Diff: i2c_api.c

Revision:

0:e4d670b91a9a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/i2c_api.c	Wed Mar 23 21:26:50 2016 +0000
@@ -0,0 +1,328 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * 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 "mbed_assert.h"
+#include "i2c_api.h"
+
+#if DEVICE_I2C
+
+#include "cmsis.h"
+#include "pinmap.h"
+#include "fsl_clock_manager.h"
+#include "fsl_i2c_hal.h"
+#include "fsl_port_hal.h"
+#include "fsl_sim_hal.h"
+#include "PeripheralPins.h"
+
+void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
+    uint32_t i2c_sda = pinmap_peripheral(sda, PinMap_I2C_SDA);
+    uint32_t i2c_scl = pinmap_peripheral(scl, PinMap_I2C_SCL);
+    obj->instance = pinmap_merge(i2c_sda, i2c_scl);
+    MBED_ASSERT((int)obj->instance != NC);
+
+    CLOCK_SYS_EnableI2cClock(obj->instance);
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    I2C_HAL_Init(i2c_addrs[obj->instance]);
+    I2C_HAL_Enable(i2c_addrs[obj->instance]);
+    I2C_HAL_SetIntCmd(i2c_addrs[obj->instance], true);
+    i2c_frequency(obj, 100000);
+
+    pinmap_pinout(sda, PinMap_I2C_SDA);
+    pinmap_pinout(scl, PinMap_I2C_SCL);
+
+    uint32_t port_addrs[] = PORT_BASE_ADDRS;
+    PORT_HAL_SetOpenDrainCmd(port_addrs[sda >> GPIO_PORT_SHIFT], sda & 0xFF, true);
+    PORT_HAL_SetOpenDrainCmd(port_addrs[scl >> GPIO_PORT_SHIFT], scl & 0xFF, true);
+}
+
+int i2c_start(i2c_t *obj) {
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    I2C_HAL_SendStart(i2c_addrs[obj->instance]);
+    return 0;
+}
+
+int i2c_stop(i2c_t *obj) {
+    volatile uint32_t n = 0;
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    if (I2C_HAL_IsMaster(i2c_addrs[obj->instance]))
+        I2C_HAL_SendStop(i2c_addrs[obj->instance]);
+    
+    // It seems that there are timing problems
+    // when there is no waiting time after a STOP.
+    // This wait is also included on the samples
+    // code provided with the freedom board
+    for (n = 0; n < 200; n++) __NOP();
+    return 0;
+}
+
+static int timeout_status_poll(i2c_t *obj, i2c_status_flag_t flag) {
+    uint32_t i, timeout = 100000;
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+
+    for (i = 0; i < timeout; i++) {
+        if (I2C_HAL_GetStatusFlag(i2c_addrs[obj->instance], flag))
+            return 0;
+    }
+    return 1;
+}
+
+// this function waits the end of a tx transfer and return the status of the transaction:
+//    0: OK ack received
+//    1: OK ack not received
+//    2: failure
+static int i2c_wait_end_tx_transfer(i2c_t *obj) {
+    // wait for the interrupt flag
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+
+    if (timeout_status_poll(obj, kI2CInterruptPending)) {
+        return 2;
+    }
+    I2C_HAL_ClearInt(i2c_addrs[obj->instance]);
+
+    // wait transfer complete
+    if (timeout_status_poll(obj, kI2CTransferComplete)) {
+        return 2;
+    }
+
+    // check if we received the ACK or not
+    return I2C_HAL_GetStatusFlag(i2c_addrs[obj->instance], kI2CReceivedNak) ? 1 : 0;
+}
+
+// this function waits the end of a rx transfer and return the status of the transaction:
+//    0: OK
+//    1: failure
+static int i2c_wait_end_rx_transfer(i2c_t *obj) {
+    // wait for the end of the rx transfer
+    if (timeout_status_poll(obj, kI2CInterruptPending)) {
+        return 1;
+    }
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    I2C_HAL_ClearInt(i2c_addrs[obj->instance]);
+
+    return 0;
+}
+
+static int i2c_do_write(i2c_t *obj, int value) {
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    I2C_HAL_WriteByte(i2c_addrs[obj->instance], value);
+
+    // init and wait the end of the transfer
+    return i2c_wait_end_tx_transfer(obj);
+}
+
+static int i2c_do_read(i2c_t *obj, char * data, int last) {
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    if (last) {
+        I2C_HAL_SendNak(i2c_addrs[obj->instance]);
+    } else {
+        I2C_HAL_SendAck(i2c_addrs[obj->instance]);
+    }
+
+    *data = (I2C_HAL_ReadByte(i2c_addrs[obj->instance]) & 0xFF);
+
+    // start rx transfer and wait the end of the transfer
+    return i2c_wait_end_rx_transfer(obj);
+}
+
+void i2c_frequency(i2c_t *obj, int hz) {
+    uint32_t busClock;
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    clock_manager_error_code_t error = CLOCK_SYS_GetFreq(kBusClock, &busClock);
+    if (error == kClockManagerSuccess) {
+        I2C_HAL_SetBaudRate(i2c_addrs[obj->instance], busClock, hz / 1000, NULL);
+    }
+}
+
+int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
+    int count;
+    char dummy_read, *ptr;
+
+    if (i2c_start(obj)) {
+        i2c_stop(obj);
+        return I2C_ERROR_BUS_BUSY;
+    }
+
+    if (i2c_do_write(obj, (address | 0x01))) {
+        i2c_stop(obj);
+        return I2C_ERROR_NO_SLAVE;
+    }
+
+    // set rx mode
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    I2C_HAL_SetDirMode(i2c_addrs[obj->instance], kI2CReceive);
+
+    // Read in bytes
+    for (count = 0; count < (length); count++) {
+        ptr = (count == 0) ? &dummy_read : &data[count - 1];
+        uint8_t stop_ = (count == (length - 1)) ? 1 : 0;
+        if (i2c_do_read(obj, ptr, stop_)) {
+            i2c_stop(obj);
+            return count;
+        }
+    }
+
+    // If not repeated start, send stop.
