[PATCH 3/3] GPIO: gpio-dwapb: Suspend & Resume PM enabling

[Weike Chen <alvin.chen@intel.com>]

This patch enables suspend and resume mode for the power management, and
it is based on Josef Ahmad's previous work.

Reviewed-by: Hock Leong Kweh <hock.leong.kweh@intel.com>
Reviewed-by: Shevchenko, Andriy <andriy.shevchenko@intel.com>
Signed-off-by: Weike Chen <alvin.chen@intel.com>
---
 drivers/gpio/gpio-dwapb.c |   67 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
index e0ab988..1055cb3 100644
--- a/drivers/gpio/gpio-dwapb.c
+++ b/drivers/gpio/gpio-dwapb.c
@@ -560,10 +560,77 @@ static const struct of_device_id dwapb_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, dwapb_of_match);
 
+#if defined CONFIG_PM_SLEEP
+/* Store GPIO context across system-wide suspend/resume transitions */
+static struct gpio_saved_regs {
+	unsigned long data;
+	unsigned long dir;
+	unsigned long int_en;
+	unsigned long int_mask;
+	unsigned long int_type;
+	unsigned long int_pol;
+	unsigned long int_deb;
+} saved_regs;
+
+static int dwapb_gpio_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct dwapb_gpio *gpio = platform_get_drvdata(pdev);
+	struct bgpio_chip *bgc	= &gpio->ports[0].bgc;
+	unsigned long flags;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+
+	saved_regs.int_mask	= dwapb_read(gpio, GPIO_INTMASK);
+	saved_regs.int_en	= dwapb_read(gpio, GPIO_INTEN);
+	saved_regs.int_deb	= dwapb_read(gpio, GPIO_PORTA_DEBOUNCE);
+	saved_regs.int_pol	= dwapb_read(gpio, GPIO_INT_POLARITY);
+	saved_regs.int_type	= dwapb_read(gpio, GPIO_INTTYPE_LEVEL);
+	saved_regs.dir		= dwapb_read(gpio, GPIO_SWPORTA_DDR);
+	saved_regs.data		= dwapb_read(gpio, GPIO_SWPORTA_DR);
+
+	/* Mask out interrupts */
+	dwapb_write(gpio, GPIO_INTMASK, 0xffffffff);
+
+	spin_unlock_irqrestore(&bgc->lock, flags);
+
+	return 0;
+}
+
+static int dwapb_gpio_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct dwapb_gpio *gpio = platform_get_drvdata(pdev);
+	struct bgpio_chip *bgc	= &gpio->ports[0].bgc;
+	unsigned long flags;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+
+	dwapb_write(gpio, GPIO_SWPORTA_DR, saved_regs.data);
+	dwapb_write(gpio, GPIO_SWPORTA_DDR, saved_regs.dir);
+	dwapb_write(gpio, GPIO_INTTYPE_LEVEL, saved_regs.int_type);
+	dwapb_write(gpio, GPIO_INT_POLARITY, saved_regs.int_pol);
+	dwapb_write(gpio, GPIO_PORTA_DEBOUNCE, saved_regs.int_deb);
+	dwapb_write(gpio, GPIO_INTEN, saved_regs.int_en);
+	dwapb_write(gpio, GPIO_INTMASK, saved_regs.int_mask);
+
+	/* Clear out spurious interrupts */
+	dwapb_write(gpio, GPIO_PORTA_EOI, 0xffffffff);
+
+	spin_unlock_irqrestore(&bgc->lock, flags);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(dwapb_gpio_pm_ops, dwapb_gpio_suspend,
+			 dwapb_gpio_resume);
+
 static struct platform_driver dwapb_gpio_driver = {
 	.driver		= {
 		.name	= "gpio-dwapb",
 		.owner	= THIS_MODULE,
+		.pm	= &dwapb_gpio_pm_ops,
 		.of_match_table = of_match_ptr(dwapb_of_match),
 	},
 	.probe		= dwapb_gpio_probe,
-- 
1.7.9.5