static ssize_t s3c2410_adc_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)
{
char str[20];
int value;
size_t len;
if (mini6410_adc_acquire_io() == 0) {
__ADC_locked = 1;
START_ADC_AIN(adcdev.channel, adcdev.prescale);
wait_event_interruptible(adcdev.wait, ev_adc);
ev_adc = 0;
DPRINTK("AIN[%d] = 0x%04x, %d\n", adcdev.channel, adc_data, ADCCON & 0x80 ? 1:0);
value = adc_data;
__ADC_locked = 0;
mini6410_adc_release_io();
} else {
value = -1;
}
len = sprintf(str, "%d\n", value);
if (count >= len) {
int r = copy_to_user(buffer, str, len);
return r ? r : len;
} else {
return -EINVAL;
}
}
int s3c2410_adc_read(int ain, wait_queue_head_t *wait)
{
int ret = 0;
if (down_interruptible(&adc_lock))
return -ERESTARTSYS;
adc_wait = wait;
START_ADC_AIN(ain);
sleep_on_timeout(adc_wait, HZ/100); /* 10ms */
#if 0
if (signal_pending(current)) {
up(&adc_lock);
return -ERESTARTSYS;
}
#endif
ret = ADCDAT0 ;
up(&adc_lock);
adc_wait = NULL;
DPRINTK("AIN[%d] = 0x%04x, %d\n", ain, ret, ADCCON & 0x80 ? 1:0);
return (ret & 0x3ff);
}
//ADC 读函数,一般对应于用户层/应用层的设备读函数(read)
static ssize_t s3c2410_adc_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)
{
char str[20];
int value;
size_t len;
//判断“A/D 转换器”资源是否可用
if (down_trylock(&ADC_LOCK) == 0)
{
OwnADC = 1; //标记“A/D 转换器”资源状态为可用
START_ADC_AIN(adcdev.channel, adcdev.prescale); //开始转换
wait_event_interruptible(adcdev.wait, ev_adc); //通过终端的方式等待转换结果
ev_adc = 0;
DPRINTK("AIN[%d] = 0x%04x, %d\n", adcdev.channel, adc_data, ADCCON & 0x80 ? 1:0);
//把转换结果赋予 value,以便传递到用户层/应用层
value = adc_data;
//释放“A/D 转换器”资源
OwnADC = 0;
up(&ADC_LOCK);
}
else
{ //没有“A/D 转换器”资源,赋值为“-1”
value = -1;
}
len = sprintf(str, "%d\n", value);
if (count >= len)
{ //把转换结果传递到用户层/应用层
int r = copy_to_user(buffer, str, len);
return r ? r : len;
}
else
{
return -EINVAL;
}
}
static ssize_t s3c2410_adc_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)
{
int ret = 0;
if (down_interruptible(&adcdev.lock))
return -ERESTARTSYS;
START_ADC_AIN(adcdev.channel, adcdev.prescale);
interruptible_sleep_on(&adcdev.wait);
ret = ADCDAT0;
ret &= 0x3ff;
DPRINTK("AIN[%d] = 0x%04x, %d\n", adcdev.channel, ret, ADCCON & 0x80 ? 1:0);
copy_to_user(buffer, (char *)&ret, sizeof(ret));
up(&adcdev.lock);
return sizeof(ret);
}
static ssize_t tq2440_adc_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)
{
char str[20];
int value;
size_t len;
if (down_trylock(&ADC_LOCK) == 0)
{
ADC_enable = 1;
START_ADC_AIN(adcdev.channel, adcdev.prescale);
wait_event_interruptible(adcdev.wait, ev_adc);
ev_adc = 0;
DPRINTK("AIN[%d] = 0x%04x, %d\n", adcdev.channel, adc_data, ((ADCCON & 0x80) ? 1:0));
value = adc_data;
sprintf(str,"%5d", adc_data);
copy_to_user(buffer, (char *)&adc_data, sizeof(adc_data));
ADC_enable = 0;
up(&ADC_LOCK);
}
else
{
value = -1;
}
len = sprintf(str, "%d\n", value);
if (count >= len)
{
int r = copy_to_user(buffer, str, len);
return r ? r : len;
}
else
{
return -EINVAL;
}
}