Hi, Scott,

I think you mean that GPIO node needs two compatibles, one for general GPIO IP block ("fsl,qoriq-gpio")
and another for chip-specific ("fsl,ls1043a-gpio").
The driver can just include general GPIO IP block compatible, and if there is a errata for ls1043 GPIO, the
chip-specific compatible can be used to fix the errata, right?

If it's right, do you think the "fsl,ls1043a-gpio" and "fsl,qoriq-gpio" are ok for our Layerscape platforms?
So maybe I need to create more patches for ls1021, ls2085 platform supported in opensource.

Best Regards,
Liu Gang

-----Original Message-----
From: Scott Wood 
Sent: Saturday, March 19, 2016 2:49 AM
To: Gang Liu <redacted>; linus.walleij at linaro.org; linux-gpio at vger.kernel.org; linux-arm-kernel at lists.infradead.org; khilman at linaro.org
Cc: robh+dt at kernel.org; Leo Li <redacted>; Mingkai Hu <mingkai.hu@nxp.com>
Subject: Re: [PATCH] gpio/ls1043a: Correct ls1043a gpio nodes compatible in dts file

Hi, Scott,
Currently all QorIQ platform's GPIO IP blocks are same, they are all 
no version register, and have same registers, offset address and other 
features, so the code can cover all of them.

So?  We have no idea what the hardware people will do in the future.

There is just one exceptional ls2080, it has the little-endian GPIO 
registers, and we added a "little-endian" property in the GPIO nodes.

Add in addition, we have deeply discussed about the GPIO compatible 
name before, you suggested using "fsl,qoriq-gpio" for all the QorIQ 
platforms. Please find some excerpt from former mail context.

It's in established use so I won't suggest that we get rid of it.  But ideally the chip-specific compatible should be in the device tree (not the driver until/unless necessary) as well, so it seemed odd to get rid of it.

If we were starting from scratch, then instead of "fsl,qoriq-gpio" it should have been a chip-based compatible for some arbitrary chip that contains this exact logic (in addition to the chip-specific compatible for the actual chip).  Neither case requires adding every chip name to the driver.

-Scott