[PATCH] GPIO/pl061: Add suspend resume capability

[Viresh Kumar]

From: Deepak Sikri <deepak.sikri@xxxxxx>

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@xxxxxx>
---
 drivers/gpio/gpio-pl061.c |   73 +++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 73 insertions(+), 0 deletions(-)

diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c
index 093c90b..d64dc1c 100644
--- a/drivers/gpio/gpio-pl061.c
+++ b/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 gpio_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 gpio_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 +360,60 @@ 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 const struct dev_pm_ops pl061_dev_pm_ops = {
+	.suspend = pl061_suspend,
+	.resume = pl061_resume,
+};
+
+#define PL061_DEV_PM_OPS (&pl061_dev_pm_ops)
+#else
+#define PL061_DEV_PM_OPS NULL
+#endif
+
 static struct amba_id pl061_ids[] = {
 	{
 		.id	= 0x00041061,
@@ -353,6 +425,7 @@ static struct amba_id pl061_ids[] = {
 static struct amba_driver pl061_gpio_driver = {
 	.drv = {
 		.name	= "pl061_gpio",
+		.pm	= PL061_DEV_PM_OPS,
 	},
 	.id_table	= pl061_ids,
 	.probe		= pl061_probe,
-- 
1.7.2.2

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