ARM: S5P: Add common S5P GPIO Interrupt support

This patch adds common code to enable support of GPIO interrupt on
S5P SoCs.

The total number of GPIO pins is quite large on S5P SoCs. Registering
irq support for all of them would be a resource waste. Because of that
the interrupt support for standard GPIO pins is registered dynamically
by the s5p_register_gpio_interrupt() function.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
[kgene.kim@samsung.com: minor title fixes]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/plat-s5p/Kconfig

@@ -32,6 +32,11 @@ config S5P_EXT_INT
 	  Use the external interrupts (other than GPIO interrupts.)
 	  Note: Do not choose this for S5P6440 and S5P6450.
 
+config S5P_GPIO_INT
+	bool
+	help
+	  Common code for the GPIO interrupts (other than external interrupts.)
+
 config S5P_DEV_FIMC0
 	bool
 	help

arch/arm/plat-s5p/Makefile

@@ -18,6 +18,7 @@ obj-y				+= cpu.o
 obj-y				+= clock.o
 obj-y				+= irq.o
 obj-$(CONFIG_S5P_EXT_INT)	+= irq-eint.o
+obj-$(CONFIG_S5P_GPIO_INT)	+= irq-gpioint.o
 
 # devices
 

arch/arm/plat-s5p/include/plat/irqs.h

@@ -94,4 +94,13 @@
 						((irq) - S5P_EINT_BASE1) : \
 						((irq) + 16 - S5P_EINT_BASE2))
 
+/* Typically only a few gpio chips require gpio interrupt support.
+   To avoid memory waste irq descriptors are allocated only for
+   S5P_GPIOINT_GROUP_COUNT chips, each with total number of
+   S5P_GPIOINT_GROUP_SIZE pins/irqs. Each GPIOINT group can be assiged
+   to any gpio chip with the s5p_register_gpio_interrupt() function */
+#define S5P_GPIOINT_GROUP_COUNT 4
+#define S5P_GPIOINT_GROUP_SIZE	8
+#define S5P_GPIOINT_COUNT	(S5P_GPIOINT_GROUP_COUNT * S5P_GPIOINT_GROUP_SIZE)
+
 #endif /* __ASM_PLAT_S5P_IRQS_H */

