drivers: add support for ADS1115 ADC

drivers/ads1115/Makefile

@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base

drivers/ads1115/Makefile.dep

@@ -0,0 +1 @@
+FEATURES_REQUIRED += periph_i2c

drivers/ads1115/Makefile.include

@@ -0,0 +1,2 @@
+USEMODULE_INCLUDES_ads1115 := $(LAST_MAKEFILEDIR)/include
+USEMODULE_INCLUDES += $(USEMODULE_INCLUDES_ads1115)

drivers/ads1115/ads1115.c

@@ -0,0 +1,175 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Baptiste Le Duc <[email protected]>
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+/**
+ * @ingroup     drivers_ads1115
+ * @{
+ * @file
+ * @brief       ADS1115 Analog-to-digital converter driver
+ * @author      Baptiste Le Duc <[email protected]>
+ * @}
+ */
+
+#include <assert.h>
+
+#include "ads1115.h"
+#include "ads1115_params.h"
+#include "ads1115_internal.h"
+
+#include "periph/i2c.h"
+#include "byteorder.h"
+
+#define ENABLE_DEBUG 0
+#include "debug.h"
+
+#define DEV (dev->params.i2c)
+#define ADDR (dev->params.addr)
+
+#define ADS1115_CONF_TEST_VALUE (1)
+
+static inline int _ads1115_get_pga_voltage(ads1115_pga_t pga)
+{
+    switch (pga) {
+    case ADS1115_PGA_6_144V: return 6144;
+    case ADS1115_PGA_4_096V: return 4096;
+    case ADS1115_PGA_2_048V: return 2048;
+    case ADS1115_PGA_1_024V: return 1024;
+    case ADS1115_PGA_0_512V: return 512;
+    case ADS1115_PGA_0_256V:
+    case ADS1115_PGA_0_256V_B:
+    case ADS1115_PGA_0_256V_C:
+        return 256;
+    default:
+        return 0;
+    }
+}
+
+/**
+ * @brief Builds the configuration register value from the parameters
+ *
+ * @param[in] params  ADS1115 parameters
+ *
+ * @return Configuration register value
+ */
+static uint16_t _build_config_reg(const ads1115_params_t *params)
+{
+    uint16_t conf = 0;
+
+    conf |= (params->mux << ADS1115_CONF_MUX_BIT);
+    conf |= (params->pga << ADS1115_CONF_PGA_BIT);
+    conf |= (params->mode << ADS1115_CONF_MODE_BIT);
+    conf |= (params->dr << ADS1115_CONF_DR_BIT);
+    conf |= (params->comp_mode << ADS1115_CONF_COMP_MODE_BIT);
+    conf |= (params->comp_polarity << ADS1115_CONF_COMP_POLARITY_BIT);
+    conf |= (params->comp_latch << ADS1115_CONF_COMP_LATCH_BIT);
+    conf |= (params->comp_queue << ADS1115_CONF_COMP_QUEUE_BIT);
+
+    return conf;
+}
+
+int ads1115_init(ads1115_t *dev, const ads1115_params_t *params)
+{
+    assert(dev && params);
+
+    dev->params = *params;
+    DEBUG("[ads1115] init - i2c=%d, addr=0x%02x\n", dev->params.i2c, dev->params.addr);
+
+    int res = ADS1115_NOI2C;
+
+    i2c_acquire(DEV);
+
+    /* Test communication */
+    uint16_t test_conf = htons(ADS1115_CONF_TEST_VALUE);
+    if (i2c_write_regs(DEV, ADDR, ADS1115_REG_CONFIG, &test_conf, sizeof(test_conf), 0) < 0) {
+        DEBUG("[ads1115] init - error: write test failed\n");
+        res = ADS1115_NODEV;
+    }
+
+    uint16_t reg;
+    if (i2c_read_regs(DEV, ADDR, ADS1115_REG_CONFIG, &reg, sizeof(reg), 0) < 0 ||
+        ntohs(reg) != ADS1115_CONF_TEST_VALUE) {
+        DEBUG("[ads1115] init - error: read test failed (reg=%04x)\n", ntohs(reg));
+        res = ADS1115_NOI2C;
+        goto release;
+    }
+
+    /* Apply actual configuration */
+    uint16_t conf = htons(_build_config_reg(&dev->params));
+    if (i2c_write_regs(DEV, ADDR, ADS1115_REG_CONFIG, &conf, sizeof(conf), 0) < 0) {
+        DEBUG("[ads1115] init - error: setting config failed\n");
+        res = ADS1115_NOI2C;
+        goto release;
+    }
+
+    res = ADS1115_OK;
+
+release:
+    i2c_release(DEV);
+    return res;
+}
+
+int ads1115_set_ain_ch_input(ads1115_t *dev, ads1115_mux_t mux)
+{
+    assert(dev);
+
+    int res = ADS1115_NOI2C;
+
+    i2c_acquire(DEV);
+
+    /* Read current configuration */
+    uint16_t reg;
+    if (i2c_read_regs(DEV, ADDR, ADS1115_REG_CONFIG, &reg, sizeof(reg), 0) < 0) {
+        i2c_release(DEV);
+        goto release;
+    }
+
+    /* Update MUX bits */
+    uint16_t conf = ntohs(reg);
+    conf &= ~(0x07 << ADS1115_CONF_MUX_BIT);    /* Clear MUX bits */
+    conf |= (mux << ADS1115_CONF_MUX_BIT);      /* Set new MUX */
+
+    /* Write back updated configuration */
+    reg = htons(conf);
+
+    if (i2c_write_regs(DEV, ADDR, ADS1115_REG_CONFIG, &reg, sizeof(reg), 0) < 0) {
+        goto release;
+    }
+
+    res = ADS1115_OK;
+    dev->params.mux = mux;
+
+release:
+    i2c_release(DEV);
+    return res;
+}
+
+int ads1115_read_conversion(ads1115_t *dev, uint16_t *value)
+{
+    assert(dev && value);
+
+    int res = ADS1115_NOI2C;
+    uint16_t buf;
+
+    i2c_acquire(DEV);
+
+    /* Read conversion register */
+    if (i2c_read_regs(DEV, ADDR, ADS1115_REG_CONVERSION, &buf, sizeof(buf), 0) < 0) {
+        goto release;
+    }
+
+    /* Combine bytes into a single value */
+    *value = ntohs(buf);
+    res = ADS1115_OK;
+
+release:
+    i2c_release(DEV);
+    return res;
+}
+
+int ads1115_convert_to_mv(ads1115_t *dev, uint16_t value)
+{
+    assert(dev);
+    return value * _ads1115_get_pga_voltage(dev->params.pga) / (1 << 15); /* Msb is sign bit */
+}

