Re: [PATCH] Correct a typo which inverted the reset GPIO pin sequence.

[Brad Kelley <brad@bradkelley.org>]

On 12/11/2025 2:19 AM, Richard Fitzgerald wrote:
> Actually this patch looks incorrect and will break things.
> The 2nd argument to gpiod_direction_output() is the initial state of
> the GPIO. The kerneldoc for the function says "The initial value of the
> output must be specified as the logical value of the GPIO"
> 
> So the original code is correct: first we assert it (logical state 1)
> then below it is deasserted (logical state 0).
> 
> The problem is that originally the code set the raw signal level
> (0 to reset, 1 to not-reset) but now that it uses gpiod you must
> add the ACTIVE_LOW flag to the gpio definition if its electrical
> signal level is inverse of its logical level.
> 
> See the code in gpiod_direction_output_nonotify() in
> drivers/gpio/gpiolib.c, which inverts the value if FLAG_ACTIVE_LOW
> is set.

Thanks to both of you for the explanations and patience.  That all 
makes sense and I appreciate the guidance.  

This my first patch. I think I need to send a withdrawal email.

The problem for my use seems to be in the superaudioboard overlay 
which sets the GPIO_ACTIVE_HIGH flag.  A quick compile of the 
edited dts file fixes the problem.  I changed the line to this:
  reset-gpio = <&gpio 26 1>; /* Pin 26, active low */
but maybe there's an updated method.

I'll do some more research and testing and submit a new patch to 
the proper maintainers for that overlay.

Thanks again,

Brad