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1// SPDX-License-Identifier: GPL-2.02/*3 * Intel INT0002 "Virtual GPIO" driver4 *5 * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>6 *7 * Loosely based on android x86 kernel code which is:8 *9 * Copyright (c) 2014, Intel Corporation.10 *11 * Author: Dyut Kumar Sil <dyut.k.sil@intel.com>12 *13 * Some peripherals on Bay Trail and Cherry Trail platforms signal a Power14 * Management Event (PME) to the Power Management Controller (PMC) to wakeup15 * the system. When this happens software needs to clear the PME bus 0 status16 * bit in the GPE0a_STS register to avoid an IRQ storm on IRQ 9.17 *18 * This is modelled in ACPI through the INT0002 ACPI device, which is19 * called a "Virtual GPIO controller" in ACPI because it defines the event20 * handler to call when the PME triggers through _AEI and _L02 / _E0221 * methods as would be done for a real GPIO interrupt in ACPI. Note this22 * is a hack to define an AML event handler for the PME while using existing23 * ACPI mechanisms, this is not a real GPIO at all.24 *25 * This driver will bind to the INT0002 device, and register as a GPIO26 * controller, letting gpiolib-acpi.c call the _L02 handler as it would27 * for a real GPIO controller.28 */29 30#include <linux/acpi.h>31#include <linux/bitmap.h>32#include <linux/gpio/driver.h>33#include <linux/interrupt.h>34#include <linux/io.h>35#include <linux/kernel.h>36#include <linux/module.h>37#include <linux/platform_data/x86/soc.h>38#include <linux/platform_device.h>39#include <linux/slab.h>40#include <linux/suspend.h>41 42#define DRV_NAME "INT0002 Virtual GPIO"43 44/* For some reason the virtual GPIO pin tied to the GPE is numbered pin 2 */45#define GPE0A_PME_B0_VIRT_GPIO_PIN 246 47#define GPE0A_PME_B0_STS_BIT BIT(13)48#define GPE0A_PME_B0_EN_BIT BIT(13)49#define GPE0A_STS_PORT 0x42050#define GPE0A_EN_PORT 0x42851 52struct int0002_data {53 struct gpio_chip chip;54 int parent_irq;55 int wake_enable_count;56};57 58/*59 * As this is not a real GPIO at all, but just a hack to model an event in60 * ACPI the get / set functions are dummy functions.61 */62 63static int int0002_gpio_get(struct gpio_chip *chip, unsigned int offset)64{65 return 0;66}67 68static void int0002_gpio_set(struct gpio_chip *chip, unsigned int offset,69 int value)70{71}72 73static int int0002_gpio_direction_output(struct gpio_chip *chip,74 unsigned int offset, int value)75{76 return 0;77}78 79static void int0002_irq_ack(struct irq_data *data)80{81 outl(GPE0A_PME_B0_STS_BIT, GPE0A_STS_PORT);82}83 84static void int0002_irq_unmask(struct irq_data *data)85{86 u32 gpe_en_reg;87 88 gpe_en_reg = inl(GPE0A_EN_PORT);89 gpe_en_reg |= GPE0A_PME_B0_EN_BIT;90 outl(gpe_en_reg, GPE0A_EN_PORT);91}92 93static void int0002_irq_mask(struct irq_data *data)94{95 u32 gpe_en_reg;96 97 gpe_en_reg = inl(GPE0A_EN_PORT);98 gpe_en_reg &= ~GPE0A_PME_B0_EN_BIT;99 outl(gpe_en_reg, GPE0A_EN_PORT);100}101 102static int int0002_irq_set_wake(struct irq_data *data, unsigned int on)103{104 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);105 struct int0002_data *int0002 = container_of(chip, struct int0002_data, chip);106 107 /*108 * Applying of the wakeup flag to our parent IRQ is delayed till system109 * suspend, because we only want to do this when using s2idle.110 */111 if (on)112 int0002->wake_enable_count++;113 else114 int0002->wake_enable_count--;115 116 return 0;117}118 119static irqreturn_t int0002_irq(int irq, void *data)120{121 struct gpio_chip *chip = data;122 u32 gpe_sts_reg;123 124 gpe_sts_reg = inl(GPE0A_STS_PORT);125 if (!