specifying order of /dev/mmcblk devices via device-tree?

[Ulf Hansson]

On 28 October 2016 at 17:37, Mark Rutland <mark.rutland at arm.com> wrote:
> On Fri, Oct 28, 2016 at 08:23:04AM -0700, Tim Harvey wrote:
>> Greetings,
>>
>> I have an IMX6 board that has the following:
>> sdhc1: mmc0: sdio radio
>> sdhc2: mmc1: /dev/mmcblk1: microSD connector
>> sdhc3: mmc2: /dev/mmcblk2: on-board eMMC
>>
>> I would like to have sdhc3 registered as /dev/mmcblk0 and sdhc2
>> registered as /dev/mmcblk1 so that permanent storage is the first
>> mmcblk device as I think this is more intuitive however currently
>> these get instanced in the order they appear in the imx6qdl.dtsi
>> device-tree configuration and are not able to be mapped the way I want
>> them in my dts file.
>>
>> Is there a way, or if not is there a desire for a way, to specify the
>> order of /dev/mmcblk devices via device-tree?
>
> As with many other devices, there is no standard way of controlling the
> Linux enumeration (and given the ID space is shared with other dynamic
> devices it's not something that could generally work).
>
> These should be refererd to by UUID if possible.
>
> If not, we could cosider adding a by-dt-path or something like that.

So does that mean you think using "DT aliases" would be okay? As
Javier pointed out, there have been some attempts [1] for that, but
they didn't make it.
Perhaps we need to re-consider, and if so please re-review the DT
bindings patch from that series.

Kind regards
Uffe

[1]
https://lkml.org/lkml/2016/4/29/610 or
http://www.spinics.net/lists/linux-mmc/msg36701.html