esp32-hal-touch.c

// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "soc/soc_caps.h"

#if SOC_TOUCH_SENSOR_SUPPORTED
#include "driver/touch_sensor.h"
#include "esp32-hal-touch.h"
#include "esp32-hal-periman.h"

/*
    Internal Private Touch Data Structure and Functions
*/

#if SOC_TOUCH_VERSION_1  // ESP32
static uint16_t __touchSleepCycles = 0x1000;
static uint16_t __touchMeasureCycles = 0x1000;
#elif SOC_TOUCH_VERSION_2  // ESP32S2, ESP32S3
static uint16_t __touchSleepCycles = TOUCH_PAD_SLEEP_CYCLE_DEFAULT;
static uint16_t __touchMeasureCycles = TOUCH_PAD_MEASURE_CYCLE_DEFAULT;
#endif

typedef void (*voidFuncPtr)(void);
typedef void (*voidArgFuncPtr)(void *);

typedef struct {
  voidFuncPtr fn;
  bool callWithArgs;
  void *arg;
#if SOC_TOUCH_VERSION_2  // Only for ESP32S2 and ESP32S3
  bool lastStatusIsPressed;
#endif
} TouchInterruptHandle_t;

static TouchInterruptHandle_t __touchInterruptHandlers[SOC_TOUCH_SENSOR_NUM] = {
  0,
};

static uint8_t used_pads = 0;
static bool initialized = false;
static bool channels_initialized[SOC_TOUCH_SENSOR_NUM] = {false};

static void ARDUINO_ISR_ATTR __touchISR(void *arg) {
#if SOC_TOUCH_VERSION_1  // ESP32
  uint32_t pad_intr = touch_pad_get_status();
  //clear interrupt
  touch_pad_clear_status();
  // call Pad ISR User callback
  for (int i = 0; i < SOC_TOUCH_SENSOR_NUM; i++) {
    if ((pad_intr >> i) & 0x01) {
      if (__touchInterruptHandlers[i].fn) {
        // keeping backward compatibility with "void cb(void)" and with new "void cb(vooid *)"
        if (__touchInterruptHandlers[i].callWithArgs) {
          ((voidArgFuncPtr)__touchInterruptHandlers[i].fn)(__touchInterruptHandlers[i].arg);
        } else {
          __touchInterruptHandlers[i].fn();
        }
      }
    }
  }
#elif SOC_TOUCH_VERSION_2  // ESP32S2, ESP32S3
  touch_pad_intr_mask_t evt = touch_pad_read_intr_status_mask();
  uint8_t pad_num = touch_pad_get_current_meas_channel();
  if (evt & TOUCH_PAD_INTR_MASK_ACTIVE) {
    // touch has been pressed / touched
    __touchInterruptHandlers[pad_num].lastStatusIsPressed = true;
  }
  if (evt & TOUCH_PAD_INTR_MASK_INACTIVE) {
    // touch has been released / untouched
    __touchInterruptHandlers[pad_num].lastStatusIsPressed = false;
  }
  if (__touchInterruptHandlers[pad_num].fn) {
    // keeping backward compatibility with "void cb(void)" and with new "void cb(vooid *)"
    if (__touchInterruptHandlers[pad_num].callWithArgs) {
      ((voidArgFuncPtr)__touchInterruptHandlers[pad_num].fn)(__touchInterruptHandlers[pad_num].arg);
    } else {
      __touchInterruptHandlers[pad_num].fn();
    }
  }
#endif
}

static void __touchSetCycles(uint16_t measure, uint16_t sleep) {
  __touchSleepCycles = sleep;
  __touchMeasureCycles = measure;
#if SOC_TOUCH_VERSION_1  // ESP32
  touch_pad_set_measurement_clock_cycles(measure);
#elif SOC_TOUCH_VERSION_2  // ESP32S2, ESP32S3
  touch_pad_set_charge_discharge_times(measure);
#endif
  touch_pad_set_measurement_interval(sleep);
}

static bool touchDetachBus(void *pin) {
  int8_t pad = digitalPinToTouchChannel((int)(pin - 1));
  channels_initialized[pad] = false;
  used_pads--;
  if (used_pads == 0) {
    if (touch_pad_deinit() != ESP_OK)  //deinit touch module, as no pads are used
    {
      log_e("Touch module deinit failed!");
      return false;
    }
    initialized = false;
  }
  return true;
}

static void __touchInit() {
  if (initialized) {
    return;
  }

  esp_err_t err = ESP_OK;

