Hello, our IMX6ul SPI interface for data reading, ADC is TI's ADC124S051. When using spi_sync, the data can be read correctly. When using spi_async to read data, some error data will be collected. Below is my driver core code:
static int adc124s_adc_conversion(struct spi_device *spi, int count)
{
int i,ret;
u8 tx_buffer[1600];
struct spi_transfer spi_trans_low = {
.rx_buf = mmap_buffer,
.tx_buf = tx_buffer,
.len = 1496,
//.cs_change = 0,
.speed_hz = 5000000,
.bits_per_word = BITS_PER_WORD,
};
struct spi_transfer spi_trans_high = {
.rx_buf = mmap_buffer + 1496,
.tx_buf = tx_buffer,
.len = 1496,
//.cs_change = 0,
.speed_hz = 5000000,
.bits_per_word = BITS_PER_WORD,
};
struct spi_message message_low;
struct spi_message message_high;
ret = 0;
for(i=0;i<1600;i++)
{
tx_buffer[i] = 0;
}
/* Do the transfer */
switch(count)
{
case 1:
date = 1;
spi_message_init(&message_low);
message_low.complete = adc_complete;
message_low.context = NULL;
spi_message_add_tail(&spi_trans_low, &message_low);
ret=spi_async(spi, &message_low);
break;
case 2:
date = 2;
spi_message_init(&message_high);
message_high.complete = adc_complete;
message_high.context = NULL;
spi_message_add_tail(&spi_trans_high, &message_high);
ret=spi_async(spi, &message_high);
break;
default:
printk("input count is err\n");
break;
}
return ret;
}
static void adc_complete(void *context)
{
int ret,i;
switch(date)
{
case 1:
//可读时第三个参数设置为POLL_IN,可写时第三个参数设置为POLL_OUT
//在这里将其仅仅作为一个参数值，POLL_IN=1；POLL_OUT=2
for(i=0;i<748;i++)
{
printk("this is mmap_buffer[%d] : %d\n",i*2,mmap_buffer[i*2]);
}
kill_fasync(&button_async, SIGIO, POLL_IN);
msleep(3000);
ret=adc124s_adc_conversion(g_spi,2);
break;
case 2:
for(i=748;i<1496;i++)
{
printk("this is mmap_buffer[%d] : %d\n",i*2,mmap_buffer[i*2]);
}
kill_fasync(&button_async, SIGIO, POLL_OUT);
msleep(3000);
ret=adc124s_adc_conversion(g_spi,1);
break;
default: printk("this is faile\n");
break;
}
}
static ssize_t adc124s_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
int ret = 0;
ret=adc124s_adc_conversion(g_spi,1);/* count每次读取的数据量 */
return ret;
}
