint16_t) 0x8000) {     // Negetive value
+		raw_adc_val = ~raw_adc_val + 1;     // 2's complement
+		*value = -raw_adc_val;
+
+	} else {
+		*value = raw_adc_val;
+	}
+
+	buf[0] = CONFIG_HIGH_OS_START_SINGLE | next_mux_reg | CONFIG_HIGH_PGA_6144 | CONFIG_HIGH_MODE_SS;
+	buf[1] = CONFIG_LOW_DR_250SPS | CONFIG_LOW_COMP_MODE_TRADITIONAL | CONFIG_LOW_COMP_POL_RESET |
+		 CONFIG_LOW_COMP_LAT_NONE | CONFIG_LOW_COMP_QU_DISABLE;
+	writeReg(ADDRESSPOINTER_REG_CONFIG, buf, 2);    // must write whole register to take effect
+	return channel;
+}
+
+int ADS1115::readReg(uint8_t addr, uint8_t *buf, size_t len)
+{
+	return transfer(&addr, 1, buf, len);
+}
+
+int ADS1115::writeReg(uint8_t addr, uint8_t *buf, size_t len)
+{
+	uint8_t buffer[len + 1];
+	buffer[0] = addr;
+	memcpy(buffer + 1, buf, sizeof(uint8_t)*len);
+	return transfer(buffer, len + 1, nullptr, 0);
+}