[pnx833x_port]: device name prefix - ttyS or ttySA?

[pnx833x_port]: device name prefix - ttyS or ttySA?

[Ihar Hrachyshka]

In 'drivers/serial/pnx833x_port.c' we define the prefix for UART serial
device as "ttyS". Anyway, we use major:minor numbers for SA1100 serial
driver (that are 204:5). Why don't we use "ttySA" prefix then? That's
what different embedded build systems expect for populating /dev (f.e.
buildroot).

Re: [pnx833x_port]: device name prefix - ttyS or ttySA?

[Florian Fainelli]

Hi,

Le Tuesday 13 January 2009 16:07:50 Ihar Hrachyshka, vous avez écrit :
> In 'drivers/serial/pnx833x_port.c' we define the prefix for UART serial
> device as "ttyS". Anyway, we use major:minor numbers for SA1100 serial
> driver (that are 204:5). Why don't we use "ttySA" prefix then? That's
> what different embedded build systems expect for populating /dev (f.e.
> buildroot).

In my experience, everything that is not ttyS is a bit confusing either when 
creating the devices in the roots, or when using the serial console in the 
kernel command line. So I will vote for ttyS.

My 2 cents.
-- 
Best regards, Florian Fainelli
Email : florian@openwrt.org
http://openwrt.org
-------------------------------

Re: [pnx833x_port]: device name prefix - ttyS or ttySA?

[Sergei Shtylyov]

Hello.

Ihar Hrachyshka wrote:

> In 'drivers/serial/pnx833x_port.c' we define the prefix for UART serial
> device as "ttyS". Anyway, we use major:minor numbers for SA1100 serial
> driver (that are 204:5).

    Why?

WBR, Sergei

Re: [pnx833x_port]: device name prefix - ttyS or ttySA?

[Ihar Hrachyshka]

On Tue, Jan 13, 2009 at 7:09 PM, Daniel James Laird
<daniel.j.laird@nxp.com> wrote:
> I cant find the file you are talking about however

Sorry, I misspelled the file name. It's 'drivers/serial/pnx8xxx_uart.c' instead.

> I think that the major number should infact be 4 with a minor number of 64,65,66 etc.  This seems to be what other devices do.  This would mean you can still be ttyS... but not clash with SA1100 if that's what you mean.

You're wrong. There are lots of board specific serial drivers that
define special major-minor numbers. For example look at sc26xx,
mpc52xx_uart, bfin_5xx drivers. The problem with pnx8xxx_uart driver
is that it uses special major:minor numbers for generic ttyS* devices.

I think we need one of these changes:
1) make a special CONFIG_PNX8XXX_UART_TTYS option for switching
between ttyS*+4:64 and ttySA*+204:5 variants (see f.e. atmel_serial
driver). Of course this CONFIG_PNX8XXX_UART_TTYS option will be
disabled if CONFIG_SERIAL_8250 enabled.
2) Just stick with ttySA*+204:5 (not with ttyS*+204:5 as it's now).

Please tell me what you prefer and I'll send you a patch.

>
> With regards,
> Daniel Laird
>
> Daniel Laird, Software Engineer
> NXP Semiconductors, BU Home, BL STB
>
> -----Original Message-----
> From: linux-mips-bounce@linux-mips.org [mailto:linux-mips-bounce@linux-mips.org] On Behalf Of Ihar Hrachyshka
> Sent: 2009 Jan 13 15:08
> To: linux-mips@linux-mips.org
> Subject: [pnx833x_port]: device name prefix - ttyS or ttySA?
>
> In 'drivers/serial/pnx833x_port.c' we define the prefix for UART serial
> device as "ttyS". Anyway, we use major:minor numbers for SA1100 serial
> driver (that are 204:5). Why don't we use "ttySA" prefix then? That's
> what different embedded build systems expect for populating /dev (f.e.
> buildroot).
>
>
>

Re: [pnx833x_port]: device name prefix - ttyS or ttySA?

[Ihar Hrachyshka]

On Tue, Jan 13, 2009 at 7:30 PM, Florian Fainelli <florian@openwrt.org> wrote:
> Hi,
>
> Le Tuesday 13 January 2009 16:07:50 Ihar Hrachyshka, vous avez écrit :
>> In 'drivers/serial/pnx833x_port.c' we define the prefix for UART serial
>> device as "ttyS". Anyway, we use major:minor numbers for SA1100 serial
>> driver (that are 204:5). Why don't we use "ttySA" prefix then? That's
>> what different embedded build systems expect for populating /dev (f.e.
>> buildroot).
>
> In my experience, everything that is not ttyS is a bit confusing either when
> creating the devices in the roots, or when using the serial console in the
> kernel command line. So I will vote for ttyS.

The problem is that use-case with generic 8250 and board specific
serial drivers both enabled is not a fantasy. So we need to
differentiate between them.

>
> My 2 cents.
> --
> Best regards, Florian Fainelli
> Email : florian@openwrt.org
> http://openwrt.org
> -------------------------------
>