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 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 int int0002_gpio_set(struct gpio_chip *chip, unsigned int offset,
69 int value)
70 {
71 return 0;
72 }
73
int0002_gpio_direction_output(struct gpio_chip * chip,unsigned int offset,int value)74 static int int0002_gpio_direction_output(struct gpio_chip *chip,
75 unsigned int offset, int value)
76 {
77 return 0;
78 }
79
int0002_irq_ack(struct irq_data * data)80 static void int0002_irq_ack(struct irq_data *data)
81 {
82 outl(GPE0A_PME_B0_STS_BIT, GPE0A_STS_PORT);
83 }
84
int0002_irq_unmask(struct irq_data * data)85 static void int0002_irq_unmask(struct irq_data *data)
86 {
87 struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
88 irq_hw_number_t hwirq = irqd_to_hwirq(data);
89 u32 gpe_en_reg;
90
91 gpiochip_enable_irq(gc, hwirq);
92
93 gpe_en_reg = inl(GPE0A_EN_PORT);
94 gpe_en_reg |= GPE0A_PME_B0_EN_BIT;
95 outl(gpe_en_reg, GPE0A_EN_PORT);
96 }
97
int0002_irq_mask(struct irq_data * data)98 static void int0002_irq_mask(struct irq_data *data)
99 {
100 struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
101 irq_hw_number_t hwirq = irqd_to_hwirq(data);
102 u32 gpe_en_reg;
103
104 gpe_en_reg = inl(GPE0A_EN_PORT);
105 gpe_en_reg &= ~GPE0A_PME_B0_EN_BIT;
106 outl(gpe_en_reg, GPE0A_EN_PORT);
107
108 gpiochip_disable_irq(gc, hwirq);
109 }
110
int0002_irq_set_wake(struct irq_data * data,unsigned int on)111 static int int0002_irq_set_wake(struct irq_data *data, unsigned int on)
112 {
113 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
114 struct int0002_data *int0002 = container_of(chip, struct int0002_data, chip);
115
116 /*
117 * Applying of the wakeup flag to our parent IRQ is delayed till system
118 * suspend, because we only want to do this when using s2idle.
119 */
120 if (on)
121 int0002->wake_enable_count++;
122 else
123 int0002->wake_enable_count--;
124
125 return 0;
126 }
127
int0002_irq(int irq,void * data)128 static irqreturn_t int0002_irq(int irq, void *data)
129 {
130 struct gpio_chip *chip = data;
131 u32 gpe_sts_reg;
132
133 gpe_sts_reg = inl(GPE0A_STS_PORT);
134 if (!(gpe_sts_reg & GPE0A_PME_B0_STS_BIT))
135 return IRQ_NONE;
136
137 generic_handle_domain_irq_safe(chip->irq.domain, GPE0A_PME_B0_VIRT_GPIO_PIN);
138
139 pm_wakeup_hard_event(chip->parent);
140
141 return IRQ_HANDLED;
142 }
143
int0002_check_wake(void * data)144 static bool int0002_check_wake(void *data)
145 {
146 u32 gpe_sts_reg;
147
148 gpe_sts_reg = inl(GPE0A_STS_PORT);
149 return (gpe_sts_reg & GPE0A_PME_B0_STS_BIT);
150 }
151
152 static const struct irq_chip int0002_irqchip = {
153 .name = DRV_NAME,
154 .irq_ack = int0002_irq_ack,
155 .irq_mask = int0002_irq_mask,
156 .irq_unmask = int0002_irq_unmask,
157 .irq_set_wake = int0002_irq_set_wake,
158 .flags = IRQCHIP_IMMUTABLE,
159 GPIOCHIP_IRQ_RESOURCE_HELPERS,
160 };
161
int0002_init_irq_valid_mask(struct gpio_chip * chip,unsigned long * valid_mask,unsigned int ngpios)162 static void int0002_init_irq_valid_mask(struct gpio_chip *chip,
163 unsigned long *valid_mask,
164 unsigned int ngpios)
165 {
166 bitmap_clear(valid_mask, 0, GPE0A_PME_B0_VIRT_GPIO_PIN);
167 }
168
int0002_probe(struct platform_device * pdev)169 static int int0002_probe(struct platform_device *pdev)
170 {
171 struct device *dev = &pdev->dev;
172 struct int0002_data *int0002;
173 struct gpio_irq_chip *girq;
174 struct gpio_chip *chip;
175 int irq, ret;
176
177 /* Menlow has a different INT0002 device? <sigh> */
178 if (!soc_intel_is_byt() && !soc_intel_is_cht())
179 return -ENODEV;
180
181 irq = platform_get_irq(pdev, 0);
182 if (irq < 0)
183 return irq;
184
185 int0002 = devm_kzalloc(dev, sizeof(*int0002), GFP_KERNEL);
186 if (!int0002)
187 return -ENOMEM;
188
189 int0002->parent_irq = irq;
190
191 chip = &int0002->chip;
192 chip->label = DRV_NAME;
193 chip->parent = dev;
194 chip->owner = THIS_MODULE;
195 chip->get = int0002_gpio_get;
196 chip->set_rv = int0002_gpio_set;
197 chip->direction_input = int0002_gpio_get;
198 chip->direction_output = int0002_gpio_direction_output;
199 chip->base = -1;
200 chip->ngpio = GPE0A_PME_B0_VIRT_GPIO_PIN + 1;
201 chip->irq.init_valid_mask = int0002_init_irq_valid_mask;
202
203 /*
204 * We directly request the irq here instead of passing a flow-handler
205 * to gpiochip_set_chained_irqchip, because the irq is shared.
