# RTTHREAD移植BSP驱动 SPI篇 ## 简介 本文介绍SPI设备驱动，drv_spi.c如何编写的，SPI驱动稍微复杂一些。 本文参考RTTHREAD官方文档[SPI 设备](https://www.rt-thread.org/document/site/programming-manual/device/spi/spi/) 一些基本知识，官方文档已经写的很详细了，大家如果不是很了解可以仔细看下官方文档，这边简单讲解下移植的时候遇到的一些问题，以及如何能快速上手的解决方案。 ## SPI简介 4根线，MOSI ,MISO , SCLK CS ## 移植前准备 先要熟悉官方的SPI的demo如何运行的。 先准备一个drv_spi.c 这边提供一个模板，基本第一次稍微修改就可以编译通过，license大家可以改成自己的，这个随意。 ``` /* * Copyright (c) 2006-2018, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2021-02-14 supperthomas first version */ #include #include #include "board.h" #include "drv_spi.h" #define DBG_LEVEL DBG_LOG #include #define LOG_TAG "drv.spi" #ifdef BSP_USING_SPI #if defined(BSP_USING_SPI0) || defined(BSP_USING_SPI1) || defined(BSP_USING_SPI2) static struct mcu_drv_spi_config spi_config[] = { #ifdef BSP_USING_SPI0 MCU_SPI0_CONFIG, #endif #ifdef BSP_USING_SPI1 MCU_SPI1_CONFIG, #endif }; static struct mcu_drv_spi spi_bus_obj[sizeof(spi_config) / sizeof(spi_config[0])]; static rt_err_t spi_configure(struct rt_spi_device *device, struct rt_spi_configuration *configuration) { //init return RT_EOK; } static rt_uint32_t spixfer(struct rt_spi_device *device, struct rt_spi_message *message) { } /* spi bus callback function */ static const struct rt_spi_ops nrfx_spi_ops = { .configure = spi_configure, .xfer = spixfer, }; /*spi bus init*/ static int rt_hw_spi_bus_init(void) { rt_err_t result = RT_ERROR; for (int i = 0; i < sizeof(spi_config) / sizeof(spi_config[0]); i++) { spi_bus_obj[i].spi_instance = spi_config[i].spi_instance; spi_bus_obj[i].spi_bus.parent.user_data = &spi_config[i]; //SPI INSTANCE result = rt_spi_bus_register(&spi_bus_obj[i].spi_bus, spi_config[i].bus_name, &nrfx_spi_ops); RT_ASSERT(result == RT_EOK); } return result; } int rt_hw_spi_init(void) { return rt_hw_spi_bus_init(); } INIT_BOARD_EXPORT(rt_hw_spi_init); /** * Attach the spi device to SPI bus, this function must be used after initialization. */ rt_err_t rt_hw_spi_device_attach(const char *bus_name, const char *device_name, rt_uint32_t cs_pin) { return RT_EOK; } #endif /* BSP_USING_SPI0 || BSP_USING_SPI1 || BSP_USING_SPI2 */ #endif /*BSP_USING_SPI*/ ``` 再加一个drv_spi.h即可 ``` /* * Copyright (c) 2006-2018, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2021-02-14 supperthomas first version */ #include #include #include #include "spi.h" #ifndef __DRV_SPI_H_ #define __DRV_SPI_H_ rt_err_t rt_hw_spi_device_attach(const char *bus_name, const char *device_name, rt_uint32_t ss_pin); //SPI bus config #ifdef BSP_USING_SPI0 #define MCU_SPI0_CONFIG \ { \ .bus_name = "spi0", \ .spi_instance = SPI0A, \ } #endif #ifdef BSP_USING_SPI1 #ifdef BSP_USING_SPI1A //The SPI1A is conflit with UART1 TX RX P0.10 P0.11 #define MCU_SPI1_CONFIG \ { \ .bus_name = "spi1", \ .spi_instance = SPI1A \ } #else #define MCU_SPI1_CONFIG \ { \ .bus_name = "spi1", \ .spi_instance = SPI1B \ } #endif #endif struct mcu_drv_spi_config { char *bus_name; spi_type spi_instance; }; struct mcu_drv_spi { spi_type spi_instance; spi_req_t spixfer_req; struct rt_spi_configuration *cfg; struct rt_spi_bus spi_bus; }; #endif /*__DRV_SPI_H_*/ ``` spi驱动主要是要提交这两个，还需要添加Kconfig ``` config BSP_USING_SPI bool "Enable SPI" select RT_USING_SPI default n ``` 这边主要添加`RT_USING_SPI` 和`BSP_USING_SPI`宏定义。 ``` ``` ## 添加spi_sample spi_sample 方便测试，先把spi_sample放好，这个sample是将MOSI和MISO对接，采用loopback的方式进行测试，这样的话，可以不依赖硬件来测试SPI，发送数据和接收数据比对能够正确即可。或者收到数据即可。 ``` #define SPI_DEVICE_BUS "spi0" #define SPI_DEVICE_NAME "spi01" #define TEST_LEN 10 uint8_t rx_data[TEST_LEN]; uint8_t tx_data[TEST_LEN]; static void spi_sample(int argc, char *argv[]) { struct rt_spi_device *spi_dev; char name[RT_NAME_MAX]; spi_dev = (struct rt_spi_device *)rt_device_find(SPI_DEVICE_NAME); if (RT_NULL == spi_dev) { rt_hw_spi_device_attach(SPI_DEVICE_BUS, SPI_DEVICE_NAME, PIN_0); spi_dev = (struct rt_spi_device *)rt_device_find(SPI_DEVICE_NAME); } struct rt_spi_configuration spi_cfg = { .mode = 0, .data_width = 8, .max_hz = 1000000, }; rt_spi_configure(spi_dev, &spi_cfg); rt_kprintf("\n************** SPI Loopback Demo ****************\n"); rt_kprintf("This example configures the SPI to send data between the MISO (P0.4) and\n"); rt_kprintf("MOSI (P0.5) pins. Connect these two pins together. \n"); for (int j = 0; j < TEST_LEN; j++) { tx_data[j] = j ; } if (argc == 2) { rt_strncpy(name, argv[1], RT_NAME_MAX); } else { rt_strncpy(name, SPI_DEVICE_NAME, RT_NAME_MAX); } spi_dev = (struct rt_spi_device *)rt_device_find(name); if (!spi_dev) { rt_kprintf("spi sample run failed! can't find %s device!\n", name); } else { rt_spi_transfer(spi_dev, tx_data, rx_data, TEST_LEN); for (int i = 0; i < TEST_LEN; i++) { rt_kprintf(" 0x%02x, ", rx_data[i]); } } } MSH_CMD_EXPORT(spi_sample, spi sample); ``` 这个sample随便放到main.c里面随便放到哪里都可以， 测试的时候在console里面输入spi_sample即可。 这边测试sample里面调用函数关系 ``` rt_hw_spi_device_attach --> rt_hw_spi_device_attach rt_spi_configure --> spi_configure rt_spi_transfer --> spixfer ``` ### 开始实现代码 这边根据一般厂商的SPI sample来 ### rt_hw_spi_init 这个函数主要设置一些和SPI不相干的一些时钟和注册一个spi0的spi bus。 这边需要注意的是： mcu_drv_spi_config： 这个是配置spi bus的名称和存放一个控制SPI的handle值，这个需要根据厂商的接口来定义 mcu_drv_spi： 这个存放的是结构体，存放当前spi的cfg（速率以及其他）， 存放一个控制SPI的handle值 这边多放了一个传输的结构体，这个根据厂商来，这边是MAX32660的参考例程。 这边完成的内容不多，只要这个device注册上去即可。 ### rt_hw_spi_device_attach 这个函数是用来选择CS片选的，SPI是一个通信总线，总线上可以有多个设备，根据SPI协议，一个CS片选对应一个device设备，调用这个设备代表该设备被选中，CS选中，对于一个MASTER而言可以有多个CS。每注册一个设备需要上拉一个cs pin脚。 cs脚可以先不实现，根据应用再实现，最后调rt_spi_bus_attach_device来实现设备的挂载在bus总线上，根据RTTHREAD官方文档，对于总线名称是spi0， 对于设备名称是spi01 所以这边主要添加一个device，需要实现的代码不多，cs可以暂时不实现。 ``` rt_err_t rt_hw_spi_device_attach(const char *bus_name, const char *device_name, rt_uint32_t cs_pin) { RT_ASSERT(bus_name != RT_NULL); RT_ASSERT(device_name != RT_NULL); RT_ASSERT(cs_pin != RT_NULL); rt_err_t result; struct rt_spi_device *spi_device; /* attach the device to spi bus*/ spi_device = (struct rt_spi_device *)rt_malloc(sizeof(struct rt_spi_device)); RT_ASSERT(spi_device != RT_NULL); /* initialize the cs pin */ result = rt_spi_bus_attach_device(spi_device, device_name, bus_name, (void *)cs_pin); if (result != RT_EOK) { LOG_E("%s attach to %s faild, %d", device_name, bus_name, result); result = RT_ERROR; } /* TODO: SET THE GPIO */ RT_ASSERT(result == RT_EOK); return result; } ``` ### rt_spi_configure 这个是用来配置spi bus的速率的，这边比较重要，需要根据configuration->mode的模式进行调整， 前期可以直接将官方的demo的初始化配置放这里， ``` static rt_err_t spi_configure(struct rt_spi_device *device, struct rt_spi_configuration *configuration) { RT_ASSERT(device != RT_NULL); RT_ASSERT(device->bus != RT_NULL); RT_ASSERT(device->bus->parent.user_data != RT_NULL); RT_ASSERT(configuration != RT_NULL); struct mcu_drv_spi *tmp_spi; tmp_spi = rt_container_of(device->bus, struct mcu_drv_spi, spi_bus); int mode; ///init switch (configuration->mode & RT_SPI_MODE_3) { case RT_SPI_MODE_0/* RT_SPI_CPOL:0 , RT_SPI_CPHA:0 */: case RT_SPI_MODE_1/* RT_SPI_CPOL:0 , RT_SPI_CPHA:1 */: case RT_SPI_MODE_2/* RT_SPI_CPOL:1 , RT_SPI_CPHA:0 */: case RT_SPI_MODE_3/* RT_SPI_CPOL:1 , RT_SPI_CPHA:1 */: mode = configuration->mode & RT_SPI_MODE_3; break; default: LOG_E("spi_configure mode error %x\n", configuration->mode); return RT_ERROR; } tmp_spi->spixfer_req.width = SPI17Y_WIDTH_1; tmp_spi->spixfer_req.bits = configuration->data_width; tmp_spi->spixfer_req.ssel = 0; tmp_spi->spixfer_req.deass = 1; tmp_spi->spixfer_req.tx_num = 0; tmp_spi->spixfer_req.rx_num = 0; tmp_spi->spixfer_req.callback = NULL; LOG_D("spi init mode:%d, rate:%d", mode, configuration->max_hz); if (SPI_Init(tmp_spi->spi_instance, mode, configuration->max_hz) != 0) { LOG_E("Error configuring SPI\n"); while (1) {} } //init return RT_EOK; } ``` ### spixfer 这个函数是主要的传输函数： 这个是主要的传输函数： 参考sample ``` static rt_uint32_t spixfer(struct rt_spi_device *device, struct rt_spi_message *message) { RT_ASSERT(device != RT_NULL); RT_ASSERT(device->bus != RT_NULL); RT_ASSERT(device->bus->parent.user_data != RT_NULL); int ret = 0; struct mcu_drv_spi *tmp_spi; tmp_spi = rt_container_of(device->bus, struct mcu_drv_spi, spi_bus); tmp_spi->spixfer_req.tx_data = message->send_buf; tmp_spi->spixfer_req.rx_data = message->recv_buf; tmp_spi->spixfer_req.len = message->length; ret = SPI_MasterTrans(tmp_spi->spi_instance, &tmp_spi->spixfer_req); if (ret == E_NO_ERROR) { return message->length; } else { LOG_E("spixfer faild, ret %d", ret); return 0; } } ```