spi从设备是20MHz的频率，CS是低电平有效。dts配置如下：
&spi3 {
clock-frequency = <100000000>;
pinctrl-0 = <&spi3_pins_a &spi3_pins_b>;
pinctrl-1 = <&spi3_pins_c>;
pinctrl-names = "default", "sleep";
spi_slave_mode = <0>;
spi_dbi_enable = <1>;
spi_cs_bitmap = <1>;
spi3_cs_number = <1>;
status = "okay";
spidev@0 {
device_type = "spidev";
compatible = "rohm,dh2228fv";
spi-max-frequency = <100000000>;
reg = <0x0>;
spi-cs-high;
spi-rx-bus-width = <0x8>;
spi-tx-bus-width = <0x8>;
status = "okay";
};
};
...
spi3_pins_a: spi3@0 {
allwinner,pins = "PH11", "PH12", "PH13";
allwinner,pname = "spi3_sclk", "spi3_mosi","spi3_miso";
allwinner,function = "spi3";
allwinner,muxsel = <6>;
allwinner,drive = <1>;
allwinner,pull = <0>;
};
spi3_pins_b: spi3@1 {
allwinner,pins = "PH14";
allwinner,pname = "spi3_cs0";
allwinner,function = "spi3";
allwinner,muxsel = <6>;
allwinner,drive = <1>;
allwinner,pull = <1>; // only CS should be pulled up
};
spi3_pins_c: spi3@2 {
allwinner,pins = "PH11", "PH12", "PH13", "PH14";
allwinner,function = "io_disabled";
allwinner,muxsel = <0xf>;
allwinner,drive = <1>;
allwinner,pull = <0>;
};
测试程序是这样的：
#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>
static uint8_t mode = 0; /* SPI通信使用全双工，设置CPOL＝0，CPHA＝0。 */
static uint8_t bits = 8; /* ８ｂiｔｓ读写，MSB first。*/
static uint32_t speed = 20 * 1000 * 1000;/* 设置20M传输速度 */
static uint16_t delay = 0;
static int g_SPI_Fd = 0;
unsigned char r_buf[256];
unsigned char w_buf[256];
int SPI_Write(uint8_t *TxBuf, int len)
{
int ret;
int fd = g_SPI_Fd;
ret = write(fd, TxBuf, len);
if (ret < 0)
printf("SPI Write error\n");
else
{
int i;
printf("\nSPI Write [Len:%d]: ", len);
for (i = 0; i < len; i++)
{
if (i % 8 == 0)
printf("\n\t");
printf("0x%02X ", TxBuf[i]);
}
printf("\n");
}
return ret;
}
static int SPI_Open(const char* device)
{
int fd;
int ret = 0;
if (g_SPI_Fd != 0) /* 设备已打开 */
return 0xF1;
fd = open(device, O_RDWR);
if (fd < 0)
printf("can't open device");
else
printf("SPI - Open Succeed. Start Init SPI...\n");
g_SPI_Fd = fd;
/*
* spi mode
*/
ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
if (ret == -1)
printf("can't set spi mode");
ret = ioctl(fd, SPI_IOC_RD_MODE, &mode);
if (ret == -1)
printf("can't get spi mode");
/*
* bits per word
*/
ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
if (ret == -1)
printf("can't set bits per word");
ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
if (ret == -1)
printf("can't get bits per word");
/*
* max speed hz
*/
ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
if (ret == -1)
printf("can't set max speed hz");
ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
if (ret == -1)
printf("can't get max speed hz");
printf("spi mode: %d\n", mode);
printf("bits per word: %d\n", bits);
printf("max speed: %d KHz (%d MHz)\n", speed / 1000, speed / 1000 / 1000);
return ret;
}
int SPI_Close(void)
{
int fd = g_SPI_Fd;
if (fd == 0) /* SPI是否已经打开*/
return 0;
close(fd);
g_SPI_Fd = 0;
return 0;
}
int main(int argc, char* argv[])
{
char *str="hello";
int len = 5;
SPI_Open("/dev/spidev3.0");
SPI_Write(str, len);
SPI_Close();
return 0;
}
交叉编译后放到板子上运行，会出现这样的超时报错，想问问看各位有没有什么思路解决，十分感谢。
root:/root# ./spi
SPI - Open Succeed. Start Init S[ 586.085918] spi_set_clk()459 - set spi clock 100000000, mclk 20000000
PI...
[ 586.095997] spi_set_clk()459 - set spi clock 100000000, mclk 100000000
[ 586.104382] spi_set_clk()459 - set spi clock 20000000, mclk 100000000
spi mode: 0[ 586.111792] sunxi_spi_transfer_one()1433 - [spi3] begin transfer, txbuf df6ab000, rxbuf (null), len 5
bits per word: 8
max speed: 2[ 586.123289] spi_set_clk()459 - set spi clock 20000000, mclk 20000000
0000 KHz (20 MHz)
[ 586.133363] sunxi_spi_mode_check()1166 - [spi3] Single mode Half duplex tx
[ 586.142730] spi_config_dbi()376 - DBI mode configurate : 40
[ 586.148979] sunxi_spi_xfer()1376 - [spi3] tx -> by ahb
[ 586.155060] sunxi_spi_cpu_writel()1250 - t->len = 5
[ 586.160602] 000: 68 65 6c 6c 6f
[ 596.275684] sunxi_spi_cpu_writel()1276 - [spi3] cpu transfer data time out!
[ 596.283516] sunxi_spi_transfer_one()1462 - [spi3] dump reg:
[ 596.289762] 0x04028000: 00010001 00000098 00002104 00000000
[ 596.296582] 0x04028010: 00000000 00000012 00200020 000f0000
[ 596.303189] 0x04028020: 00000000 00000002 00002000 00000000
[ 596.309535] 0x04028030: 00000005 00000005 00000005 00000000
[ 601.351828] sunxi_spi_transfer_one()1471 - [spi3] xfer timeout
[ 601.358391] spidev spi3.0: SPI transfer failed: -1
[ 601.364475] spi_master spi3: failed to transfer one message from queue
SPI Write error
启动时的spi log
[ 0.650370] sunxi_spi_probe()2251 - [spi3] SPI DBI INTERFACE
[ 0.656168] sunxi_spi_probe()2260 - [spi3] SPI MASTER MODE
[ 0.661799] sunxi_spi_resource_get()1909 - Failed to get sample mode
[ 0.668268] sunxi_spi_resource_get()1914 - Failed to get sample delay
[ 0.674824] sunxi_spi_resource_get()1918 - sample_mode:aaaaffff sample_delay:aaaaffff
[ 0.682785] spi3 supply spi not found, using dummy regulator
[ 0.688624] sunxi_spi_request_gpio()1884 - [spi3] Pinctrl init spi3
[ 0.695128] sunxi_spi_clk_init()1955 - [spi3] mclk 100000000
[ 0.701466] spi_master spi3: spi-tx-bus-width 8 not supported
[ 0.707476] spi_master spi3: spi-rx-bus-width 8 not supported
[ 0.713865] sunxi_spi_probe()2340 - [spi3]: driver probe succeed, base e0834000, irq 295
