Diff: drivers/source/I2C.cpp

Revision:

1:9db0e321a9f4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/source/I2C.cpp	Tue Dec 31 06:02:27 2019 +0000
@@ -0,0 +1,267 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2019 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * 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 "drivers/I2C.h"
+#include "drivers/DigitalInOut.h"
+#include "platform/mbed_wait_api.h"
+
+#if DEVICE_I2C
+
+#if DEVICE_I2C_ASYNCH
+#include "platform/mbed_power_mgmt.h"
+#endif
+
+namespace mbed {
+
+I2C *I2C::_owner = NULL;
+SingletonPtr<PlatformMutex> I2C::_mutex;
+
+I2C::I2C(PinName sda, PinName scl) :
+#if DEVICE_I2C_ASYNCH
+    _irq(this), _usage(DMA_USAGE_NEVER), _deep_sleep_locked(false),
+#endif
+    _i2c(), _hz(100000)
+{
+    lock();
+    // The init function also set the frequency to 100000
+    _sda = sda;
+    _scl = scl;
+    recover(sda, scl);
+    i2c_init(&_i2c, _sda, _scl);
+    // Used to avoid unnecessary frequency updates
+    _owner = this;
+    unlock();
+}
+
+I2C::I2C(const i2c_pinmap_t &static_pinmap) :
+#if DEVICE_I2C_ASYNCH
+    _irq(this), _usage(DMA_USAGE_NEVER), _deep_sleep_locked(false),
+#endif
+    _i2c(), _hz(100000)
+{
+    lock();
+    // The init function also set the frequency to 100000
+    _sda = static_pinmap.sda_pin;
+    _scl = static_pinmap.scl_pin;
+    recover(static_pinmap.sda_pin, static_pinmap.scl_pin);
+    i2c_init_direct(&_i2c, &static_pinmap);
+    // Used to avoid unnecessary frequency updates
+    _owner = this;
+    unlock();
+}
+
+void I2C::frequency(int hz)
+{
+    lock();
+    _hz = hz;
+
+    // We want to update the frequency even if we are already the bus owners
+    i2c_frequency(&_i2c, _hz);
+
+    // Updating the frequency of the bus we become the owners of it
+    _owner = this;
+    unlock();
+}
+
+void I2C::aquire()
+{
+    lock();
+    if (_owner != this) {
+        i2c_frequency(&_i2c, _hz);
+        _owner = this;
+    }
+    unlock();
+}
+
+// write - Master Transmitter Mode
+int I2C::write(int address, const char *data, int length, bool repeated)
+{
+    lock();
+    aquire();
+
+    int stop = (repeated) ? 0 : 1;
+    int written = i2c_write(&_i2c, address, data, length, stop);
+
+    unlock();
+    return length != written;
+}
+
+int I2C::write(int data)
+{
+    lock();
+    int ret = i2c_byte_write(&_i2c, data);
+    unlock();
+    return ret;
+}
+
+// read - Master Receiver Mode
+int I2C::read(int address, char *data, int length, bool repeated)
+{
+    lock();
+    aquire();
+
+    int stop = (repeated) ? 0 : 1;
+    int read = i2c_read(&_i2c, address, data, length, stop);
+
+    unlock();
+    return length != read;
+}
+
+int I2C::read(int ack)
+{
+    lock();
+    int ret;
+    if (ack) {
+        ret = i2c_byte_read(&_i2c, 0);
+    } else {
+        ret = i2c_byte_read(&_i2c, 1);
+    }
+    unlock();
+    return ret;
+}
+
+void I2C::start(void)
+{
+    lock();
+    i2c_start(&_i2c);
+    unlock();
+}
+
+void I2C::stop(void)
+{
+    lock();
+    i2c_stop(&_i2c);
+    unlock();
+}
+
+void I2C::lock()
+{
+    _mutex->lock();
+}
+
+void I2C::unlock()
+{
+    _mutex->unlock();
+}
+
+int I2C::recover(PinName sda, PinName scl)
+{
+    DigitalInOut pin_sda(sda, PIN_INPUT, PullNone, 1);
+    DigitalInOut pin_scl(scl, PIN_INPUT, PullNone, 1);
+
+    // Return as SCL is low and no access to become master.
+    if (pin_scl == 0) {
+        return I2C_ERROR_BUS_BUSY;
+    }
+
+    // Return successfully as SDA and SCL is high
+    if (pin_sda == 1) {
+        return 0;
+    }
+
+    // Send clock pulses, for device to recover 9
+    pin_scl.mode(PullNone);
+    pin_scl.output();
+    for (int count = 0; count < 10; count++) {
+        pin_scl.mode(PullNone);
+        pin_scl = 0;
+        wait_us(5);
+        pin_scl.mode(PullUp);
+        pin_scl = 1;
+        wait_us(5);
+    }
+
+    // Send Stop
+    pin_sda.output();
+    pin_sda = 0;
+    wait_us(5);
+    pin_scl = 1;
+    wait_us(5);
+    pin_sda = 1;
+    wait_us(5);
+
+    pin_sda.input();
+    pin_scl.input();
+    if ((pin_scl == 0) || (pin_sda == 0)) {
+        // Return as SCL is low and no access to become master.
+        return I2C_ERROR_BUS_BUSY;
+    }
+
+    return 0;
+}
+
+#if DEVICE_I2C_ASYNCH
+
+int I2C::transfer(int address, const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length, const event_callback_t &callback, int event, bool repeated)
+{
+    lock();
+    if (i2c_active(&_i2c)) {
+        unlock();
+        return -1; // transaction ongoing
+    }
+    lock_deep_sleep();
+    aquire();
+
+    _callback = callback;
+    int stop = (repeated) ? 0 : 1;
+    _irq.callback(&I2C::irq_handler_asynch);
+    i2c_transfer_asynch(&_i2c, (void *)tx_buffer, tx_length, (void *)rx_buffer, rx_length, address, stop, _irq.entry(), event, _usage);
+    unlock();
+    return 0;
+}
+
+void I2C::abort_transfer(void)
+{
+    lock();
+    i2c_abort_asynch(&_i2c);
+    unlock_deep_sleep();
+    unlock();
+}
+
+void I2C::irq_handler_asynch(void)
+{
+    int event = i2c_irq_handler_asynch(&_i2c);
+    if (_callback && event) {
+        _callback.call(event);
+    }
+
+    if (event) {
+        unlock_deep_sleep();
+    }
+}
+
+void I2C::lock_deep_sleep()
+{
+    if (_deep_sleep_locked == false) {
+        sleep_manager_lock_deep_sleep();
+        _deep_sleep_locked = true;
+    }
+}
+
+void I2C::unlock_deep_sleep()
+{
+    if (_deep_sleep_locked == true) {
+        sleep_manager_unlock_deep_sleep();
+        _deep_sleep_locked = false;
+    }
+}
+
+#endif
+
+} // namespace mbed
+
+#endif