Re: [PATCH v5 2/3] Documentation: gpio: Update description for X-Gene standby GPIO controller DTS binding

[Rob Herring <robh@kernel.org>]

On Tue, Feb 02, 2016 at 08:46:25AM +0700, Quan Nguyen wrote:
> On Mon, Feb 1, 2016 at 10:35 PM, Rob Herring <robh@kernel.org> wrote:
> > On Fri, Jan 29, 2016 at 11:28:54AM +0700, Quan Nguyen wrote:
> >> Update description for X-Gene standby GPIO controller DTS binding to
> >> support GPIO line configuration as input, output or external IRQ pin.
> >>
> >> Signed-off-by: Y Vo <yvo@apm.com>
> >> Signed-off-by: Quan Nguyen <qnguyen@apm.com>
> >> ---
> >>  .../devicetree/bindings/gpio/gpio-xgene-sb.txt     | 47 ++++++++++++++++++----
> >>  1 file changed, 40 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/gpio/gpio-xgene-sb.txt b/Documentation/devicetree/bindings/gpio/gpio-xgene-sb.txt
> >> index dae1300..7b8b4cb 100644
> >> --- a/Documentation/devicetree/bindings/gpio/gpio-xgene-sb.txt
> >> +++ b/Documentation/devicetree/bindings/gpio/gpio-xgene-sb.txt
> >> @@ -1,10 +1,20 @@
> >>  APM X-Gene Standby GPIO controller bindings
> >>
> >> -This is a gpio controller in the standby domain.
> >> -
> >> -There are 20 GPIO pins from 0..21. There is no GPIO_DS14 or GPIO_DS15,
> >> -only GPIO_DS8..GPIO_DS13 support interrupts. The IRQ mapping
> >> -is currently 1-to-1 on interrupts 0x28 thru 0x2d.
> >> +This is a gpio controller in the standby domain. It also supports interrupt in
> >> +some particular pins which are sourced to its parent interrupt controller
> >> +as diagram below:
> >> +                           +-----------------+
> >> +                           | X-Gene standby  |
> >> +                           | GPIO controller +--------- GPIO_0
> >> ++------------+             |                 | ...
> >> +| Parent IRQ |             |                 +--------- GPIO_8/EXT_INT_0
> >> +| controller |  EXT_INT_0  |                 | ...
> >> +| (GICv2)    +-------------+                 +--------- GPIO_[N+8]/EXT_INT_N
> >> +|            |  ...        |                 |
> >> +|            |  EXT_INT_N  |                 +--------- GPIO_[N+9]
> >> +|            +-------------+                 | ...
> >> +|            |             |                 +--------- GPIO_MAX
> >> ++------------+             +-----------------+
> >>
> >>  Required properties:
> >>  - compatible: "apm,xgene-gpio-sb" for the X-Gene Standby GPIO controller
> >> @@ -15,10 +25,18 @@ Required properties:
> >>               0 = active high
> >>               1 = active low
> >>  - gpio-controller: Marks the device node as a GPIO controller.
> >> -- interrupts: Shall contain exactly 6 interrupts.
> >> +- interrupts: The EXT_INT_0 parent interrupt resource must be listed first.
> >> +- interrupt-parent: Phandle of the parent interrupt controller.
> >> +- interrupt-cells: Should be two.
> >> +       - first cell is 0-N coresponding for EXT_INT_0 to EXT_INT_N.
> >> +       - second cell is used to specify flags.
> >> +- interrupt-controller: Marks the device node as an interrupt controller.
> >> +- apm,nr-gpios: Optional, specify number of gpios pin.
> >> +- apm,nr-irqs: Optional, specify number of interrupt pins.
> >
> > When is this not 6?
> >
> Hi Rob,  by default, this should be 6, but I think this property can
> help in cases:
> + Used only 5(or less) first pin as interrupt.
> + For similar device which has different interrupt pins (8 for example).
> My idea is to make it a bit more generic by using this optional property.

What is similar device? Another SoC? board? Is 6 fixed in the SoC? I 
think you need more specific compatible string with the SoC name in it 
to determine these setting rather than trying to do something generic.

Rob