在用户使用设备节点的IOCTL命令传输数据的时候,需要用到 spi_ioc_transfer结构体,它的成员如程序清单 1.2所示。 程序清单 1.2 spi_ioc_transfer struct spi_ioc_transfer { __u64 tx_buf;/* 写数据缓冲 */ __u64 rx_buf;/* 读数据缓冲 */ __u32 len;/* 缓冲的长度 */ __u32 speed_hz;/* 通信...
ret =ioctl(fd,SPI_IOC_MESSAGE(1), &tr);if(ret <1)pabort("can't send spi message");for(ret =0; ret <ARRAY_SIZE(tx); ret++) {if(!(ret %6))puts("");printf("%.2X ", rx[ret]); }puts(""); }staticvoidprint_usage(constchar*prog){printf("Usage: %s [-DsbdlHOLC3]\n"...
在Linux中用spi_driver来描述一个SPI外设驱动。 struct spi_driver { int (*probe)(struct spi_device *spi); int (*remove)(struct spi_device *spi); void (*shutdown)(struct spi_device *spi); int (*suspend)(struct spi_device *spi, pm_message_t mesg); int (*resume)(struct spi_dev...
MODULE_DEVICE_TABLE(spi, spidev_spi_ids); 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 匹配成功后spidev.c里面的spidev_probe就会被调用。 spidev_spi_driver源码分析 spidev_spi_driver源码具体实现如下: static struct spi_driver spidev_spi_driver = { .driver = { .name = "spidev",...
1. static long deviceB_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 2 { 3. ... 4. if (__copy_from_user(idc, (void __user *)arg, tmp)) { 5. kfree(idc); 6. err = -EFAULT; 7. } else { 8. err = spi_message(spi, idc, n_ioc); 9. } 10. kfree...
1、spi 2、源码分析: 分析linux 4.19 spidev设备驱动代码,代码文件为spidev.c 设备驱动的初始化和退出函数: static int __init spidev_init(void) { int status; /* Claim our 256 reserved device numbers. Then register a class * that will key udev/mdev to add/remove /dev nodes. Last, register...
ret = ioctl(fd, SPI_IOC_MESSAGE(2), xfer); if (ret == -1 ) err_print("can't send spi message"); return ret; } 我是使用ioctl进行传输的,当然也可以使用read/write进行,只不过ioctl可以进行全双工的数据传输,read/write则只能是单工传输,还有就是读写spi设备的流控并不都是一样的,也就是说,...
arg 是 spi_ioc_transfer 用法:全双工传输数据 struct spi_ioc_transfer tr = { .tx_buf = (unsigned long)tx, .rx_buf = (unsigned long)rx, .len = ARRAY_SIZE(tx), .delay_usecs = delay, .speed_hz = speed, .bits_per_word = bits, }; ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr)...
0 成功 * 开发⼈员：Lzy 2013－5－22 */ int SPI_Transfer(const uint8_t *TxBuf, uint8_t *RxBuf, int len){ int ret;int fd = g_SPI_Fd;struct spi_ioc_transfer tr ={ .tx_buf = (unsigned long) TxBuf,.rx_buf = (unsigned ) RxBuf,.len =len,.delay_usecs = delay,};
42 * - prevent concurrent SPI_IOC_WR_* from morphing 43 * data fields while SPI_IOC_RD_* reads them;44 * - SPI_IOC_MESSAGE needs the buffer locked "normally".45*/ 46 mutex_lock(&spidev->buf_lock);47//以上是进⾏check,检查命令有效性,以及进⾏初始化数据,这⾥不在多...