drivers/platform/x86/intel_int0002_vgpio.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Intel INT0002 "Virtual GPIO" driver
  *
  * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
  *
  * Loosely based on android x86 kernel code which is:
  *
  * Copyright (c) 2014, Intel Corporation.
  *
  * Author: Dyut Kumar Sil <dyut.k.sil@intel.com>
  *
  * Some peripherals on Bay Trail and Cherry Trail platforms signal a Power
  * Management Event (PME) to the Power Management Controller (PMC) to wakeup
  * the system. When this happens software needs to clear the PME bus 0 status
  * bit in the GPE0a_STS register to avoid an IRQ storm on IRQ 9.
  *
  * This is modelled in ACPI through the INT0002 ACPI device, which is
  * called a "Virtual GPIO controller" in ACPI because it defines the event
  * handler to call when the PME triggers through _AEI and _L02 / _E02
  * methods as would be done for a real GPIO interrupt in ACPI. Note this
  * is a hack to define an AML event handler for the PME while using existing
  * ACPI mechanisms, this is not a real GPIO at all.
  *
  * This driver will bind to the INT0002 device, and register as a GPIO
  * controller, letting gpiolib-acpi.c call the _L02 handler as it would
  * for a real GPIO controller.
  */

 #include <linux/acpi.h>
 #include <linux/bitmap.h>
 #include <linux/gpio/driver.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>

 #include <asm/cpu_device_id.h>
 #include <asm/intel-family.h>

 #define DRV_NAME			"INT0002 Virtual GPIO"

 /* For some reason the virtual GPIO pin tied to the GPE is numbered pin 2 */
 #define GPE0A_PME_B0_VIRT_GPIO_PIN	2

 #define GPE0A_PME_B0_STS_BIT		BIT(13)
 #define GPE0A_PME_B0_EN_BIT		BIT(13)
 #define GPE0A_STS_PORT			0x420
 #define GPE0A_EN_PORT			0x428

 /*
  * As this is not a real GPIO at all, but just a hack to model an event in
  * ACPI the get / set functions are dummy functions.
  */

 static int int0002_gpio_get(struct gpio_chip *chip, unsigned int offset)
 {
 	return 0;
 }

 static void int0002_gpio_set(struct gpio_chip *chip, unsigned int offset,
 			     int value)
 {
 }

 static int int0002_gpio_direction_output(struct gpio_chip *chip,
 					 unsigned int offset, int value)
 {
 	return 0;
 }

 static void int0002_irq_ack(struct irq_data *data)
 {
 	outl(GPE0A_PME_B0_STS_BIT, GPE0A_STS_PORT);
 }

 static void int0002_irq_unmask(struct irq_data *data)
 {
 	u32 gpe_en_reg;

 	gpe_en_reg = inl(GPE0A_EN_PORT);
 	gpe_en_reg |= GPE0A_PME_B0_EN_BIT;
 	outl(gpe_en_reg, GPE0A_EN_PORT);
 }

 static void int0002_irq_mask(struct irq_data *data)
 {
 	u32 gpe_en_reg;

 	gpe_en_reg = inl(GPE0A_EN_PORT);
 	gpe_en_reg &= ~GPE0A_PME_B0_EN_BIT;
 	outl(gpe_en_reg, GPE0A_EN_PORT);
 }

 static int int0002_irq_set_wake(struct irq_data *data, unsigned int on)
 {
 	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 	struct platform_device *pdev = to_platform_device(chip->parent);
 	int irq = platform_get_irq(pdev, 0);

 	/* Propagate to parent irq */
 	if (on)
 		enable_irq_wake(irq);
 	else
 		disable_irq_wake(irq);

 	return 0;
 }

 static irqreturn_t int0002_irq(int irq, void *data)
 {
 	struct gpio_chip *chip = data;
 	u32 gpe_sts_reg;

 	gpe_sts_reg = inl(GPE0A_STS_PORT);
 	if (!(gpe_sts_reg & GPE0A_PME_B0_STS_BIT))
 		return IRQ_NONE;

 	generic_handle_irq(irq_find_mapping(chip->irq.domain,
 					    GPE0A_PME_B0_VIRT_GPIO_PIN));

 	pm_wakeup_hard_event(chip->parent);

 	return IRQ_HANDLED;
 }

 static bool int0002_check_wake(void *data)
 {
 	u32 gpe_sts_reg;

