Re: [PATCH v2 2/2] mtd: rawnand: Add NAND controller support on Intel LGM SoC

From: Boris Brezillon <boris.brezillon@collabora.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@intel.com>,
	"Ramuthevar,Vadivel MuruganX" 
	<vadivel.muruganx.ramuthevar@linux.intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"open list:MEMORY TECHNOLOGY..." <linux-mtd@lists.infradead.org>,
	devicetree <devicetree@vger.kernel.org>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>, Vignesh R <vigneshr@ti.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Brendan Higgins <brendanhiggins@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Anders Roxell <anders.roxell@linaro.org>,
	masonccyang@mxic.com.tw, piotrs@cadence.com,
	Rob Herring <robh+dt@kernel.org>,
	linux-mips@vger.kernel.org,
	"hauke.mehrtens" <hauke.mehrtens@intel.com>,
	qi-ming.wu@intel.com, cheol.yong.kim@intel.com
Subject: Re: [PATCH v2 2/2] mtd: rawnand: Add NAND controller support on Intel LGM SoC
Date: Mon, 20 Apr 2020 11:52:56 +0200	[thread overview]
Message-ID: <20200420115256.3a0ff647@collabora.com> (raw)
In-Reply-To: <CAHp75VeOH+DC362tsEo13gr9fJpeCHXok=7O19B3njbxCOzd2A@mail.gmail.com>

On Mon, 20 Apr 2020 12:44:51 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Mon, Apr 20, 2020 at 12:21 PM Boris Brezillon
> <boris.brezillon@collabora.com> wrote:
> > On Mon, 20 Apr 2020 01:20:40 +0300
> > Andy Shevchenko <andriy.shevchenko@intel.com> wrote:  
> > > On Sat, Apr 18, 2020 at 10:55:33AM +0200, Boris Brezillon wrote:  
> > > > On Fri, 17 Apr 2020 16:21:47 +0800
> > > > "Ramuthevar,Vadivel MuruganX"
> > > > <vadivel.muruganx.ramuthevar@linux.intel.com> wrote:
> > > >  
> > > > > From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>  
> > >  
> > > > > +static const struct of_device_id lgm_nand_match[] = {
> > > > > + { .compatible = "intel,lgm-nand", },
> > > > > + {}
> > > > > +};
> > > > > +MODULE_DEVICE_TABLE(of, lgm_nand_match);  
> > > >
> > > > You probably have a missing "depends on OF" in your Kconfig.  
> > >
> > > Since it's using device property API, dependency is not needed.
> > >  
> >
> > There's no compile-time dependency, but this driver will be pretty
> > useless if all its users have the NAND controller node defined in their
> > DT and CONFIG_OF is not enabled.  
> 
> No, it's not.
> See [1] for the details how ACPI may utilize this table.
> 
> [1]: https://www.kernel.org/doc/html/latest/firmware-guide/acpi/enumeration.html#device-tree-namespace-link-device-id

Except the NAND framework does use the OF lib when parsing common DT
properties (like nand-ecc-mode, etc), so it does depend on OF if you
want those props to be parsed, which, according to the DT binding patch,
is the case.