Enable X-Gene standby GPIO controller as interrupt controller to provide
its own resources. This avoids ambiguity where GIC interrupt resource is
use as X-Gene standby GPIO interrupt resource in user driver.

Signed-off-by: Y Vo <redacted>
Signed-off-by: Quan Nguyen <redacted>
---
 drivers/gpio/gpio-xgene-sb.c | 275 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 243 insertions(+), 32 deletions(-)

diff --git a/drivers/gpio/gpio-xgene-sb.c b/drivers/gpio/gpio-xgene-sb.c
index 282004d..026da90 100644
--- a/drivers/gpio/gpio-xgene-sb.c
+++ b/drivers/gpio/gpio-xgene-sb.c

@@ -2,8 +2,9 @@
  * AppliedMicro X-Gene SoC GPIO-Standby Driver
  *
  * Copyright (c) 2014, Applied Micro Circuits Corporation
- * Author: 	Tin Huynh <tnhuynh@apm.com>.
- * 		Y Vo <yvo@apm.com>.
+ * Author:	Tin Huynh <tnhuynh@apm.com>.
+ *		Y Vo <yvo@apm.com>.
+ *		Quan Nguyen <qnguyen@apm.com>.
  *
  * This program is free software; you can redistribute  it and/or modify it
  * under  the terms of  the GNU General  Public License as published by the

@@ -28,9 +29,14 @@
 
 #include "gpiolib.h"
 
-#define XGENE_MAX_GPIO_DS		22
-#define XGENE_MAX_GPIO_DS_IRQ		6
+/* Common property names */
+#define XGENE_NIRQ_PROPERTY		"apm,nr-irqs"
+#define XGENE_NGPIO_PROPERTY		"apm,nr-gpios"
+#define XGENE_IRQ_START_PROPERTY	"apm,irq-start"
 
+#define XGENE_DFLT_MAX_NGPIO		22
+#define XGENE_DFLT_MAX_NIRQ		6
+#define XGENE_DFLT_IRQ_START_PIN	8
 #define GPIO_MASK(x)			(1U << ((x) % 32))
 
 #define MPA_GPIO_INT_LVL		0x0290

@@ -39,19 +45,32 @@
 #define MPA_GPIO_IN_ADDR 		0x02a4
 #define MPA_GPIO_SEL_LO 		0x0294
 
+#define GPIO_INT_LEVEL_H	0x000001
+#define GPIO_INT_LEVEL_L	0x000000
+
 /**
  * struct xgene_gpio_sb - GPIO-Standby private data structure.
  * @gc:				memory-mapped GPIO controllers.
- * @irq:			Mapping GPIO pins and interrupt number
- * nirq:			Number of GPIO pins that supports interrupt
+ * @regs:			GPIO register base offset
+ * @irq_domain:			GPIO interrupt domain
+ * @irq_start:			GPIO pin that start support interrupt
+ * @nirq:			Number of GPIO pins that supports interrupt
+ * @parent_irq_base:		Start parent HWIRQ
  */
 struct xgene_gpio_sb {
 	struct gpio_chip	gc;
-	u32 *irq;
-	u32 nirq;
+	void __iomem		*regs;
+	struct irq_domain	*irq_domain;
+	u16			irq_start;
+	u16			nirq;
+	u16			parent_irq_base;
 };
 
-static void xgene_gpio_set_bit(struct gpio_chip *gc, void __iomem *reg, u32 gpio, int val)
+#define HWIRQ_TO_GPIO(priv, hwirq) ((hwirq) + (priv)->irq_start)
+#define GPIO_TO_HWIRQ(priv, gpio) ((gpio) - (priv)->irq_start)
+
+static void xgene_gpio_set_bit(struct gpio_chip *gc,
+				void __iomem *reg, u32 gpio, int val)
 {
 	u32 data;
 

