Diff: targets/TARGET_NORDIC/TARGET_NRF5/i2c_api.c

Revision:

0:f269e3021894

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NORDIC/TARGET_NRF5/i2c_api.c	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,302 @@
+/* 
+ * Copyright (c) 2013 Nordic Semiconductor ASA
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ * 
+ *   1. Redistributions of source code must retain the above copyright notice, this list 
+ *      of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form, except as embedded into a Nordic Semiconductor ASA 
+ *      integrated circuit in a product or a software update for such product, must reproduce 
+ *      the above copyright notice, this list of conditions and the following disclaimer in 
+ *      the documentation and/or other materials provided with the distribution.
+ *
+ *   3. Neither the name of Nordic Semiconductor ASA nor the names of its contributors may be 
+ *      used to endorse or promote products derived from this software without specific prior 
+ *      written permission.
+ *
+ *   4. This software, with or without modification, must only be used with a 
+ *      Nordic Semiconductor ASA integrated circuit.
+ *
+ *   5. Any software provided in binary or object form under this license must not be reverse 
+ *      engineered, decompiled, modified and/or disassembled. 
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ */
+
+
+#include "i2c_api.h"
+
+#if DEVICE_I2C
+
+#include "mbed_assert.h"
+#include "mbed_error.h"
+#include "nrf_drv_twi.h"
+#include "app_util_platform.h"
+
+#if DEVICE_I2C_ASYNCH
+    #define TWI_IDX(obj)    ((obj)->i2c.twi_idx)
+#else
+    #define TWI_IDX(obj)    ((obj)->twi_idx)
+#endif
+#define TWI_INFO(obj)   (&m_twi_info[TWI_IDX(obj)])
+
+typedef struct {
+    bool initialized;
+    nrf_drv_twi_config_t config;
+    volatile bool transfer_finished;
+
+    #if DEVICE_I2C_ASYNCH
+    volatile uint32_t events;
+    void (*handler)(void);
+    uint32_t event_mask;
+    #endif
+} twi_info_t;
+static twi_info_t m_twi_info[TWI_COUNT];
+
+static nrf_drv_twi_t const m_twi_instances[TWI_COUNT] = {
+#if TWI0_ENABLED
+    NRF_DRV_TWI_INSTANCE(0),
+#endif
+#if TWI1_ENABLED
+    NRF_DRV_TWI_INSTANCE(1),
+#endif
+};
+
+static void twi_event_handler(nrf_drv_twi_evt_t const *event, void *context)
+{
+    twi_info_t * twi_info = TWI_INFO((i2c_t *)context);
+    twi_info->transfer_finished = true;
+
+#if DEVICE_I2C_ASYNCH
+    switch (event->type) {
+    case NRF_DRV_TWI_EVT_DONE:
+        twi_info->events |= I2C_EVENT_TRANSFER_COMPLETE;
+        break;
+
+    case NRF_DRV_TWI_EVT_ADDRESS_NACK:
+        twi_info->events |= I2C_EVENT_ERROR_NO_SLAVE;
+        break;
+
+    case NRF_DRV_TWI_EVT_DATA_NACK:
+        twi_info->events |= I2C_EVENT_ERROR;
+        break;
+    }
+
+    if (twi_info->handler) {
+        twi_info->handler();
+    }
+#endif // DEVICE_I2C_ASYNCH
+}
+
+static uint8_t twi_address(int i2c_address)
+{
+    // The TWI driver requires 7-bit slave address (without R/W bit).
+    return (i2c_address >> 1);
+}
+
+void i2c_init(i2c_t *obj, PinName sda, PinName scl)
+{
+    int i;
+    for (i = 0; i < TWI_COUNT; ++i) {
+        if (m_twi_info[i].initialized &&
+            m_twi_info[i].config.sda == (uint32_t)sda &&
+            m_twi_info[i].config.scl == (uint32_t)scl) {
+            TWI_IDX(obj) = i;
+            TWI_INFO(obj)->config.frequency = NRF_TWI_FREQ_100K;
+            i2c_reset(obj);
+            return;
+        }
+    }
+
+    nrf_drv_twi_config_t const config = {
+        .scl                = scl,
+        .sda                = sda,
+        .frequency          = NRF_TWI_FREQ_100K,
+        .interrupt_priority = APP_IRQ_PRIORITY_LOW,
+    };
+
+    for (i = 0; i < TWI_COUNT; ++i) {
+        if (!m_twi_info[i].initialized) {
+            nrf_drv_twi_t const *twi = &m_twi_instances[i];
+            ret_code_t ret_code =
+                nrf_drv_twi_init(twi, &config, twi_event_handler, obj);
+            if (ret_code == NRF_SUCCESS) {
+                TWI_IDX(obj) = i;
+                TWI_INFO(obj)->initialized = true;
+                TWI_INFO(obj)->config = config;
+
+                nrf_drv_twi_enable(twi);
