Re: [PATCH v7 1/2] spi: Add Renesas R-Car Gen3 RPC-IF SPI controller driver

From: Boris Brezillon <bbrezillon@kernel.org>
To: Marek Vasut <marek.vasut@gmail.com>
Cc: masonccyang@mxic.com.tw, broonie@kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Simon Horman <horms@verge.net.au>,
	juliensu@mxic.com.tw, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org, linux-spi@vger.kernel.org,
	sergei.shtylyov@cogentembedded.com, zhengxunli@mxic.com.tw
Subject: Re: [PATCH v7 1/2] spi: Add Renesas R-Car Gen3 RPC-IF SPI controller driver
Date: Wed, 30 Jan 2019 10:26:46 +0100	[thread overview]
Message-ID: <20190130102646.23c798fc@bbrezillon> (raw)
In-Reply-To: <e4351834-5c7d-b751-b3c7-97dce5207783@gmail.com>

On Wed, 30 Jan 2019 08:15:25 +0100
Marek Vasut <marek.vasut@gmail.com> wrote:

> >> > So far as I know that HF is provided by Cypress only and
> >> > any mass production product use the component which is provided by only
> >> > one provider
> >> > will be a big risk.
> >> >
> >> > Compare to HF, there are more provider of SPI/Octa could support the
> >> > mass production product
> >> > as their second provider.
> >> >
> >> > In addition, from the technical points of view, mx25uw51245g is more
> >> > powerful than HF and
> >> > good for complicate user application, i.e., OTA and so on.  
> >>
> >> Did you consider protocol overhead too ? I don't think you can compare
> >> them just by raw numbers of pins and bus frequency.
> >>
> >> Note that over-the-air update (if that's what you mean by OTA) is
> >> completely separate from the underlying storage device.  
> > 
> > It's key feature of mx25uw51245g supports Read-while-Write capability
> > that allows read access from one memory bank while writing to another
> > memory bank.  
> 
> Note that this sales pitch is rather off-topic.
> 

Fully agree with Marek on that point. The discussion is about
supporting both HF and SPI-MEM modes (or, at least have a plan to
support HF at some point) not figuring out which option is better.