Several drivers (e.g. gpio-keys) allow for GPIOs to be configured as
wakeup sources, and this GPIO controller supports that through a
separate interrupt path.

The de-facto standard DT property "wakeup-source" is checked, since
that indicates whether the GPIO controller hardware can wake.  Uses
the IRQCHIP_MASK_ON_SUSPEND irq_chip flag because UPG GIO doesn't have
any of its own wakeup source configuration.

Signed-off-by: Gregory Fong <gregory.0...@gmail.com>
---
New in v2.

 drivers/gpio/gpio-brcmstb.c | 53 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/drivers/gpio/gpio-brcmstb.c b/drivers/gpio/gpio-brcmstb.c
index b9962ff..2598c1e 100644
--- a/drivers/gpio/gpio-brcmstb.c
+++ b/drivers/gpio/gpio-brcmstb.c
@@ -19,6 +19,7 @@
 #include <linux/basic_mmio_gpio.h>
 #include <linux/irqdomain.h>
 #include <linux/irqchip/chained_irq.h>
+#include <linux/interrupt.h>
 
 #define GIO_BANK_SIZE           0x20
 #define GIO_ODEN(bank)          (((bank) * GIO_BANK_SIZE) + 0x00)
@@ -48,6 +49,7 @@ struct brcmstb_gpio_priv {
        struct irq_domain *irq_domain;
        int parent_irq;
        int gpio_base;
+       int parent_wake_irq;
 };
 
 #define MAX_GPIO_PER_BANK           32
@@ -183,6 +185,31 @@ static int brcmstb_gpio_irq_set_type(struct irq_data *d, 
unsigned int type)
        return 0;
 }
 
+static int brcmstb_gpio_irq_set_wake(struct irq_data *d, unsigned int enable)
+{
+       struct brcmstb_gpio_bank *bank = irq_data_get_irq_chip_data(d);
+       struct brcmstb_gpio_priv *priv = bank->parent_priv;
+
+       /*
+        * Only enable wake IRQ once for however many hwirqs can wake
+        * since they all use the same wake IRQ.  Mask will be set
+        * up appropriately thanks to IRQCHIP_MASK_ON_SUSPEND flag.
+        */
+       if (enable)
+               enable_irq_wake(priv->parent_wake_irq);
+       else
+               disable_irq_wake(priv->parent_wake_irq);
+       return 0;
+}
+
+static irqreturn_t brcmstb_gpio_wake_irq_handler(int irq, void *data)
+{
+       struct brcmstb_gpio_priv *priv = data;
+
+       pm_wakeup_event(&priv->pdev->dev, 0);
+       return IRQ_HANDLED;
+}
+
 static void brcmstb_gpio_irq_bank_handler(int irq,
                struct brcmstb_gpio_bank *bank)
 {
@@ -369,6 +396,32 @@ static int brcmstb_gpio_irq_setup(struct platform_device 
*pdev,
        priv->irq_chip.irq_mask = brcmstb_gpio_irq_mask;
        priv->irq_chip.irq_unmask = brcmstb_gpio_irq_unmask;
        priv->irq_chip.irq_set_type = brcmstb_gpio_irq_set_type;
+
+       /* Ensures that all non-wakeup IRQs are disabled at suspend */
+       priv->irq_chip.flags = IRQCHIP_MASK_ON_SUSPEND;
+
+       if (IS_ENABLED(CONFIG_PM_SLEEP) &&
+                       of_get_property(np, "wakeup-source", NULL)) {
+               priv->parent_wake_irq = platform_get_irq(pdev, 1);
+               if (priv->parent_wake_irq < 0)  {
+                       dev_warn(dev,
+                               "Couldn't get wake IRQ - GPIOs will not be able 
to wake from sleep");
+               } else {
+                       int err = devm_request_irq(dev, priv->parent_wake_irq,
+                                       brcmstb_gpio_wake_irq_handler, 0,
+                                       "brcmstb-gpio-wake", priv);
+
+                       if (err < 0) {
+                               dev_err(dev, "Couldn't request wake IRQ");
+                               return err;
+                       }
+
+                       device_set_wakeup_capable(dev, true);
+                       device_wakeup_enable(dev);
+                       priv->irq_chip.irq_set_wake = brcmstb_gpio_irq_set_wake;
+               }
+       }
+
        priv->irq_domain =
                irq_domain_add_linear(np, priv->num_gpios,
                                      &brcmstb_gpio_irq_domain_ops,
-- 
1.9.1

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