(gpe_sts_reg & GPE0A_PME_B0_STS_BIT))126 return IRQ_NONE;127 128 generic_handle_domain_irq_safe(chip->irq.domain, GPE0A_PME_B0_VIRT_GPIO_PIN);129 130 pm_wakeup_hard_event(chip->parent);131 132 return IRQ_HANDLED;133}134 135static bool int0002_check_wake(void *data)136{137 u32 gpe_sts_reg;138 139 gpe_sts_reg = inl(GPE0A_STS_PORT);140 return (gpe_sts_reg & GPE0A_PME_B0_STS_BIT);141}142 143static struct irq_chip int0002_irqchip = {144 .name = DRV_NAME,145 .irq_ack = int0002_irq_ack,146 .irq_mask = int0002_irq_mask,147 .irq_unmask = int0002_irq_unmask,148 .irq_set_wake = int0002_irq_set_wake,149};150 151static void int0002_init_irq_valid_mask(struct gpio_chip *chip,152 unsigned long *valid_mask,153 unsigned int ngpios)154{155 bitmap_clear(valid_mask, 0, GPE0A_PME_B0_VIRT_GPIO_PIN);156}157 158static int int0002_probe(struct platform_device *pdev)159{160 struct device *dev = &pdev->dev;161 struct int0002_data *int0002;162 struct gpio_irq_chip *girq;163 struct gpio_chip *chip;164 int irq, ret;165 166 /* Menlow has a different INT0002 device? <sigh> */167 if (!soc_intel_is_byt() && !soc_intel_is_cht())168 return -ENODEV;169 170 irq = platform_get_irq(pdev, 0);171 if (irq < 0)172 return irq;173 174 int0002 = devm_kzalloc(dev, sizeof(*int0002), GFP_KERNEL);175 if (!int0002)176 return -ENOMEM;177 178 int0002->parent_irq = irq;179 180 chip = &int0002->chip;181 chip->label = DRV_NAME;182 chip->parent = dev;183 chip->owner = THIS_MODULE;184 chip->get = int0002_gpio_get;185 chip->set = int0002_gpio_set;186 chip->direction_input = int0002_gpio_get;187 chip->direction_output = int0002_gpio_direction_output;188 chip->base = -1;189 chip->ngpio = GPE0A_PME_B0_VIRT_GPIO_PIN + 1;190 chip->irq.init_valid_mask = int0002_init_irq_valid_mask;191 192 /*193 * We directly request the irq here instead of passing a flow-handler194 * to gpiochip_set_chained_irqchip, because the irq is shared.195 * FIXME: augment this if we managed to pull handling of shared196 * IRQs into gpiolib.197 */198 ret = devm_request_irq(dev, irq, int0002_irq,199 IRQF_ONESHOT | IRQF_SHARED, "INT0002", chip);200 if (ret) {201 dev_err(dev, "Error requesting IRQ %d: %d\n", irq, ret);202 return ret;203 }204 205 girq = &chip->irq;206 girq->chip = &int0002_irqchip;207 /* This let us handle the parent IRQ in the driver */208 girq->parent_handler = NULL;209 girq->num_parents = 0;210 girq->parents = NULL;211 girq->default_type = IRQ_TYPE_NONE;212 girq->handler = handle_edge_irq;213 214 ret = devm_gpiochip_add_data(dev, chip, NULL);215 if (ret) {216 dev_err(dev, "Error adding gpio chip: %d\n", ret);217 return ret;218 }219 220 acpi_register_wakeup_handler(irq, int0002_check_wake, NULL);221 device_init_wakeup(dev, true);222 dev_set_drvdata(dev, int0002);223 return 0;224}225 226static void int0002_remove(struct platform_device *pdev)227{228 device_init_wakeup(&pdev->dev, false);229 acpi_unregister_wakeup_handler(int0002_check_wake, NULL);230}231 232static int int0002_suspend(struct device *dev)233{234 struct int0002_data *int0002 = dev_get_drvdata(dev);235 236 /*237 * The INT0002 parent IRQ is often shared with the ACPI GPE IRQ, don't238 * muck with it when firmware based suspend is used, otherwise we may239 * cause spurious wakeups from firmware managed suspend.240 */241 if (!pm_suspend_via_firmware() && int0002->wake_enable_count)242 enable_irq_wake(int0002->parent_irq);243 244 return 0;245}246 247static int int0002_resume(struct device *dev)248{249 struct int0002_data *int0002 = dev_get_drvdata(dev);250 251 if (!pm_suspend_via_firmware() && int0002->wake_enable_count)252 disable_irq_wake(int0002->parent_irq);253 254 return 0;255}256 257static const struct dev_pm_ops int0002_pm_ops = {258 .suspend = int0002_suspend,259 .resume = int0002_resume,260};261 262static const struct acpi_device_id int0002_acpi_ids[] = {263 { "INT0002", 0 },264 { },265};266MODULE_DEVICE_TABLE(acpi, int0002_acpi_ids);267 268static struct platform_driver int0002_driver = {269 .driver = {270 .name = DRV_NAME,271 .acpi_match_table = int0002_acpi_ids,272 .pm = &int0002_pm_ops,273 },274 .probe = int0002_probe,275 .remove_new = int0002_remove,276};277 278module_platform_driver(int0002_driver);279 280MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");281MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver");282MODULE_LICENSE("GPL v2");283