Jonathan Cameron wrote on 2010-12-17: > On 12/17/10 13:47, Hennerich, Michael wrote: >> Hi Jonathan, >> >> I'm currently working on a high speed ADC driver, that requires a >> different ring buffer use case scenario. Let me explain a little bit >> the setup. I'm running Linux on a Microblaze softcore inside an Virtex6 >> FPGA. Part of the system is a peripheral interface block, we call it >> the ADC Interface Module (AIM). External to the FPGA we connect a >> single channel high speed ADC AD9649, to the AIM signals. >> >> The AIM features a FIFO, with watermark interrupt capabilities. There >> are two modes that need to be supported. Continues Sampling Mode and >> Single Shot Sample Mode. In Single Shot Sample Mode, the user reads an >> arbitrary Number of samples from the > ADC, and then the sampling stops. This mode does not need to have a > ringbuffer at all. >> A simple chardev might be sufficient. >> >> Any objections creating a driver private chardev? > None at all. > Is it appropriate to maintain the interfaces and buffer description we > have for those where there is a buffer involved? I think those > interfaces are flexible enough... If not we probably want to make it > so they are. > > I did think of creating a pass through buffer that would effectively > allow other devices to simulate this behaviour. Basically to the core > it would look like a buffer, but it would only store one scan and then > only if someone has the chrdev open. It would support select type > calls. This would be needed for the input bridge to no apply any delay > to the data stream. > > Not actually done any work on it though. Hi Jonathan, For a project I'm currently working on I need such a pass through buffer. The requirements I have are pretty basic. When user space reads x number of elements >From the buffer, the generic pass through buffer implementation calls a registered function in the ADC driver, that may sleep until the requested amount of elements are available. I wonder if you have something in the make already? Greetings, Michael -- Analog Devices GmbH Wilhelm-Wagenfeld-Str. 6 80807 Muenchen Sitz der Gesellschaft: Muenchen; Registergericht: Muenchen HRB 40368; Geschaeftsfuehrer:Dr.Carsten Suckrow, Thomas Wessel, William A. Martin, Margaret Seif -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
