Hi Dough,Thanks for your review!
thanks for your patch!
"Communication is hard" and I may be confused about your confusion, but hopefully we can work it out.
I'm a bit confused here:
I think we are in agreement here. For extra clarity, I will add that in my understanding pinspec.args[0] corresponds to [GPIO controller offset] and pinspec.args[2] corresponds to [number of pins].
On Wed, Apr 24, 2024 at 8:51 PM Doug Berger <opendmb@xxxxxxxxx> wrote:
+ /* Ignore ranges outside of this GPIO chip */
+ if (pinspec.args[0] >= (chip->offset + chip->ngpio))
+ continue;
+ if (pinspec.args[0] + pinspec.args[2] <= chip->offset)
+ continue;
Here pinspec.args[0] and [2] comes directly from the device tree.
The documentation in Documentation/devicetree/bindings/gpio/gpio.txt
says:
2.2) Ordinary (numerical) GPIO ranges
-------------------------------------
It is useful to represent which GPIOs correspond to which pins on which pin
controllers. The gpio-ranges property described below represents this with
a discrete set of ranges mapping pins from the pin controller local number space
to pins in the GPIO controller local number space.
The format is: <[pin controller phandle], [GPIO controller offset],
[pin controller offset], [number of pins]>;
The GPIO controller offset pertains to the GPIO controller node containing the
range definition.
The struct gpio_chip documentation in include/linux/gpio/driver.h says:
So I do not understand how pinspec[0] and [2] can ever be compared
to something involving chip->offset which is a Linux-specific offset.
It rather looks like you are trying to accomodate the Linux numberspace
in the ranges, which it was explicitly designed to avoid.
I hope it makes sense now, but if not please help me understand what I may be missing.
I just don't get it.
So NACK until I understand what is going on here.
Yours,
Linus Walleij