arch/arm/plat-s5p/irq-gpioint.c

@@ -0,0 +1,242 @@
+/* linux/arch/arm/plat-s5p/irq-gpioint.c
+ *
+ * Copyright (c) 2010 Samsung Electronics Co., Ltd.
+ * Author: Kyungmin Park <kyungmin.park@samsung.com>
+ * Author: Joonyoung Shim <jy0922.shim@samsung.com>
+ * Author: Marek Szyprowski <m.szyprowski@samsung.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
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/gpio.h>
+
+#include <mach/map.h>
+#include <plat/gpio-core.h>
+#include <plat/gpio-cfg.h>
+
+#define S5P_GPIOREG(x)			(S5P_VA_GPIO + (x))
+
+#define GPIOINT_CON_OFFSET		0x700
+#define GPIOINT_MASK_OFFSET		0x900
+#define GPIOINT_PEND_OFFSET		0xA00
+
+#define GPIOINT_LEVEL_LOW		0x0
+#define GPIOINT_LEVEL_HIGH		0x1
+#define GPIOINT_EDGE_FALLING		0x2
+#define GPIOINT_EDGE_RISING		0x3
+#define GPIOINT_EDGE_BOTH		0x4
+
+static struct s3c_gpio_chip *irq_chips[S5P_GPIOINT_GROUP_MAXNR];
+
+static int s5p_gpioint_get_group(unsigned int irq)
+{
+	struct gpio_chip *chip = get_irq_data(irq);
+	struct s3c_gpio_chip *s3c_chip = container_of(chip,
+			struct s3c_gpio_chip, chip);
+	int group;
+
+	for (group = 0; group < S5P_GPIOINT_GROUP_MAXNR; group++)
+		if (s3c_chip == irq_chips[group])
+			break;
+
+	return group;
+}
+
+static int s5p_gpioint_get_offset(unsigned int irq)
+{
+	struct gpio_chip *chip = get_irq_data(irq);
+	struct s3c_gpio_chip *s3c_chip = container_of(chip,
+			struct s3c_gpio_chip, chip);
+
+	return irq - s3c_chip->irq_base;
+}
+
+static void s5p_gpioint_ack(unsigned int irq)
+{
+	int group, offset, pend_offset;
+	unsigned int value;
+
+	group = s5p_gpioint_get_group(irq);
+	offset = s5p_gpioint_get_offset(irq);
+	pend_offset = group << 2;
+
+	value = __raw_readl(S5P_GPIOREG(GPIOINT_PEND_OFFSET) + pend_offset);
+	value |= 1 << offset;
+	__raw_writel(value, S5P_GPIOREG(GPIOINT_PEND_OFFSET) + pend_offset);
+}
+
+static void s5p_gpioint_mask(unsigned int irq)
+{
+	int group, offset, mask_offset;
+	unsigned int value;
+
+	group = s5p_gpioint_get_group(irq);
+	offset = s5p_gpioint_get_offset(irq);
+	mask_offset = group << 2;
+
+	value = __raw_readl(S5P_GPIOREG(GPIOINT_MASK_OFFSET) + mask_offset);
+	value |= 1 << offset;
+	__raw_writel(value, S5P_GPIOREG(GPIOINT_MASK_OFFSET) + mask_offset);
+}
+
+static void s5p_gpioint_unmask(unsigned int irq)
+{
+	int group, offset, mask_offset;
+	unsigned int value;
+
+	group = s5p_gpioint_get_group(irq);
+	offset = s5p_gpioint_get_offset(irq);
+	mask_offset = group << 2;
+
+	value = __raw_readl(S5P_GPIOREG(GPIOINT_MASK_OFFSET) + mask_offset);
+	value &= ~(1 << offset);
+	__raw_writel(value, S5P_GPIOREG(GPIOINT_MASK_OFFSET) + mask_offset);
+}
+
+static void s5p_gpioint_mask_ack(unsigned int irq)
+{
+	s5p_gpioint_mask(irq);
+	s5p_gpioint_ack(irq);
+}
+
+static int s5p_gpioint_set_type(unsigned int irq, unsigned int type)
+{
+	int group, offset, con_offset;
+	unsigned int value;
+
+	group = s5p_gpioint_get_group(irq);
+	offset = s5p_gpioint_get_offset(irq);
+	con_offset = group << 2;
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_RISING:
+		type = GPIOINT_EDGE_RISING;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		type = GPIOINT_EDGE_FALLING;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		type = GPIOINT_EDGE_BOTH;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		type = GPIOINT_LEVEL_HIGH;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		type = GPIOINT_LEVEL_LOW;
+		break;
+	case IRQ_TYPE_NONE:
+	default:
+		printk(KERN_WARNING "No irq type\n");
+		return -EINVAL;
+	}
+
+	value = __raw_readl(S5P_GPIOREG(GPIOINT_CON_OFFSET) + con_offset);
+	value &= ~(0x7 << (offset * 0x4));
+	value |= (type << (offset * 0x4));
+	__raw_writel(value, S5P_GPIOREG(GPIOINT_CON_OFFSET) + con_offset);
+
+	return 0;
+}
+
+struct irq_chip s5p_gpioint = {
+	.name		= "s5p_gpioint",
+	.ack		= s5p_gpioint_ack,
+	.mask		= s5p_gpioint_mask,
+	.mask_ack	= s5p_gpioint_mask_ack,
+	.unmask		= s5p_gpioint_unmask,
+	.set_type	= s5p_gpioint_set_type,
+};
+
+static void s5p_gpioint_handler(unsigned int irq, struct irq_desc *desc)
+{
+	int group, offset, pend_offset, mask_offset;
+	int real_irq;
+	unsigned int pend, mask;
+
+	for (group = 0; group < S5P_GPIOINT_GROUP_MAXNR; group++) {
+		pend_offset = group << 2;
+		pend = __raw_readl(S5P_GPIOREG(GPIOINT_PEND_OFFSET) +
+				pend_offset);
+		if (!pend)
+			continue;
+
+		mask_offset = group << 2;
+		mask = __raw_readl(S5P_GPIOREG(GPIOINT_MASK_OFFSET) +
+				mask_offset);
+		pend &= ~mask;
+
+		for (offset = 0; offset < 8; offset++) {
+			if (pend & (1 << offset)) {
+				struct s3c_gpio_chip *chip = irq_chips[group];
+				if (chip) {
+					real_irq = chip->irq_base + offset;
+					generic_handle_irq(real_irq);
+				}
+			}
+		}
+	}
+}
+
+static __init int s5p_gpioint_add(struct s3c_gpio_chip *chip)
+{
+	static int used_gpioint_groups = 0;
+	static bool handler_registered = 0;
+	int irq, group = chip->group;
+	int i;
+
+	if (used_gpioint_groups >= S5P_GPIOINT_GROUP_COUNT)
+		return -ENOMEM;
+
+	chip->irq_base = S5P_GPIOINT_BASE +
+			 used_gpioint_groups * S5P_GPIOINT_GROUP_SIZE;
+	used_gpioint_groups++;
+
+	if (!handler_registered) {
+		set_irq_chained_handler(IRQ_GPIOINT, s5p_gpioint_handler);
+		handler_registered = 1;
+	}
+
+	irq_chips[group] = chip;
+	for (i = 0; i < chip->chip.ngpio; i++) {
+		irq = chip->irq_base + i;
+		set_irq_chip(irq, &s5p_gpioint);
+		set_irq_data(irq, &chip->chip);
+		set_irq_handler(irq, handle_level_irq);
+		set_irq_flags(irq, IRQF_VALID);
+	}
+	return 0;
+}
+
+int __init s5p_register_gpio_interrupt(int pin)
+{
+	struct s3c_gpio_chip *my_chip = s3c_gpiolib_getchip(pin);
+	int offset, group;
+	int ret;
+
+	if (!my_chip)
+		return -EINVAL;
+
+	offset = pin - my_chip->chip.base;
+	group = my_chip->group;
+
+	/* check if the group has been already registered */
+	if (my_chip->irq_base)
+		return my_chip->irq_base + offset;
+
+	/* register gpio group */
+	ret = s5p_gpioint_add(my_chip);
+	if (ret == 0) {
+		printk(KERN_INFO "Registered interrupt support for gpio group %d.\n",
+		       group);
+		return my_chip->irq_base + offset;
+	}
+	return ret;
+}

