[PATCH v2 2/2] gpio: aggregator: add gpio-aggregator DT compatible

[James Hilliard]

Add an OF match entry for "gpio-aggregator" to support plain GPIO
forwarding from devicetree without delay semantics.

This allows exposing selected lines as a logical GPIO controller with
stable aggregated offsets, so consumers can reference forwarded lines
instead of physical controller offsets. It also allows creating bundled
groups of named lines that can be exposed to userspace as a convenient
virtual gpiochip interface. Using "gpio-delay" for this case is not
suitable because it enables delay features and requires 3-cell GPIO
specifiers.

Signed-off-by: James Hilliard <james.hilliard1@xxxxxxxxx>
---
Changes v1 -> v2:
  - Split DT schema into a separate patch
    (suggested by Krzysztof Kozlowski)
  - Expand commit message rationale and use-case explanation
    (suggested by Krzysztof Kozlowski)
  - Clarify userspace use case with bundled named line groups
---
 drivers/gpio/gpio-aggregator.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpio/gpio-aggregator.c b/drivers/gpio/gpio-aggregator.c
index 416f265d09d0..a09752fc5fe2 100644
--- a/drivers/gpio/gpio-aggregator.c
+++ b/drivers/gpio/gpio-aggregator.c
@@ -1635,6 +1635,9 @@ static int gpio_aggregator_probe(struct platform_device *pdev)
 }
 
 static const struct of_device_id gpio_aggregator_dt_ids[] = {
+	{
+		.compatible = "gpio-aggregator",
+	},
 	{
 		.compatible = "gpio-delay",
 		.data = (void *)FWD_FEATURE_DELAY,
-- 
2.43.0