[PATCH] gpio: pca953x: Add wake-up support

[Geert Uytterhoeven <geert+renesas@xxxxxxxxx>]

Implement the irq_set_wake() method in the (optional) irq_chip of the
GPIO expander, and propagate wake-up settings to the upstream interrupt
controller.  This allows GPIOs connected to a PCA953X GPIO expander to
serve as wake-up sources.

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
Tested with a PCA9654 and gpio-keys on an R-Car Ebisu-4D board.
---
 drivers/gpio/gpio-pca953x.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index de52f63863dbe59b..8dfb8e326b9d12ca 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -151,6 +151,7 @@ struct pca953x_chip {
 	u8 irq_trig_raise[MAX_BANK];
 	u8 irq_trig_fall[MAX_BANK];
 	struct irq_chip irq_chip;
+	unsigned int irq_parent;
 #endif
 
 	struct i2c_client *client;
@@ -513,6 +514,24 @@ static void pca953x_irq_unmask(struct irq_data *d)
 	chip->irq_mask[d->hwirq / BANK_SZ] |= 1 << (d->hwirq % BANK_SZ);
 }
 
+static int pca953x_irq_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct pca953x_chip *chip = gpiochip_get_data(gc);
+	int error = 0;
+
+	if (chip->irq_parent) {
+		error = irq_set_irq_wake(chip->irq_parent, on);
+		if (error) {
+			dev_dbg(&chip->client->dev,
+				"irq %u doesn't support irq_set_wake\n",
+				chip->irq_parent);
+			chip->irq_parent = 0;
+		}
+	}
+	return error;
+}
+
 static void pca953x_irq_bus_lock(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
@@ -732,6 +751,7 @@ static int pca953x_irq_setup(struct pca953x_chip *chip,
 	irq_chip->name = dev_name(&chip->client->dev);
 	irq_chip->irq_mask = pca953x_irq_mask;
 	irq_chip->irq_unmask = pca953x_irq_unmask;
+	irq_chip->irq_set_wake = pca953x_irq_set_wake;
 	irq_chip->irq_bus_lock = pca953x_irq_bus_lock;
 	irq_chip->irq_bus_sync_unlock = pca953x_irq_bus_sync_unlock;
 	irq_chip->irq_set_type = pca953x_irq_set_type;
@@ -747,6 +767,7 @@ static int pca953x_irq_setup(struct pca953x_chip *chip,
 	}
 
 	gpiochip_set_nested_irqchip(&chip->gpio_chip, irq_chip, client->irq);
+	chip->irq_parent = client->irq;
 
 	return 0;
 }
-- 
2.17.1