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From: Philippe Langlais <philippe.langlais@stericsson.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: "gregkh@suse.de" <gregkh@suse.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Ludovic BARRE <ludovic.barre@stericsson.com>,
	Vincent GUITTOT <vincent.guittot@stericsson.com>
Subject: Re: patch "U6715 8250 serial like driver" added to gregkh-2.6 tree
Date: Tue, 27 Jul 2010 16:46:10 +0200	[thread overview]
Message-ID: <4C4EF132.7090304@stericsson.com> (raw)
In-Reply-To: <20100727091408.49d55447@lxorguk.ukuu.org.uk>



On 07/27/10 10:14, Alan Cox wrote:
>>> I think what you need to keep this clean is to create a
>>> port->set_termios() for the 8250 port (akin to
>>> port->serial_in/serial_out) which does the specials you need each end and
>>> calls the standard serial8250_set_termios)
>>>
>>>        
>> I don't think so, call a function which compute clock each time
>> we access UART registers isn't optimal, another function to overload ?
>>      
> set_termios() gets called once at init time and once each time a
> caller requests a change in serial parameters. That's not usually
> considered a hot path. I'm not suggesting you hide it in the register
> methods but add ->set_termios as a method that can be overridden, plus
> export the existing one so you can wrap it.
>
> If you can't detect the chip then create yourself a u6715 driver file
> which registers the ports you have and specifies the relevant
> serial_in/out methods and other detail as well as containing the board
> specific routines needed.
>
> See arch/arm/mach-omap2/serial.c for a ARM example doing this, where all
> the chip knowledge is nicely buried away in the platform support.
>    
We have such a platform driver, but I can't see anywhere an example of 
set_termios()
or another uart_ops function overriding.
These platform drivers only add new functions around power & clock.
Platform drivers are initialized before 8250 driver, how to override 
8250 driver ?




  reply	other threads:[~2010-07-27 14:47 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-19  9:27 [PATCH] U6715 8250 serial like driver Philippe Langlais
2010-07-22 23:57 ` patch "U6715 8250 serial like driver" added to gregkh-2.6 tree gregkh
2010-07-23  8:01   ` Alan Cox
2010-07-23 12:37     ` Greg KH
2010-07-27  7:53     ` Philippe Langlais
2010-07-27  8:14       ` Alan Cox
2010-07-27 14:46         ` Philippe Langlais [this message]
2010-07-27 15:05           ` Alan Cox
2010-07-27 15:01             ` Philippe Langlais

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