Subject: [PATCH 2/4] of: DT quirks infrastructure

From: [email-masked] (Sylvain Rochet)
Date: Thu, 19 Feb 2015 19:12:18 +0100

Hello,

On Thu, Feb 19, 2015 at 07:01:59PM +0100, Maxime Bizon wrote:
> On Thu, 2015-02-19 at 19:38 +0200, Pantelis Antoniou wrote:
> 
> > Having to boot and tweak the bootloader settings to select the correct
> > dtb (even if it?s present on the flash medium) takes time and is
> > error-prone.
> 
> Dedicate a set of GPIO for board/PCB revision detection (it only costs a
> few resistors connected to VCC or GND), then use that information to
> choose the correct DTB.

Or use a 1-wire or I2C EEPROM to store your board information.

Or, even better, if you have an I2C device, just chose a different 
address on each board for this device and then probe I2C devices in your 
boot loader until you found one you are looking for, this way, you don't 
need spare GPIO at all. You don't even need to populate the same I2C 
device on all boards, you can actually probe anything.

Sylvain
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