misc: microchip: pci1xxxx: Add power management functions - suspend & resume handlers.

Power event handlers suspend and resume are invoked by the operating
system to notify the driver about the power events. Wakeup is enabled
before entering suspend and disabled after resuming.
Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
Link: https://lore.kernel.org/r/20220824200047.150308-6-kumaravel.thiagarajan@microchip.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mchp_pci1xxxx/mchp_pci1xxxx_gpio.c

@@ -14,6 +14,7 @@
 #include "mchp_pci1xxxx_gp.h"
 
 #define PCI1XXXX_NR_PINS		93
+#define PERI_GEN_RESET			0
 #define OUT_EN_OFFSET(x)		((((x) / 32) * 4) + 0x400)
 #define INP_EN_OFFSET(x)		((((x) / 32) * 4) + 0x400 + 0x10)
 #define OUT_OFFSET(x)			((((x) / 32) * 4) + 0x400 + 0x20)
@@ -291,6 +292,38 @@ static struct irq_chip pci1xxxx_gpio_irqchip = {
 	.irq_set_type = pci1xxxx_gpio_set_type,
 };
 
+static int pci1xxxx_gpio_suspend(struct device *dev)
+{
+	struct pci1xxxx_gpio *priv = dev_get_drvdata(dev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	pci1xxx_assign_bit(priv->reg_base, PIO_GLOBAL_CONFIG_OFFSET,
+			   16, true);
+	pci1xxx_assign_bit(priv->reg_base, PIO_GLOBAL_CONFIG_OFFSET,
+			   17, false);
+	pci1xxx_assign_bit(priv->reg_base, PERI_GEN_RESET, 16, true);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int pci1xxxx_gpio_resume(struct device *dev)
+{
+	struct pci1xxxx_gpio *priv = dev_get_drvdata(dev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	pci1xxx_assign_bit(priv->reg_base, PIO_GLOBAL_CONFIG_OFFSET,
+			   17, true);
+	pci1xxx_assign_bit(priv->reg_base, PIO_GLOBAL_CONFIG_OFFSET,
+			   16, false);
+	pci1xxx_assign_bit(priv->reg_base, PERI_GEN_RESET, 16, false);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
 static int pci1xxxx_gpio_setup(struct pci1xxxx_gpio *priv, int irq)
 {
 	struct gpio_chip *gchip = &priv->gpio;
@@ -325,6 +358,7 @@ static int pci1xxxx_gpio_setup(struct pci1xxxx_gpio *priv, int irq)
 	girq->parents = NULL;
 	girq->default_type = IRQ_TYPE_NONE;
 	girq->handler = handle_bad_irq;
+
 	return 0;
 }
 
@@ -370,6 +404,8 @@ static int pci1xxxx_gpio_probe(struct auxiliary_device *aux_dev,
 	return devm_gpiochip_add_data(&aux_dev->dev, &priv->gpio, priv);
 }
 
+static SIMPLE_DEV_PM_OPS(pci1xxxx_gpio_pm_ops, pci1xxxx_gpio_suspend, pci1xxxx_gpio_resume);
+
 const struct auxiliary_device_id pci1xxxx_gpio_auxiliary_id_table[] = {
 	{.name = "mchp_pci1xxxx_gp.gp_gpio"},
 	{}
@@ -378,6 +414,7 @@ const struct auxiliary_device_id pci1xxxx_gpio_auxiliary_id_table[] = {
 static struct auxiliary_driver pci1xxxx_gpio_driver = {
 	.driver = {
 		.name = "PCI1xxxxGPIO",
+		.pm = &pci1xxxx_gpio_pm_ops,
 		},
 	.probe = pci1xxxx_gpio_probe,
 	.id_table = pci1xxxx_gpio_auxiliary_id_table