Re: Initialization order

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hi,

On 6/25/26 11:02 AM, Renaud Barbier wrote:
> What about an init call back like in the pair: arch/arm/boards/tqma93xx/board.c  and drivers/mfd/pca9450.c 

Not really a fan of these ad-hoc interfaces. In Linux you can register
callbacks for different life cycle stages via bus notifier:
BUS_NOTIFY_*, but we don't have something similar in barebox yet.

Your suggestion reminded me of something we _do_ have: PCI fixups!

Check out ventana_pciesw_early_fixup()

You could add a fixup like that matching your VID/PID in your board code
and call of_ensure_probed() inside on your SPI flash and do your
necessary writes?

Cheers,
Ahmad

> 
>> -----Original Message-----
>> From: Ahmad Fatoum <a.fatoum@pengutronix.de>
>> Sent: 24 June 2026 21:19
>> To: Renaud Barbier <Renaud.Barbier@ametek.com>; Barebox List
>> <barebox@lists.infradead.org>
>> Subject: Re: Initialization order
>>
>> ***NOTICE*** This came from an external source. Use caution when
>> replying, clicking links, or opening attachments.
>>
>> Hello Renaud,
>>
>> On 6/24/26 17:51, Renaud Barbier wrote:
>>> Hello,
>>> I have a LS1021A connected to a device via SPI bus and PCIe bus. To enable
>> the PCIe bus on this device , I need to write registers via the SPI bus.
>>> I created a small SPI driver using the regmap layer to access the chip and I
>> am able to  display or write registers via md and mw.
>>>
>>> I have tried (core)device_initcall opening the device using
>>> open_and_lseek but it is either called after ls_pcie_probe or too
>>> early and failed
>>>
>>> What would be the best approach to do this initialization before
>> ls_pcie_probe is called?
>>
>> The easy way would be doing it in the board driver by enabling deep probe
>> and calling
>> of_device_ensure_probed() on the SPI device to ensure it's available.
>>
>> The more proper way would be to reflect the dependency in the device tree.
>> Sascha did some work with creating DT nodes for PCI devices recently, so
>> maybe he has some advice to share.
>>
>> Cheers,
>> Ahmad
>>
>>>
>>>
>>> Cheers,
>>> Renaud
>>>
>>>
>>>
>>
>>
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