GPIO/pl061: Add suspend resume capability

This patch adds the suspend and resume operations in the driver. The patch
ensures the data save and restore for the device registers during the
suspend and resume operations respectively.

Signed-off-by: Deepak Sikri <deepak.sikri@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/gpio/gpio-pl061.c

@@ -23,6 +23,7 @@
 #include <linux/amba/bus.h>
 #include <linux/amba/pl061.h>
 #include <linux/slab.h>
+#include <linux/pm.h>
 
 #define GPIODIR 0x400
 #define GPIOIS  0x404
@@ -35,6 +36,17 @@
 
 #define PL061_GPIO_NR	8
 
+#ifdef CONFIG_PM
+struct pl061_context_save_regs {
+	u8 gpio_data;
+	u8 gpio_dir;
+	u8 gpio_is;
+	u8 gpio_ibe;
+	u8 gpio_iev;
+	u8 gpio_ie;
+};
+#endif
+
 struct pl061_gpio {
 	/* We use a list of pl061_gpio structs for each trigger IRQ in the main
 	 * interrupts controller of the system. We need this to support systems
@@ -54,6 +66,10 @@ struct pl061_gpio {
 	void __iomem		*base;
 	unsigned		irq_base;
 	struct gpio_chip	gc;
+
+#ifdef CONFIG_PM
+	struct pl061_context_save_regs csave_regs;
+#endif
 };
 
 static int pl061_direction_input(struct gpio_chip *gc, unsigned offset)
@@ -330,6 +346,8 @@ static int pl061_probe(struct amba_device *dev, const struct amba_id *id)
 		irq_set_chip_data(i + chip->irq_base, chip);
 	}
 
+	amba_set_drvdata(dev, chip);
+
 	return 0;
 
 iounmap:
@@ -342,6 +360,53 @@ free_mem:
 	return ret;
 }
 
+#ifdef CONFIG_PM
+static int pl061_suspend(struct device *dev)
+{
+	struct pl061_gpio *chip = dev_get_drvdata(dev);
+	int offset;
+
+	chip->csave_regs.gpio_data = 0;
+	chip->csave_regs.gpio_dir = readb(chip->base + GPIODIR);
+	chip->csave_regs.gpio_is = readb(chip->base + GPIOIS);
+	chip->csave_regs.gpio_ibe = readb(chip->base + GPIOIBE);
+	chip->csave_regs.gpio_iev = readb(chip->base + GPIOIEV);
+	chip->csave_regs.gpio_ie = readb(chip->base + GPIOIE);
+
+	for (offset = 0; offset < PL061_GPIO_NR; offset++) {
+		if (chip->csave_regs.gpio_dir & (1 << offset))
+			chip->csave_regs.gpio_data |=
+				pl061_get_value(&chip->gc, offset) << offset;
+	}
+
+	return 0;
+}
+
+static int pl061_resume(struct device *dev)
+{
+	struct pl061_gpio *chip = dev_get_drvdata(dev);
+	int offset;
+
+	for (offset = 0; offset < PL061_GPIO_NR; offset++) {
+		if (chip->csave_regs.gpio_dir & (1 << offset))
+			pl061_direction_output(&chip->gc, offset,
+					chip->csave_regs.gpio_data &
+					(1 << offset));
+		else
+			pl061_direction_input(&chip->gc, offset);
+	}
+
+	writeb(chip->csave_regs.gpio_is, chip->base + GPIOIS);
+	writeb(chip->csave_regs.gpio_ibe, chip->base + GPIOIBE);
+	writeb(chip->csave_regs.gpio_iev, chip->base + GPIOIEV);
+	writeb(chip->csave_regs.gpio_ie, chip->base + GPIOIE);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(pl061_dev_pm_ops, pl061_suspend, pl061_resume);
+#endif
+
 static struct amba_id pl061_ids[] = {
 	{
 		.id	= 0x00041061,
@@ -353,6 +418,9 @@ static struct amba_id pl061_ids[] = {
 static struct amba_driver pl061_gpio_driver = {
 	.drv = {
 		.name	= "pl061_gpio",
+#ifdef CONFIG_PM
+		.pm	= &pl061_dev_pm_ops,
+#endif
 	},
 	.id_table	= pl061_ids,
 	.probe		= pl061_probe,