> > > -----Original Message----- > > > From: gregkh@xxxxxxxxxxxxxxxxxxx <gregkh@xxxxxxxxxxxxxxxxxxx> > > > Sent: Friday, July 1, 2022 3:16 PM > > > To: Neal Liu <neal_liu@xxxxxxxxxxxxxx> > > > Cc: linux-usb@xxxxxxxxxxxxxxx; linux-serial@xxxxxxxxxxxxxxx > > > Subject: Re: Questions about usb to serial driver > > > > > > On Fri, Jul 01, 2022 at 03:16:13AM +0000, Neal Liu wrote: > > > > Hi all, > > > > > > > > I have a question about USB-serial and I hope I can find the > > > > answer from > > > here. > > > > I'll be appreciated it if there is any feedback from you. > > > > > > > > My question is If I have a USB device controller (udc) and a uart > > > > controller (16550) independently in a SoC, is there any usb-serial > > > > drivers or > > > applications that could possible to support/connect: > > > > - udc tx to uart rx > > > > - uart tx to udc rx > > > > > > > > Any chance I can make this SoC as a usb-serial devices? > > > > > > Sure, use the CONFIG_USB_CONFIGFS_SERIAL or > CONFIG_USB_CONFIGFS_ACM > > > build options and hook your gadget up to the serial port in > > > userspace and you will have a very expensive usb-serial converter > > > (there are very cheap chips that do the same thing if you want to > > > make a simpler > > > device.) > > > > > > hope this helps, > > > > Thanks Greg! > > > > What the detail steps exactly for "hook your gadget up to the serial port in > userspace"? > > Assume my system has: > > 1 system uart: ttyS0 > > 1 uart: ttyS1 > > 1 usb gadget cdc acm: ttyGS0 > > > > How to hook up ttyS1 to ttyGS0, so that I could communicate through below > path. > > PC1 - usb interface - my SoC (ttyGS0 - ttyS1) - rs232 interface - PC2? > > That's an exercise left for the reader to do, odds are you need a userspace > program that just copies the data back and forth. Try it and see! Thanks for your guides, I have implemented it and it works well. The most tricky part is to configure serial port configuration through termios struct. -Neal
