[PATCH 2/2] ARM: dts: imx6q: add Novena board

Marek Vasut
2015-11-18T11:32:42Z

On Wednesday, November 18, 2015 at 12:25:58 PM, Lucas Stach wrote:
> Am Mittwoch, den 18.11.2015, 11:35 +0100 schrieb Marek Vasut:
> > On Wednesday, November 18, 2015 at 11:10:12 AM, Lucas Stach wrote:
> > > Hi Marek,
> >
> > Hi!
> >
> > > some comments below.
> >
> > Thanks!
> >
> > [...]
> >
> > > > + regulators {
> > > > + compatible = "simple-bus";
> > > > + #address-cells = <1>;
> > > > + #size-cells = <0>;
> > > > +
> > >
> > > Remove this simple bus. It's not there in hardware, regulators are
> > > board level components just like the nodes below.
> >
> > This is surprising to me, since all the boards I checked use this
> > /regulators simple bus to contain all the regulators. Is this going to
> > change now ?
>
> Yes, there are a lot of bad examples out there, mainly because people
> wanted to logically group the regulators together.

Yeah, that's what I wanted to do as well :)

> But as it isn't
> representing any real hardware we should really try to move away from
> this practice.

Oh, thanks for this input.

> > [...]
> >
> > > > +&ecspi3 {
> > > > + pinctrl-names = "default";
> > > > + pinctrl-0 = <&pinctrl_ecspi3_novena>;
> > > > + fsl,spi-num-chipselects = <3>;
> > > > + status = "okay";
> > > > +
> > > > + spidev at 0 {
> > > > + compatible = "spidev";
> > >
> > > This will explode on a new kernel. Specifying spidev without using a
> > > more specific compatible will trigger a WARN_ON(), as it's considered
> > > bad style.
> >
> > Oh, looks like imx_v6_v7_defconfig didn't have SPIDEV active, which is
> > why I didn't catch it during my last test, dang.
> >
> > This SPI interface is routed into the FPGA, so what do you suggest I put
> > in the compatible string? There is no other sensible driver for the
> > peripheral, since the peripheral can be anything.
>
> I'm not really the right person to ask for that, but I would guess that
> inventing a "novena,fpga-spi" compatible or something like that and
> adding it to the spidev driver would be the right thing to do.

So what's the rationale behind generic "spidev" being bad ? In my mind, it
is much better to use generic driver and generic compatible prop "spidev"
than to generate many one-off compatible props and have a driver with a list
of all of those.

Best regards,
Marek Vasut