Device tree probe order

Device tree probe order

[Renaud Barbier]

We have a board based on the LS1026A with a boot SPI NOR on the QSPI controller and FRAM on the DSPI controller.
Currently, the DSPI is being probed first and got the device node /dev/m25p0. The boot SPI get /dev/m25p1.

I would like the  QSPI NOR to be assigned to /dev/m25p0 and the FRAM to /dev/m25p1.

Is it possible to change the probing order or the device node assignment?

Cheers,
Renaud

Re: Device tree probe order

[Sascha Hauer]

Hi Renauld,

On Wed, Nov 15, 2023 at 04:47:03PM +0000, Renaud Barbier wrote:
> We have a board based on the LS1026A with a boot SPI NOR on the QSPI
> controller and FRAM on the DSPI controller.  Currently, the DSPI is
> being probed first and got the device node /dev/m25p0. The boot SPI
> get /dev/m25p1.
> 
> I would like the  QSPI NOR to be assigned to /dev/m25p0 and the FRAM
> to /dev/m25p1.
> 
> Is it possible to change the probing order or the device node
> assignment?

You can create aliases in the device tree for both flashes, see
drivers/mtd/devices/m25p80.c:258:

        if (dev->of_node)
                flash_name = of_alias_get(dev->of_node);

Sascha

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RE: Device tree probe order

[Renaud Barbier]

Thanks.
 I had found that swapping the device driver registration made the QSPI probe first.  Changing DSPI to be registered by device_initall and QSPI by coredevice_initcall does what I am expected. 
I will look at the method you offered.

> -----Original Message-----
> From: Sascha Hauer <sha@pengutronix.de>
> Sent: Thursday, November 16, 2023 7:56 AM
> To: Renaud Barbier <Renaud.Barbier@ametek.com>
> Cc: Barebox List <barebox@lists.infradead.org>
> Subject: Re: Device tree probe order
> 
> ***NOTICE*** This came from an external source. Use caution when replying,
> clicking links, or opening attachments.
> 
> Hi Renauld,
> 
> On Wed, Nov 15, 2023 at 04:47:03PM +0000, Renaud Barbier wrote:
> > We have a board based on the LS1026A with a boot SPI NOR on the QSPI
> > controller and FRAM on the DSPI controller.  Currently, the DSPI is
> > being probed first and got the device node /dev/m25p0. The boot SPI
> > get /dev/m25p1.
> >
> > I would like the  QSPI NOR to be assigned to /dev/m25p0 and the FRAM
> > to /dev/m25p1.
> >
> > Is it possible to change the probing order or the device node
> > assignment?
> 
> You can create aliases in the device tree for both flashes, see
> drivers/mtd/devices/m25p80.c:258:
> 
>         if (dev->of_node)
>                 flash_name = of_alias_get(dev->of_node);
> 
> Sascha
> 
> --
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> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |