drivers/gpio/gpio-lynxpoint.c - kernel/msm-5.4 - Gitiles

 /*
  * GPIO controller driver for Intel Lynxpoint PCH chipset>
  * Copyright (c) 2012, Intel Corporation.
  *
  * Author: Mathias Nyman <mathias.nyman@linux.intel.com>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  *
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/bitops.h>
 #include <linux/interrupt.h>
 #include <linux/gpio.h>
 #include <linux/slab.h>
 #include <linux/acpi.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/io.h>

 /* LynxPoint chipset has support for 94 gpio pins */

 #define LP_NUM_GPIO	94

 /* Bitmapped register offsets */
 #define LP_ACPI_OWNED	0x00 /* Bitmap, set by bios, 0: pin reserved for ACPI */
 #define LP_GC		0x7C /* set APIC IRQ to IRQ14 or IRQ15 for all pins */
 #define LP_INT_STAT	0x80
 #define LP_INT_ENABLE	0x90

 /* Each pin has two 32 bit config registers, starting at 0x100 */
 #define LP_CONFIG1	0x100
 #define LP_CONFIG2	0x104

 /* LP_CONFIG1 reg bits */
 #define OUT_LVL_BIT	BIT(31)
 #define IN_LVL_BIT	BIT(30)
 #define TRIG_SEL_BIT	BIT(4) /* 0: Edge, 1: Level */
 #define INT_INV_BIT	BIT(3) /* Invert interrupt triggering */
 #define DIR_BIT		BIT(2) /* 0: Output, 1: Input */
 #define USE_SEL_BIT	BIT(0) /* 0: Native, 1: GPIO */

 /* LP_CONFIG2 reg bits */
 #define GPINDIS_BIT	BIT(2) /* disable input sensing */
 #define GPIWP_BIT	(BIT(0) | BIT(1)) /* weak pull options */

 struct lp_gpio {
 	struct gpio_chip	chip;
 	struct platform_device	*pdev;
 	spinlock_t		lock;
 	unsigned long		reg_base;
 };

 /*
  * Lynxpoint gpios are controlled through both bitmapped registers and
  * per gpio specific registers. The bitmapped registers are in chunks of
  * 3 x 32bit registers to cover all 94 gpios
  *
  * per gpio specific registers consist of two 32bit registers per gpio
  * (LP_CONFIG1 and LP_CONFIG2), with 94 gpios there's a total of
  * 188 config registers.
  *
  * A simplified view of the register layout look like this:
  *
  * LP_ACPI_OWNED[31:0] gpio ownerships for gpios 0-31  (bitmapped registers)
  * LP_ACPI_OWNED[63:32] gpio ownerships for gpios 32-63
  * LP_ACPI_OWNED[94:64] gpio ownerships for gpios 63-94
  * ...
  * LP_INT_ENABLE[31:0] ...
  * LP_INT_ENABLE[63:31] ...
  * LP_INT_ENABLE[94:64] ...
  * LP0_CONFIG1 (gpio 0) config1 reg for gpio 0 (per gpio registers)
  * LP0_CONFIG2 (gpio 0) config2 reg for gpio 0
  * LP1_CONFIG1 (gpio 1) config1 reg for gpio 1
  * LP1_CONFIG2 (gpio 1) config2 reg for gpio 1
  * LP2_CONFIG1 (gpio 2) ...
  * LP2_CONFIG2 (gpio 2) ...
  * ...
  * LP94_CONFIG1 (gpio 94) ...
  * LP94_CONFIG2 (gpio 94) ...
  */

 static unsigned long lp_gpio_reg(struct gpio_chip *chip, unsigned offset,
 				 int reg)
 {
 	struct lp_gpio *lg = gpiochip_get_data(chip);
 	int reg_offset;

 	if (reg == LP_CONFIG1 || reg == LP_CONFIG2)
 		/* per gpio specific config registers */
 		reg_offset = offset * 8;
 	else
 		/* bitmapped registers */
 		reg_offset = (offset / 32) * 4;

 	return lg->reg_base + reg + reg_offset;
 }

 static int lp_gpio_request(struct gpio_chip *chip, unsigned offset)
 {
 	struct lp_gpio *lg = gpiochip_get_data(chip);
 	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
 	unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);
 	unsigned long acpi_use = lp_gpio_reg(chip, offset, LP_ACPI_OWNED);

 	pm_runtime_get(&lg->pdev->dev); /* should we put if failed */

 	/* Fail if BIOS reserved pin for ACPI use */
 	if (!(inl(acpi_use) & BIT(offset % 32))) {
 		dev_err(&lg->pdev->dev, "gpio %d reserved for ACPI\n", offset);
 		return -EBUSY;
 	}
 	/* Fail if pin is in alternate function mode (not GPIO mode) */
 	if (!(inl(reg) & USE_SEL_BIT))
 		return -ENODEV;

 	/* enable input sensing */
 	outl(inl(conf2) & ~GPINDIS_BIT, conf2);


 	return 0;
 }

 static void lp_gpio_free(struct gpio_chip *chip, unsigned offset)
 {
 	struct lp_gpio *lg = gpiochip_get_data(chip);
 	unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);

 	/* disable input sensing */
 	outl(inl(conf2) | GPINDIS_BIT, conf2);

 	pm_runtime_put(&lg->pdev->dev);
 }

 static int lp_irq_type(struct irq_data *d, unsigned type)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct lp_gpio *lg = gpiochip_get_data(gc);
 	u32 hwirq = irqd_to_hwirq(d);
 	unsigned long flags;
 	u32 value;
 	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_CONFIG1);

 	if (hwirq >= lg->chip.ngpio)
 		return -EINVAL;

 	spin_lock_irqsave(&lg->lock, flags);
 	value = inl(reg);

 	/* set both TRIG_SEL and INV bits to 0 for rising edge */
 	if (type & IRQ_TYPE_EDGE_RISING)
 		value &= ~(TRIG_SEL_BIT | INT_INV_BIT);

 	/* TRIG_SEL bit 0, INV bit 1 for falling edge */
 	if (type & IRQ_TYPE_EDGE_FALLING)
 		value = (value | INT_INV_BIT) & ~TRIG_SEL_BIT;

 	/* TRIG_SEL bit 1, INV bit 0 for level low */
 	if (type & IRQ_TYPE_LEVEL_LOW)
 		value = (value | TRIG_SEL_BIT) & ~INT_INV_BIT;

 	/* TRIG_SEL bit 1, INV bit 1 for level high */
 	if (type & IRQ_TYPE_LEVEL_HIGH)
 		value |= TRIG_SEL_BIT | INT_INV_BIT;

 	outl(value, reg);
 	spin_unlock_irqrestore(&lg->lock, flags);

 	return 0;
 }

 static int lp_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
 	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
 	return !!(inl(reg) & IN_LVL_BIT);
 }

 static void lp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct lp_gpio *lg = gpiochip_get_data(chip);
 	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
 	unsigned long flags;

 	spin_lock_irqsave(&lg->lock, flags);

 	if (value)
 		outl(inl(reg) | OUT_LVL_BIT, reg);
 	else
 		outl(inl(reg) & ~OUT_LVL_BIT, reg);

 	spin_unlock_irqrestore(&lg->lock, flags);
 }

 static int lp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 {
 	struct lp_gpio *lg = gpiochip_get_data(chip);
 	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
 	unsigned long flags;

 	spin_lock_irqsave(&lg->lock, flags);
 	outl(inl(reg) | DIR_BIT, reg);
 	spin_unlock_irqrestore(&lg->lock, flags);

 	return 0;
 }

 static int lp_gpio_direction_output(struct gpio_chip *chip,
 				      unsigned offset, int value)
 {
 	struct lp_gpio *lg = gpiochip_get_data(chip);
 	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
 	unsigned long flags;

