From: Frank Rowand <frowand.list@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: robh+dt@kernel.org, david@gibson.dropbear.id.au,
pantelis.antoniou@konsulko.com, stephen.boyd@linaro.org,
grant.likely@secretlab.ca, mark.rutland@arm.com,
mporter@konsulko.com, koen@dominion.thruhere.net,
linux@roeck-us.net, marex@denx.de, wsa@the-dreams.de,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-i2c@vger.kernel.org, panto@antoniou-consulting.com
Subject: Re: [RFC PATCH 0/1] Portable Device Tree Connector -- conceptual
Date: Mon, 4 Jul 2016 11:15:44 -0700 [thread overview]
Message-ID: <577AA7D0.7050402@gmail.com> (raw)
In-Reply-To: <20160704152226.GJ6247@sirena.org.uk>
On 07/04/16 08:22, Mark Brown wrote:
> On Sat, Jul 02, 2016 at 04:55:49PM -0700, frowand.list@gmail.com wrote:
>
>> This is an extremely simple example to illustrate the concepts. It is not
>> meant to represent the complexity of a real board.
>>
>> To start with, assume that the device that will eventually be on a daughter
>> board is first soldered onto the mother board. The mother board contains
>> two devices connected via bus spi_1. One device is described in the .dts
>> file, the other is described in an included .dtsi file.
>> Then the device tree files will look like:
>
> Can I suggest not using SPI as an example here? It's particularly
> messy since addresses are essentially just a random signal that can be
> totally separate to the controller hardware which might be adding more
> complexity early on in building up your model than is really desirable.
> It will need to be dealt with but perhaps not right now. I2C might be
> easier.
>
> The initial issue with SPI is that you really need to do something like
> bring out individual slots on the bus rather than the bus as a whole
> since you're going to need a remapping layer to map chip selects on the
> module to chip selects on the host board.
>
Yes, thank you for pointing that out.
For the purposes of the mental model, when thinking about what I wrote,
just change SPI to I2C everywhere.
-Frank
next prev parent reply other threads:[~2016-07-04 18:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-02 23:55 [RFC PATCH 0/1] Portable Device Tree Connector -- conceptual frowand.list
2016-07-02 23:55 ` [RFC PATCH 1/1] device tree connectors, using plugs and sockets frowand.list
2016-07-03 6:06 ` [RFC PATCH 0/1] Portable Device Tree Connector -- conceptual Frank Rowand
2016-07-04 15:22 ` Mark Brown
2016-07-04 18:15 ` Frank Rowand [this message]
2016-07-05 18:01 ` Pantelis Antoniou
2016-07-06 17:40 ` Frank Rowand
2016-07-07 7:15 ` David Gibson
2016-07-08 7:26 ` Pantelis Antoniou
2016-07-08 7:43 ` David Gibson
2016-07-08 19:20 ` Frank Rowand
2016-07-08 19:25 ` Frank Rowand
2016-07-08 19:22 ` Frank Rowand
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