@@ -63,23 +82,180 @@ static void xgene_gpio_set_bit(struct gpio_chip *gc, void __iomem *reg, u32 gpio
 	gc->write_reg(reg, data);
 }
 
-static int apm_gpio_sb_to_irq(struct gpio_chip *gc, u32 gpio)
+static int xgene_gpio_sb_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct xgene_gpio_sb *priv = irq_data_get_irq_chip_data(d);
+	int gpio = HWIRQ_TO_GPIO(priv, d->hwirq);
+	int lvl_type = GPIO_INT_LEVEL_H;
+
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_RISING:
+	case IRQ_TYPE_LEVEL_HIGH:
+		lvl_type = GPIO_INT_LEVEL_H;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+	case IRQ_TYPE_LEVEL_LOW:
+		lvl_type = GPIO_INT_LEVEL_L;
+		break;
+	default:
+		break;
+	}
+
+	xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_SEL_LO,
+			gpio * 2, 1);
+	xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_INT_LVL,
+			d->hwirq, lvl_type);
+
+	/* Propagate IRQ type setting to parent */
+	if (type & IRQ_TYPE_EDGE_BOTH)
+		return irq_chip_set_type_parent(d, IRQ_TYPE_EDGE_RISING);
+	else
+		return irq_chip_set_type_parent(d, IRQ_TYPE_LEVEL_HIGH);
+}
+
+static void xgene_gpio_sb_irq_shutdown(struct irq_data *d)
+{
+	struct xgene_gpio_sb *priv = irq_data_get_irq_chip_data(d);
+
+	gpiochip_unlock_as_irq(&priv->gc, HWIRQ_TO_GPIO(priv, d->hwirq));
+}
+
+static struct irq_chip xgene_gpio_sb_irq_chip = {
+	.name           = "sbgpio",
+	.irq_ack        = irq_chip_ack_parent,

+		parent_fwspec.param_count = 2;
+		parent_fwspec.param[0] = hwirq + priv->parent_irq_base;
+		parent_fwspec.param[1] = fwspec->param[1];
+	} else
+		return -EINVAL;
 
-	return -ENXIO;
+	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
+			&parent_fwspec);
 }
 
+static void xgene_gpio_sb_domain_free(struct irq_domain *domain,
+		unsigned int virq,
+		unsigned int nr_irqs)
+{
+	struct irq_data *d;
+	unsigned int i;
+
+	for (i = 0; i < nr_irqs; i++) {
+		d = irq_domain_get_irq_data(domain, virq + i);
+		irq_domain_reset_irq_data(d);
+	}
+}
+
+static const struct irq_domain_ops xgene_gpio_sb_domain_ops = {
+	.translate      = xgene_gpio_sb_domain_translate,
+	.alloc          = xgene_gpio_sb_domain_alloc,
+	.free           = xgene_gpio_sb_domain_free,
+	.activate	= xgene_gpio_sb_domain_activate,
+	.deactivate	= xgene_gpio_sb_domain_deactivate,
+};
+
 static int xgene_gpio_sb_probe(struct platform_device *pdev)
 {
 	struct xgene_gpio_sb *priv;
-	u32 ret, i;
-	u32 default_lines[] = {0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D};
+	u32 ret;
 	struct resource *res;
 	void __iomem *regs;
+	struct irq_domain *parent_domain = NULL;
+	struct fwnode_handle *fwnode;
+	u32 val32;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)

@@ -90,6 +266,18 @@ static int xgene_gpio_sb_probe(struct platform_device *pdev)
 	if (IS_ERR(regs))
 		return PTR_ERR(regs);
 
+	priv->regs = regs;
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret > 0) {
+		priv->parent_irq_base = irq_get_irq_data(ret)->hwirq;
+		parent_domain = irq_get_irq_data(ret)->domain;
+	}
+	if (!parent_domain) {
+		dev_err(&pdev->dev, "unable to obtain parent domain\n");
+		return -ENODEV;
+	}
+
 	ret = bgpio_init(&priv->gc, &pdev->dev, 4,
 			regs + MPA_GPIO_IN_ADDR,
 			regs + MPA_GPIO_OUT_ADDR, NULL,

