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- // 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
- struct int0002_data {
- struct gpio_chip chip;
- int parent_irq;
- int wake_enable_count;
- };
- /*
- * 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 int0002_data *int0002 = container_of(chip, struct int0002_data, chip);
- /*
- * Applying of the wakeup flag to our parent IRQ is delayed till system
- * suspend, because we only want to do this when using s2idle.
- */
- if (on)
- int0002->wake_enable_count++;
- else
- int0002->wake_enable_count--;
- 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_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 const struct x86_cpu_id int0002_cpu_ids[] = {
- X86_MATCH_INTEL_FAM6_MODEL(ATOM_SILVERMONT, NULL),
- X86_MATCH_INTEL_FAM6_MODEL(ATOM_AIRMONT, NULL),
- {}
- };
- 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 int0002_data *int0002;
- struct gpio_irq_chip *girq;
- struct gpio_chip *chip;
- 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;
- int0002 = devm_kzalloc(dev, sizeof(*int0002), GFP_KERNEL);
- if (!int0002)
- return -ENOMEM;
- int0002->parent_irq = irq;
- chip = &int0002->chip;
- 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 = &int0002_irqchip;
- /* 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);
- dev_set_drvdata(dev, int0002);
- 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 int int0002_suspend(struct device *dev)
- {
- struct int0002_data *int0002 = dev_get_drvdata(dev);
- /*
- * The INT0002 parent IRQ is often shared with the ACPI GPE IRQ, don't
- * muck with it when firmware based suspend is used, otherwise we may
- * cause spurious wakeups from firmware managed suspend.
- */
- if (!pm_suspend_via_firmware() && int0002->wake_enable_count)
- enable_irq_wake(int0002->parent_irq);
- return 0;
- }
- static int int0002_resume(struct device *dev)
- {
- struct int0002_data *int0002 = dev_get_drvdata(dev);
- if (!pm_suspend_via_firmware() && int0002->wake_enable_count)
- disable_irq_wake(int0002->parent_irq);
- return 0;
- }
- static const struct dev_pm_ops int0002_pm_ops = {
- .suspend = int0002_suspend,
- .resume = int0002_resume,
- };
- 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,
- .pm = &int0002_pm_ops,
- },
- .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");
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