[PATCH v2 4/4] arm64: dts: imx8mm-var-som-symphony: Add Variscite Symphony board with VAR-SOM-MX8MM

[Krzysztof Kozlowski]

On Mon, Aug 24, 2020 at 06:47:19PM +0800, Shawn Guo wrote:
> On Sun, Aug 23, 2020 at 10:58:47AM +0200, Krzysztof Kozlowski wrote:
> > On Sun, Aug 23, 2020 at 10:00:51AM +0800, Shawn Guo wrote:
> > > On Mon, Aug 17, 2020 at 09:01:20AM +0200, Krzysztof Kozlowski wrote:
> > > > Add a DTS for Variscite Symphony evaluation kit with VAR-SOM-MX8MM
> > > > System on Module.
> > > > 
> > > > Signed-off-by: Krzysztof Kozlowski <krzk at kernel.org>
> > > > 
> > > > ---
> > > > 
> > > > Changes since v1:
> > > > 1. Remove duplicated "leds" node,
> > > > 2. Fix heartbeat to active low,
> > > > 3. Add nxp,ptn5150 extcon.
> > > > ---
> > > >  arch/arm64/boot/dts/freescale/Makefile        |   1 +
> > > >  .../dts/freescale/imx8mm-var-som-symphony.dts | 248 ++++++++++++++++++
> > > >  2 files changed, 249 insertions(+)
> > > >  create mode 100644 arch/arm64/boot/dts/freescale/imx8mm-var-som-symphony.dts
> > > > 
> > > > diff --git a/arch/arm64/boot/dts/freescale/Makefile b/arch/arm64/boot/dts/freescale/Makefile
> > > > index a39f0a1723e0..dcfb8750cd78 100644
> > > > --- a/arch/arm64/boot/dts/freescale/Makefile
> > > > +++ b/arch/arm64/boot/dts/freescale/Makefile
> > > > @@ -29,6 +29,7 @@ dtb-$(CONFIG_ARCH_LAYERSCAPE) += fsl-lx2160a-qds.dtb
> > > >  dtb-$(CONFIG_ARCH_LAYERSCAPE) += fsl-lx2160a-rdb.dtb
> > > >  
> > > >  dtb-$(CONFIG_ARCH_MXC) += imx8mm-evk.dtb
> > > > +dtb-$(CONFIG_ARCH_MXC) += imx8mm-var-som-symphony.dtb
> > > >  dtb-$(CONFIG_ARCH_MXC) += imx8mn-evk.dtb
> > > >  dtb-$(CONFIG_ARCH_MXC) += imx8mn-ddr4-evk.dtb
> > > >  dtb-$(CONFIG_ARCH_MXC) += imx8mp-evk.dtb
> > > > diff --git a/arch/arm64/boot/dts/freescale/imx8mm-var-som-symphony.dts b/arch/arm64/boot/dts/freescale/imx8mm-var-som-symphony.dts
> > > > new file mode 100644
> > > > index 000000000000..2d3c30ac5e04
> > > > --- /dev/null
> > > > +++ b/arch/arm64/boot/dts/freescale/imx8mm-var-som-symphony.dts
> > > > @@ -0,0 +1,248 @@
> > > > +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> > > > +/*
> > > > + * Copyright (C) 2020 Krzysztof Kozlowski <krzk at kernel.org>
> > > > + */
> > > > +
> > > > +/dts-v1/;
> > > > +
> > > > +#include "imx8mm-var-som.dtsi"
> > > > +
> > > > +/ {
> > > > +	model = "Variscite VAR-SOM-MX8MM Symphony evaluation board";
> > > > +	compatible = "variscite,var-som-mx8mm-symphony", "variscite,var-som-mx8mm", "fsl,imx8mm";
> > > > +
> > > > +	reg_usdhc2_vmmc: regulator-1 {
> > > 
> > > regulator-usdhc2-vmmc
> > 
> > You mean the node name? If so, it's not correct with device tree
> > specification:
> > "The node-name (...) should describe the general class of device.:
> > If appropriate, the name should be one of the following choices:
> > (...)
> >  - regulator"
> > 
> > Adding specific function/type/usage to the name of the node is a
> > opposite choice to "general class".
> 
> Well, the node is named in general class, i.e. regulator-xxx, and we
> would like the suffix to be a bit more specific.  We have been using
> this name schema for fixed-regulator on i.MX platforms for long time.

Name "regulator-usdhc2-vmmc" is not general, it is specific. The DT
specification gives the example of generic name and it is "regulator".

It is the same with CPU nodes having names "cpu at 0", not "cpu-a53 at 0" or
whatever other suffix. It is the same reason why I2C is "i2c at 12345678",
not "i2c_1@" or "i2c_for_abcd".

The suffix is not needed as Linux does not use it (instead uses
regulator-name which is specific). Humans on the other hand can
understand the specifics from the label and from the regulator name.
Therefore they also do not need the suffix.

I know that other i.MX DTSes follow this pattern but it is still not the
recommended one. It's a pattern which should be replaced.

Anyway, if the names of regulators stop this patch from being applied, I
will change them to expected.

Best regards,
Krzysztof