SSD_SPI使用参考
1. 概述¶
本文档介绍了如何在Linux用户空间中使用spi驱动程序和uboot。
2. SPI控制¶
2.1. SPI概述¶
Sigmastar Takoyaki平台支持主SPI控制器（spi0）。
2.2. SPI Pads¶
SPI pad modes 可设定的mode 和脚位对应如下表。
表2-1
| SPI0_CZ | SPI0_CK | SPI0_DI(MOSI) | SPI0_DO(MISO) | |
|---|---|---|---|---|
| Pad mode=1 | PAD_SD_CMD | PAD_SD_CLK | PAD_SD_D0 | PAD_SD_D1 |
| Pad mode=2 | PAD_TTL16 | PAD_TTL17 | PAD_TTL18 | PAD_TTL19 |
| Pad mode=3 | PAD_GPIO7 | PAD_GPIO6 | PAD_GPIO5 | PAD_GPIO4 |
| Pad mode=4 | PAD_FUART_RX | PAD_FUART_TX | PAD_FUART_CTS | PAD_FUART_RTS |
| Pad mode=5 | PAD_GPIO8 | PAD_GPIO9 | PAD_GPIO10 | PAD_GPIO11 |
| Pad mode=6 | PAD_GPIO0 | PAD_GPIO1 | PAD_GPIO2 | PAD_GPIO3 |
2.3. 在Linux用户空间中使用SPI¶
2.3.1. Enable spi¶
测试spi前需要在kernel打开如下两个config：
CONFIG_SPI_SPIDEV CONFIG_MS_SPI_INFINITY
2.3.2. SPI Pad Mode设定¶
Enable spi后，还需要把spi pin设定正确才可以工作，实际使用的pad可透过平台对应的infinity2m_xxxx_padmux.dtsi中对应PINMUX_FOR_SPI0_MODE_x 来指定：
<PAD_GPIO8 PINMUX_FOR_SPI0_MODE_5 MDRV_PUSE_SPI0_CZ>, <PAD_GPIO9 PINMUX_FOR_SPI0_MODE_5 MDRV_PUSE_SPI0_CK>, <PAD_GPIO10 PINMUX_FOR_SPI0_MODE_5 MDRV_PUSE_SPI0_DI>, <PAD_GPIO11 PINMUX_FOR_SPI0_MODE_5 MDRV_PUSE_SPI0_DO>,
2.3.3. SPI device¶
/dev/spidev0.0
2.3.4. Sample code¶
static const char *device = "/dev/spidev0.0";
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 = 60*1000*1000;/* 设置传输速度 */
static uint16_t delay = 0;
static int g_SPI_Fd = 0;
static void pabort(const char *s)
{
perror(s);
abort();
}
/**
* 功 能：同步数据传输
* 入口参数 ：
* TxBuf -> 发送数据首地址
* len -> 交换数据的长度
* 出口参数：
* RxBuf -> 接收数据缓冲区
* 返回值：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 long) RxBuf,
.len =len,
.delay_usecs = delay,
};
ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
if (ret < 1)
perror("can't send spi message\n");
else
{
#if SPI_DEBUG
int i;
printf("nsend spi message Succeed\n");
printf("nSPI Send [Len:%d]: \n", len);
for (i = 0; i < len; i++)
{
if (i % 8 == 0)
printf("nt\n");
printf("0x%02X \n", TxBuf[i]);
}
printf("n");
printf("SPI Receive [len:%d]:\n", len);
for (i = 0; i < len; i++)
{
if (i % 8 == 0)
printf("nt\n");
printf("0x%02X \n", RxBuf[i]);
}
printf("\n");
#endif
}
return ret;
}
/**
* 功 能：发送数据
* 入口参数 ：
* TxBuf -> 发送数据首地址
*len -> 发送与长度
*返回值：0 成功
* 开发人员：Lzy 2013－5－22
*/
int SPI_Write(uint8_t *TxBuf, int len)
{
int ret;
int fd = g_SPI_Fd;
ret = write(fd, TxBuf, len);
if (ret < 0)
perror("SPI Write error\n");
else
{
#if SPI_DEBUG
int i;
printf("SPI Write [Len:%d]: \n", len);
for (i = 0; i < len; i++)
{
if (i % 8 == 0)
printf("\n\t");
printf("0x%02X \n", TxBuf[i]);
}
printf("\n");
#endif
}
return ret;
}
/**
* 功 能：接收数据
* 出口参数：
* RxBuf -> 接收数据缓冲区
* rtn -> 接收到的长度
* 返回值：>=0 成功
* 开发人员：Lzy 2013－5－22
*/
int SPI_Read(uint8_t *RxBuf, int len)
{
int ret;
int fd = g_SPI_Fd;
ret = read(fd, RxBuf, len);
if (ret < 0)
printf("SPI Read error\n");
else
{
#if SPI_DEBUG
int i;
printf("SPI Read [len:%d]:\n", len);
for (i = 0; i < len; i++)
{
if (i % 8 == 0)
printf("\n\t");
printf("0x%02X \n", RxBuf[i]);
}
printf("\n");
#endif
}
return ret;
}
/**
* 功 能：打开设备 并初始化设备
* 入口参数 ：
* 出口参数：
* 返回值：0 表示已打开 0XF1 表示SPI已打开 其它出错
* 开发人员：Lzy 2013－5－22
*/
int SPI_Open(void)
{
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)
pabort("can't open device\n");
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)
