Re: [PATCH v2 02/32] devicetree: bindings: scsi: HiSi SAS

[zhangfei]

On 10/27/2015 10:39 PM, Mark Rutland wrote:
> On Tue, Oct 27, 2015 at 01:09:15PM +0000, John Garry wrote:
> > On 26/10/2015 14:45, Mark Rutland wrote:
> > > On Mon, Oct 26, 2015 at 10:14:33PM +0800, John Garry wrote:
> > > > Add devicetree bindings for HiSilicon SAS driver.
> > > >
> > > > Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> > > > ---
> > > >   .../devicetree/bindings/scsi/hisilicon-sas.txt     | 70 ++++++++++++++++++++++
> > > >   1 file changed, 70 insertions(+)
> > > >   create mode 100644 Documentation/devicetree/bindings/scsi/hisilicon-sas.txt
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/scsi/hisilicon-sas.txt b/Documentation/devicetree/bindings/scsi/hisilicon-sas.txt
> > > > new file mode 100644
> > > > index 0000000..d1e7b2a
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/scsi/hisilicon-sas.txt
> > > > @@ -0,0 +1,70 @@
> > > > +* HiSilicon SAS controller
> > > > +
> > > > +The HiSilicon SAS controller supports SAS/SATA.
> > > > +
> > > > +Main node required properties:
> > > > +  - compatible : value should be as follows:
> > > > +	(a) "hisilicon,sas-controller-v1" for v1 of HiSilicon SAS controller IP
> > > > +  - reg : Address and length of the SAS register
> > > > +  - hisilicon,sas-syscon: phandle of syscon used for sas control
> > > > +  - ctrl-reg : offset to the following SAS control registers (in order):
> > > > +		- reset assert
> > > > +		- clock disable
> > > > +		- reset status
> > > > +		- reset de-assert
> > > > +		- clock enable
> > >
> > > This needs a better name, and it should probably be split up into
> > > several properties.
> > >
> > > However, it sounds like the syscon is actually a clock+reset
> > > controller, and should be modelled as such. It's not actually a part of
> > > the SAS controller as such.
> >
> > The syscon block is a general subsystem control block, and it is not
> > specifically only for controlling reset and enabling clocks (other
> > functions include serdes control, for example). It is also shared
> > with other peripherals.
> >
> > So we can remove the ctrl-reg property (since it is not part of the
> > SAS controller), and add the relevant syscon register offsets to the
> > "hisilicon,sas-syscon" property, like this:
> > hisilicon,sas-syscon = <&sas_ctrl0 0xa60 0x33c 0x5a30 0xa64 0x338>;
> >
> > Ok?
>
> It would be better to have each offset in a separate property.
These register are not used for different purpose.
Instead, they are all used for one purpose, reset the sas controller;
Though a bit complicated, the silicon has special requirement here.

So still prefer using the original method,
ctrl-reg = <0xa60 0x33c 0x5a30 0xa64 0x338>;
Since we can simply use of_property_read_u32_array.

Thanks

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