RK3288 android7.1.2 android studio 用户空间调用Linux spi_dev.c 通过spi ioctl 进行spi单字节/多字节读写（进阶篇六）
1.初始化open/close SPI device
#include
#include
#include
#include
#include
#include
#include
#define TAG "terawins" // 这个是自定义的LOG的标识
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,TAG ,__VA_ARGS__) // 定义LOGD类型
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,TAG ,__VA_ARGS__) // 定义LOGI类型
#define LOGW(...) __android_log_print(ANDROID_LOG_WARN,TAG ,__VA_ARGS__) // 定义LOGW类型
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,TAG ,__VA_ARGS__) // 定义LOGE类型
#define LOGF(...) __android_log_print(ANDROID_LOG_FATAL,TAG ,__VA_ARGS__) // 定义LOGF类型
static unsigned char mode=SPI_MODE_0;
static unsigned char bits = 8;
static unsigned char delay = 10;
static unsigned int speed = 10000000;
#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
/**************************************************************************
* unsigned char u8BusIndex 是从UI 中获取的使用spidev2.x 表示使用0 还是 1
* 这里cs 硬件连接的是0
*
**************************************************************************/
int SPI_open(unsigned char u8BusIndex) {
char szDev[16] = {0};
int fd,ret;
sprintf(szDev, "/dev/spidev2.%d", u8BusIndex);
fd = open(szDev, O_RDWR);
//LOGD("*************************************************fd = %d", fd);
if (fd < 0) {
LOGE( "can not open SPI device\n" );
}
ret = ioctl(fd, SPI_IOC_WR_MODE,&mode);
if (ret == -1)
LOGE("can't set spi mode");
ret = ioctl(fd, SPI_IOC_RD_MODE,&mode);
if (ret == -1)
LOGE("can't get spi mode");
ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
if (ret == -1)
LOGE("can't set bits per word");
ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
if (ret == -1)
LOGE("can't get bits per word");
ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
if (ret == -1)
LOGE("can't set max speed hz");
ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
if (ret == -1)
LOGE("can't get max speed hz");
LOGD("spi mode: %d\n", mode);
LOGD("bits per word: %d\n", bits);
LOGD("max speed: %d Hz (%d MHz)\n", speed, speed/1000000);
return fd;
}
int SPI_close(int dev_fh) {
return close(dev_fh);
} 2.SPI 单字节写
1）定义tx 长度 cmd + addr + data (6字节)；
2）.len 表示发送总数据的长度（cmd + addr + data）；
3）ioctl(fd, SPI_IOC_MESSAGE(1), &tr); MESSAGE(1)表示：半双工；MESSAGE(2)表示全双工；
4）单字节写 rx 数据长度为与data 长度一致，写了1个字节rx就设定为1（根据实际情况，也不可不设定）；
void SPI_write_single(int fd, int addr, unsigned char data) {
int ret;
uint8_t tx[6] = {0};
uint8_t rx[1] = {0};
tx[0] = 0x01;
tx[1] = (unsigned char)(addr >> 24 & 0xFF);
tx[2] = (unsigned char)(addr >> 16 & 0xFF);
tx[3] = (unsigned char)(addr >> 8 & 0xFF);
tx[4] = (unsigned char)(addr & 0xFF);
tx[5] = data;
struct spi_ioc_transfer tr = {
.tx_buf = (unsigned long) tx, //定义发送缓冲区指针
.rx_buf = (unsigned long) rx, //定义接收缓冲区指针
.len = ARRAY_SIZE(tx),
.delay_usecs = delay,
.speed_hz = speed,
.bits_per_word = bits,
};
ret = ioctl(fd, SPI_IOC_MESSAGE(2), &tr);//执行spidev.c中ioctl的default进行数据传输
if (ret < 0) {
LOGD("can't send spi message");
}
}3.SPI 单字节读
1）定义tx 长度 cmd + addr + Dummy（15字节） ，有些spi slave 读的时候需要发送一些固定数量的空字节之后，才开始读data，该例子的Dummy 数量为10 ，发送了十个0x00，之后rx开始接收数据（rx在第十六个数组rx[15]里存放了接收的数据）；