 	gpe_sts_reg = inl(GPE0A_STS_PORT);
 	return (gpe_sts_reg & GPE0A_PME_B0_STS_BIT);
 }

 static struct irq_chip int0002_byt_irqchip = {
 	.name			= DRV_NAME,
 	.irq_ack		= int0002_irq_ack,
 	.irq_mask		= int0002_irq_mask,
 	.irq_unmask		= int0002_irq_unmask,
 	.irq_set_wake		= int0002_irq_set_wake,
 };

 static struct irq_chip int0002_cht_irqchip = {
 	.name			= DRV_NAME,
 	.irq_ack		= int0002_irq_ack,
 	.irq_mask		= int0002_irq_mask,
 	.irq_unmask		= int0002_irq_unmask,
 	/*
 	 * No set_wake, on CHT the IRQ is typically shared with the ACPI SCI
 	 * and we don't want to mess with the ACPI SCI irq settings.
 	 */
 	.flags			= IRQCHIP_SKIP_SET_WAKE,
 };

 static const struct x86_cpu_id int0002_cpu_ids[] = {
 	X86_MATCH_INTEL_FAM6_MODEL(ATOM_SILVERMONT,	&int0002_byt_irqchip),
 	X86_MATCH_INTEL_FAM6_MODEL(ATOM_AIRMONT,	&int0002_cht_irqchip),
 	{}
 };

 static void int0002_init_irq_valid_mask(struct gpio_chip *chip,
 					unsigned long *valid_mask,
 					unsigned int ngpios)
 {
 	bitmap_clear(valid_mask, 0, GPE0A_PME_B0_VIRT_GPIO_PIN);
 }

 static int int0002_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	const struct x86_cpu_id *cpu_id;
 	struct gpio_chip *chip;
 	struct gpio_irq_chip *girq;
 	int irq, ret;

 	/* Menlow has a different INT0002 device? <sigh> */
 	cpu_id = x86_match_cpu(int0002_cpu_ids);
 	if (!cpu_id)
 		return -ENODEV;

 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
 		return irq;

 	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;

 	chip->label = DRV_NAME;
 	chip->parent = dev;
 	chip->owner = THIS_MODULE;
 	chip->get = int0002_gpio_get;
 	chip->set = int0002_gpio_set;
 	chip->direction_input = int0002_gpio_get;
 	chip->direction_output = int0002_gpio_direction_output;
 	chip->base = -1;
 	chip->ngpio = GPE0A_PME_B0_VIRT_GPIO_PIN + 1;
 	chip->irq.init_valid_mask = int0002_init_irq_valid_mask;

 	/*
 	 * We directly request the irq here instead of passing a flow-handler
 	 * to gpiochip_set_chained_irqchip, because the irq is shared.
 	 * FIXME: augment this if we managed to pull handling of shared
 	 * IRQs into gpiolib.
 	 */
 	ret = devm_request_irq(dev, irq, int0002_irq,
 			       IRQF_SHARED, "INT0002", chip);
 	if (ret) {
 		dev_err(dev, "Error requesting IRQ %d: %d\n", irq, ret);
 		return ret;
 	}

 	girq = &chip->irq;
 	girq->chip = (struct irq_chip *)cpu_id->driver_data;
 	/* This let us handle the parent IRQ in the driver */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;
 	girq->parents = NULL;
 	girq->default_type = IRQ_TYPE_NONE;
 	girq->handler = handle_edge_irq;

 	ret = devm_gpiochip_add_data(dev, chip, NULL);
 	if (ret) {
 		dev_err(dev, "Error adding gpio chip: %d\n", ret);
 		return ret;
 	}

 	acpi_register_wakeup_handler(irq, int0002_check_wake, NULL);
 	device_init_wakeup(dev, true);
 	return 0;
 }

 static int int0002_remove(struct platform_device *pdev)
 {
 	device_init_wakeup(&pdev->dev, false);
 	acpi_unregister_wakeup_handler(int0002_check_wake, NULL);
 	return 0;
 }

 static const struct acpi_device_id int0002_acpi_ids[] = {
 	{ "INT0002", 0 },
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, int0002_acpi_ids);

 static struct platform_driver int0002_driver = {
 	.driver = {
 		.name			= DRV_NAME,
 		.acpi_match_table	= int0002_acpi_ids,
 	},
 	.probe	= int0002_probe,
 	.remove	= int0002_remove,
 };

 module_platform_driver(int0002_driver);

