[<prev] [next>] [day] [month] [year] [list]
Message-ID: <2d762c16-d714-9171-9450-b6adf1a6509c@gmail.com>
Date: Mon, 28 Jan 2019 12:03:00 +0100
From: Marek Vasut <marek.vasut@...il.com>
To: masonccyang@...c.com.tw
Cc: bbrezillon@...nel.org, broonie@...nel.org,
Geert Uytterhoeven <geert+renesas@...der.be>,
Simon Horman <horms@...ge.net.au>, juliensu@...c.com.tw,
linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
linux-spi@...r.kernel.org, sergei.shtylyov@...entembedded.com,
zhengxunli@...c.com.tw
Subject: Re: [PATCH v7 1/2] spi: Add Renesas R-Car Gen3 RPC-IF SPI controller
driver
On 1/28/19 2:38 AM, masonccyang@...c.com.tw wrote:
> Hi Marek,
Hi,
>> "Marek Vasut" <marek.vasut@...il.com>
>> >> >> > +module_platform_driver(rpc_spi_driver);
>> >> >>
>> >> >> RPC is not a SPI controller, it's a SPI and HF controller.
>> >> >>
>> >> >> Also, how difficult will it be to add the HF support ?
>> >> >
>> >> > One of my customers needs RPC SPI driver for our company's
>> >> > Octal-Flash,MX25UW51245G.
>> >> > We don't have HF product and hope you could understanding.
>> >>
>> >> I am worried that when we need to add RPC HF support (which is what all
>> >> boards but the D3 Draak use), we will have to rewrite the entire driver
>> >> and/or convert it to MFD and that would be a tremendous
> undertaking. I'd
>> >> prefer to have the driver ready for the HF addition before it's
> accepted
>> >> upstream.
>> >>
>> >
>> > I think maybe your concerned would be happened only if HF driver
> goes with
>> > spi-mem layer.
>> >
>> > A comment for HF from Daniel Fishman. FYR.
>> >
>> > https://www.quora.com/What-is-a-hyper-flash-memory-and-how-is-it-
>> different-from-normal-flash-memory
>>
>> I have a decent idea what HF and SPI NOR are, since I wrote the RPC
>> driver for both HF and SPI mode for U-Boot (as I mentioned earlier).
>>
>> The HF in Linux would use the CFI NOR part of MTD framework. My concern
>> is that when we need to add HF support into this driver, this driver
>> will have to be basically rewritten, since the architecture won't allow
>> for that. I'd like to avoid that, since the majority of Gen3 boards,
>> expect for the D3 Draak, use RPC in HF mode.
>
> FYI~
>
> MX25UW51245g(64MByte Octa) S26KL512S(64MByte HF)
> 8 IO 8 IO
> 200MHz DDR@...v 166MHz DDR@...v
>
> support Read-while-write Not support
> good for OTA,etc
> powerful application
What does that mean ?
--
Best regards,
Marek Vasut
Powered by blists - more mailing lists