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From: Chris Brandt <Chris.Brandt@renesas.com>
To: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	linux-spi <linux-spi@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	Mason Yang <masonccyang@mxic.com.tw>
Subject: RE: [PATCH v2 2/6] dt-bindings: spi: Document Renesas SPIBSC bindings
Date: Tue, 10 Dec 2019 20:23:06 +0000	[thread overview]
Message-ID: <TY1PR01MB15628EA9B46BD12B9D2AAD6F8A5B0@TY1PR01MB1562.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <0cbd8556-cf17-7d6b-5c12-e8d663a39cfa@cogentembedded.com>

On Tue, Dec 10, 2019, Sergei Shtylyov wrote:
> >> +    items:
> >> +      - description: Registers
> >> +      - description: Memory Mapped Address Space
> >
> > The second one is not needed, if you would add "ranges" for the
> > memory-mapped mode.
> 
>    I'm not sure we can do that. The flash bus is accessed via a window with
> the high bits in the DREAR reg, even in the direct read mode...

The purpose of this driver was to allow R/W access using the existing 
MTD/SPI layer.
When the HW is operating in this mode, the driver basically just needs 
to read the vale of "ranges" in the DT to know the base address, and 
that's all it uses it for.

If the HW is going to be used in 'direct read mode', then the MTD/SPI 
layer will not be used. Instead the MTD/ROM driver will be used.
Configuring the HW for this mode is out of scope at the moment and 
should be done in the boot loader (just like DDR or SDRAM is configured by 
the boot loader).
The MTD/ROM driver will also handle all the ioremapping based on the 
values in the partition values under the flash node.

Chris


  parent reply	other threads:[~2019-12-10 20:23 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-06 13:41 [PATCH v2 0/6] spi: Add Renesas SPIBSC controller Chris Brandt
2019-12-06 13:41 ` [PATCH v2 1/6] spi: Add SPIBSC driver Chris Brandt
2019-12-12 19:36   ` Sergei Shtylyov
2019-12-12 20:19     ` Chris Brandt
2019-12-13 10:01       ` Geert Uytterhoeven
2019-12-13 14:45         ` Chris Brandt
2019-12-13 14:48           ` Geert Uytterhoeven
2019-12-13 19:37           ` Sergei Shtylyov
2019-12-13 18:36       ` Sergei Shtylyov
2019-12-13 19:40         ` Sergei Shtylyov
2019-12-13 20:43           ` Chris Brandt
2019-12-16 18:47             ` Sergei Shtylyov
2019-12-06 13:41 ` [PATCH v2 2/6] dt-bindings: spi: Document Renesas SPIBSC bindings Chris Brandt
2019-12-09 14:09   ` Geert Uytterhoeven
2019-12-09 15:45     ` Chris Brandt
2019-12-09 19:34       ` Geert Uytterhoeven
2019-12-10 20:07     ` Sergei Shtylyov
2019-12-10 20:17       ` Geert Uytterhoeven
2019-12-10 20:33         ` Chris Brandt
2019-12-10 20:23       ` Chris Brandt [this message]
2019-12-06 13:41 ` [PATCH v2 3/6] clk: renesas: r7s9210: Add SPIBSC clock Chris Brandt
2019-12-06 18:40   ` Sergei Shtylyov
2019-12-06 19:49     ` Chris Brandt
2019-12-20 14:38       ` Geert Uytterhoeven
2019-12-20 14:50         ` Chris Brandt
2019-12-06 13:42 ` [PATCH v2 4/6] ARM: dts: r7s72100: Add SPIBSC devices Chris Brandt
2019-12-06 13:42 ` [PATCH v2 5/6] ARM: dts: r7s9210: Add SPIBSC device Chris Brandt
2019-12-06 13:42 ` [PATCH v2 6/6] ARM: dts: gr-peach: Enable SPIBSC Chris Brandt
2019-12-07 20:28 ` [PATCH v2 0/6] spi: Add Renesas SPIBSC controller Sergei Shtylyov
2019-12-09 15:10   ` Chris Brandt
2019-12-11 19:09     ` Sergei Shtylyov
2019-12-12 14:29       ` Chris Brandt
2019-12-12 15:28         ` Mark Brown
2019-12-12 16:53           ` Chris Brandt
2019-12-12 17:13             ` Mark Brown
2019-12-12 17:25               ` Chris Brandt
2019-12-16 15:21                 ` Mark Brown
2019-12-16 20:31         ` Sergei Shtylyov
2019-12-16 22:21           ` Chris Brandt
2019-12-17 19:30             ` Sergei Shtylyov
2019-12-17 20:26               ` Geert Uytterhoeven
2019-12-19 16:57               ` Chris Brandt
2019-12-19 19:01                 ` Sergei Shtylyov
2019-12-19 21:04                   ` Chris Brandt
2019-12-20  1:45                   ` masonccyang
2019-12-20  7:55                     ` Geert Uytterhoeven
2019-12-24 16:58                     ` Sergei Shtylyov
2019-12-27  0:58                       ` Mark Brown
2019-12-17 19:44           ` Sergei Shtylyov
2019-12-18  8:09             ` Boris Brezillon
2019-12-19 16:32               ` Chris Brandt

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