langwell_gpio: add runtime pm support

While this is essentially a no-op for this driver, it has the
side effect of letting the PMU driver snoop D3 requests from
the PCI core for this driver.

This is only for langwell, not for whitney point.

Signed-off-by: Kristen Carlson Accardi <[e-mail]>
Signed-off-by: Alan Cox <[e-mail]>
Signed-off-by: Dirk Brandewie <[e-mail]>
Signed-off-by: Grant Likely <[e-mail]>

drivers/gpio/langwell_gpio.c

···
 #include <linux/io.h>
 #include <linux/gpio.h>
 #include <linux/slab.h>
+#include <linux/pm_runtime.h>
 
 /*
  * Langwell chip has 64 pins and thus there are 2 32bit registers to control
···
 	void				*reg_base;
 	spinlock_t			lock;
 	unsigned			irq_base;
+	struct pci_dev			*pdev;
 };
 
 static void __iomem *gpio_reg(struct gpio_chip *chip, unsigned offset,
···
 	u32 value;
 	unsigned long flags;
 
+	if (lnw->pdev)
+		pm_runtime_get(&lnw->pdev->dev);
+
 	spin_lock_irqsave(&lnw->lock, flags);
 	value = readl(gpdr);
 	value &= ~BIT(offset % 32);
 	writel(value, gpdr);
 	spin_unlock_irqrestore(&lnw->lock, flags);
+
+	if (lnw->pdev)
+		pm_runtime_put(&lnw->pdev->dev);
+
 	return 0;
 }
 
···
 	unsigned long flags;
 
 	lnw_gpio_set(chip, offset, value);
+
+	if (lnw->pdev)
+		pm_runtime_get(&lnw->pdev->dev);
+
 	spin_lock_irqsave(&lnw->lock, flags);
 	value = readl(gpdr);
 	value |= BIT(offset % 32);
 	writel(value, gpdr);
 	spin_unlock_irqrestore(&lnw->lock, flags);
+
+	if (lnw->pdev)
+		pm_runtime_put(&lnw->pdev->dev);
+
 	return 0;
 }
 
···
 
 	if (gpio >= lnw->chip.ngpio)
 		return -EINVAL;
+
+	if (lnw->pdev)
+		pm_runtime_get(&lnw->pdev->dev);
+
 	spin_lock_irqsave(&lnw->lock, flags);
 	if (type & IRQ_TYPE_EDGE_RISING)
 		value = readl(grer) | BIT(gpio % 32);
···
 		value = readl(gfer) & (~BIT(gpio % 32));
 	writel(value, gfer);
 	spin_unlock_irqrestore(&lnw->lock, flags);
+
+	if (lnw->pdev)
+		pm_runtime_put(&lnw->pdev->dev);
 
 	return 0;
 }
···
 
 	chip->irq_eoi(data);
 }
+
+#ifdef CONFIG_PM
+static int lnw_gpio_runtime_resume(struct device *dev)
+{
+	return 0;
+}
+
+static int lnw_gpio_runtime_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int lnw_gpio_runtime_idle(struct device *dev)
+{
+	int err = pm_schedule_suspend(dev, 500);
+
+	if (!err)
+		return 0;
+
+	return -EBUSY;
+}
+
+#else
+#define lnw_gpio_runtime_suspend	NULL
+#define lnw_gpio_runtime_resume		NULL
+#define lnw_gpio_runtime_idle		NULL
+#endif
+
+static const struct dev_pm_ops lnw_gpio_pm_ops = {
+	.runtime_suspend = lnw_gpio_runtime_suspend,
+	.runtime_resume = lnw_gpio_runtime_resume,
+	.runtime_idle = lnw_gpio_runtime_idle,
+};
 
 static int __devinit lnw_gpio_probe(struct pci_dev *pdev,
 			const struct pci_device_id *id)
···
 	lnw->chip.base = gpio_base;
 	lnw->chip.ngpio = id->driver_data;
 	lnw->chip.can_sleep = 0;
+	lnw->pdev = pdev;
 	pci_set_drvdata(pdev, lnw);
 	retval = gpiochip_add(&lnw->chip);
 	if (retval) {
···
 	}
 
 	spin_lock_init(&lnw->lock);
+
+	pm_runtime_put_noidle(&pdev->dev);
+	pm_runtime_allow(&pdev->dev);
+
 	goto done;
 err5:
 	kfree(lnw);
···
 	.name		= "langwell_gpio",
 	.id_table	= lnw_gpio_ids,
 	.probe		= lnw_gpio_probe,
+	.driver		= {
+		.pm	= &lnw_gpio_pm_ops,
+	},
 };