* Tomi Valkeinen [off-list ref] [140519 02:22]:

On 16/05/14 21:01, Tony Lindgren wrote:

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IMHO appending -omap-dss to a random device is an even bigger hack,
since its adding lots of bloat to the API. Let's assume there is
another OS using DT for ARM, but has no proper API for SPI
controllers and it introduces your hack to SPI devices. That would
mean each SPI device has -omap-spi appended (or -exynos-spi,
-foo-spi, ...). At least I would blame them for creating a huge
unmaintainable mess.

I think you're misunderstanding. I do not want the naming to
be Linux specific. The naming should naturally be as hardware
specific as possible. In this case something like:

compatible = "sharp,ls037v7dw01-dss", "sharp,ls037v7dw01";

Or we should probably use:

compatible = "sharp,ls037v7dw01-dpi", "sharp,ls037v7dw01";

As dpi here reflects the hardware it's connected to. The dss
is probably a Linux name.

Well, "dss" or "omapdss" is as much a hardware term as "dpi". And "dpi"
wouldn't really be a good extension, as what we want is an omapdss
driver specific compatible string. So I think "-omapdss" is the best
extension if that method is used.

But I don't think that's really the point. The point is that the panel's
compatible string should be "sharp,ls037v7dw01", nothing else.

All the variations of "sharp,ls037v7dw01-dss" are not correct, and are
only made for Linux SW reasons. So I would say they are Linux specific
SW names, even if the words themselves are also HW terms.

If you really want to use only "sharp,ls037v7dw01" as the compatible
string, then you can still do that and bail out from the undesired
drivers by using of_machine_is_compatible check.

In many cases however we do have multiple compatible strings that
describe how the device is wired. See drivers/tty/serial/of_serial.c
for example. It has "ns16550" but then it also has additional
"nvidia,tegra20-uart", "nxp,lpc3220-uart" and "ibm,qpace-nwp-serial".
 

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Not use what you're after with the SPI example though, but sounds
like that's something different.

I think Sebastien's example is just like the issue here.

Hmm is there some existing example in the kernel like that?

Regards,

Tony