 	lp_gpio_set(chip, offset, value);

 	spin_lock_irqsave(&lg->lock, flags);
 	outl(inl(reg) & ~DIR_BIT, reg);
 	spin_unlock_irqrestore(&lg->lock, flags);

 	return 0;
 }

 static void lp_gpio_irq_handler(struct irq_desc *desc)
 {
 	struct irq_data *data = irq_desc_get_irq_data(desc);
 	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
 	struct lp_gpio *lg = gpiochip_get_data(gc);
 	struct irq_chip *chip = irq_data_get_irq_chip(data);
 	u32 base, pin, mask;
 	unsigned long reg, ena, pending;

 	/* check from GPIO controller which pin triggered the interrupt */
 	for (base = 0; base < lg->chip.ngpio; base += 32) {
 		reg = lp_gpio_reg(&lg->chip, base, LP_INT_STAT);
 		ena = lp_gpio_reg(&lg->chip, base, LP_INT_ENABLE);

 		while ((pending = (inl(reg) & inl(ena)))) {
 			unsigned irq;

 			pin = __ffs(pending);
 			mask = BIT(pin);
 			/* Clear before handling so we don't lose an edge */
 			outl(mask, reg);
 			irq = irq_find_mapping(lg->chip.irqdomain, base + pin);
 			generic_handle_irq(irq);
 		}
 	}
 	chip->irq_eoi(data);
 }

 static void lp_irq_unmask(struct irq_data *d)
 {
 }

 static void lp_irq_mask(struct irq_data *d)
 {
 }

 static void lp_irq_enable(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct lp_gpio *lg = gpiochip_get_data(gc);
 	u32 hwirq = irqd_to_hwirq(d);
 	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
 	unsigned long flags;

 	spin_lock_irqsave(&lg->lock, flags);
 	outl(inl(reg) | BIT(hwirq % 32), reg);
 	spin_unlock_irqrestore(&lg->lock, flags);
 }

 static void lp_irq_disable(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct lp_gpio *lg = gpiochip_get_data(gc);
 	u32 hwirq = irqd_to_hwirq(d);
 	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
 	unsigned long flags;

 	spin_lock_irqsave(&lg->lock, flags);
 	outl(inl(reg) & ~BIT(hwirq % 32), reg);
 	spin_unlock_irqrestore(&lg->lock, flags);
 }

 static struct irq_chip lp_irqchip = {
 	.name = "LP-GPIO",
 	.irq_mask = lp_irq_mask,
 	.irq_unmask = lp_irq_unmask,
 	.irq_enable = lp_irq_enable,
 	.irq_disable = lp_irq_disable,
 	.irq_set_type = lp_irq_type,
 	.flags = IRQCHIP_SKIP_SET_WAKE,
 };

 static void lp_gpio_irq_init_hw(struct lp_gpio *lg)
 {
 	unsigned long reg;
 	unsigned base;

 	for (base = 0; base < lg->chip.ngpio; base += 32) {
 		/* disable gpio pin interrupts */
 		reg = lp_gpio_reg(&lg->chip, base, LP_INT_ENABLE);
 		outl(0, reg);
 		/* Clear interrupt status register */
 		reg = lp_gpio_reg(&lg->chip, base, LP_INT_STAT);
 		outl(0xffffffff, reg);
 	}
 }

 static int lp_gpio_probe(struct platform_device *pdev)
 {
 	struct lp_gpio *lg;
 	struct gpio_chip *gc;
 	struct resource *io_rc, *irq_rc;
 	struct device *dev = &pdev->dev;
 	unsigned long reg_len;
 	int ret = -ENODEV;

 	lg = devm_kzalloc(dev, sizeof(struct lp_gpio), GFP_KERNEL);
 	if (!lg)
 		return -ENOMEM;

 	lg->pdev = pdev;
 	platform_set_drvdata(pdev, lg);

 	io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
 	irq_rc = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

