Re: [PATCH 0/4] mtd: nand: atmel: Rework DT representation of NFC/NAND

From: Nicolas Ferre <nicolas.ferre@atmel.com>
To: Boris Brezillon <boris.brezillon@free-electrons.com>,
	Brian Norris <computersforpeace@gmail.com>,
	<linux-mtd@lists.infradead.org>, Josh Wu <josh.wu@atmel.com>,
	Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
	Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
	Andrew Victor <linux@maxim.org.za>,
	Rob Herring <robh+dt@kernel.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>, <devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/4] mtd: nand: atmel: Rework DT representation of NFC/NAND
Date: Fri, 5 Dec 2014 18:07:08 +0100	[thread overview]
Message-ID: <5481E63C.5020208@atmel.com> (raw)
In-Reply-To: <1417732214-3292-1-git-send-email-boris.brezillon@free-electrons.com>

Le 04/12/2014 23:30, Boris Brezillon a écrit :
> Hello,
> 
> While working on the EBI driver [1] I noticed that the relationship between
> the NFC (NAND Flash Controller) and the NAND chip it is attached to would
> make things harder to represent when moving the NAND node under the EBI bus
> (another useless 'ranges' definition).
> 
> Actually this representation might be even more problematic if one wants
> decide to connect two NAND chips on his sama5 based board, because the NFC
> node is a child of the NAND chip node, and thus can only be attached to a
> single NAND chip.
> 
> To address this problem the current series moves the NFC node outside of
> the NAND chip device which then reference the NFC using the "atmel,nfc"
> property.
> 
> The series does not implement multi-chip support, but at least the new
> representation should make it possible.
> 
> Best Regards,
> 
> Boris
> 
> [1]https://lkml.org/lkml/2014/12/3/806

Boris,

It sounds promising and for sure we have to think about a way to deal
with SMC (EBI interface) and the NAND controller with its attributes
(PMECC) or flavors (plain SMC or NFC).

Let's consider this as a RFC and discuss how to deal with the DT
modifications and the representation hierarchy all together.

Thanks, bye.

> Boris Brezillon (4):
>   mtd: nand: atmel: Rework driver to separate nfc and nand nodes
>   mtd: nand: atmel: Update DT documentation after splitting NFC and NAND
>   ARM: at91/dt: sama5: move NFC nodes outside of NAND nodes
>   ARM: at91/dt: sama5: move NAND nodes into board dts/dtsi
> 
>  .../devicetree/bindings/mtd/atmel-nand.txt         | 46 +++++++------
>  arch/arm/boot/dts/at91-sama5d3_xplained.dts        | 18 ++++-
>  arch/arm/boot/dts/at91-sama5d4ek.dts               | 16 ++++-
>  arch/arm/boot/dts/sama5d3.dtsi                     | 36 ++--------
>  arch/arm/boot/dts/sama5d3xcm.dtsi                  | 18 ++++-
>  arch/arm/boot/dts/sama5d4.dtsi                     | 36 ++--------
>  drivers/mtd/nand/atmel_nand.c                      | 76 +++++++++++++++++-----
>  7 files changed, 149 insertions(+), 97 deletions(-)
> 

-- 
Nicolas Ferre