206 * FIXME: augment this if we managed to pull handling of shared
207 * IRQs into gpiolib.
208 */
209 ret = devm_request_irq(dev, irq, int0002_irq,
210 IRQF_ONESHOT | IRQF_SHARED, "INT0002", chip);
211 if (ret) {
212 dev_err(dev, "Error requesting IRQ %d: %d\n", irq, ret);
213 return ret;
214 }
215
216 girq = &chip->irq;
217 gpio_irq_chip_set_chip(girq, &int0002_irqchip);
218 /* This let us handle the parent IRQ in the driver */
219 girq->parent_handler = NULL;
220 girq->num_parents = 0;
221 girq->parents = NULL;
222 girq->default_type = IRQ_TYPE_NONE;
223 girq->handler = handle_edge_irq;
224
225 ret = devm_gpiochip_add_data(dev, chip, NULL);
226 if (ret) {
227 dev_err(dev, "Error adding gpio chip: %d\n", ret);
228 return ret;
229 }
230
231 acpi_register_wakeup_handler(irq, int0002_check_wake, NULL);
232 device_init_wakeup(dev, true);
233 dev_set_drvdata(dev, int0002);
234 return 0;
235 }
236
int0002_remove(struct platform_device * pdev)237 static void int0002_remove(struct platform_device *pdev)
238 {
239 device_init_wakeup(&pdev->dev, false);
240 acpi_unregister_wakeup_handler(int0002_check_wake, NULL);
241 }
242
int0002_suspend(struct device * dev)243 static int int0002_suspend(struct device *dev)
244 {
245 struct int0002_data *int0002 = dev_get_drvdata(dev);
246
247 /*
248 * The INT0002 parent IRQ is often shared with the ACPI GPE IRQ, don't
249 * muck with it when firmware based suspend is used, otherwise we may
250 * cause spurious wakeups from firmware managed suspend.
251 */
252 if (!pm_suspend_via_firmware() && int0002->wake_enable_count)
253 enable_irq_wake(int0002->parent_irq);
254
255 return 0;
256 }
257
int0002_resume(struct device * dev)258 static int int0002_resume(struct device *dev)
259 {
260 struct int0002_data *int0002 = dev_get_drvdata(dev);
261
262 if (!pm_suspend_via_firmware() && int0002->wake_enable_count)
263 disable_irq_wake(int0002->parent_irq);
264
265 return 0;
266 }
267
268 static const struct dev_pm_ops int0002_pm_ops = {
269 .suspend = int0002_suspend,
270 .resume = int0002_resume,
271 };
272
273 static const struct acpi_device_id int0002_acpi_ids[] = {
274 { "INT0002", 0 },
275 { },
276 };
277 MODULE_DEVICE_TABLE(acpi, int0002_acpi_ids);
278
279 static struct platform_driver int0002_driver = {
280 .driver = {
281 .name = DRV_NAME,
282 .acpi_match_table = int0002_acpi_ids,
283 .pm = &int0002_pm_ops,
284 },
285 .probe = int0002_probe,
286 .remove = int0002_remove,
287 };
288
289 module_platform_driver(int0002_driver);
290
291 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
292 MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver");
293 MODULE_LICENSE("GPL v2");
294