Add SPI api

libraries/mbed/vendor/STM/capi/spi_api.c

@@ -0,0 +1,218 @@
+/* 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 "spi_api.h"
+
+#if DEVICE_SPI
+#include <math.h>
+
+#include "cmsis.h"
+#include "pinmap.h"
+#include "error.h"
+
+static const PinMap PinMap_SPI_SCLK[] = {
+    {PA_5, SPI_1, 2, 5},
+    {PB_3, SPI_1, 2, 5},
+    {PB_3, SPI_3, 2, 6},
+    {PB_10, SPI_2, 2, 5},
+    {PB_13, SPI_2, 2, 5},
+    {PC_10, SPI_3, 2, 6},
+    {NC   , NC   , 0, 0}
+};
+
+static const PinMap PinMap_SPI_MOSI[] = {
+    {PA_7, SPI_1, 2, 5},
+    {PB_5, SPI_1, 2, 5},
+    {PB_5, SPI_3, 2, 6},
+    {PB_15, SPI_2, 2, 5},
+    {PC_3, SPI_2, 2, 5},
+    {PC_12, SPI_3, 2, 6},
+    {NC   , NC   , 0, 0}
+};
+
+static const PinMap PinMap_SPI_MISO[] = {
+    {PA_6, SPI_1, 2, 5},
+    {PB_4, SPI_1, 2, 5},
+    {PB_4, SPI_3, 2, 6},
+    {PB_14, SPI_2, 2, 5},
+    {PC_2, SPI_2, 2, 5},
+    {PC_11, SPI_3, 2, 6},
+    {NC   , NC   , 0, 0}
+};
+
+static const PinMap PinMap_SPI_SSEL[] = {
+    {PA_4, SPI_1, 2, 5},
+    {PA_4, SPI_3, 2, 6},
+    {PA_15, SPI_1, 2, 5},
+    {PA_15, SPI_3, 2, 6},
+    {PB_9, SPI_2, 2, 5}, 
+    {PB_12, SPI_2, 2, 5},
+    {NC   , NC   , 0, 0}
+};
+
+
+static inline int ssp_disable(spi_t *obj);
+static inline int ssp_enable(spi_t *obj);
+
+void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
+    // determine the SPI to use
+    SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
+    SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
+    SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
+    SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
+    SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
+    SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
+    obj->spi = (SPI_TypeDef*)pinmap_merge(spi_data, spi_cntl);
+    if ((int)obj->spi == NC) {
+        error("SPI pinout mapping failed");
+    }
+
+    // enable power and clocking
+    switch ((int)obj->spi) {
+        case SPI_1: RCC->APB2ENR |= RCC_APB2ENR_SPI1EN; break;
+        case SPI_2: RCC->APB1ENR |= RCC_APB1ENR_SPI2EN; break;
+        case SPI_3: RCC->APB1ENR |= RCC_APB1ENR_SPI3EN; break;
+    }
+    
+
+    // set default format and frequency
+    if (ssel == NC) {
+        spi_format(obj, 8, 0, 0);  // 8 bits, mode 0, master
+    } else {
+        spi_format(obj, 8, 0, 1);  // 8 bits, mode 0, slave
+    }
+    spi_frequency(obj, 1000000);
+    
+    // enable the ssp channel
+    ssp_enable(obj);
+
+    // pin out the spi pins
+    pinmap_pinout(mosi, PinMap_SPI_MOSI);
+    pinmap_pinout(miso, PinMap_SPI_MISO);
+    pinmap_pinout(sclk, PinMap_SPI_SCLK);
+    if (ssel != NC) {
+        pinmap_pinout(ssel, PinMap_SPI_SSEL);
+    }
+}
+
+void spi_free(spi_t *obj) {}
+
+void spi_format(spi_t *obj, int bits, int mode, int slave) {
+    ssp_disable(obj);
+    
+    if (!(bits == 8 || bits == 16) || !(mode >= 0 && mode <= 3)) {
+        error("SPI format error");
+    }
+    
+
+    int polarity = (mode & 0x2) ? 1 : 0;
+    int phase = (mode & 0x1) ? 1 : 0;
+
+    uint32_t tmp = obj->spi->CR1;
+    tmp &= ~(0xFFFF);
+    tmp |= ((phase) ? 1 : 0) << 0
+        | ((polarity) ? 1 : 0) << 1
+        | ((slave) ? 0: 1) << 2
+        | ((bits == 16) ? 1 : 0) << 11;
+    obj->spi->CR1 = tmp;
+
+    ssp_enable(obj);
+}
+
+void spi_frequency(spi_t *obj, int hz) {
+    ssp_disable(obj);
+
+    // SPI1 runs from PCLK2, which runs at SystemCoreClock / 2.  SPI2 and SPI3
+    // run from PCLK1, which runs at SystemCoreClock / 4.
+    uint32_t PCLK = SystemCoreClock;
+    switch ((int)obj->spi) {
+        case SPI_1: PCLK = PCLK >> 1; break;
+        case SPI_2: PCLK = PCLK >> 2; break;
+        case SPI_3: PCLK = PCLK >> 2; break;
+    }
+
+    // Choose the baud rate divisor (between 2 and 256)
+    uint32_t divisor = PCLK / hz;
+
+    // Find the nearest power-of-2
+    divisor = divisor > 0 ? divisor-1 : 0;
+    divisor |= divisor >> 1;
+    divisor |= divisor >> 2;
+    divisor |= divisor >> 4;
+    divisor |= divisor >> 8;
+    divisor |= divisor >> 16;
+    divisor++;
+
+    uint32_t baud_rate = ffz(divisor) - 1;
+    baud_rate = baud_rate > 0x7 ? 0x7 : baud_rate;
+
+    obj->spi->CR1 &= ~(0x7 << 3);
+    obj->spi->CR1 |= baud_rate << 3;
+}
+
+static inline int ssp_disable(spi_t *obj) {
+    // TODO: Follow the instructions in 25.3.8 for safely disabling the SPI
+    return obj->spi->CR1 &= ~(1 << 6);
+}
+
+static inline int ssp_enable(spi_t *obj) {
+    return obj->spi->CR1 |= (1 << 6);
+}
+
+static inline int ssp_readable(spi_t *obj) {
+    return obj->spi->SR & (1 << 0);
+}
+
+static inline int ssp_writeable(spi_t *obj) {
+    return obj->spi->SR & (1 << 1);
+}
+
+static inline void ssp_write(spi_t *obj, int value) {
+    while (!ssp_writeable(obj));
+    obj->spi->DR = value;
+}
+
+static inline int ssp_read(spi_t *obj) {
+    while (!ssp_readable(obj));
+    return obj->spi->DR;
+}
+
+static inline int ssp_busy(spi_t *obj) {
+    return (obj->spi->SR & (1 << 7)) ? (1) : (0);
+}
+
+int spi_master_write(spi_t *obj, int value) {
+    ssp_write(obj, value);
+    return ssp_read(obj);
+}
+
+int spi_slave_receive(spi_t *obj) {
+    return (ssp_readable(obj) && !ssp_busy(obj)) ? (1) : (0);
+};
+
+int spi_slave_read(spi_t *obj) {
+    return obj->spi->DR;
+}
+
+void spi_slave_write(spi_t *obj, int value) {
+    while (ssp_writeable(obj) == 0) ;
+    obj->spi->DR = value;
+}
+
+int spi_busy(spi_t *obj) {
+    return ssp_busy(obj);
+}
+
+#endif