GPIO: gpio-dwapb: Suspend & Resume PM enabling

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: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Weike Chen <alvin.chen@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-dwapb.c

@@ -51,10 +51,28 @@
 
 struct dwapb_gpio;
 
+#ifdef CONFIG_PM_SLEEP
+/* Store GPIO context across system-wide suspend/resume transitions */
+struct dwapb_context {
+	u32 data;
+	u32 dir;
+	u32 ext;
+	u32 int_en;
+	u32 int_mask;
+	u32 int_type;
+	u32 int_pol;
+	u32 int_deb;
+};
+#endif
+
 struct dwapb_gpio_port {
 	struct bgpio_chip	bgc;
 	bool			is_registered;
 	struct dwapb_gpio	*gpio;
+#ifdef CONFIG_PM_SLEEP
+	struct dwapb_context	*ctx;
+#endif
+	unsigned int		idx;
 };
 
 struct dwapb_gpio {
@@ -381,6 +399,13 @@ static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
 
 	port = &gpio->ports[offs];
 	port->gpio = gpio;
+	port->idx = pp->idx;
+
+#ifdef CONFIG_PM_SLEEP
+	port->ctx = devm_kzalloc(gpio->dev, sizeof(*port->ctx), GFP_KERNEL);
+	if (!port->ctx)
+		return -ENOMEM;
+#endif
 
 	dat = gpio->regs + GPIO_EXT_PORTA + (pp->idx * GPIO_EXT_PORT_SIZE);
 	set = gpio->regs + GPIO_SWPORTA_DR + (pp->idx * GPIO_SWPORT_DR_SIZE);
@@ -586,10 +611,100 @@ static const struct of_device_id dwapb_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, dwapb_of_match);
 
+#ifdef CONFIG_PM_SLEEP
+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;
+	int i;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+	for (i = 0; i < gpio->nr_ports; i++) {
+		unsigned int offset;
+		unsigned int idx = gpio->ports[i].idx;
+		struct dwapb_context *ctx = gpio->ports[i].ctx;
+
+		BUG_ON(ctx == 0);
+
+		offset = GPIO_SWPORTA_DDR + idx * GPIO_SWPORT_DDR_SIZE;
+		ctx->dir = dwapb_read(gpio, offset);
+
+		offset = GPIO_SWPORTA_DR + idx * GPIO_SWPORT_DR_SIZE;
+		ctx->data = dwapb_read(gpio, offset);
+
+		offset = GPIO_EXT_PORTA + idx * GPIO_EXT_PORT_SIZE;
+		ctx->ext = dwapb_read(gpio, offset);
+
+		/* Only port A can provide interrupts */
+		if (idx == 0) {
+			ctx->int_mask	= dwapb_read(gpio, GPIO_INTMASK);
+			ctx->int_en	= dwapb_read(gpio, GPIO_INTEN);
+			ctx->int_pol	= dwapb_read(gpio, GPIO_INT_POLARITY);
+			ctx->int_type	= dwapb_read(gpio, GPIO_INTTYPE_LEVEL);
+			ctx->int_deb	= dwapb_read(gpio, GPIO_PORTA_DEBOUNCE);
+
+			/* 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;
+	int i;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+	for (i = 0; i < gpio->nr_ports; i++) {
+		unsigned int offset;
+		unsigned int idx = gpio->ports[i].idx;
+		struct dwapb_context *ctx = gpio->ports[i].ctx;
+
+		BUG_ON(ctx == 0);
+
+		offset = GPIO_SWPORTA_DR + idx * GPIO_SWPORT_DR_SIZE;
+		dwapb_write(gpio, offset, ctx->data);
+
+		offset = GPIO_SWPORTA_DDR + idx * GPIO_SWPORT_DDR_SIZE;
+		dwapb_write(gpio, offset, ctx->dir);
+
+		offset = GPIO_EXT_PORTA + idx * GPIO_EXT_PORT_SIZE;
+		dwapb_write(gpio, offset, ctx->ext);
+
+		/* Only port A can provide interrupts */
+		if (idx == 0) {
+			dwapb_write(gpio, GPIO_INTTYPE_LEVEL, ctx->int_type);
+			dwapb_write(gpio, GPIO_INT_POLARITY, ctx->int_pol);
+			dwapb_write(gpio, GPIO_PORTA_DEBOUNCE, ctx->int_deb);
+			dwapb_write(gpio, GPIO_INTEN, ctx->int_en);
+			dwapb_write(gpio, GPIO_INTMASK, ctx->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,