atbetaflight/src/main/drivers/accgyro/accgyro_spi_lsm6dsl.c

/*
 * This file is part of Cleanflight and Betaflight.
 *
 * Cleanflight and Betaflight are free software. You can redistribute
 * this software and/or modify this software under the terms of the
 * GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option)
 * any later version.
 *
 * Cleanflight and Betaflight are distributed in the hope that they
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this software.
 *
 * If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "platform.h"

#ifdef USE_ACCGYRO_LSM6DSL

#include "drivers/accgyro/accgyro.h"
#include "drivers/accgyro/accgyro_spi_lsm6dsl.h"
#include "drivers/bus_spi.h"
#include "drivers/exti.h"
#include "drivers/io.h"
#include "drivers/io_impl.h"
#include "drivers/nvic.h"
#include "drivers/sensor.h"
#include "drivers/system.h"
#include "drivers/time.h"

// Need to see at least this many interrupts during initialisation to confirm EXTI connectivity
#define GYRO_EXTI_DETECT_THRESHOLD 1000

#ifdef USE_GYRO_EXTI
// Called in ISR context
// Gyro read has just completed
busStatus_e lsm6dslIntcallback(uint32_t arg)
{
    gyroDev_t *gyro = (gyroDev_t *)arg;
    int32_t gyroDmaDuration = cmpTimeCycles(getCycleCounter(), gyro->gyroLastEXTI);

    if (gyroDmaDuration > gyro->gyroDmaMaxDuration) {
        gyro->gyroDmaMaxDuration = gyroDmaDuration;
    }

    gyro->dataReady = true;

    return BUS_READY;
}

void lsm6dslExtiHandler(extiCallbackRec_t *cb)
{
    gyroDev_t *gyro = container_of(cb, gyroDev_t, exti);
    // Ideally we'd use a timer to capture such information, but unfortunately the port used for EXTI interrupt does
    // not have an associated timer
    uint32_t nowCycles = getCycleCounter();
    gyro->gyroSyncEXTI = gyro->gyroLastEXTI + gyro->gyroDmaMaxDuration;
    gyro->gyroLastEXTI = nowCycles;

    if (gyro->gyroModeSPI == GYRO_EXTI_INT_DMA) {
        spiSequence(&gyro->dev, gyro->segments);
    }

    gyro->detectedEXTI++;

}
#else
void lsm6dslExtiHandler(extiCallbackRec_t *cb)
{
    gyroDev_t *gyro = container_of(cb, gyroDev_t, exti);
    gyro->dataReady = true;
}
#endif

bool lsm6dslAccRead(accDev_t *acc)
{
    switch (acc->gyro->gyroModeSPI) {
    case GYRO_EXTI_INT:
    case GYRO_EXTI_NO_INT:
    {
        acc->gyro->dev.txBuf[1] = LSM6DSL_REG_OUTX_L_A | 0x80;

        busSegment_t segments[] = {
                {.u.buffers = {NULL, NULL}, 8, true, NULL},
                {.u.link = {NULL, NULL}, 0, true, NULL},
        };
        segments[0].u.buffers.txData = &acc->gyro->dev.txBuf[1];
        segments[0].u.buffers.rxData = &acc->gyro->dev.rxBuf[1];

        spiSequence(&acc->gyro->dev, &segments[0]);

        // Wait for completion
        spiWait(&acc->gyro->dev);

        int16_t *accData = (int16_t *)acc->gyro->dev.rxBuf;
        acc->ADCRaw[X] = accData[1];
        acc->ADCRaw[Y] = accData[2];
        acc->ADCRaw[Z] = accData[3];
        break;
    }

    case GYRO_EXTI_INT_DMA:
    {
        // If read was triggered in interrupt don't bother waiting. The worst that could happen is that we pick
        // up an old value.

        // This data was read from the gyro, which is the same SPI device as the acc
        int16_t *accData = (int16_t *)acc->gyro->dev.rxBuf;
        acc->ADCRaw[X] = accData[4];
        acc->ADCRaw[Y] = accData[5];
        acc->ADCRaw[Z] = accData[6];
        break;
    }

    case GYRO_EXTI_INIT:
    default:
        break;
    }

    return true;
}

bool lsm6dslGyroRead(gyroDev_t *gyro)
{
    int16_t *gyroData = (int16_t *)gyro->dev.rxBuf;
    switch (gyro->gyroModeSPI) {
    case GYRO_EXTI_INIT:
    {
        // Initialise the tx buffer to all 0x00
        memset(gyro->dev.txBuf, 0x00, 14);
#ifdef USE_GYRO_EXTI
        // Check that minimum number of interrupts have been detected

        // We need some offset from the gyro interrupts to ensure sampling after the interrupt
        gyro->gyroDmaMaxDuration = 5;
        // Using DMA for gyro access upsets the scheduler on the F4
        if (gyro->detectedEXTI > GYRO_EXTI_DETECT_THRESHOLD) {
            if (spiUseDMA(&gyro->dev)) {
                gyro->dev.callbackArg = (uint32_t)gyro;
                gyro->dev.txBuf[1] = LSM6DSL_REG_OUTX_L_G | 0x80;
                gyro->segments[0].len = 13;
                gyro->segments[0].callback = lsm6dslIntcallback;
                gyro->segments[0].u.buffers.txData = &gyro->dev.txBuf[1];
                gyro->segments[0].u.buffers.rxData = &gyro->dev.rxBuf[1];
                gyro->segments[0].negateCS = true;
                gyro->gyroModeSPI = GYRO_EXTI_INT_DMA;
            } else {
                // Interrupts are present, but no DMA
                gyro->gyroModeSPI = GYRO_EXTI_INT;
            }
        } else
#endif
        {
            gyro->gyroModeSPI = GYRO_EXTI_NO_INT;
        }
        break;
    }

    case GYRO_EXTI_INT:
    case GYRO_EXTI_NO_INT:
    {
        gyro->dev.txBuf[1] = LSM6DSL_REG_OUTX_L_G | 0x80;

        busSegment_t segments[] = {
                {.u.buffers = {NULL, NULL}, 7, true, NULL},
                {.u.link = {NULL, NULL}, 0, true, NULL},
        };
        segments[0].u.buffers.txData = &gyro->dev.txBuf[1];
        segments[0].u.buffers.rxData = &gyro->dev.rxBuf[1];

        spiSequence(&gyro->dev, &segments[0]);

        // Wait for completion
        spiWait(&gyro->dev);

        // Fall through
        FALLTHROUGH;
    }

    case GYRO_EXTI_INT_DMA:
    {
        // If read was triggered in interrupt don't bother waiting. The worst that could happen is that we pick
        // up an old value.
        gyro->gyroADCRaw[X] = gyroData[1];
        gyro->gyroADCRaw[Y] = gyroData[2];
        gyro->gyroADCRaw[Z] = gyroData[3];
        break;
    }

    default:
        break;
    }

    return true;
}
#endif