// SPDX-License-Identifier: GPL-2.0 /* * Intel INT0002 "Virtual GPIO" driver * * Copyright (C) 2017 Hans de Goede * * Loosely based on android x86 kernel code which is: * * Copyright (c) 2014, Intel Corporation. * * Author: Dyut Kumar Sil * * 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 #include #include #include #include #include #include #include #include #include #include #include #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 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? */ 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; } device_init_wakeup(dev, true); return 0; } static int int0002_remove(struct platform_device *pdev) { device_init_wakeup(&pdev->dev, false); 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 "); MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver"); MODULE_LICENSE("GPL v2");