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
int0002_gpio_get(struct gpio_chip * chip,unsigned int offset)63 static int int0002_gpio_get(struct gpio_chip *chip, unsigned int offset)
64 {
65 return 0;
66 }
67
int0002_gpio_set(struct gpio_chip * chip,unsigned int offset,int value)68 static void int0002_gpio_set(struct gpio_chip *chip, unsigned int offset,
69 int value)
70 {
71 }
72
int0002_gpio_direction_output(struct gpio_chip * chip,unsigned int offset,int value)73 static int int0002_gpio_direction_output(struct gpio_chip *chip,
74 unsigned int offset, int value)
75 {
76 return 0;
77 }
78
int0002_irq_ack(struct irq_data * data)79 static void int0002_irq_ack(struct irq_data *data)
80 {
81 outl(GPE0A_PME_B0_STS_BIT, GPE0A_STS_PORT);
82 }
83
int0002_irq_unmask(struct irq_data * data)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
int0002_irq_mask(struct irq_data * data)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
int0002_irq_set_wake(struct irq_data * data,unsigned int on)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
int0002_irq(int irq,void * data)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
int0002_check_wake(void * data)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
int0002_init_irq_valid_mask(struct gpio_chip * chip,unsigned long * valid_mask,unsigned int ngpios)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
int0002_probe(struct platform_device * pdev)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
int0002_remove(struct platform_device * pdev)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
int0002_suspend(struct device * dev)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
int0002_resume(struct device * dev)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_new = 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");
283