gpio: handle also nested irqchips in the chained handler set-up

To unify how we connect cascaded IRQ chips to parent IRQs, if
NULL us passed as handler to the gpiochip_set_chained_irqchip()
function, assume the chips is nested rather than chained, and
we still get the parent set up correctly by way of this function
call.

Alter the drivers for tc3589x and stmpe to use this to set up
their chained handlers as a demonstration of the usage.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 12 insertions, 6 deletions

diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
index 845025a57240..b0b342787c37 100644
--- a/drivers/gpio/gpio-stmpe.c
+++ b/drivers/gpio/gpio-stmpe.c
@@ -308,6 +308,12 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
 	if (ret)
 		goto out_free;
 
+	ret = gpiochip_add(&stmpe_gpio->chip);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
+		goto out_disable;
+	}
+
 	if (irq > 0) {
 		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
 				stmpe_gpio_irq, IRQF_ONESHOT,
@@ -324,14 +330,13 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
 		if (ret) {
 			dev_err(&pdev->dev,
 				"could not connect irqchip to gpiochip\n");
-			return ret;
+			goto out_disable;
 		}
-	}
 
-	ret = gpiochip_add(&stmpe_gpio->chip);
-	if (ret) {
-		dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
-		goto out_disable;
+		gpiochip_set_chained_irqchip(&stmpe_gpio->chip,
+					     &stmpe_gpio_irq_chip,
+					     irq,
+					     NULL);
 	}
 
 	if (pdata && pdata->setup)
@@ -343,6 +348,7 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
 
 out_disable:
 	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
+	gpiochip_remove(&stmpe_gpio->chip);
 out_free:
 	kfree(stmpe_gpio);
 	return ret;