Re: [PATCH] ARM: dts: imx6q-icore-rqs: Add Engicam IMX6 Q7 initial support

[Lucas Stach <l.stach-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

Am Dienstag, den 24.11.2015, 17:19 +0800 schrieb Shawn Guo:
> On Mon, Nov 16, 2015 at 12:38:15PM +0100, Lucas Stach wrote:
> <snip>
> > > > > +		reg_sd3_vmmc: sd3_vmmc {
> > > > > +			compatible = "regulator-fixed";
> > > > > +			regulator-name = "P3V3_SD3_SWITCHED";
> > > > > +			regulator-min-microvolt = <3300000>;
> > > > > +			regulator-max-microvolt = <3300000>;
> > > > > +			gpio = <&gpio1 4 GPIO_ACTIVE_LOW>;
> > > > > +			regulator-boot-on;
> > > > > +			regulator-always-on;
> > > > > +		};
> > > > 
> > > > A lot of those regulators look like they don't need to be always-on.
> > > > 
> > > > Also the use of a simple-bus, while giving some structure to the DT is
> > > > considered bad style as it doesn't reflect any real hardware.
> > > > 
> > > 
> > > I will check how other boards do it
> > > 
> > Note that there are a lot of bad examples still around. What you need to
> > do is essentially just remove the additional DT level of the regulator
> > bus. The regulators are board components that belong to the same level
> > as the usb hub below, or the memory node above.
> 
> Will kernel populate platform_device for these fixed regulators if they
> are being put directly under root node?  Kernel used to only do that for
> devices under simple-bus.
> 
It does, as other behavior would clearly be a bug that should not be
worked around in the DT itself.

We are using of_platform_populate() to populate the root bus. From the
comment above this function:
"It differs in that it follows the modern convention of requiring all
device nodes to have a 'compatible' property, and it is suitable for
creating devices which are children of the root node
(of_platform_bus_probe will only create children of the root which are
selected by the @matches argument)."

Regards,
Lucas
-- 
Pengutronix e.K.             | Lucas Stach                 |
Industrial Linux Solutions   | http://www.pengutronix.de/  |

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