2）tx和rx 的len 读的时候，数组长度设定为一致；
3）ioctl(fd, SPI_IOC_MESSAGE(1), &tr); MESSAGE(1)表示：半双工；MESSAGE(2)表示全双工；
unsigned char SPI_read_single(int fd, int addr) {
int ret,i;
uint8_t tx[16] = {0};
uint8_t rx[16] = {0};
tx[0] = 0x02;
tx[1] = (unsigned char)(addr >> 24 & 0xFF);
tx[2] = (unsigned char)(addr >> 16 & 0xFF);
tx[3] = (unsigned char)(addr >> 8 & 0xFF);
tx[4] = (unsigned char)(addr & 0xFF);
for(i = 5;i < 16;i++){
tx[i] = 0x00;
}
struct spi_ioc_transfer tr = {
.tx_buf = (unsigned long) tx, //定义发送缓冲区指针
.rx_buf = (unsigned long) rx, //定义接收缓冲区指针
.len = ARRAY_SIZE(tx),
.delay_usecs = delay,
.speed_hz = speed,
.bits_per_word = bits,
};
ret = ioctl(fd, SPI_IOC_MESSAGE(2), &tr);//执行spidev.c中ioctl的default进行数据传输
if (ret < 0) {
LOGD("can't send spi message");
}
return rx[15];
}4.SPI 多字节写
1）定义tx 长度 cmd + addr + data ；
2）.len 表示发送总数据的长度（cmd + addr + data）；
3）ioctl(fd, SPI_IOC_MESSAGE(1), &tr); MESSAGE(1)表示：半双工；MESSAGE(2)表示全双工；
4）一般tx 缓存区的buffer 限定在4096，如果想每次burst 的data 大于4096 个，就要去修改spidev.c内容，修改后重新编译内核，如下；
static LIST_HEAD(device_list);
static DEFINE_MUTEX(device_list_lock);
static unsigned bufsiz = 4096;//tx 大小
module_param(bufsiz, uint, S_IRUGO);
MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");切记，tx 的大小4096 是总的cmd + addr + data 长度，所以如果每次burst data 数量等于4096，再加上cmd+addr >4096 ,buffer 就会爆掉；burst 指的是只发送一次cmd 和addr ，后面写很多个data；
void SPI_nbytes_write(int fd, int addr, unsigned char *data, unsigned int len) {
int ret,i;
uint8_t tx[4096] = {0};
uint8_t rx[4096] = {0};
tx[0] = 0x01;
tx[1] = (unsigned char)(addr >> 24 & 0xFF);
tx[2] = (unsigned char)(addr >> 16 & 0xFF);
tx[3] = (unsigned char)(addr >> 8 & 0xFF);
tx[4] = (unsigned char)(addr & 0xFF);
for(i = 0;i5.SPI 多字节读
1）定义tx 长度 cmd + addr + data ，rx 长度和tx一致；
2）.len 表示发送总数据的长度（cmd + addr + data）；
3）ioctl(fd, SPI_IOC_MESSAGE(1), &tr); MESSAGE(1)表示：半双工；MESSAGE(2)表示全双工；
4）一般tx 缓存区的buffer 限定在4096，如果想每次burst 的data 大于4096 个，就要去修改spidev.c内容，修改后重新编译内核，如下；
static LIST_HEAD(device_list);
static DEFINE_MUTEX(device_list_lock);
static unsigned bufsiz = 4096;//tx 大小
module_param(bufsiz, uint, S_IRUGO);
MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");切记，rx 的大小4096 是总的cmd + addr + data 长度，所以如果每次burst data 数量等于4096，再加上cmd+addr >4096 ,buffer 就会爆掉；burst 指的是只发送一次cmd 和addr ，后面读很多个data；
void SPI_nbyte_read(int fd, int addr, unsigned char *data, unsigned int len) {
int ret,i;
uint8_t tx[4096]={0};
uint8_t rx[4096]={0};
tx[0] = 0x02;
tx[1] = (unsigned char)(addr >> 24 & 0xFF);
tx[2] = (unsigned char)(addr >> 16 & 0xFF);
tx[3] = (unsigned char)(addr >> 8 & 0xFF);
tx[4] = (unsigned char)(addr & 0xFF);
struct spi_ioc_transfer tr = {
.tx_buf = (unsigned long) tx, //定义发送缓冲区指针
.rx_buf = (unsigned long) rx, //定义接收缓冲区指针
.len = 15+len,
.delay_usecs = delay,
.speed_hz = speed,
.bits_per_word = bits,
};
ret = ioctl(fd, SPI_IOC_MESSAGE(2), &tr);//执行spidev.c中ioctl的default进行数据传输
if (ret < 0) {
LOGD("can't send spi message");
}else {
for(i = 0;i < len;i++){
data[i] = rx[15+i];
}
}
}rk3288 spi硬件连接可参考：https://blog.csdn.net/Chhjnavy/article/details/100158719