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Subject: Re: [PATCHv4] mtd: gpio-nand: add device tree bindings
From: Artem Bityutskiy <dedekind1@gmail.com>
To: Jamie Iles <jamie@jamieiles.com>
Date: Mon, 15 Aug 2011 17:45:31 +0300
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Cc: Scott Wood <scottwood@freescale.com>, David Woodhouse <dwmw2@infradead.org>,
	devicetree-discuss@lists.ozlabs.org, linux-mtd@lists.infradead.org,
	Grant Likely <grant.likely@secretlab.ca>
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On Mon, 2011-08-15 at 15:38 +0100, Jamie Iles wrote:
> On Mon, Aug 15, 2011 at 05:28:57PM +0300, Artem Bityutskiy wrote:
> > On Tue, 2011-08-09 at 16:12 +0100, Jamie Iles wrote:
> > > -	res1 = platform_get_resource(dev, IORESOURCE_MEM, 1);
> > > +	if (!dev->dev.of_node)
> > > +		res1 = platform_get_resource(dev, IORESOURCE_MEM, 1);
> > > +	else
> > > +		res1 = gpio_nand_of_get_io_sync(&dev->dev);
> > > +
> > >  	if (res1) {
> > >  		gpiomtd->io_sync = request_and_remap(res1, 4, "NAND sync", &ret);
> > >  		if (!gpiomtd->io_sync) {
> > > @@ -257,7 +362,16 @@ static int __devinit gpio_nand_probe(struct platform_device *dev)
> > >  		}
> > >  	}
> > >  
> > > -	memcpy(&gpiomtd->plat, dev->dev.platform_data, sizeof(gpiomtd->plat));
> > > +	if (dev->dev.of_node)
> > > +		kfree(res1);
> > > +
> > > +	if (dev->dev.platform_data)
> > > +		memcpy(&gpiomtd->plat, dev->dev.platform_data,
> > > +		       sizeof(gpiomtd->plat));
> > > +	else
> > > +		ret = gpio_nand_of_get_config(&dev->dev, &gpiomtd->plat);
> > > +	if (ret)
> > > +		goto err_nce;
> > >  
> > 
> > So with this code you can mix platform data and DT? Say, io_sync may
> > come from platform data and the rest from the DT? Is this normal
> > practice?
> 
> Well you can use platform_data with DT - it's the only way to pass 
> function pointers for example, but I'm not convinced it's required in 
> this case (there is the adjust_parts callback, but I can't see a user of 
> it) so I'd be inclined to change the conditionals to:
> 
> 	if (!dev->dev.of_node)
> 		memcpy(&gpiomtd->plat, dev->dev.platform_data, ...);
> 	else
> 		gpio_nand_of_get_config(...);
> 
> so that we don't use platform_data for the DT case.

Yeah, would be nice to have only one "read platform data" and only one
"read DT information" call - this is just cleaner design.

-- 
Best Regards,
Artem Bityutskiy