 	if (!io_rc) {
 		dev_err(dev, "missing IO resources\n");
 		return -EINVAL;
 	}

 	lg->reg_base = io_rc->start;
 	reg_len = resource_size(io_rc);

 	if (!devm_request_region(dev, lg->reg_base, reg_len, "lp-gpio")) {
 		dev_err(dev, "failed requesting IO region 0x%x\n",
 			(unsigned int)lg->reg_base);
 		return -EBUSY;
 	}

 	spin_lock_init(&lg->lock);

 	gc = &lg->chip;
 	gc->label = dev_name(dev);
 	gc->owner = THIS_MODULE;
 	gc->request = lp_gpio_request;
 	gc->free = lp_gpio_free;
 	gc->direction_input = lp_gpio_direction_input;
 	gc->direction_output = lp_gpio_direction_output;
 	gc->get = lp_gpio_get;
 	gc->set = lp_gpio_set;
 	gc->base = -1;
 	gc->ngpio = LP_NUM_GPIO;
 	gc->can_sleep = false;
 	gc->parent = dev;

 	ret = gpiochip_add_data(gc, lg);
 	if (ret) {
 		dev_err(dev, "failed adding lp-gpio chip\n");
 		return ret;
 	}

 	/* set up interrupts  */
 	if (irq_rc && irq_rc->start) {
 		lp_gpio_irq_init_hw(lg);
 		ret = gpiochip_irqchip_add(gc, &lp_irqchip, 0,
 					   handle_simple_irq, IRQ_TYPE_NONE);
 		if (ret) {
 			dev_err(dev, "failed to add irqchip\n");
 			gpiochip_remove(gc);
 			return ret;
 		}

 		gpiochip_set_chained_irqchip(gc, &lp_irqchip,
 					     (unsigned)irq_rc->start,
 					     lp_gpio_irq_handler);
 	}

 	pm_runtime_enable(dev);

 	return 0;
 }

 static int lp_gpio_runtime_suspend(struct device *dev)
 {
 	return 0;
 }

 static int lp_gpio_runtime_resume(struct device *dev)
 {
 	return 0;
 }

 static int lp_gpio_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct lp_gpio *lg = platform_get_drvdata(pdev);
 	unsigned long reg;
 	int i;

 	/* on some hardware suspend clears input sensing, re-enable it here */
 	for (i = 0; i < lg->chip.ngpio; i++) {
 		if (gpiochip_is_requested(&lg->chip, i) != NULL) {
 			reg = lp_gpio_reg(&lg->chip, i, LP_CONFIG2);
 			outl(inl(reg) & ~GPINDIS_BIT, reg);
 		}
 	}
 	return 0;
 }

 static const struct dev_pm_ops lp_gpio_pm_ops = {
 	.runtime_suspend = lp_gpio_runtime_suspend,
 	.runtime_resume = lp_gpio_runtime_resume,
 	.resume = lp_gpio_resume,
 };

 static const struct acpi_device_id lynxpoint_gpio_acpi_match[] = {
 	{ "INT33C7", 0 },
 	{ "INT3437", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(acpi, lynxpoint_gpio_acpi_match);

 static int lp_gpio_remove(struct platform_device *pdev)
 {
 	struct lp_gpio *lg = platform_get_drvdata(pdev);
 	pm_runtime_disable(&pdev->dev);
 	gpiochip_remove(&lg->chip);
 	return 0;
 }

 static struct platform_driver lp_gpio_driver = {
 	.probe          = lp_gpio_probe,
 	.remove         = lp_gpio_remove,
 	.driver         = {
 		.name   = "lp_gpio",
 		.pm	= &lp_gpio_pm_ops,
 		.acpi_match_table = ACPI_PTR(lynxpoint_gpio_acpi_match),
 	},
 };

 static int __init lp_gpio_init(void)
 {
 	return platform_driver_register(&lp_gpio_driver);
 }

 static void __exit lp_gpio_exit(void)
 {
 	platform_driver_unregister(&lp_gpio_driver);
 }

 subsys_initcall(lp_gpio_init);
 module_exit(lp_gpio_exit);

