On Tue, Jun 24, 2014 at 11:49 PM, Torrie Fischer <tdfischer@xxxxxxxxxxxxxx> wrote: > Apparently all I had to do was set the type attribute on the uart_port > structure to anything that isn't PORT_UNKNOWN. > Arhh.. I see. I overlooked that since tty->type was being set. Good to know you got it working. > Here's a functional driver that takes a GPIO pin and creates a read-only > serial TTY: So multiple open don't harm? The startup routine is called only once is that right? > > https://github.com/tdfischer/gpio_serial/blob/master/gpiotty.c > > :) > > On Tuesday, June 24, 2014 21:27:46 Pranay Srivastava wrote: >> 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
