mirror of
https://github.com/ByteWelder/Tactility.git
synced 2026-10-17 10:55:06 +00:00
139 lines
4.3 KiB
C++
139 lines
4.3 KiB
C++
// SPDX-License-Identifier: Apache-2.0
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#include <drivers/ads1115.h>
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#include <ads1115_module.h>
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#include <tactility/check.h>
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#include <tactility/delay.h>
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#include <tactility/device.h>
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#include <tactility/driver.h>
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#include <tactility/drivers/adc_controller.h>
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#include <tactility/drivers/i2c_controller.h>
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#include <tactility/log.h>
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constexpr auto* TAG = "ADS1115";
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#define GET_CONFIG(device) (static_cast<const Ads1115Config*>((device)->config))
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static constexpr uint8_t REG_CONVERSION = 0x00;
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static constexpr uint8_t REG_CONFIG = 0x01;
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static constexpr uint16_t CONFIG_OS = 1U << 15;
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static constexpr uint16_t CONFIG_MUX_SINGLE_AIN0 = 0b100U << 12;
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static constexpr uint16_t CONFIG_PGA_SHIFT = 9;
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static constexpr uint16_t CONFIG_MODE_SINGLE_SHOT = 1U << 8;
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static constexpr uint16_t CONFIG_DR_860_SPS = 0b111U << 5;
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static constexpr uint16_t CONFIG_COMP_QUE_DISABLE = 0b11U;
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static constexpr uint8_t CHANNEL_COUNT = 4;
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// A conversion at 860 SPS takes about 1.2 ms
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static constexpr int CONVERSION_POLL_LIMIT = 10;
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extern "C" {
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static bool pga_bits_for(uint16_t full_scale_mv, uint16_t* out_bits) {
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static constexpr uint16_t FULL_SCALES_MV[] = { 6144, 4096, 2048, 1024, 512, 256 };
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for (uint16_t i = 0; i < sizeof(FULL_SCALES_MV) / sizeof(FULL_SCALES_MV[0]); i++) {
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if (FULL_SCALES_MV[i] == full_scale_mv) {
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*out_bits = i;
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return true;
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}
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}
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return false;
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}
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static error_t convert(Device* device, uint8_t channel, int16_t* out_code, TickType_t timeout) {
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const auto* config = GET_CONFIG(device);
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auto* i2c = device_get_parent(device);
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uint16_t pga_bits = 0;
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check(pga_bits_for(config->full_scale_mv, &pga_bits));
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uint16_t start = CONFIG_OS | (CONFIG_MUX_SINGLE_AIN0 + (static_cast<uint16_t>(channel) << 12)) | (pga_bits << CONFIG_PGA_SHIFT) |
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CONFIG_MODE_SINGLE_SHOT | CONFIG_DR_860_SPS | CONFIG_COMP_QUE_DISABLE;
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error_t error = i2c_controller_register16be_set(i2c, config->address, REG_CONFIG, start, timeout);
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if (error != ERROR_NONE) {
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return error;
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}
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// OS reads back as 1 once the conversion is done
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for (int i = 0; i < CONVERSION_POLL_LIMIT; i++) {
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delay_millis(1);
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uint16_t status;
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error = i2c_controller_register16be_get(i2c, config->address, REG_CONFIG, &status, timeout);
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if (error != ERROR_NONE) {
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return error;
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}
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if ((status & CONFIG_OS) != 0) {
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uint16_t code;
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error = i2c_controller_register16be_get(i2c, config->address, REG_CONVERSION, &code, timeout);
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if (error == ERROR_NONE) {
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*out_code = static_cast<int16_t>(code);
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}
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return error;
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}
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}
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return ERROR_TIMEOUT;
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}
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static error_t read_raw(Device* device, uint8_t channel, int* out_raw, TickType_t timeout) {
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if (channel >= CHANNEL_COUNT) {
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return ERROR_OUT_OF_RANGE;
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}
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// A conversion is a sequence of transfers that must not interleave with another read
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device_lock(device);
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int16_t code = 0;
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error_t error = convert(device, channel, &code, timeout);
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device_unlock(device);
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if (error != ERROR_NONE) {
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return error;
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}
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// 15 bits of positive range scaled to 12 bits
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*out_raw = code < 0 ? 0 : code >> 3;
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return ERROR_NONE;
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}
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static constexpr AdcControllerApi ADS1115_API = {
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.read_raw = read_raw
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};
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static error_t start(Device* device) {
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check(device_get_type(device_get_parent(device)) == &I2C_CONTROLLER_TYPE);
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const auto* config = GET_CONFIG(device);
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uint16_t pga_bits;
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if (!pga_bits_for(config->full_scale_mv, &pga_bits)) {
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LOG_E(TAG, "Unsupported full-scale-mv %u", config->full_scale_mv);
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return ERROR_INVALID_ARGUMENT;
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}
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uint16_t value;
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error_t error = i2c_controller_register16be_get(device_get_parent(device), config->address, REG_CONFIG, &value, pdMS_TO_TICKS(50));
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if (error != ERROR_NONE) {
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LOG_E(TAG, "Not responding at 0x%02X", config->address);
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return error;
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}
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return ERROR_NONE;
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}
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static error_t stop(Device*) {
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return ERROR_NONE;
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}
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Driver ads1115_driver = {
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.name = "ads1115",
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.compatible = (const char*[]) { "ti,ads1115", nullptr },
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.start_device = start,
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.stop_device = stop,
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.probe = nullptr,
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.api = &ADS1115_API,
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.device_type = &ADC_CONTROLLER_TYPE,
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.owner = &ads1115_module,
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.internal = nullptr
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};
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}
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