Re: [PATCH v3 2/2] gnss: ubx: add support for the safeboot gpio

[Johan Hovold <johan@kernel.org>]

On Fri, Nov 14, 2025 at 03:59:24PM +0100, Johan Hovold wrote:
> On Thu, Sep 11, 2025 at 02:58:29PM +0200, Alejandro Enrique via B4 Relay wrote:
> > From: Alejandro Enrique <alejandroe1@geotab.com>
> > 
> > U-Blox 8/M8/M9 chip have a pin to start it in safeboot mode, to be
> > used to recover from situations where the flash content has become
> > corrupted and needs to be restored. If this pin is asserted at power
> > up/reset, the receiver starts in safeboot mode and GNSS operation is
> > disabled.
> > 
> > Deassert the safeboot pin when probing this driver.

> Note however that both the RESET_N and SAFEBOOT_N pins should be
> declared as open-drain to avoid driving them while the main supply is
> off.
> 
> I added a comment about this to the commit message about this when
> applying and will send a follow-on patch to update the binding example.

I was playing with the idea of adding a warning about this to the driver
when realised that there would typically be a level shifter for these
signals that makes sure they are not driven while the supply is off so I
dropped the comment instead.

Johan