 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Intel INT0002 "Virtual GPIO" driver
	*
	* Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
	*
	* Loosely based on android x86 kernel code which is:
	*
	* Copyright (c) 2014, Intel Corporation.
	*
	* Author: Dyut Kumar Sil <dyut.k.sil@intel.com>
	*
	* Some peripherals on Bay Trail and Cherry Trail platforms signal a Power
	* Management Event (PME) to the Power Management Controller (PMC) to wakeup
	* the system. When this happens software needs to clear the PME bus 0 status
	* bit in the GPE0a_STS register to avoid an IRQ storm on IRQ 9.
	*
	* This is modelled in ACPI through the INT0002 ACPI device, which is
	* called a "Virtual GPIO controller" in ACPI because it defines the event
	* handler to call when the PME triggers through _AEI and _L02 / _E02
	* methods as would be done for a real GPIO interrupt in ACPI. Note this
	* is a hack to define an AML event handler for the PME while using existing
	* ACPI mechanisms, this is not a real GPIO at all.
	*
	* This driver will bind to the INT0002 device, and register as a GPIO
	* controller, letting gpiolib-acpi.c call the _L02 handler as it would
	* for a real GPIO controller.
	*/

	#include <linux/acpi.h>
	#include <linux/bitmap.h>
	#include <linux/gpio/driver.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/suspend.h>

	#include <asm/cpu_device_id.h>
	#include <asm/intel-family.h>

	#define DRV_NAME "INT0002 Virtual GPIO"

	/* For some reason the virtual GPIO pin tied to the GPE is numbered pin 2 */
	#define GPE0A_PME_B0_VIRT_GPIO_PIN 2

	#define GPE0A_PME_B0_STS_BIT BIT(13)
	#define GPE0A_PME_B0_EN_BIT BIT(13)
	#define GPE0A_STS_PORT 0x420
	#define GPE0A_EN_PORT 0x428

	/*
	* As this is not a real GPIO at all, but just a hack to model an event in
	* ACPI the get / set functions are dummy functions.
	*/

	static int int0002_gpio_get(struct gpio_chip *chip, unsigned int offset)
	{
	return 0;
	}

	static void int0002_gpio_set(struct gpio_chip *chip, unsigned int offset,
	int value)
	{
	}

	static int int0002_gpio_direction_output(struct gpio_chip *chip,
	unsigned int offset, int value)
	{
	return 0;
	}

	static void int0002_irq_ack(struct irq_data *data)
	{
	outl(GPE0A_PME_B0_STS_BIT, GPE0A_STS_PORT);
	}

	static void int0002_irq_unmask(struct irq_data *data)
	{
	u32 gpe_en_reg;

	gpe_en_reg = inl(GPE0A_EN_PORT);
	gpe_en_reg \|= GPE0A_PME_B0_EN_BIT;
	outl(gpe_en_reg, GPE0A_EN_PORT);
	}

	static void int0002_irq_mask(struct irq_data *data)
	{
	u32 gpe_en_reg;

	gpe_en_reg = inl(GPE0A_EN_PORT);
	gpe_en_reg &= ~GPE0A_PME_B0_EN_BIT;
	outl(gpe_en_reg, GPE0A_EN_PORT);
	}

	static int int0002_irq_set_wake(struct irq_data *data, unsigned int on)
	{
	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
	struct platform_device *pdev = to_platform_device(chip->parent);
	int irq = platform_get_irq(pdev, 0);

	/* Propagate to parent irq */
	if (on)
	enable_irq_wake(irq);
	else
	disable_irq_wake(irq);

	return 0;
	}

	static irqreturn_t int0002_irq(int irq, void *data)
	{
	struct gpio_chip *chip = data;
	u32 gpe_sts_reg;

	gpe_sts_reg = inl(GPE0A_STS_PORT);
	if (!(gpe_sts_reg & GPE0A_PME_B0_STS_BIT))
	return IRQ_NONE;

	generic_handle_irq(irq_find_mapping(chip->irq.domain,
	GPE0A_PME_B0_VIRT_GPIO_PIN));

	pm_wakeup_hard_event(chip->parent);

	return IRQ_HANDLED;
	}

	static bool int0002_check_wake(void *data)
	{
	u32 gpe_sts_reg;

