Hi all, This might be a silly question, but I want to make sure I understand things correctly. I have a driver with a sysfs entry to get the next data sample every time I read the file. Used like below it works wonderful: # cat next 0x15814 # cat next 0x1682B The last 12 bits are the sample and the first (20) bits are the channel the sample is from (some ADC hardware board with 24 inputs). Now I have some C code that will loop periodically to collect the samples and do some magic with them and I was hoping I could simply keep a FILE * open with a loop like this: for (i = 0; i < count; i++) { if (fscanf(fd_next, "0x%X", &sample) != 1) { /* No data */ continue; } channel = sample >> 12; adc_data = sample & 0xFFF; if (channel > 23) { /* Sample out of range */ error_helper("ADC sample out of range", 0x32000010, 0); continue; } a_in[channel] = adc_data; fseek(fd_next, 0, SEEK_SET); } The problem is that after storing 1 sample, the next samples are never getting updated. I suppose the last line (fseek) does not cause the sysfs function to be called again as I hoped. But the sysfs documentation in the kernel says: If userspace seeks back to zero or does a pread(2) with an offset of '0' the show() method will be called again, rearmed, to fill the buffer. Can anyone tell me what I might be doing wrong? Wouter