#if SOC_TOUCH_VERSION_1  // ESP32
  err = touch_pad_init();
  if (err != ESP_OK) {
    goto err;
  }
  // the next two lines will drive the touch reading values -- both will return ESP_OK
  touch_pad_set_voltage(TOUCH_HVOLT_2V7, TOUCH_LVOLT_0V5, TOUCH_HVOLT_ATTEN_0V);
  touch_pad_set_measurement_clock_cycles(__touchMeasureCycles);
  touch_pad_set_measurement_interval(__touchSleepCycles);
  // Touch Sensor Timer initiated
  touch_pad_set_fsm_mode(TOUCH_FSM_MODE_TIMER);  // returns ESP_OK
  err = touch_pad_filter_start(10);
  if (err != ESP_OK) {
    goto err;
  }
  // keep ISR activated - it can run all together (ISR + touchRead())
  err = touch_pad_isr_register(__touchISR, NULL);
  if (err != ESP_OK) {
    goto err;
  }
  touch_pad_intr_enable();  // returns ESP_OK
#elif SOC_TOUCH_VERSION_2   // ESP32S2, ESP32S3
  err = touch_pad_init();
  if (err != ESP_OK) {
    goto err;
  }
  // the next lines will drive the touch reading values -- all os them return ESP_OK
  touch_pad_set_charge_discharge_times(__touchMeasureCycles);
  touch_pad_set_measurement_interval(__touchSleepCycles);
  touch_pad_set_voltage(TOUCH_PAD_HIGH_VOLTAGE_THRESHOLD, TOUCH_PAD_LOW_VOLTAGE_THRESHOLD, TOUCH_PAD_ATTEN_VOLTAGE_THRESHOLD);
  touch_pad_set_idle_channel_connect(TOUCH_PAD_IDLE_CH_CONNECT_DEFAULT);
  touch_pad_denoise_t denoise = {
    .grade = TOUCH_PAD_DENOISE_BIT4,
    .cap_level = TOUCH_PAD_DENOISE_CAP_L4,
  };
  touch_pad_denoise_set_config(&denoise);
  touch_pad_denoise_enable();
  // Touch Sensor Timer initiated
  touch_pad_set_fsm_mode(TOUCH_FSM_MODE_TIMER);  // returns ESP_OK
  touch_pad_fsm_start();                         // returns ESP_OK
  //ISR setup moved to __touchChannelInit
#endif

  initialized = true;
  return;
err:
  log_e(" Touch sensor initialization error.");
  initialized = false;
  return;
}

static void __touchChannelInit(int pad) {
  if (channels_initialized[pad]) {
    return;
  }

#if SOC_TOUCH_VERSION_1  // ESP32
  // Initial no Threshold and setup
  __touchInterruptHandlers[pad].fn = NULL;
  touch_pad_config(pad, SOC_TOUCH_PAD_THRESHOLD_MAX);  // returns ESP_OK
#elif SOC_TOUCH_VERSION_2                              // ESP32S2, ESP32S3
  // Initial no Threshold and setup
  __touchInterruptHandlers[pad].fn = NULL;
  touch_pad_config(pad);  // returns ESP_OK
  // keep ISR activated - it can run all together (ISR + touchRead())
  esp_err_t err = touch_pad_isr_register(__touchISR, NULL, TOUCH_PAD_INTR_MASK_ACTIVE | TOUCH_PAD_INTR_MASK_INACTIVE);
  if (err != ESP_OK) {
    log_e(" Touch sensor initialization error.");
    return;
  }
  touch_pad_intr_enable(TOUCH_PAD_INTR_MASK_ACTIVE | TOUCH_PAD_INTR_MASK_INACTIVE);  // returns ESP_OK
#endif

  channels_initialized[pad] = true;
  used_pads++;
  delay(20);  //delay needed before reading from touch channel after config
}

static touch_value_t __touchRead(uint8_t pin) {
  int8_t pad = digitalPinToTouchChannel(pin);
  if (pad < 0) {
    log_e(" No touch pad on selected pin!");
    return 0;
  }

  if (perimanGetPinBus(pin, ESP32_BUS_TYPE_TOUCH) == NULL) {
    perimanSetBusDeinit(ESP32_BUS_TYPE_TOUCH, touchDetachBus);
    if (!perimanClearPinBus(pin)) {
      return 0;
    }
    __touchInit();
    __touchChannelInit(pad);

    if (!perimanSetPinBus(pin, ESP32_BUS_TYPE_TOUCH, (void *)(pin + 1), -1, pad)) {
      touchDetachBus((void *)(pin + 1));
      return 0;
    }
  }

