Re: [PATCH] mtd: spi-nor: don't claim mr25h40 to be JEDEC compatible

["Uwe Kleine-König" <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

Hello,

On Fri, Jan 13, 2017 at 07:42:27PM +0000, Mark Rutland wrote:
> On Fri, Jan 13, 2017 at 07:42:34PM +0100, Geert Uytterhoeven wrote:
> > CC devicetree
thanks

> > 
> > On Fri, Jan 13, 2017 at 10:35 AM, Uwe Kleine-König
> > <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> wrote:
> > > Commit edd0c8f4932d ("mtd: spi-nor: Add support for mr25h40") made it
> > > possible to use a mr25h40 by writing
> > >
> > >         compatible = "mr25h40", "jedec,spi-nor";
> > 
> > No vendor prefix?
> > 
> > >
> > > in a device tree. This chip however isn't JEDEC compatible however, so
> > > change the chip string and add a compatible entry to bless
> > >
> > >         compatible = "mr25h40-nonjedec";
> > >
> > > as the right way.
> > 
> > This whole "-nonjedec" business looks wrong to me.
> > If the device is called "mr25h40", its compatible value should be
> > "everspin,mr25h40". Adding some (in)compatibility indicator violates the
> > spirit of compatible values, IMHO.
> 
> Agreed on all counts.
> 
> The compatible string should specify the vendor and device, any
> compliance details should either be known for that string or derived
> from other properties.
> 
> IIUC this is following an existing pattern, which we should deprecate
> (retaining support for those strings so old DTBs work).

Looking at drivers/mtd/spi-nor/spi-nor.c there is in the spi_nor_ids
array:

	...
        { "m25p05",  INFO(0x202010,  0,  32 * 1024,   2, 0) },
	...
        { "m25p05-nonjedec",  INFO(0, 0,  32 * 1024,   2, 0) },

and similar entries for the other M25P members. So I guess these chips
couldn't do JEDEC at the beginning, then got feature updates but no new
name. So "m25p05-nonjedec" is fine as compatibility string?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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