Re: [PATCH 0/3 - V2] Introducing Device Tree Overlays

[Pantelis Antoniou]

Hi Guenter,

On Nov 6, 2013, at 11:17 PM, Guenter Roeck wrote:

> On Wed, Nov 06, 2013 at 09:38:21PM +0100, Sebastian Andrzej Siewior wrote:
>> On 06.11.13, Guenter Roeck wrote:
>>> At least that is our use case. u-boot doesn't know which cards are going to be
>>> inserted at runtime. Even PCIe hotplug itself is insufficient, as the PCIe
>>> configuration differs per card, and the cards support a variety of i2c devices
>>> as well as other card specific devices such LEDs and multi-function FPGAs.
>> 
>> So you have your FPGA behind PCIe and you use the DT to describe the
>> chips behind i2c? And then you update your FPGA and want update the
>> devices in DT without reboot?
>> 
> No.
> 
> We have a variety of boards ...
[snip]

TL;DR the real world...

> 
> We use DT overlays to describe the hardware on those boards and, if necessary,
> its configuration. For example, if there is a PCIe switch, the overlay would
> describe its memory and bus number configuration.
> 
> Guenter

Glad it's been useful...

Regards

-- Pantelis--
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