On Fri, 11 Sep 2020 at 08:24, Joel Stanley [off-list ref] wrote:

On Thu, 10 Sep 2020 at 17:57, Krzysztof Kozlowski [off-list ref] wrote:

quoted

Convert the NXP PCA953x family of GPIO expanders bindings to device tree
schema.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

quoted

+patternProperties:
+  "^(hog-[0-9]+|.+-hog(-[0-9]+)?)$":
+    type: object
+    properties:
+      gpio-hog: true
+      gpios: true
+      input: true
+      output-high: true
+      output-low: true
+      line-name: true
+
+    required:
+      - gpio-hog
+      - gpios
+

quoted

+            usb3-sata-sel-hog {
+                gpio-hog;
+                gpios = <4 GPIO_ACTIVE_HIGH>;
+                output-low;
+                line-name = "usb3_sata_sel";

I would prefer we didn't require the addition of hte -hog prefix. It's
mostly just a matter of taste, but I can think of a few more concrete
reasons:

We don't require -high or -low prefixes, so the node name doesn't need
to describe the properties that will be found below.

Thanks for the comments.

It is not about properties (high or low) but the role of a device
node. The node names should represent a generic class of device (ePAPR
and device tree spec) and "hog" is such class.

The Documentation/devicetree/bindings/gpio/fsl-imx-gpio.yaml already
uses such naming so the best would be to unify.

Changing around node names for existing boards carries with it the
chance of userspace breakage (as sysfs paths change). I would prefer
we avoid that if possible.

The impact on userspace is indeed important, but are you sure that
hogs are visible to user-space via sysfs and configurable? I guess you
think of deprecated CONFIG_GPIO_SYSFS?

Rob,
Any hints from you about hog-naming?

Best regards,
Krzysztof

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