+                return;
+            }
+        }
+    }
+
+    // No available peripheral
+    error("No available I2C peripheral\r\n");
+}
+
+void i2c_reset(i2c_t *obj)
+{
+    twi_info_t *twi_info = TWI_INFO(obj);
+    nrf_drv_twi_t const *twi = &m_twi_instances[TWI_IDX(obj)];
+
+    nrf_drv_twi_uninit(twi);
+    nrf_drv_twi_init(twi, &twi_info->config, twi_event_handler, obj);
+    nrf_drv_twi_enable(twi);
+}
+
+int i2c_start(i2c_t *obj)
+{
+    (void)obj;
+
+    return -1; // Not implemented.
+}
+
+int i2c_stop(i2c_t *obj)
+{
+    (void)obj;
+
+    return -1; // Not implemented.
+}
+
+void i2c_frequency(i2c_t *obj, int hz)
+{
+    twi_info_t *twi_info = TWI_INFO(obj);
+    nrf_drv_twi_t const *twi = &m_twi_instances[TWI_IDX(obj)];
+
+    if (hz < 250000) {
+        twi_info->config.frequency = NRF_TWI_FREQ_100K;
+    } else if (hz < 400000) {
+        twi_info->config.frequency = NRF_TWI_FREQ_250K;
+    } else {
+        twi_info->config.frequency = NRF_TWI_FREQ_400K;
+    }
+    nrf_twi_frequency_set(twi->reg.p_twi, twi_info->config.frequency);
+}
+
+int i2c_read(i2c_t *obj, int address, char *data, int length, int stop)
+{
+    (void)stop;
+
+    twi_info_t *twi_info = TWI_INFO(obj);
+    nrf_drv_twi_t const *twi = &m_twi_instances[TWI_IDX(obj)];
+
+    twi_info->transfer_finished = false;
+    ret_code_t ret_code = nrf_drv_twi_rx(twi, twi_address(address),
+        (uint8_t *)data, length);
+    if (ret_code != NRF_SUCCESS) {
+        return 0;
+    }
+    while (!twi_info->transfer_finished) {}
+    return nrf_drv_twi_data_count_get(twi);
+}
+
+int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop)
+{
+    twi_info_t *twi_info = TWI_INFO(obj);
+    nrf_drv_twi_t const *twi = &m_twi_instances[TWI_IDX(obj)];
+
+    twi_info->transfer_finished = false;
+    ret_code_t ret_code = nrf_drv_twi_tx(twi, twi_address(address),
+        (uint8_t const *)data, length, (stop == 0));
+    if (ret_code != NRF_SUCCESS) {
+        return 0;
+    }
+    while (!twi_info->transfer_finished) {}
+    return nrf_drv_twi_data_count_get(twi);
+}
+
+int i2c_byte_read(i2c_t *obj, int last)
+{
+    (void)obj;
+    (void)last;
+
+    return -1; // Not implemented.
+}
+
+int i2c_byte_write(i2c_t *obj, int data)
+{
+    (void)obj;
+    (void)data;
+
+    return -1; // Not implemented.
+}
+
+
+#if DEVICE_I2C_ASYNCH
+
+void i2c_transfer_asynch(i2c_t *obj, const void *tx, size_t tx_length,
+                         void *rx, size_t rx_length, uint32_t address,
+                         uint32_t stop, uint32_t handler,
+                         uint32_t event, DMAUsage hint)
+{
+    (void)stop;
+    (void)hint;
+
+    if (i2c_active(obj)) {
+        return;
+    }
+    if ((tx_length == 0) && (rx_length == 0)) {
+        return;
+    }
+
+    twi_info_t *twi_info = TWI_INFO(obj);
+    twi_info->events     = 0;
+    twi_info->handler    = (void (*)(void))handler;
+    twi_info->event_mask = event;
+
+    uint8_t twi_addr = twi_address(address);
+    nrf_drv_twi_t const *twi = &m_twi_instances[TWI_IDX(obj)];
+
+    if ((tx_length > 0) && (rx_length == 0)) {
+        nrf_drv_twi_xfer_desc_t const xfer =
+            NRF_DRV_TWI_XFER_DESC_TX(twi_addr, (uint8_t *)tx, tx_length);
+        nrf_drv_twi_xfer(twi, &xfer,
+            stop ? 0 : NRF_DRV_TWI_FLAG_TX_NO_STOP);
+    }
+    else if ((tx_length == 0) && (rx_length > 0)) {
+        nrf_drv_twi_xfer_desc_t const xfer =
+            NRF_DRV_TWI_XFER_DESC_RX(twi_addr, rx, rx_length);
+        nrf_drv_twi_xfer(twi, &xfer, 0);
+    }
+    else if ((tx_length > 0) && (rx_length > 0)) {
+        nrf_drv_twi_xfer_desc_t const xfer =
+            NRF_DRV_TWI_XFER_DESC_TXRX(twi_addr,
+                (uint8_t *)tx, tx_length, rx, rx_length);
+        nrf_drv_twi_xfer(twi, &xfer, 0);
+    }
+}
+
+uint32_t i2c_irq_handler_asynch(i2c_t *obj)
+{
+    twi_info_t *twi_info = TWI_INFO(obj);
+    return (twi_info->events & twi_info->event_mask);
+}
+
+uint8_t i2c_active(i2c_t *obj)
+{
+    nrf_drv_twi_t const *twi = &m_twi_instances[TWI_IDX(obj)];
+    return nrf_drv_twi_is_busy(twi);
+}
+
+void i2c_abort_asynch(i2c_t *obj)
+{
+    i2c_reset(obj);
+}
+
+#endif // DEVICE_I2C_ASYNCH
+
+#endif // DEVICE_I2C