  touch_value_t touch_value;
  touch_pad_read_raw_data(pad, &touch_value);

  return touch_value;
}

static void __touchConfigInterrupt(uint8_t pin, void (*userFunc)(void), void *Args, touch_value_t threshold, bool callWithArgs) {
  int8_t pad = digitalPinToTouchChannel(pin);
  if (pad < 0) {
    log_e(" No touch pad on selected pin!");
    return;
  }

  if (userFunc == NULL) {
    // detach ISR User Call
    __touchInterruptHandlers[pad].fn = NULL;
    threshold = SOC_TOUCH_PAD_THRESHOLD_MAX;  // deactivate the ISR with SOC_TOUCH_PAD_THRESHOLD_MAX
  } else {
    // attach ISR User Call
    __touchInit();
    __touchChannelInit(pad);
    __touchInterruptHandlers[pad].fn = userFunc;
    __touchInterruptHandlers[pad].callWithArgs = callWithArgs;
    __touchInterruptHandlers[pad].arg = Args;
  }

  touch_pad_set_thresh(pad, threshold);
}

// it keeps backwards compatibility
static void __touchAttachInterrupt(uint8_t pin, void (*userFunc)(void), touch_value_t threshold) {
  __touchConfigInterrupt(pin, userFunc, NULL, threshold, false);
}

// new additional version of the API with User Args
static void __touchAttachArgsInterrupt(uint8_t pin, void (*userFunc)(void), void *args, touch_value_t threshold) {
  __touchConfigInterrupt(pin, userFunc, args, threshold, true);
}

// new additional API to detach touch ISR
static void __touchDettachInterrupt(uint8_t pin) {
  __touchConfigInterrupt(pin, NULL, NULL, 0, false);  // userFunc as NULL acts as detaching
}

/*
    External Public Touch API Functions
*/

#if SOC_TOUCH_VERSION_1  // Only for ESP32 SoC
void touchInterruptSetThresholdDirection(bool mustbeLower) {
  if (mustbeLower) {
    touch_pad_set_trigger_mode(TOUCH_TRIGGER_BELOW);
  } else {
    touch_pad_set_trigger_mode(TOUCH_TRIGGER_ABOVE);
  }
}
#elif SOC_TOUCH_VERSION_2  // Only for ESP32S2 and ESP32S3
// returns true if touch pad has been and continues pressed and false otherwise
bool touchInterruptGetLastStatus(uint8_t pin) {
  int8_t pad = digitalPinToTouchChannel(pin);
  if (pad < 0) {
    return false;
  }

  return __touchInterruptHandlers[pad].lastStatusIsPressed;
}
#endif

void touchSleepWakeUpEnable(uint8_t pin, touch_value_t threshold) {
  int8_t pad = digitalPinToTouchChannel(pin);
  if (pad < 0) {
    log_e(" No touch pad on selected pin!");
    return;
  }

  if (perimanGetPinBus(pin, ESP32_BUS_TYPE_TOUCH) == NULL) {
    perimanSetBusDeinit(ESP32_BUS_TYPE_TOUCH, touchDetachBus);
    __touchInit();
    __touchChannelInit(pad);
    if (!perimanSetPinBus(pin, ESP32_BUS_TYPE_TOUCH, (void *)(pin + 1), -1, pad)) {
      log_e("Failed to set bus to Peripheral manager");
      touchDetachBus((void *)(pin + 1));
      return;
    }
  }
#if SOC_TOUCH_VERSION_1  // Only for ESP32 SoC
  touch_pad_set_thresh(pad, threshold);

#elif SOC_TOUCH_VERSION_2
  touch_pad_sleep_channel_enable(pad, true);
  touch_pad_sleep_set_threshold(pad, threshold);

#endif
  esp_sleep_enable_touchpad_wakeup();
}

extern touch_value_t touchRead(uint8_t) __attribute__((weak, alias("__touchRead")));
extern void touchAttachInterrupt(uint8_t, voidFuncPtr, touch_value_t) __attribute__((weak, alias("__touchAttachInterrupt")));
extern void touchAttachInterruptArg(uint8_t, voidArgFuncPtr, void *, touch_value_t) __attribute__((weak, alias("__touchAttachArgsInterrupt")));
extern void touchDetachInterrupt(uint8_t) __attribute__((weak, alias("__touchDettachInterrupt")));
extern void touchSetCycles(uint16_t, uint16_t) __attribute__((weak, alias("__touchSetCycles")));

#endif /* SOC_TOUCH_SENSOR_SUPPORTED */