Re: [RFC v3 06/14] MIPS: dts: qca: ar9132: use short references for uart and spi nodes

[Antony Pavlov <antonynpavlov@gmail.com>]

On Mon, 25 Jan 2016 23:31:48 +0100
Alban <albeu@free.fr> wrote:

> On Sat, 23 Jan 2016 23:17:23 +0300
> Antony Pavlov <antonynpavlov@gmail.com> wrote:
> 
> I personally prefer the version without aliases :) Is there any
> guidelines on this?

Here are some Sascha Hauer's arguments for using aliases in the dts files:

 - Using aliases reduces the number of indentations in dts files;

 - dts files become independent of the layout of the dtsi files (it
   becomes possible to introduce another bus {} hierarchy between a
   toplevel bus and the devices when you have to);

 - less chances for typos. if &i2c2 does not exist you get an error. If
   instead you duplicate the whole path in the dts file a typo in the
   path will just create another node.

And here is a Marek Vasut's additional argument:

 - Aliases allow you to introduce some sort of ordering. For example if you have
   gmac0 and gmac1 and you want to have them ordered correctly, you use aliases.
   (in case we're talking about the /aliases node).


> > Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
> > Cc: Alban Bedel <albeu@free.fr>
> > Cc: linux-mips@linux-mips.org
> > Cc: devicetree@vger.kernel.org
> > ---
> >  arch/mips/boot/dts/qca/ar9132.dtsi               |  4 +-
> >  arch/mips/boot/dts/qca/ar9132_tl_wr1043nd_v1.dts | 70 +++++++++++-------------
> >  2 files changed, 35 insertions(+), 39 deletions(-)
> > 
> > diff --git a/arch/mips/boot/dts/qca/ar9132.dtsi b/arch/mips/boot/dts/qca/ar9132.dtsi
> > index cd1602f..a14f6f2 100644
> > --- a/arch/mips/boot/dts/qca/ar9132.dtsi
> > +++ b/arch/mips/boot/dts/qca/ar9132.dtsi
> > @@ -61,7 +61,7 @@
> >  				#qca,ddr-wb-channel-cells = <1>;
> >  			};
> >  
> > -			uart@18020000 {
> > +			uart: uart@18020000 {
> >  				compatible = "ns8250";
> >  				reg = <0x18020000 0x20>;
> >  				interrupts = <3>;
> > @@ -134,7 +134,7 @@
> >  			};
> >  		};
> >  
> > -		spi@1f000000 {
> > +		spi: spi@1f000000 {
> >  			compatible = "qca,ar9132-spi", "qca,ar7100-spi";
> >  			reg = <0x1f000000 0x10>;
> >  
> > diff --git a/arch/mips/boot/dts/qca/ar9132_tl_wr1043nd_v1.dts b/arch/mips/boot/dts/qca/ar9132_tl_wr1043nd_v1.dts
> > index 9618105..f22c22c 100644
> > --- a/arch/mips/boot/dts/qca/ar9132_tl_wr1043nd_v1.dts
> > +++ b/arch/mips/boot/dts/qca/ar9132_tl_wr1043nd_v1.dts
> > @@ -14,43 +14,6 @@
> >  		reg = <0x0 0x2000000>;
> >  	};
> >  
> > -	ahb {
> > -		apb {
> > -			uart@18020000 {
> > -				status = "okay";
> > -			};
> > -		};
> > -
> > -		spi@1f000000 {
> > -			status = "okay";
> > -			num-cs = <1>;
> > -
> > -			flash@0 {
> > -				#address-cells = <1>;
> > -				#size-cells = <1>;
> > -				compatible = "s25sl064a";
> > -				reg = <0>;
> > -				spi-max-frequency = <25000000>;
> > -
> > -				partition@0 {
> > -					label = "u-boot";
> > -					reg = <0x000000 0x020000>;
> > -				};
> > -
> > -				partition@1 {
> > -					label = "firmware";
> > -					reg = <0x020000 0x7D0000>;
> > -				};
> > -
> > -				partition@2 {
> > -					label = "art";
> > -					reg = <0x7F0000 0x010000>;
> > -					read-only;
> > -				};
> > -			};
> > -		};
> > -	};
> > -
> >  	gpio-keys {
> >  		compatible = "gpio-keys-polled";
> >  		#address-cells = <1>;
> > @@ -100,3 +63,36 @@
> >  &extosc {
> >  	clock-frequency = <40000000>;
> >  };
> > +
> > +&uart {
> > +	status = "okay";
> > +};
> > +
> > +&spi {
> > +	status = "okay";
> > +	num-cs = <1>;
> > +
> > +	flash@0 {
> > +		#address-cells = <1>;
> > +		#size-cells = <1>;
> > +		compatible = "s25sl064a";
> > +		reg = <0>;
> > +		spi-max-frequency = <25000000>;
> > +
> > +		partition@0 {
> > +			label = "u-boot";
> > +			reg = <0x000000 0x020000>;
> > +		};
> > +
> > +		partition@1 {
> > +			label = "firmware";
> > +			reg = <0x020000 0x7D0000>;
> > +		};
> > +
> > +		partition@2 {
> > +			label = "art";
> > +			reg = <0x7F0000 0x010000>;
> > +			read-only;
> > +		};
> > +	};
> > +};
> 


-- 
-- 
Best regards,
  Antony Pavlov