From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
Subject: Re: [PATCH v3 05/11] memory: add Atmel EBI (External Bus Interface) driver
Date: Mon, 01 Dec 2014 17:26:27 +0100
Message-ID: <4214030.Z2iCEM6hVA@wuerfel>
References: <1417429647-3419-1-git-send-email-boris.brezillon@free-electrons.com> <1417429647-3419-6-git-send-email-boris.brezillon@free-electrons.com>
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Cc: Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>, Nicolas Ferre <nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>, Jean-Christophe Plagniol-Villard <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>, Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>, Andrew Victor <linux-PelNFVqkFnVyf+4FbqDuWQ@public.gmane.org>, Samuel Ortiz <sameo-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>, Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jean-Jacques Hiblot <jjhiblot-dLKeG7h1OhBDOHtkgc7UlQ@public.gmane.org>, Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>, Ian Campbell <ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
List-Id: devicetree@vger.kernel.org

On Monday 01 December 2014 11:27:21 Boris Brezillon wrote:
> The EBI (External Bus Interface) is used to access external peripherals
> (NOR, SRAM, NAND, and other specific devices like ethernet controllers).
> Each device is assigned a CS line and an address range and can have its
> own configuration (timings, access mode, bus width, ...).
> This driver provides a generic DT binding to configure a device according
> to its requirements.
> For specific device controllers (like the NAND one) the SMC timings
> should be configured by the controller driver through the matrix and
> smc syscon regmaps.

Nice!

> +
> +#define AT91_EBICSA_REGFIELD(soc)			\
> +	REG_FIELD(soc ## _MATRIX_EBICSA_OFF, 0,		\
> +		  AT91_MATRIX_EBI_NUM_CS - 1)
> +
> +#define AT91_MULTI_EBICSA_REGFIELD(soc, n)		\
> +	REG_FIELD(soc ## _MATRIX_EBI ## n ## CSA_OFF,	\
> +		  0, AT91_MATRIX_EBI_NUM_CS - 1)

I don't like the use macros that concatenate symbol names like
this. Why not do either

- open-code the macro contents in the few uses, to allow
  grepping for them, or

- put the register number in the syscon reference and look it
  up from there (this would be slightly more complicated for the
  second macro)

> +
> +	np = of_parse_phandle(pdev->dev.of_node, "atmel,smc", 0);
> +	if (!np)
> +		return -EINVAL;
> +
> +	ebi->smc = syscon_node_to_regmap(np);
> +	if (IS_ERR(ebi->smc))
> +		return PTR_ERR(ebi->smc);

I think this and the second instance of it can be shortened to

	ebi->smc = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "atmel,smc");


	Arnd
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