Re: [PATCH] drivers:staging: sources for ST core

[Pavan Savoy <pavan_savoy@ti.com>]

--- On Wed, 31/3/10, Greg KH <gregkh@suse.de> wrote:

> From: Greg KH <gregkh@suse.de>
> Subject: Re: [PATCH] drivers:staging: sources for ST core
> To: "Pavan Savoy" <pavan_savoy@ti.com>
> Cc: "Marcel Holtmann" <marcel@holtmann.org>, alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org
> Date: Wednesday, 31 March, 2010, 11:49 PM
> On Wed, Mar 31, 2010 at 11:32:39PM
> +0530, Pavan Savoy wrote:
> > --- On Wed, 31/3/10, Greg KH <gregkh@suse.de>
> wrote:
> > 
> > > From: Greg KH <gregkh@suse.de>
> > > Subject: Re: [PATCH] drivers:staging: sources for
> ST core
> > > To: "Pavan Savoy" <pavan_savoy@ti.com>
> > > Cc: "Marcel Holtmann" <marcel@holtmann.org>,
> alan@lxorguk.ukuu.org.uk,
> linux-kernel@vger.kernel.org
> > > Date: Wednesday, 31 March, 2010, 11:00 PM
> > > On Wed, Mar 31, 2010 at 04:20:22AM
> > > +0530, Pavan Savoy wrote:
> > > > 
> > > > --- On Wed, 31/3/10, Pavan Savoy <pavan_savoy@ti.com>
> > > wrote:
> > > > 
> > > > > From: Pavan Savoy <pavan_savoy@ti.com>
> > > > > Subject: Re: [PATCH] drivers:staging:
> sources for
> > > ST core
> > > > > To: gregkh@suse.de
> > > > > Cc: "Marcel Holtmann" <marcel@holtmann.org>,
> > > alan@lxorguk.ukuu.org.uk
> > > > > Date: Wednesday, 31 March, 2010, 4:11
> AM
> > > > > --- On Wed, 31/3/10, Pavan Savoy
> > > > > <pavan_savoy@yahoo.co.in>
> > > > > wrote:
> > > > > 
> > > > > > From: Pavan Savoy <pavan_savoy@yahoo.co.in>
> > > > > > Subject: Re: [PATCH]
> drivers:staging:
> > > sources for ST
> > > > > core
> > > > > > To: "pavan_savoy@yahoo.co.in"
> > > > > <pavan_savoy@yahoo.co.in>
> > > > > > Date: Wednesday, 31 March, 2010,
> 4:06 AM
> > > > > > > From: Greg KH [gregkh@suse.de]
> > > > > > > Sent: Wednesday, March 31,
> 2010 3:17
> > > AM
> > > > > > > To: Savoy, Pavan
> > > > > > > Cc: Alan Cox; marcel@holtmann.org;
> > > > > > > linux-kernel@vger.kernel.org
> > > > > > > Subject: Re: [PATCH]
> drivers:staging:
> > > sources for
> > > > > ST
> > > > > > core
> > > > > > > 
> > > > > > > On Wed, Mar 31, 2010 at
> 02:35:55AM
> > > +0530, Pavan
> > > > > Savoy
> > > > > > > wrote:
> > > > > > > > So, something like the
> below is
> > > ok, I have
> > > > > > defined my
> > > > > > > own pr_fmt,
> > > > > > > > however default log
> level on my
> > > board is 7,
> > > > > and
> > > > > > hence
> > > > > > > pr_info is a bit
> > > > > > > > more annoying than
> usual.
> > > > > > > 
> > > > > > > No, a driver should use
> dev_dbg() and
> > > other
> > > > > > dev_printk()
> > > > > > > calls, not
> > > > > > > pr_debug() or anything like
> that.
> > > > > > > 
> > > > > > > Please don't roll your own
> formats, use
> > > the ones
> > > > > that
> > > > > > are
> > > > > > > well defined
> > > > > > > and uniquely describe your
> driver and
> > > device in
> > > > > a
> > > > > > format
> > > > > > > that the whole
> > > > > > > kernel uses.
> > > > > > 
> > > > > 
> > > > 
> > > > forgot lkml the last time..
> > > > 
> > > > Nope, I couldn't find any instance of struct
> device at
> > > all,
> > > > I need that to use dev_dbg right ? - None of
> the
> > > tty_*
> > > > structure accessible by ldiscs seems to have
> a
> > > reference to
> > > > it.
> > > > Also I happened to look at other line
> discipline
> > > driver, if
> > > > they have a smarter way of doing this, Nope
> - n_tty,
> > > n_hdlc,
> > > > n_slip all seem to use plain old printks.
> > > >? 
> > > > Any clues ??
> > > 
> > > Sorry, you are correct, we only have a struct
> kref right
> > > now for tty
> > > core objects, not a struct device.? So nevermind,
> this
> > > should be fine.
> > 
> > Oh cool. Thanks, So that leaves me with 1 pending item
> from Alan which is to tie these 3 modules (KIM/Core/LL) up
> onto a TTY device specific context, and avoid all global
> ptrs.
> > 
> > So without that is it good to go in ?
> 
> Yes, care to do that and resubmit?

Oh, But that would take some major re-structuring with the driver, because with the existing driver being a platform_device/driver structure-I can't do that.

I have made it similar to TTY<->LDISCs, LDISCs register to TTY core, here BT/FM/GPS register to ST core.
TTY has a array of ldisc registered which is global, locked resource, I have st_gdata which is global and locked resource.

Each ldisc is to be in context of tty, because multiple UART exist, but this is also a platform device and exports symbols for other drivers to register in, so essentially only 1 such device exist per platform.

I agree it's unlike other device drivers in kernel, But is this unacceptable this way ?
Are there any specific architectural inputs ? is this supposed to be similar to other drivers ? Please suggest...


> thanks,
> 
> greg k-h
> --
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