Re: custom serial driver node not created

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On Wed, May 18, 2022 at 2:42 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, May 18, 2022 at 02:24:43PM +0200, Belisko Marek wrote:
> > On Wed, May 18, 2022 at 1:59 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > On Wed, May 18, 2022 at 01:41:18PM +0200, Belisko Marek wrote:
> > > > Hello,
> > > >
> > > > I'm writing serial tty driver (it's SPI/UART converter) and I get
> > > > inspired by this driver:
> > > > https://github.com/raspberrypi/linux/blob/rpi-5.15.y/drivers/tty/serial/sc16is7xx.c
> > > >
> > > > I have driver probed and also added port to driver which I see in console:
> > > > [ 2616.826105] spi0.0: ttyTX0 at I/O 0x1 (irq = 0, base_baud = 9375)
> > > > is a test_driver
> > > >
> > > > so I should see it in /dev/ttyTX0 but it seems node is not created.
> > > > Udev is running on a platform.
> > > > Any ideas what can cause this?
> > >
> > > Without seeing the code itself, it's almost impossible to guess.
> > >
> > > Also note that udev does not create device nodes (hasn't for over a
> > > decade).  devtmpfs in the kernel does that, udev just helps with
> > > managing the permissions of created nodes if needed.
> > OK thanks for clarification.
> > >
> > > And why did you pick the ttyTX name?  That's already reserved for that
> > > driver, you should use a new one, right?
> > I've should used also others like ttyTEST but result was same.
> > >
> > > And what hardware are you writing this driver for that we don't already
> > > have a driver for it?
> > I'm writing a driver for the following model: Linux CPU is connected
> > with SPI with another CPU (Cortex M3) and this other CPU performs UART
> > handling based on data which comes over SPI. I would like to expose
> > Cortex M3 UARTS on linux as tty ports so it will act as standar serial
> > device.
> >
> > Code can be found here: https://pastebin.com/6qpUw2Jt
>
> Are you sure that your test_probe() call is really being called?
Of course I've added tons of debugging to the driver and it is probed.
As I mentioned in first topic I see this printout:
[ 2616.826105] spi0.0: ttyTX0 at I/O 0x1 (irq = 0, base_baud = 9375)
is a test_driver

which came from uart_report_port() foom serial_core.c
>

marek
-- 
as simple and primitive as possible
-------------------------------------------------
Marek Belisko - OPEN-NANDRA
Freelance Developer

Ruska Nova Ves 219 | Presov, 08005 Slovak Republic
Tel: +421 915 052 184
skype: marekwhite
twitter: #opennandra
web: http://open-nandra.com



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