drivers/ads1115/include/ads1115_internal.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) Baptiste Le Duc <[email protected]>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+#pragma once
+
+/**
+ * @ingroup     drivers_ads1115
+ * @{
+ *
+ * @file
+ * @brief       Internal definitions for ADS1115 Analog-to-digital converter
+ *
+ * @author      Baptiste Le Duc <[email protected]>
+ * @}
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @name    ADS1115 registers
+ * @{
+ */
+
+#define ADS1115_REG_CONVERSION  (0x00)  /**< Conversion register */
+#define ADS1115_REG_CONFIG      (0x01)  /**< Configuration register */
+/** @} */
+
+/**
+ * @name    ADS1115 configuration register bits
+ * @{
+ */
+#define ADS1115_CONF_OS_BIT            (15) /**< Operational status */
+#define ADS1115_CONF_MUX_BIT           (12) /**< Input multiplexer configuration */
+#define ADS1115_CONF_PGA_BIT           (9)  /**< Programmable gain amplifier configuration */
+#define ADS1115_CONF_MODE_BIT          (8)  /**< Device mode */
+#define ADS1115_CONF_DR_BIT            (5)  /**< Data rate configuration */
+#define ADS1115_CONF_COMP_MODE_BIT     (4)  /**< Comparator mode */
+#define ADS1115_CONF_COMP_POLARITY_BIT (3)  /**< Comparator polarity */
+#define ADS1115_CONF_COMP_LATCH_BIT    (2)  /**< Comparator latch */
+#define ADS1115_CONF_COMP_QUEUE_BIT    (0)  /**< Comparator queue */
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif

drivers/ads1115/include/ads1115_params.h

@@ -0,0 +1,141 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Baptiste Le Duc <[email protected]>
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+#pragma once
+
+/**
+ * @ingroup     drivers_ads1115
+ * @{
+ *
+ * @file
+ * @brief       Default configuration for ADS1115 device
+ *
+ * @author      Baptiste Le Duc <[email protected]>
+ */
+
+#include "board.h"
+#include "ads1115.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @name    Set default configuration parameters for the ADS1115 driver
+ * @{
+ */
+
+/**
+ * @def ADS1115_PARAM_I2C
+ * @brief Default I2C bus
+ */
+#ifndef ADS1115_PARAM_I2C
+#  define ADS1115_PARAM_I2C      (I2C_DEV(0))
+#endif
+
+/**
+ * @def ADS1115_PARAM_ADDR
+ * @brief Default I2C address
+ */
+#ifndef ADS1115_PARAM_ADDR
+#  define ADS1115_PARAM_ADDR     (0x48)
+#endif
+
+/**
+ * @def ADS1115_PARAM_MUX
+ * @brief Default multiplexer configuration
+ */
+#ifndef ADS1115_PARAM_MUX
+#  define ADS1115_PARAM_MUX      (ADS1115_MUX_AIN0_AIN1)
+#endif
+
+/**
+ * @def ADS1115_PARAM_PGA
+ * @brief Default programmable gain amplifier configuration
+ */
+#ifndef ADS1115_PARAM_PGA
+#  define ADS1115_PARAM_PGA      (ADS1115_PGA_2_048V)
+#endif
+
+/**
+ * @def ADS1115_PARAM_MODE
+ * @brief Default device mode
+ */
+#ifndef ADS1115_PARAM_MODE
+#  define ADS1115_PARAM_MODE     (ADS1115_MODE_SINGLE)
+#endif
+
+/**
+ * @def ADS1115_PARAM_DR
+ * @brief Default data rate configuration
+ */
+#ifndef ADS1115_PARAM_DR
+#  define ADS1115_PARAM_DR       (ADS1115_DR_128)
+#endif
+
+/**
+ * @def ADS1115_PARAM_COMP_MODE
+ * @brief Default comparator mode
+ */
+#ifndef ADS1115_PARAM_COMP_MODE
+#  define ADS1115_PARAM_COMP_MODE  (ADS1115_COMP_MODE_TRADITIONAL)
+#endif
+
+/**
+ * @def ADS1115_PARAM_COMP_POLARITY
+ * @brief Default comparator polarity
+ */
+#ifndef ADS1115_PARAM_COMP_POLARITY
+#  define ADS1115_PARAM_COMP_POLARITY (ADS1115_COMP_POLARITY_LOW)
+#endif
+
+/**
+ * @def ADS1115_PARAM_COMP_LATCH
+ * @brief Default comparator latch
+ */
+#ifndef ADS1115_PARAM_COMP_LATCH
+#  define ADS1115_PARAM_COMP_LATCH (ADS1115_COMP_LATCH_DISABLE)
+#endif
+
+/**
+ * @def ADS1115_PARAM_COMP_QUEUE
+ * @brief Default comparator queue
+ */
+#ifndef ADS1115_PARAM_COMP_QUEUE
+#  define ADS1115_PARAM_COMP_QUEUE (ADS1115_COMP_QUEUE_DISABLE)
+#endif
+
+/**
+ * @def ADS1115_PARAMS
+ * @brief Default configuration structure for the ADS1115 driver
+ */
+#ifndef ADS1115_PARAMS
+#  define ADS1115_PARAMS          { \
+    .i2c = ADS1115_PARAM_I2C, \
+    .addr = ADS1115_PARAM_ADDR, \
+    .mux = ADS1115_PARAM_MUX, \
+    .pga = ADS1115_PARAM_PGA, \
+    .mode = ADS1115_PARAM_MODE, \
+    .dr = ADS1115_PARAM_DR, \
+    .comp_mode = ADS1115_PARAM_COMP_MODE, \
+    .comp_polarity = ADS1115_PARAM_COMP_POLARITY, \
+    .comp_latch = ADS1115_PARAM_COMP_LATCH, \
+    .comp_queue = ADS1115_PARAM_COMP_QUEUE \
+}
+#endif
+/** @} */
+
+/**
+ * @brief Default parameters structure
+ */
+static const ads1115_params_t ads1115_params[] = {
+    ADS1115_PARAMS
+};
+
+/** @} */  /* close @ingroup drivers_ads1115 */ 
+
+#ifdef __cplusplus
+}
+#endif