From: Sergei Shtylyov <email@example.com>
To: Chris Brandt <Chris.Brandt@renesas.com>,
Rob Herring <firstname.lastname@example.org>,
Cc: Mark Rutland <email@example.com>,
Philipp Zabel <firstname.lastname@example.org>,
Mason Yang <email@example.com>,
Subject: Re: [PATCH RFC 0/2] Add Renesas RPC-IF support
Date: Wed, 11 Dec 2019 19:08:51 +0300 [thread overview]
Message-ID: <firstname.lastname@example.org> (raw)
On 12/11/2019 05:33 PM, Chris Brandt wrote:
>> Here's a set of 2 patches against Linus' repo. Renesas Reduced Pin Count
>> Interface (RPC-IF) allows a SPI flash or HyperFlash connected to the SoC to
>> be accessed via the external address space read mode or the manual mode.
> Looking at this driver, all it is are APIs. Meaning another driver is
> needed to sit in between the MTD layer and this HW driver layer.
Between the hardware and SPI, and between the hardware and HyperFlash
infrastructure. There's a lot of the common hardware code common between
these 2 driver areas.
> In the driver that I did, if the "RPC" HW is going to be used to control
> a SPI Flash device, it registered a spi controller and then the MTD
> layer could access the device just like any other SPI controller driver. No
> additional drivers are needed.
We're already been thru that with Mason's patch -- I don't want the code
duplicated between 2 drivers.
> Looking at the hyperbus driver that is in drivers/mtd/hyperbus/, it
> seems that if the "RPC" HW is going to be used to control HyperFlash, then
Sure. But the code controlling RPC hardware is largely the same b/w 2 cases.
> all you would need to do is register a hyperbus controller using
> hyperbus_register_device(). Then the MTD layer could read/write the flash using
> normal MTD CFI interface.
That's what I do (the current realization makes too many assumptions about
the HF hardware (both direct read and write).
> Why do you think you need another layer in between the HW driver and the
> MTD layer?
Because we don't want any duplicated code. Also, think about DT -- it
describes the hardware, not the driver configuration.
> Is your goal to make a multi-layered system where the HW jumps back and forth
> in between operating modes at runtime? I'm not sure of the use case for all of
My goal is to prevent the code duplication (and keep DT sane too).
next prev parent reply other threads:[~2019-12-11 16:08 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-10 19:34 [PATCH RFC 0/2] Add Renesas RPC-IF support Sergei Shtylyov
2019-12-10 19:37 ` [PATCH RFC 1/2] dt-bindings: memory: document Renesas RPC-IF bindings Sergei Shtylyov
2019-12-19 20:38 ` Rob Herring
2019-12-10 19:39 ` [PATCH RFC 2/2] memory: add Renesas RPC-IF driver Sergei Shtylyov
2019-12-11 9:58 ` Philipp Zabel
2020-02-10 10:21 ` Behme Dirk (CM/ESO2)
[not found] ` <5760bcdb-e44b-6f18-7262-9526684e5780-V5te9oGctAVWk0Htik3Jemail@example.com>
2020-02-22 20:42 ` Sergei Shtylyov
[not found] ` <5603f393-554d-e2a8-c2d8-6bafc20f4169-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org>
2020-02-24 5:46 ` Behme Dirk (CM/ESO2)
[not found] ` <cba1e2ec-4896-23ef-ef7b-0f80d4310127-V5te9oGctAVWk0Htik3Jfirstname.lastname@example.org>
2020-02-24 17:28 ` Chris Brandt
2020-02-24 18:59 ` Sergei Shtylyov
2020-02-25 9:33 ` Behme Dirk (CM/ESO2)
[not found] ` <3a182ac7-8d41-cdc7-2b87-7c503f68a426-V5te9oGctAVWk0Htik3Jemail@example.com>
2020-02-25 20:41 ` Sergei Shtylyov
[not found] ` <f21a9444-9541-6558-f5f5-ca0b733768ff-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org>
2020-02-26 9:54 ` Behme Dirk (CM/ESO2)
2020-02-27 20:32 ` Sergei Shtylyov
2019-12-11 14:33 ` [PATCH RFC 0/2] Add Renesas RPC-IF support Chris Brandt
2019-12-11 16:08 ` Sergei Shtylyov [this message]
2019-12-11 16:20 ` Sergei Shtylyov
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