Re: [PATCH (v6) 1/2] mtd: brcmnand: Add brcm,bcm63268-nand device tree binding

From: Brian Norris <computersforpeace@gmail.com>
To: Simon Arlott <simon@fire.lp0.eu>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
	Rob Herring <robh@kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	David Woodhouse <dwmw2@infradead.org>,
	linux-mtd@lists.infradead.org, Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	Jonas Gorski <jogo@openwrt.org>,
	bcm-kernel-feedback-list@broadcom.com,
	Kamal Dasu <kdasu.kdev@gmail.com>,
	Boris Brezillon <boris.brezillon@free-electrons.com>
Subject: Re: [PATCH (v6) 1/2] mtd: brcmnand: Add brcm,bcm63268-nand device tree binding
Date: Wed, 2 Dec 2015 12:48:18 -0800	[thread overview]
Message-ID: <20151202204818.GP64635@google.com> (raw)
In-Reply-To: <565F55DE.4050703@simon.arlott.org.uk>

On Wed, Dec 02, 2015 at 08:34:38PM +0000, Simon Arlott wrote:
> On 02/12/15 20:21, Brian Norris wrote:
> > On Wed, Dec 02, 2015 at 08:12:32PM +0000, Simon Arlott wrote:
> >> On 02/12/15 20:00, Brian Norris wrote:
> >> > On Wed, Dec 02, 2015 at 07:41:07PM +0000, Simon Arlott wrote:
> >> >> I've created a bcm963268part driver so there won't need to be any
> >> >> partitions in DT for bcm63268.
> >> > 
> >> > Just curious, do you plan to submit this driver? We're working on
> >> 
> >> Yes, it's just the most recent one I've been working on. I still have
> >> USBH and IUDMA to submit
> >> 
> >> > matching up partition parsers to flash devices via device tree
> >> > of_match_table's, so you could do something like this:
> >> > 
> >> > 	nand0: nandcs@0 {
> >> > 		compatible = "brcm,nandcs";
> >> > 		...
> >> > 
> >> > 		partitions {
> >> > 			compatible = "brcm,bcm963268-partitions";
> >> > 			...
> >> > 		};
> >> > 	};
> >> 
> >> I modified brcmnand to look for a machine matching "brcm,bcm963268", but
> > 
> > Like this?
> > 
> > http://patchwork.ozlabs.org/patch/473180/
> > 
> > I'd like to avoid that (hence the "Rejected" status).
> 
> I exported default_mtd_part_types, copied it, and then added to it:
> +	for (i = 0; i < nr_types; i++)
> +		part_types[i] = default_mtd_part_types[i];
> +
> +	/* Add partition type based on machine */
> +	if (of_machine_is_compatible("brcm,bcm963268"))
> +		part_types[i++] = "bcm963268part";
> +	else
> +		part_types[i++] = NULL;
> +
> +	part_types[i++] = NULL;

OK, so even uglier :)

> >> that way is ok with me. Presumably "ofpart" defers to another matching
> >> partition parser?
> > 
> > Yes, "ofpart" is for specifying the entire partition table in the device
> > tree as subnodes of either the flash node or of the flash's "partitions"
> > subnode. It's not the most flexible, but it does work generically.
> > 
> >> Is there a patch for that method of parser detection available?
> > 
> > I have something working here, but I haven't had time to finish cleaning
> > it up and submitting it. There's an older patch that works similarly,
> > though it has some deficiencies:
> > 
> > http://patchwork.ozlabs.org/patch/475988/
> > 
> > The main difference between that and my (yet-to-be-submitted) proposal
> > is that I'd like parsers to opt in by adding a proper of_match_table
> > with non-Linux-specific DT bindings, and then we can drop the
> > "linux,..." naming and make it a reasonably generic property.
> 
> I'll submit my parser without any means of using it,

Sounds fine.

> let me know if you
> want me to work on a patch for a match table.

If you're interested, I may CC you on my patches for testing/review.

Brian