Re: [PATCH 1/2] ARM: dts: imx6q: extend support for the cm-fx6

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

Hi Igor,

Am Donnerstag, den 26.05.2016, 11:50 +0300 schrieb Igor Grinberg:
> Hi Lucas,
> 
> Thanks for reviewing the patch(es).
> 
> On 05/23/2016 12:03 PM, Lucas Stach wrote:
> > Am Montag, den 23.05.2016, 00:47 +0200 schrieb
> > christopher.spinrath-vA1bhqPz9FBZXbeN9DUtxg@public.gmane.org:
> >> From: Christopher Spinrath <christopher.spinrath-vA1bhqPz9FBZXbeN9DUtxg@public.gmane.org>
> 
> [...]
> 
> >> +&ecspi1 {
> >> +	fsl,spi-num-chipselects = <2>;
> >> +	cs-gpios = <&gpio2 30 0>, <&gpio3 19 0>;
> >> +	pinctrl-names = "default";
> >> +	pinctrl-0 = <&pinctrl_ecspi1>;
> >> +	status = "okay";
> >> +
> >> +	flash: m25p80@0 {
> >> +		#address-cells = <1>;
> >> +		#size-cells = <1>;
> >> +		compatible = "st,m25p", "jedec,spi-nor";
> >> +		spi-max-frequency = <20000000>;
> >> +		reg = <0>;
> >> +
> >> +		partition@0 {
> >> +			label = "uboot";
> >> +			reg = <0x0 0xc0000>;
> >> +		};
> >> +
> >> +		partition@c0000 {
> >> +			label = "uboot environment";
> >> +			reg = <0xc0000 0x40000>;
> >> +		};
> >> +
> >> +		partition@100000 {
> >> +			label = "reserved";
> >> +			reg = <0x100000 0x100000>;
> >> +		};
> > 
> > Partition layouts don't belong in the upstream DT, as it a device
> > configuration thing. Please kep them in the bootloader/firmware and make
> > this one pass the partition layout to the kernel.
> 
> I don't completely agree with this.
> We have lots of partition layouts in the upstream DT.

No, we don't. At least not for the i.MX6. There are some for the earlier
i.MX boards, but IMO it's wrong to put device configuration into the
upstream DT. Let's not start doing this again.

> Moreover, this is the default layout and changing it, will
> result in incompatibilities and also might result in device "bricking".
> Those can be changed from the boot loader in case you need those
> the other way around.
> Another question of mine is, why should you?
> 
Partition layout is device configuration, which is governed by the
device firmware. By not having the partition layout in the upstream DT
people are forced to set it from the firmware, which is exactly the
right thing to do, weather or not you plan to change it at any time.

Regards,
Lucas


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