arch/arm/plat-samsung/include/plat/gpio-cfg.h

@@ -169,4 +169,22 @@ extern s5p_gpio_drvstr_t s5p_gpio_get_drvstr(unsigned int pin);
 */
 extern int s5p_gpio_set_drvstr(unsigned int pin, s5p_gpio_drvstr_t drvstr);
 
+/**
+ * s5p_register_gpio_interrupt() - register interrupt support for a gpio group
+ * @pin: The pin number from the group to be registered
+ *
+ * This function registers gpio interrupt support for the group that the
+ * specified pin belongs to.
+ *
+ * The total number of gpio pins is quite large ob s5p series. Registering
+ * irq support for all of them would be a resource waste. Because of that the
+ * interrupt support for standard gpio pins is registered dynamically.
+ *
+ * It will return the irq number of the interrupt that has been registered
+ * or -ENOMEM if no more gpio interrupts can be registered. It is allowed
+ * to call this function more than once for the same gpio group (the group
+ * will be registered only once).
+ */
+extern int s5p_register_gpio_interrupt(int pin);
+
 #endif /* __PLAT_GPIO_CFG_H */

arch/arm/plat-samsung/include/plat/gpio-core.h

@@ -43,6 +43,8 @@ struct s3c_gpio_cfg;
  * struct s3c_gpio_chip - wrapper for specific implementation of gpio
  * @chip: The chip structure to be exported via gpiolib.
  * @base: The base pointer to the gpio configuration registers.
+ * @group: The group register number for gpio interrupt support.
+ * @irq_base: The base irq number.
  * @config: special function and pull-resistor control information.
  * @lock: Lock for exclusive access to this gpio bank.
  * @pm_save: Save information for suspend/resume support.
@@ -63,6 +65,8 @@ struct s3c_gpio_chip {
 	struct s3c_gpio_cfg	*config;
 	struct s3c_gpio_pm	*pm;
 	void __iomem		*base;
+	int			irq_base;
+	int			group;
 	spinlock_t		 lock;
 #ifdef CONFIG_PM
 	u32			pm_save[4];