@@ -97,30 +285,51 @@ static int xgene_gpio_sb_probe(struct platform_device *pdev)
         if (ret)
                 return ret;
 
-	priv->gc.to_irq = apm_gpio_sb_to_irq;
-	priv->gc.ngpio = XGENE_MAX_GPIO_DS;
+	priv->gc.to_irq = xgene_gpio_sb_to_irq;
 
-	priv->nirq = XGENE_MAX_GPIO_DS_IRQ;
+	/* Retrieve start irq pin, use default if property not found */
+	priv->irq_start = XGENE_DFLT_IRQ_START_PIN;
+	if (!device_property_read_u32(&pdev->dev,
+					XGENE_IRQ_START_PROPERTY, &val32))

+		priv->irq_start = val32;
 
-	priv->irq = devm_kzalloc(&pdev->dev, sizeof(u32) * XGENE_MAX_GPIO_DS,
-				   GFP_KERNEL);
-	if (!priv->irq)
-		return -ENOMEM;
+	/* Retrieve number irqs, use default if property not found */
+	priv->nirq = XGENE_DFLT_MAX_NIRQ;
+	if (!device_property_read_u32(&pdev->dev, XGENE_NIRQ_PROPERTY, &val32))
+		priv->nirq = val32;
 
-	for (i = 0; i < priv->nirq; i++) {
-		priv->irq[default_lines[i]] = platform_get_irq(pdev, i);
-		xgene_gpio_set_bit(&priv->gc, regs + MPA_GPIO_SEL_LO,
-                                   default_lines[i] * 2, 1);
-		xgene_gpio_set_bit(&priv->gc, regs + MPA_GPIO_INT_LVL, i, 1);
-	}
+	/* Retrieve number gpio, use default if property not found */
+	priv->gc.ngpio = XGENE_DFLT_MAX_NGPIO;
+	if (!device_property_read_u32(&pdev->dev, XGENE_NGPIO_PROPERTY, &val32))
+		priv->gc.ngpio = val32;
+
+	dev_info(&pdev->dev, "Support %d gpios, %d irqs start from pin %d\n",
+			priv->gc.ngpio, priv->nirq, priv->irq_start);
 
 	platform_set_drvdata(pdev, priv);
 
-	ret = gpiochip_add_data(&priv->gc, priv);
-	if (ret)
-		dev_err(&pdev->dev, "failed to register X-Gene GPIO Standby driver\n");
+	if (pdev->dev.of_node)
+		fwnode = of_node_to_fwnode(pdev->dev.of_node);
 	else
-		dev_info(&pdev->dev, "X-Gene GPIO Standby driver registered\n");
+		fwnode = pdev->dev.fwnode;
+
+	priv->irq_domain = irq_domain_create_hierarchy(parent_domain,
+					0, priv->nirq, fwnode,
+					&xgene_gpio_sb_domain_ops, priv);
+	if (!priv->irq_domain)
+		return -ENODEV;
+
+	priv->gc.irqdomain = priv->irq_domain;
+
+	ret = gpiochip_add_data(&priv->gc, priv);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"failed to register X-Gene GPIO Standby driver\n");
+		irq_domain_remove(priv->irq_domain);
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "X-Gene GPIO Standby driver registered\n");
 
 	if (priv->nirq > 0) {
 		/* Register interrupt handlers for gpio signaled acpi events */

@@ -138,6 +347,8 @@ static int xgene_gpio_sb_remove(struct platform_device *pdev)
 		acpi_gpiochip_free_interrupts(&priv->gc);
 	}
 
+	irq_domain_remove(priv->irq_domain);
+
 	gpiochip_remove(&priv->gc);
 	return 0;
 }