[PATCH] gpio: Add designware gpio controller support

[Sascha Hauer]

On Mon, Sep 09, 2013 at 06:28:48PM +0200, Sebastian Hesselbarth wrote:
> I have seen this driver and think it can be improved by exploiting
> its config1/2 registers where synthesis settings are stored. Please
> also look at [1] pp.1229; you can read out number of ports, port
> width, interrupt, and debounce features.

Ok, the port width feature is easy enough to implement. Will add it in
the next version.

I also added a check for multiple ports, but just ignore the additional
ports for now since I don't know the register offsets and also have no
hardware to actually test it (The SoCFPGA only has one port)

> 
> Unfortunately, I am not ready to run barebox on Armada 1500 and I
> don't have a socfpga to test. So if you are not eager to modify it now,
> I can add config reg based read-out later.
> 
> [1] http://www.altera.com/literature/hb/arria-v/hps.pdf
> 
> [...]
> >+static __maybe_unused struct of_device_id dwgpio_match[] = {
> >+	{
> >+		.compatible = "snps,dw-gpio",
> >+	}, {
> 
> Please add "snps,dw-apb-gpio", that's what the linux driver
> will look for if make to pick it up for Armada 1500.

I'll better just change it to "snps,dw-apb-gpio". There already is a
dtsi file in the kernel which uses this binding (although it looks like
it hasn't been approved by anyone)

Sascha

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