drivers/platform/x86/intel/int0002_vgpio.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Intel INT0002 "Virtual GPIO" driver
   4  *
   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 Power
  14  * Management Event (PME) to the Power Management Controller (PMC) to wakeup
  15  * the system. When this happens software needs to clear the PME bus 0 status
  16  * 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 is
  19  * called a "Virtual GPIO controller" in ACPI because it defines the event
  20  * handler to call when the PME triggers through _AEI and _L02 / _E02
  21  * methods as would be done for a real GPIO interrupt in ACPI. Note this
  22  * is a hack to define an AML event handler for the PME while using existing
  23  * ACPI mechanisms, this is not a real GPIO at all.
  24  *
  25  * This driver will bind to the INT0002 device, and register as a GPIO
  26  * controller, letting gpiolib-acpi.c call the _L02 handler as it would
  27  * 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      2
  46
  47 #define GPE0A_PME_B0_STS_BIT            BIT(13)
  48 #define GPE0A_PME_B0_EN_BIT             BIT(13)
  49 #define GPE0A_STS_PORT                  0x420
  50 #define GPE0A_EN_PORT                   0x428
  51
  52 struct 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 in
  60  * ACPI the get / set functions are dummy functions.
  61  */
  62
  63 static int int0002_gpio_get(struct gpio_chip *chip, unsigned int offset)
  64 {
  65         return 0;
  66 }
  67
  68 static void int0002_gpio_set(struct gpio_chip *chip, unsigned int offset,
  69                              int value)
  70 {
  71 }
  72
  73 static int int0002_gpio_direction_output(struct gpio_chip *chip,
  74                                          unsigned int offset, int value)
  75 {
  76         return 0;
  77 }
  78
  79 static void int0002_irq_ack(struct irq_data *data)
  80 {
  81         outl(GPE0A_PME_B0_STS_BIT, GPE0A_STS_PORT);
  82 }
  83
  84 static 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
  93 static 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
 102 static 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 system
 109          * suspend, because we only want to do this when using s2idle.
 110          */
 111         if (on)
 112                 int0002->wake_enable_count++;
 113         else
 114                 int0002->wake_enable_count--;
 115
 116         return 0;
 117 }
 118
 119 static 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
 135 static 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
 143 static 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
 151 static 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
 158 static 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-handler
 194          * to gpiochip_set_chained_irqchip, because the irq is shared.
 195          * FIXME: augment this if we managed to pull handling of shared
 196          * 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
 226 static 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
 232 static 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't
 238          * muck with it when firmware based suspend is used, otherwise we may
 239          * 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
 247 static 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
 257 static const struct dev_pm_ops int0002_pm_ops = {
 258         .suspend = int0002_suspend,
 259         .resume = int0002_resume,
 260 };
 261
 262 static const struct acpi_device_id int0002_acpi_ids[] = {
 263         { "INT0002", 0 },
 264         { },
 265 };
 266 MODULE_DEVICE_TABLE(acpi, int0002_acpi_ids);
 267
 268 static 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 = int0002_remove,
 276 };
 277
 278 module_platform_driver(int0002_driver);
 279
 280 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 281 MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver");
 282 MODULE_LICENSE("GPL v2");