+    if (stop)
+        i2c_stop(obj);
+
+    // last read
+    data[count-1] = I2C_HAL_ReadByte(i2c_addrs[obj->instance]);
+
+    return length;
+}
+
+int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
+    int i;
+
+    if (i2c_start(obj)) {
+        i2c_stop(obj);
+        return I2C_ERROR_BUS_BUSY;
+    }
+
+    if (i2c_do_write(obj, (address & 0xFE))) {
+        i2c_stop(obj);
+        return I2C_ERROR_NO_SLAVE;
+    }
+
+    for (i = 0; i < length; i++) {
+        if(i2c_do_write(obj, data[i])) {
+            i2c_stop(obj);
+            return i;
+        }
+    }
+
+    if (stop)
+        i2c_stop(obj);
+
+    return length;
+}
+
+void i2c_reset(i2c_t *obj) {
+    i2c_stop(obj);
+}
+
+int i2c_byte_read(i2c_t *obj, int last) {
+    char data;
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    // set rx mode
+    I2C_HAL_SetDirMode(i2c_addrs[obj->instance], kI2CReceive);
+
+    // Setup read
+    i2c_do_read(obj, &data, last);
+
+    // set tx mode
+    I2C_HAL_SetDirMode(i2c_addrs[obj->instance], kI2CSend);
+    return I2C_HAL_ReadByte(i2c_addrs[obj->instance]);
+}
+
+int i2c_byte_write(i2c_t *obj, int data) {
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    // set tx mode
+    I2C_HAL_SetDirMode(i2c_addrs[obj->instance], kI2CSend);
+
+    return !i2c_do_write(obj, (data & 0xFF));
+}
+
+
+#if DEVICE_I2CSLAVE
+void i2c_slave_mode(i2c_t *obj, int enable_slave) {
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    if (enable_slave) {
+        // set slave mode
+        BW_I2C_C1_MST(i2c_addrs[obj->instance], 0);
+        I2C_HAL_SetIntCmd(i2c_addrs[obj->instance], true);
+    } else {
+        // set master mode
+        BW_I2C_C1_MST(i2c_addrs[obj->instance], 1);
+    }
+}
+
+int i2c_slave_receive(i2c_t *obj) {
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    switch(HW_I2C_S_RD(i2c_addrs[obj->instance])) {
+        // read addressed
+        case 0xE6:
+            return 1;
+        // write addressed
+        case 0xE2:
+            return 3;
+        default:
+            return 0;
+    }
+}
+
+int i2c_slave_read(i2c_t *obj, char *data, int length) {
+    uint8_t dummy_read;
+    uint8_t *ptr;
+    int count;
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    // set rx mode
+    I2C_HAL_SetDirMode(i2c_addrs[obj->instance], kI2CSend);
+
+    // first dummy read
+    dummy_read = I2C_HAL_ReadByte(i2c_addrs[obj->instance]);
+    if (i2c_wait_end_rx_transfer(obj))
+        return 0;
+
+    // read address
+    dummy_read = I2C_HAL_ReadByte(i2c_addrs[obj->instance]);
+    if (i2c_wait_end_rx_transfer(obj))
+        return 0;
+
+    // read (length - 1) bytes
+    for (count = 0; count < (length - 1); count++) {
+        data[count] = I2C_HAL_ReadByte(i2c_addrs[obj->instance]);
+        if (i2c_wait_end_rx_transfer(obj))
+            return count;
+    }
+
+    // read last byte
+    ptr = (length == 0) ? &dummy_read : (uint8_t *)&data[count];
+    *ptr = I2C_HAL_ReadByte(i2c_addrs[obj->instance]);
+
+    return (length) ? (count + 1) : 0;
+}
+
+int i2c_slave_write(i2c_t *obj, const char *data, int length) {
+    int i, count = 0;
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+
+    // set tx mode
+    I2C_HAL_SetDirMode(i2c_addrs[obj->instance], kI2CSend);
+
+    for (i = 0; i < length; i++) {
+        if (i2c_do_write(obj, data[count++]) == 2)
+            return i;
+    }
+
+    // set rx mode
+    I2C_HAL_SetDirMode(i2c_addrs[obj->instance], kI2CReceive);
+
+    // dummy rx transfer needed
+    // otherwise the master cannot generate a stop bit
+    I2C_HAL_ReadByte(i2c_addrs[obj->instance]);
+    if (i2c_wait_end_rx_transfer(obj) == 2)
+        return count;
+
+    return count;
+}
+
+void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
+    uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
+    I2C_HAL_SetUpperAddress7bit(i2c_addrs[obj->instance], address & 0xfe);
+}
+#endif
+
+#endif