pabort("can't set spi mode\n");
ret = ioctl(fd, SPI_IOC_RD_MODE, &mode);
if (ret == -1)
pabort("can't get spi mode\n");
/*
* bits per word
*/
ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't set bits per word\n");
ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't get bits per word\n");
/*
* max speed hz
*/
ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't set max speed hz\n");
ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't get max speed hz\n");
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;
}
/**
* 功 能：关闭SPI模块
*/
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;
}
/**
* 功 能：自发自收测试程序
* 接收到的数据与发送的数据如果不一样 ，则失败
* 说明：
* 在硬件上需要把输入与输出引脚短跑
* 开发人员：Lzy 2013－5－22
*/
int SPI_LookBackTest(void)
{
int ret, i;
const int BufSize = 16;
uint8_t tx[BufSize], rx[BufSize];
bzero(rx, sizeof(rx));
for (i = 0; i < BufSize; i++)
tx[i] = i;
printf("nSPI - LookBack Mode Test...\n");
ret = SPI_Transfer(tx, rx, BufSize);
if (ret > 1)
{
ret = memcmp(tx, rx, BufSize);
if (ret != 0)
{
printf("tx:\n");
for (i = 0; i < BufSize; i++)
{
printf("%d ", tx[i]);
}
printf("\n");
printf("rx:\n");
for (i = 0; i < BufSize; i++)
{
printf("%d ", rx[i]);
}
printf("\n");
perror("LookBack Mode Test error\n");
}
else
printf("SPI - LookBack Mode OK\n");
}
return ret;
}
2.4. 在uboot中使用SPI¶
2.4.1. Enable spi¶
操作spi前需要在uboot的config文件中打开如下config开启spi
CONFIG_CMD_SPI CONFIG_SSTAR_MSPI
2.4.2. SPI Pad Mode设定¶
开启spi后，还需要把spi pin设定正确才能正常工作。实际使用的pad可透过修改uboot 下的drivers/mstar/spi/infinity2m/mspi.c 中的 #define MSPI0_PADMUX_MODE 5可设定的数值为 1 ~ 6。
2.4.3. 使用uboot命令行控制SPI设备¶
可以透过 uboot command line 来控制/测试 spi:
The u-boot command sspi Usage:
sspi - SPI utility command
Usage:
sspi [<bus>:]<cs>[.<mode>] <bit_len> <dout> - Send and receive bits <bus> - Identifies the SPI bus <cs> - Identifies the chip select <mode> - Identifies the SPI mode to use <bit_len> - Number of bits to send (base 10) <dout> - Hexadecimal string that gets sent <dout> is in hex but without the prefix "0x". All others are in decimal. The following is SPI mode defined in u-boot/include/spi.h. But still depends on the mode that SPI controller/driver can handle: /* SPI mode flags */ #define SPI_CPHA 0x01 /* clock phase */ #define SPI_CPOL 0x02 /* clock polarity */ #define SPI_MODE_0 (0|0) /* (original MicroWire) */ #define SPI_MODE_1 (0|SPI_CPHA) #define SPI_MODE_2 (SPI_CPOL|0) #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) #define SPI_CS_HIGH 0x04 /* CS active high */ #define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */ #define SPI_3WIRE 0x10 /* SI/SO signals shared */ #define SPI_LOOP 0x20 /* loopback mode */ #define SPI_SLAVE 0x40 /* slave mode */ #define SPI_PREAMBLE 0x80 /* Skip preamble bytes */
使用举例：
SigmaStar # sspi 0:0.0 16 0055 bs->tx_buf=0,55... len=2 byte(s) dma=1 ### MDrv_MSPI_DMA_Write <<<<<<<<<<<<<<<<<<< SPI_Done >>>>>>>>>>>>>>>>> <<<<<<<<<<<<<<<<<<< SPI_Done >>>>>>>>>>>>>>>>>
2.4.4. SPI API¶
uboot 支持uboot 标准 spi API，调用 API 请加:
#include <spi.h>
API 说明如下(引用 spi.h 说明):
-
spi_setup_slave
