linux-kernel - Re: [RESEND PATCH v4 0/8] i2c: Relax mandatory I2C ID table passing

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Message-ID: <20151002093512.GB23213@x1>
Date:	Fri, 2 Oct 2015 10:35:12 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Wolfram Sang <wsa@...-dreams.de>
Cc:	Javier Martinez Canillas <javier@....samsung.com>,
	Kieran Bingham <kieranbingham@...il.com>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
	grant.likely@...aro.org
Subject: Re: [RESEND PATCH v4 0/8] i2c: Relax mandatory I2C ID table passing

On Thu, 01 Oct 2015, Wolfram Sang wrote:

> 
> > > Yes but that is not true for drivers that support both OF and legacy board
> > > files. For those drivers, there will be a lot of boiler plate code duplicated
> > > that would look something like:
> > > 
> > >      unsigned long data;
> > >      struct of_device_id *match;
> > >      struct i2c_devicd_id *id;
> > > 
> > >      if (i2c->dev.of_node) {
> > >             match = i2c_of_match_device(of_match_table, i2c);
> > > 	    if (!match)
> > > 	           return -EINVAL;
> > > 
> > >             data = (unsigned long)match->data;
> > >      } else {
> > >             id = i2c_match_id(id_table, i2c);
> > > 	    if (!id)
> > > 	           return -EINVAL;
> > > 
> > >             data = id->driver_data;
> > >      }
> 
> I said this before: It is not only the additional code, I think it is
> quite unelegant to to do the matching again which has already been done.
> (and DT boottime has already increased, partly due to the excessive
> string matching). Also, I wouldn't like to see an I2C specific solution;
> this problem exists for other subsystems, too.
> 
> > I'm fine with a new API for this stuff.  I'm even happy to go ahead
> > and code it up, but it's important to note that this is work which
> > should be based on this set and not a blocker for this set to be
> > accepted.
> 
> Is that a promise? :)

Yes.

> > The correct approach is the former.  One of the aims of this set was
> > to bring the I2C .probe() call-back more into line with the majority
> > of the other .probe() calls in the kernel i.e. with only a single
> > parameter.  I'm really not a fan of passing some random void pointer
> 
> Yes, I like this about this series.
> 
> > in.  Using a look-up call to fetch ACPI/OF/I2C/etc data is the current
> > norm and is a very viable option.
> 
> It is the status quo, but that doesn't make it better IMO.
> 
> > Wolfram, please (finally :D) take this set.
> 
> I tend to give in ;)

Great.  Although, I don't see a "applied, thanks". :)

Please just take it, so we can breathe a sigh of relief and move on to
the next stage. :D

> Maybe we can talk in Dublin a bit about a possible
> next step after this series?

I'm happy to chat, although I'm afraid I won't be in Dublin this
time.  Kieran will be though, so feel free to so some lobby loitering
and I'll discuss with him when he returns.  Failing that we can
hook-up on Gtalk or IRC etc.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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