 MODULE_AUTHOR("Mathias Nyman (Intel)");
 MODULE_DESCRIPTION("GPIO interface for Intel Lynxpoint");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:lp_gpio");
	/*
	* GPIO controller driver for Intel Lynxpoint PCH chipset>
	* Copyright (c) 2012, Intel Corporation.
	*
	* Author: Mathias Nyman <mathias.nyman@linux.intel.com>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program; if not, write to the Free Software Foundation, Inc.,
	* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
	*
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/types.h>
	#include <linux/bitops.h>
	#include <linux/interrupt.h>
	#include <linux/gpio.h>
	#include <linux/slab.h>
	#include <linux/acpi.h>
	#include <linux/platform_device.h>
	#include <linux/pm_runtime.h>
	#include <linux/io.h>

	/* LynxPoint chipset has support for 94 gpio pins */

	#define LP_NUM_GPIO 94

	/* Bitmapped register offsets */
	#define LP_ACPI_OWNED 0x00 /* Bitmap, set by bios, 0: pin reserved for ACPI */
	#define LP_GC 0x7C /* set APIC IRQ to IRQ14 or IRQ15 for all pins */
	#define LP_INT_STAT 0x80
	#define LP_INT_ENABLE 0x90

	/* Each pin has two 32 bit config registers, starting at 0x100 */
	#define LP_CONFIG1 0x100
	#define LP_CONFIG2 0x104

	/* LP_CONFIG1 reg bits */
	#define OUT_LVL_BIT BIT(31)
	#define IN_LVL_BIT BIT(30)
	#define TRIG_SEL_BIT BIT(4) /* 0: Edge, 1: Level */
	#define INT_INV_BIT BIT(3) /* Invert interrupt triggering */
	#define DIR_BIT BIT(2) /* 0: Output, 1: Input */
	#define USE_SEL_BIT BIT(0) /* 0: Native, 1: GPIO */

	/* LP_CONFIG2 reg bits */
	#define GPINDIS_BIT BIT(2) /* disable input sensing */
	#define GPIWP_BIT (BIT(0) \| BIT(1)) /* weak pull options */

	struct lp_gpio {
	struct gpio_chip chip;
	struct platform_device *pdev;
	spinlock_t lock;
	unsigned long reg_base;
	};

	/*
	* Lynxpoint gpios are controlled through both bitmapped registers and
	* per gpio specific registers. The bitmapped registers are in chunks of
	* 3 x 32bit registers to cover all 94 gpios
	*
	* per gpio specific registers consist of two 32bit registers per gpio
	* (LP_CONFIG1 and LP_CONFIG2), with 94 gpios there's a total of
	* 188 config registers.
	*
	* A simplified view of the register layout look like this:
	*
	* LP_ACPI_OWNED[31:0] gpio ownerships for gpios 0-31 (bitmapped registers)
	* LP_ACPI_OWNED[63:32] gpio ownerships for gpios 32-63
	* LP_ACPI_OWNED[94:64] gpio ownerships for gpios 63-94
	* ...
	* LP_INT_ENABLE[31:0] ...
	* LP_INT_ENABLE[63:31] ...
	* LP_INT_ENABLE[94:64] ...
	* LP0_CONFIG1 (gpio 0) config1 reg for gpio 0 (per gpio registers)
	* LP0_CONFIG2 (gpio 0) config2 reg for gpio 0
	* LP1_CONFIG1 (gpio 1) config1 reg for gpio 1
	* LP1_CONFIG2 (gpio 1) config2 reg for gpio 1
	* LP2_CONFIG1 (gpio 2) ...
	* LP2_CONFIG2 (gpio 2) ...
	* ...
	* LP94_CONFIG1 (gpio 94) ...
	* LP94_CONFIG2 (gpio 94) ...
	*/

