Hi, On Wed, Sep 02, 2015 at 08:12:19PM -0300, Rodolfo Labiapari Mansur wrote: > Your answering a help wanted me doubt. I am developing a driver for > communication with an FPGA. For communication I am using a UART > converter that is making the USB converter of paper for serial. And which USB-to-UART converter would that be ? Most likely we already have support for it in the kernel and if we do, it's far better that you read the source code that's in place, than try to roll your own. If you want to start learning kernel development, my suggestion would be spend time on something else, rather than trying to solve something that was already solved (in this USB-to-UART devices). > I'm doing my own driver this converter because I want to learn how to > develop drivers. > > I followed the example usb-skel.c available on the internet. In my > driver, I can recognize the converter device, get all your > information. :) > However, when we send data to the drive, the driver reports it was > sent successfully but the converter does not receive. (I also tried what do you mean it "it was sent successfully but the converted does not receive." ? Do you mean to say that a function returned zero ? Or that the device returned you an ACK package > with Arduino and RS-232, but did not succeed). :( okay, so what happened there ? Have you tried usbmon ? (see Documentation/usb/usbmon.txt from a kernel source tree for details) > So in the current situation, my driver informs that has been sent, but > the device connected to the computer receives no signal. and how do you know it "received no signal" ? Which signal are you talking about ? > My main question is: I need to 'start' communication before sending a > package? For example, you would have to tell the device will start > sending the package? Because it makes no sense I send my package, > return success and the device does not receive anything. My driver > needs to send pro device control signals warning that he wants to > start data transmission? you need to figure out the protocol which your device talks. Sometimes they just want raw data, but sometimes there's something else they need. Also, are you sending your data to the correct endpoints ? Grab some usbmon traces, then it'll be easier to figure out what's going on. -- balbi
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