On Mon, Jul 26, 2021 at 2:54 PM Andy Shevchenko
[off-list ref] wrote:

For backward compatibility with some legacy devices introduce
a new (*) property gpio-base to read GPIO base. This will allow
further cleanup of the driver.

*) Note, it's not new for GPIO library since mockup driver is
   using it already.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

(...)

-               pp->gpio_base   = -1;
+               if (fwnode_property_read_u32(fwnode, "gpio-base", &pp->gpio_base))
+                       pp->gpio_base = -1;

This is problematic because we have repeatedly NACKed this property
to be added to device trees.

I don't know about fwnode policies, but in the device tree this would have
to be "linux,gpio-base" and then it would be NACKed because of adding
an operating-system specific thing to a OS-independent hardware
description.

I don't know what to do with this really, but I understand the need of it
as a kernel-internal thing, however I am afraid that adding this will make
it possible to add linux,gpio-base = <n> to any device tree gpio_chip
as well and that encourages bad behaviour even if we don't allow a
DT binding (YAML) like that.

Is there a way to make a fwnode property only come from software
nodes and not allowed to be used in ACPI or DT? (I guess not...)

Yours,
Linus Walleij