	static unsigned long lp_gpio_reg(struct gpio_chip *chip, unsigned offset,
	int reg)
	{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	int reg_offset;

	if (reg == LP_CONFIG1 \|\| reg == LP_CONFIG2)
	/* per gpio specific config registers */
	reg_offset = offset * 8;
	else
	/* bitmapped registers */
	reg_offset = (offset / 32) * 4;

	return lg->reg_base + reg + reg_offset;
	}

	static int lp_gpio_request(struct gpio_chip *chip, unsigned offset)
	{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);
	unsigned long acpi_use = lp_gpio_reg(chip, offset, LP_ACPI_OWNED);

	pm_runtime_get(&lg->pdev->dev); /* should we put if failed */

	/* Fail if BIOS reserved pin for ACPI use */
	if (!(inl(acpi_use) & BIT(offset % 32))) {
	dev_err(&lg->pdev->dev, "gpio %d reserved for ACPI\n", offset);
	return -EBUSY;
	}
	/* Fail if pin is in alternate function mode (not GPIO mode) */
	if (!(inl(reg) & USE_SEL_BIT))
	return -ENODEV;

	/* enable input sensing */
	outl(inl(conf2) & ~GPINDIS_BIT, conf2);


	return 0;
	}

	static void lp_gpio_free(struct gpio_chip *chip, unsigned offset)
	{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);

	/* disable input sensing */
	outl(inl(conf2) \| GPINDIS_BIT, conf2);

	pm_runtime_put(&lg->pdev->dev);
	}

	static int lp_irq_type(struct irq_data *d, unsigned type)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct lp_gpio *lg = gpiochip_get_data(gc);
	u32 hwirq = irqd_to_hwirq(d);
	unsigned long flags;
	u32 value;
	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_CONFIG1);

	if (hwirq >= lg->chip.ngpio)
	return -EINVAL;

	spin_lock_irqsave(&lg->lock, flags);
	value = inl(reg);

	/* set both TRIG_SEL and INV bits to 0 for rising edge */
	if (type & IRQ_TYPE_EDGE_RISING)
	value &= ~(TRIG_SEL_BIT \| INT_INV_BIT);

	/* TRIG_SEL bit 0, INV bit 1 for falling edge */
	if (type & IRQ_TYPE_EDGE_FALLING)
	value = (value \| INT_INV_BIT) & ~TRIG_SEL_BIT;

	/* TRIG_SEL bit 1, INV bit 0 for level low */
	if (type & IRQ_TYPE_LEVEL_LOW)
	value = (value \| TRIG_SEL_BIT) & ~INT_INV_BIT;

	/* TRIG_SEL bit 1, INV bit 1 for level high */
	if (type & IRQ_TYPE_LEVEL_HIGH)
	value \|= TRIG_SEL_BIT \| INT_INV_BIT;

	outl(value, reg);
	spin_unlock_irqrestore(&lg->lock, flags);

	return 0;
	}

	static int lp_gpio_get(struct gpio_chip *chip, unsigned offset)
	{
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	return !!(inl(reg) & IN_LVL_BIT);
	}

	static void lp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
	{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	unsigned long flags;

	spin_lock_irqsave(&lg->lock, flags);

	if (value)
	outl(inl(reg) \| OUT_LVL_BIT, reg);
	else
	outl(inl(reg) & ~OUT_LVL_BIT, reg);

	spin_unlock_irqrestore(&lg->lock, flags);
	}

	static int lp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
	{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	unsigned long flags;

	spin_lock_irqsave(&lg->lock, flags);
	outl(inl(reg) \| DIR_BIT, reg);
	spin_unlock_irqrestore(&lg->lock, flags);

	return 0;
	}

	static int lp_gpio_direction_output(struct gpio_chip *chip,
	unsigned offset, int value)
	{
	struct lp_gpio *lg = gpiochip_get_data(chip);
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
	unsigned long flags;

