Hi Andy,

On Mon, Nov 11, 2024 at 10:57 AM Andy Shevchenko
[off-list ref] wrote:

On Mon, Nov 11, 2024 at 10:45:13AM +0100, Geert Uytterhoeven wrote:

quoted

On Mon, Nov 4, 2024 at 10:37 AM Andy Shevchenko
[off-list ref] wrote:

...

quoted

quoted

-       if (template->active_low)
-               flags |= GPIOF_ACTIVE_LOW;
-
-       ret = devm_gpio_request_one(dev, template->gpio, flags,
+       ret = devm_gpio_request_one(dev, template->gpio, GPIOF_OUT_INIT_LOW,
                                    template->name);

Just wondering, as I am not 100% sure: can this change change the
initial state of the GPIO?

You probably wonder how ACTIVE_LOW affects the OUT_INIT_LOW given above.
I have an answer to you, however I might be mistaken as well, but I spent some
time to investigate.

The above mentioned call ends up in the gpiod_direction_output_raw_commit() which
uses the value (low in this case) as an absolute value. It does not include the
ACTIVE_LOW in the value calculations. Hence, setting ACTIVE_LOW before or afterwards
has no effect on the existing flow.

If you notice a mistake, please elaborate this, so I can fix the approach!

Thanks, I had discovered the same, but wanted to double-check!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds