Hi Torrie, On Tue, Jun 24, 2014 at 6:26 PM, Torrie Fischer <tdfischer@xxxxxxxxxxxxxx> wrote: > Hi, Pranay. > > Thanks for having a look. > > On Tuesday, June 24, 2014 13:42:35 Pranay Srivastava wrote: >> >> I looked at uart_register code, it seems there's no read callback so >> that's why you are getting that -EIO. > > From what I understand, I'm supposed to set up the interrupts needed in the > startup function which is called when the device is opened. This never happens > though, as adding a printk results in no output. I think this might be causing it, if you see tty_open then it has a call to , tty_open_current_tty , this seems to be the only one which I think is not making the driver being looked up and hence no uport->open so in case there's an already a tty attached to current then i think it isn't opening a new one. Maybe you need to detach this tty? Not so sure I'll look again what can be done. > >> I think you can put this call in your start_tx since uart_start is >> calling port->start_tx at the end so i guess you should be good there. > > I suspect that start_tx is not getting called since adding a printk in my > start_tx function doesn't result in any output. > >> >> I don't have much idea how will you read from it though. > > I'm able to read from it by waiting for a rising edge interrupt and then bit- > banging the GPIO line in userspace, though at a slow baud that is unusable. I > need 9600 to read from my device :) Ok good!. I don't have much idea about GPIO. While searching I found there's a GPIO library for Raspi. I don't know how much help that would be but i guess you don't want to use it. -- ---P.K.S _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies