On Tue, Jun 24, 2014 at 11:49 PM, Torrie Fischer <tdfischer@hackerbots.net> 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@hackerbots.net> 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