	lp_gpio_set(chip, offset, value);

	spin_lock_irqsave(&lg->lock, flags);
	outl(inl(reg) & ~DIR_BIT, reg);
	spin_unlock_irqrestore(&lg->lock, flags);

	return 0;
	}

	static void lp_gpio_irq_handler(struct irq_desc *desc)
	{
	struct irq_data *data = irq_desc_get_irq_data(desc);
	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
	struct lp_gpio *lg = gpiochip_get_data(gc);
	struct irq_chip *chip = irq_data_get_irq_chip(data);
	u32 base, pin, mask;
	unsigned long reg, ena, pending;

	/* check from GPIO controller which pin triggered the interrupt */
	for (base = 0; base < lg->chip.ngpio; base += 32) {
	reg = lp_gpio_reg(&lg->chip, base, LP_INT_STAT);
	ena = lp_gpio_reg(&lg->chip, base, LP_INT_ENABLE);

	while ((pending = (inl(reg) & inl(ena)))) {
	unsigned irq;

	pin = __ffs(pending);
	mask = BIT(pin);
	/* Clear before handling so we don't lose an edge */
	outl(mask, reg);
	irq = irq_find_mapping(lg->chip.irqdomain, base + pin);
	generic_handle_irq(irq);
	}
	}
	chip->irq_eoi(data);
	}

	static void lp_irq_unmask(struct irq_data *d)
	{
	}

	static void lp_irq_mask(struct irq_data *d)
	{
	}

	static void lp_irq_enable(struct irq_data *d)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct lp_gpio *lg = gpiochip_get_data(gc);
	u32 hwirq = irqd_to_hwirq(d);
	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
	unsigned long flags;

	spin_lock_irqsave(&lg->lock, flags);
	outl(inl(reg) \| BIT(hwirq % 32), reg);
	spin_unlock_irqrestore(&lg->lock, flags);
	}

	static void lp_irq_disable(struct irq_data *d)
	{
	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
	struct lp_gpio *lg = gpiochip_get_data(gc);
	u32 hwirq = irqd_to_hwirq(d);
	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
	unsigned long flags;

	spin_lock_irqsave(&lg->lock, flags);
	outl(inl(reg) & ~BIT(hwirq % 32), reg);
	spin_unlock_irqrestore(&lg->lock, flags);
	}

	static struct irq_chip lp_irqchip = {
	.name = "LP-GPIO",
	.irq_mask = lp_irq_mask,
	.irq_unmask = lp_irq_unmask,
	.irq_enable = lp_irq_enable,
	.irq_disable = lp_irq_disable,
	.irq_set_type = lp_irq_type,
	.flags = IRQCHIP_SKIP_SET_WAKE,
	};

	static void lp_gpio_irq_init_hw(struct lp_gpio *lg)
	{
	unsigned long reg;
	unsigned base;

	for (base = 0; base < lg->chip.ngpio; base += 32) {
	/* disable gpio pin interrupts */
	reg = lp_gpio_reg(&lg->chip, base, LP_INT_ENABLE);
	outl(0, reg);
	/* Clear interrupt status register */
	reg = lp_gpio_reg(&lg->chip, base, LP_INT_STAT);
	outl(0xffffffff, reg);
	}
	}

	static int lp_gpio_probe(struct platform_device *pdev)
	{
	struct lp_gpio *lg;
	struct gpio_chip *gc;
	struct resource io_rc, irq_rc;
	struct device *dev = &pdev->dev;
	unsigned long reg_len;
	int ret = -ENODEV;

	lg = devm_kzalloc(dev, sizeof(struct lp_gpio), GFP_KERNEL);
	if (!lg)
	return -ENOMEM;

	lg->pdev = pdev;
	platform_set_drvdata(pdev, lg);

	io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
	irq_rc = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

	if (!io_rc) {
	dev_err(dev, "missing IO resources\n");
	return -EINVAL;
	}

	lg->reg_base = io_rc->start;
	reg_len = resource_size(io_rc);

