Re: [PATCH 00/16] mtd: spi-nor: aspeed: AST2600 support and extensions

From: Boris Brezillon <boris.brezillon@collabora.com>
To: "Cédric Le Goater" <clg@kaod.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	linux-aspeed@lists.ozlabs.org,
	Tudor Ambarus <tudor.ambarus@microchip.com>,
	Andrew Jeffery <andrew@aj.id.au>,
	Richard Weinberger <richard@nod.at>,
	Marek Vasut <marek.vasut@gmail.com>,
	linux-mtd@lists.infradead.org, Joel Stanley <joel@jms.id.au>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Brian Norris <computersforpeace@gmail.com>,
	David Woodhouse <dwmw2@infradead.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 00/16] mtd: spi-nor: aspeed: AST2600 support and extensions
Date: Wed, 9 Oct 2019 22:55:55 +0200	[thread overview]
Message-ID: <20191009225555.67622339@dhcp-172-31-174-146.wireless.concordia.ca> (raw)
In-Reply-To: <20191004115919.20788-1-clg@kaod.org>

Hi Cedric,

On Fri,  4 Oct 2019 13:59:03 +0200
Cédric Le Goater <clg@kaod.org> wrote:

> Hello,
> 
> This series first extends the support for the Aspeed AST2500 and
> AST2400 SMC driver. It adds Dual Data support and read training giving
> the best read settings for a given chip. Support for the new AST2600
> SoC is added at the end.
> 
> I understand that a new spi_mem framework exists and I do have an
> experimental driver using it. But unfortunately, it is difficult to
> integrate the read training. The Aspeed constraints are not compatible
> and i haven't had the time to extend the current framework.

Hm, I don't think that's a good reason to push new features to the
existing driver, especially since I asked others to migrate their
drivers to spi-mem in the past. I do understand your concerns, and I'll
let the SPI NOR/MTD maintainers make the final call, but I think it'd
be better for the SPI MEM ecosystem to think about this link-training
API (Vignesh needs it for the Cadence driver IIRC) rather than pushing
this kind of feature to spi-nor controller drivers.

> 
> This patchset has been in use for some time in the OpenBMC kernel on
> these systems :
> 
>  * OpenPOWER Palmetto (AST2400)
>  * Evaluation board (AST2500) 
>  * OpenPOWER Witherspoon (AST2500)
>  * OpenPOWER Romulus (AST2500)
>  * OpenPOWER Zaius (AST2500)
>    and many others
>  
> and it is now in use on these boards with the new SoC :
> 
>  * Evaluation board (AST2600) 
>  * Tacoma board (AST2600) 
> 
> Thanks,
> 
> C.
> 
> Alexander Soldatov (1):
>   mtd: spi-nor: fix options for mx66l51235f
> 
> Cédric Le Goater (15):
>   mtd: spi-nor: aspeed: Use command mode for reads
>   mtd: spi-nor: aspeed: Add support for SPI dual IO read mode
>   mtd: spi-nor: aspeed: Link controller with the ahb clock
>   mtd: spi-nor: aspeed: Add read training
>   mtd: spi-nor: aspeed: Limit the maximum SPI frequency
>   mtd: spi-nor: aspeed: Add support for the 4B opcodes
>   mtd: spi-nor: Add support for w25q512jv
>   mtd: spi-nor: aspeed: Introduce a field for the AHB physical address
>   mtd: spi-nor: aspeed: Introduce segment operations
>   dt-bindings: mtd: aspeed-smc: Add new comptatible for AST2600
>   mtd: spi-nor: aspeed: Add initial support for the AST2600
>   mtd: spi-nor: aspeed: Check for disabled segments on the AST2600
>   mtd: spi-nor: aspeed: Introduce training operations per platform
>   mtd: spi-nor: aspeed: Introduce a HCLK mask for training
>   mtd: spi-nor: aspeed: Add read training support for the AST2600
> 
>  drivers/mtd/spi-nor/aspeed-smc.c              | 593 ++++++++++++++++--
>  drivers/mtd/spi-nor/spi-nor.c                 |   5 +-
>  .../devicetree/bindings/mtd/aspeed-smc.txt    |   2 +
>  3 files changed, 551 insertions(+), 49 deletions(-)
> 

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