	gpe_sts_reg = inl(GPE0A_STS_PORT);
	return (gpe_sts_reg & GPE0A_PME_B0_STS_BIT);
	}

	static struct irq_chip int0002_byt_irqchip = {
	.name = DRV_NAME,
	.irq_ack = int0002_irq_ack,
	.irq_mask = int0002_irq_mask,
	.irq_unmask = int0002_irq_unmask,
	.irq_set_wake = int0002_irq_set_wake,
	};

	static struct irq_chip int0002_cht_irqchip = {
	.name = DRV_NAME,
	.irq_ack = int0002_irq_ack,
	.irq_mask = int0002_irq_mask,
	.irq_unmask = int0002_irq_unmask,
	/*
	* No set_wake, on CHT the IRQ is typically shared with the ACPI SCI
	* and we don't want to mess with the ACPI SCI irq settings.
	*/
	.flags = IRQCHIP_SKIP_SET_WAKE,
	};

	static const struct x86_cpu_id int0002_cpu_ids[] = {
	X86_MATCH_INTEL_FAM6_MODEL(ATOM_SILVERMONT, &int0002_byt_irqchip),
	X86_MATCH_INTEL_FAM6_MODEL(ATOM_AIRMONT, &int0002_cht_irqchip),
	{}
	};

	static void int0002_init_irq_valid_mask(struct gpio_chip *chip,
	unsigned long *valid_mask,
	unsigned int ngpios)
	{
	bitmap_clear(valid_mask, 0, GPE0A_PME_B0_VIRT_GPIO_PIN);
	}

	static int int0002_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	const struct x86_cpu_id *cpu_id;
	struct gpio_chip *chip;
	struct gpio_irq_chip *girq;
	int irq, ret;

	/* Menlow has a different INT0002 device? <sigh> */
	cpu_id = x86_match_cpu(int0002_cpu_ids);
	if (!cpu_id)
	return -ENODEV;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
	return irq;

	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
	if (!chip)
	return -ENOMEM;

	chip->label = DRV_NAME;
	chip->parent = dev;
	chip->owner = THIS_MODULE;
	chip->get = int0002_gpio_get;
	chip->set = int0002_gpio_set;
	chip->direction_input = int0002_gpio_get;
	chip->direction_output = int0002_gpio_direction_output;
	chip->base = -1;
	chip->ngpio = GPE0A_PME_B0_VIRT_GPIO_PIN + 1;
	chip->irq.init_valid_mask = int0002_init_irq_valid_mask;

	/*
	* We directly request the irq here instead of passing a flow-handler
	* to gpiochip_set_chained_irqchip, because the irq is shared.
	* FIXME: augment this if we managed to pull handling of shared
	* IRQs into gpiolib.
	*/
	ret = devm_request_irq(dev, irq, int0002_irq,
	IRQF_SHARED, "INT0002", chip);
	if (ret) {
	dev_err(dev, "Error requesting IRQ %d: %d\n", irq, ret);
	return ret;
	}

	girq = &chip->irq;
	girq->chip = (struct irq_chip *)cpu_id->driver_data;
	/* This let us handle the parent IRQ in the driver */
	girq->parent_handler = NULL;
	girq->num_parents = 0;
	girq->parents = NULL;
	girq->default_type = IRQ_TYPE_NONE;
	girq->handler = handle_edge_irq;

	ret = devm_gpiochip_add_data(dev, chip, NULL);
	if (ret) {
	dev_err(dev, "Error adding gpio chip: %d\n", ret);
	return ret;
	}

	acpi_register_wakeup_handler(irq, int0002_check_wake, NULL);
	device_init_wakeup(dev, true);
	return 0;
	}

	static int int0002_remove(struct platform_device *pdev)
	{
	device_init_wakeup(&pdev->dev, false);
	acpi_unregister_wakeup_handler(int0002_check_wake, NULL);
	return 0;
	}

	static const struct acpi_device_id int0002_acpi_ids[] = {
	{ "INT0002", 0 },
	{ },
	};
	MODULE_DEVICE_TABLE(acpi, int0002_acpi_ids);

	static struct platform_driver int0002_driver = {
	.driver = {
	.name = DRV_NAME,
	.acpi_match_table = int0002_acpi_ids,
	},
	.probe = int0002_probe,
	.remove = int0002_remove,
	};

	module_platform_driver(int0002_driver);

	MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
	MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver");
	MODULE_LICENSE("GPL v2");