	if (!devm_request_region(dev, lg->reg_base, reg_len, "lp-gpio")) {
	dev_err(dev, "failed requesting IO region 0x%x\n",
	(unsigned int)lg->reg_base);
	return -EBUSY;
	}

	spin_lock_init(&lg->lock);

	gc = &lg->chip;
	gc->label = dev_name(dev);
	gc->owner = THIS_MODULE;
	gc->request = lp_gpio_request;
	gc->free = lp_gpio_free;
	gc->direction_input = lp_gpio_direction_input;
	gc->direction_output = lp_gpio_direction_output;
	gc->get = lp_gpio_get;
	gc->set = lp_gpio_set;
	gc->base = -1;
	gc->ngpio = LP_NUM_GPIO;
	gc->can_sleep = false;
	gc->parent = dev;

	ret = gpiochip_add_data(gc, lg);
	if (ret) {
	dev_err(dev, "failed adding lp-gpio chip\n");
	return ret;
	}

	/* set up interrupts */
	if (irq_rc && irq_rc->start) {
	lp_gpio_irq_init_hw(lg);
	ret = gpiochip_irqchip_add(gc, &lp_irqchip, 0,
	handle_simple_irq, IRQ_TYPE_NONE);
	if (ret) {
	dev_err(dev, "failed to add irqchip\n");
	gpiochip_remove(gc);
	return ret;
	}

	gpiochip_set_chained_irqchip(gc, &lp_irqchip,
	(unsigned)irq_rc->start,
	lp_gpio_irq_handler);
	}

	pm_runtime_enable(dev);

	return 0;
	}

	static int lp_gpio_runtime_suspend(struct device *dev)
	{
	return 0;
	}

	static int lp_gpio_runtime_resume(struct device *dev)
	{
	return 0;
	}

	static int lp_gpio_resume(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct lp_gpio *lg = platform_get_drvdata(pdev);
	unsigned long reg;
	int i;

	/* on some hardware suspend clears input sensing, re-enable it here */
	for (i = 0; i < lg->chip.ngpio; i++) {
	if (gpiochip_is_requested(&lg->chip, i) != NULL) {
	reg = lp_gpio_reg(&lg->chip, i, LP_CONFIG2);
	outl(inl(reg) & ~GPINDIS_BIT, reg);
	}
	}
	return 0;
	}

	static const struct dev_pm_ops lp_gpio_pm_ops = {
	.runtime_suspend = lp_gpio_runtime_suspend,
	.runtime_resume = lp_gpio_runtime_resume,
	.resume = lp_gpio_resume,
	};

	static const struct acpi_device_id lynxpoint_gpio_acpi_match[] = {
	{ "INT33C7", 0 },
	{ "INT3437", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(acpi, lynxpoint_gpio_acpi_match);

	static int lp_gpio_remove(struct platform_device *pdev)
	{
	struct lp_gpio *lg = platform_get_drvdata(pdev);
	pm_runtime_disable(&pdev->dev);
	gpiochip_remove(&lg->chip);
	return 0;
	}

	static struct platform_driver lp_gpio_driver = {
	.probe = lp_gpio_probe,
	.remove = lp_gpio_remove,
	.driver = {
	.name = "lp_gpio",
	.pm = &lp_gpio_pm_ops,
	.acpi_match_table = ACPI_PTR(lynxpoint_gpio_acpi_match),
	},
	};

	static int __init lp_gpio_init(void)
	{
	return platform_driver_register(&lp_gpio_driver);
	}

	static void __exit lp_gpio_exit(void)
	{
	platform_driver_unregister(&lp_gpio_driver);
	}

	subsys_initcall(lp_gpio_init);
	module_exit(lp_gpio_exit);

	MODULE_AUTHOR("Mathias Nyman (Intel)");
	MODULE_DESCRIPTION("GPIO interface for Intel Lynxpoint");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:lp_gpio");