Re: [PATCH V8 1/2] mtd: spi-nor: Bindings for Cadence Quad SPI Flash Controller driver.

On Thursday, February 04, 2016 at 08:38:47 AM, Vignesh R wrote:

On 02/02/2016 02:43 AM, Marek Vasut wrote:

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On Monday, February 01, 2016 at 10:03:35 PM, Brian Norris wrote:

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On Wed, Jan 13, 2016 at 03:39:17AM +0100, Marek Vasut wrote:

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On Wednesday, January 13, 2016 at 03:26:08 AM, Rob Herring wrote:

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On Mon, Jan 11, 2016 at 05:34:45AM +0100, Marek Vasut wrote:

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All these SoCs should be capable of tweaking the block to fit their
needs by just the DT properties. I believe they differ only in the
FIFO depth and sometimes someone is greedy and uses 4:16 CS
multiplexer, which is an external passive component, but that's all.

Would we need soc-specific compatible strings if this is the case?

It's nice when most things can be supported with a small set of DT
properties, as you've done. But IUIC, I think it's usually good practice
to define and use SoC-specific (or maybe SoC family) compatible strings
in the docs and DTS files, in addition to the generic one, in case there
are future quirks that need to be handled. Note that you don't actually
have to use these in the driver yet, but it's good to have a definition.

So you can, today, have:
	foo@xxxx {
	
		compatible = "ti,baz-12345", "cdns,qspi-nor";
		...
	
	};

And we have the option to pick up "ti,baz-12345" in the Linux driver *if
needed.*

The support for TI SoC that has this IP is not in upstream yet. I will
add TI-specific compatible later. It will be:

	foo@xxxx {
		compatible = "ti,k2g-qspi", "cdns,qspi-nor";
 		...
 	};

Do you expect any specifics which cannot be handled by the current bindings btw?
In my socfpga case, the compatible strings will be probably:

"altr,socfpga-gen5-qspi"

Dinh, Graham, do you agree with this or should we use something else ?

Thanks!

Best regards,
Marek Vasut
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