/** * Set up communications parameters for a SPI slave. * This must be called once for each slave. Note that this function * usually doesn't touch any actual hardware, it only initializes the * contents of spi_slave so that the hardware can be easily * initialized later. * * @bus: Bus ID of the slave chip. * @cs: Chip select ID of the slave chip on the specified bus. * @max_hz: Maximum SCK rate in Hz. * @mode: Clock polarity, clock phase and other parameters. * * Returns: A spi_slave reference that can be used in subsequent SPI * calls, or NULL if one or more of the parameters are not supported. */ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, unsigned int max_hz, unsigned int mode); -
spi_free_slave
/** * Free any memory associated with a SPI slave. * * @slave: The SPI slave */ void spi_free_slave(struct spi_slave *slave);
-
spi_claim_bus
/** * Claim the bus and prepare it for communication with a given slave. * * This must be called before doing any transfers with a SPI slave. It * will enable and initialize any SPI hardware as necessary, and make * sure that the SCK line is in the correct idle state. It is not * allowed to claim the same bus for several slaves without releasing * the bus in between. * * @slave: The SPI slave * * Returns: 0 if the bus was claimed successfully, or a negative value * if it wasn't. */ int spi_claim_bus(struct spi_slave *slave);
-
spi_release_bus
/** * Release the SPI bus * * This must be called once for every call to spi_claim_bus() after * all transfers have finished. It may disable any SPI hardware as * appropriate. * * @slave: The SPI slave */ void spi_release_bus(struct spi_slave *slave);
-
spi_xfer
/** * SPI transfer * * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks * "bitlen" bits in the SPI MISO port. That's just the way SPI works. * * The source of the outgoing bits is the "dout" parameter and the * destination of the input bits is the "din" parameter. Note that "dout" * and "din" can point to the same memory location, in which case the * input data overwrites the output data (since both are buffered by * temporary variables, this is OK). * * spi_xfer() interface: * @slave: The SPI slave which will be sending/receiving the data. * @bitlen: How many bits to write and read. * @dout: Pointer to a string of bits to send out. The bits are * held in a byte array and are sent MSB first. * @din: Pointer to a string of bits that will be filled in. * @flags: A bitwise combination of SPI_XFER_* flags. * * Returns: 0 on success, not 0 on failure */ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, void *din, unsigned long flags);
2.4.5. SPI API使用示例¶
#include <spi.h>
static unsigned int bus = 0;
static unsigned int cs = 0;
static unsigned int mode = 0;
static int bitlen = 32;
static uchar dout[MAX_SPI_BYTES];
static uchar din[MAX_SPI_BYTES];
#define SPI_MAX_SPEED_HZ 60000000 //1000000
int sstar_spi_xfer(int bus, int cs, unsigned int mod, int bitlen , uchar *dout, uchar *din )
{
struct spi_slave *slave;
int ret = 0;
slave = spi_setup_slave(bus, cs, SPI_MAX_SPEED_HZ, mode);
if (!slave) {
printf("Invalid device %d:%d\n", bus, cs);
return -EINVAL;
}
ret = spi_claim_bus(slave);
if (ret)
goto done;
ret = spi_xfer(slave, bitlen, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
if (ret) {
printf("Error %d during SPI transaction\n", ret);
}
done:
spi_release_bus(slave);
return ret;
}