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1 | /* |
2 | * ACPI helpers for GPIO API |
3 | * |
4 | * Copyright (C) 2012, Intel Corporation |
5 | * Authors: Mathias Nyman <mathias.nyman@linux.intel.com> |
6 | * Mika Westerberg <mika.westerberg@linux.intel.com> |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify |
9 | * it under the terms of the GNU General Public License version 2 as |
10 | * published by the Free Software Foundation. |
11 | */ |
12 | |
13 | #include <linux/errno.h> |
14 | #include <linux/gpio.h> |
15 | #include <linux/export.h> |
16 | #include <linux/acpi_gpio.h> |
17 | #include <linux/acpi.h> |
18 | #include <linux/interrupt.h> |
19 | |
20 | struct acpi_gpio_evt_pin { |
21 | struct list_head node; |
22 | acpi_handle *evt_handle; |
23 | unsigned int pin; |
24 | unsigned int irq; |
25 | }; |
26 | |
27 | static int acpi_gpiochip_find(struct gpio_chip *gc, void *data) |
28 | { |
29 | if (!gc->dev) |
30 | return false; |
31 | |
32 | return ACPI_HANDLE(gc->dev) == data; |
33 | } |
34 | |
35 | /** |
36 | * acpi_get_gpio() - Translate ACPI GPIO pin to GPIO number usable with GPIO API |
37 | * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1") |
38 | * @pin: ACPI GPIO pin number (0-based, controller-relative) |
39 | * |
40 | * Returns GPIO number to use with Linux generic GPIO API, or errno error value |
41 | */ |
42 | |
43 | int acpi_get_gpio(char *path, int pin) |
44 | { |
45 | struct gpio_chip *chip; |
46 | acpi_handle handle; |
47 | acpi_status status; |
48 | |
49 | status = acpi_get_handle(NULL, path, &handle); |
50 | if (ACPI_FAILURE(status)) |
51 | return -ENODEV; |
52 | |
53 | chip = gpiochip_find(handle, acpi_gpiochip_find); |
54 | if (!chip) |
55 | return -ENODEV; |
56 | |
57 | if (!gpio_is_valid(chip->base + pin)) |
58 | return -EINVAL; |
59 | |
60 | return chip->base + pin; |
61 | } |
62 | EXPORT_SYMBOL_GPL(acpi_get_gpio); |
63 | |
64 | static irqreturn_t acpi_gpio_irq_handler(int irq, void *data) |
65 | { |
66 | acpi_handle handle = data; |
67 | |
68 | acpi_evaluate_object(handle, NULL, NULL, NULL); |
69 | |
70 | return IRQ_HANDLED; |
71 | } |
72 | |
73 | static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data) |
74 | { |
75 | struct acpi_gpio_evt_pin *evt_pin = data; |
76 | struct acpi_object_list args; |
77 | union acpi_object arg; |
78 | |
79 | arg.type = ACPI_TYPE_INTEGER; |
80 | arg.integer.value = evt_pin->pin; |
81 | args.count = 1; |
82 | args.pointer = &arg; |
83 | |
84 | acpi_evaluate_object(evt_pin->evt_handle, NULL, &args, NULL); |
85 | |
86 | return IRQ_HANDLED; |
87 | } |
88 | |
89 | static void acpi_gpio_evt_dh(acpi_handle handle, void *data) |
90 | { |
91 | /* The address of this function is used as a key. */ |
92 | } |
93 | |
94 | /** |
95 | * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events |
96 | * @chip: gpio chip |
97 | * |
98 | * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are |
99 | * handled by ACPI event methods which need to be called from the GPIO |
100 | * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which |
101 | * gpio pins have acpi event methods and assigns interrupt handlers that calls |
102 | * the acpi event methods for those pins. |
103 | */ |
104 | void acpi_gpiochip_request_interrupts(struct gpio_chip *chip) |
105 | { |
106 | struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL}; |
107 | struct acpi_resource *res; |
108 | acpi_handle handle, evt_handle; |
109 | struct list_head *evt_pins = NULL; |
110 | acpi_status status; |
111 | unsigned int pin; |
112 | int irq, ret; |
113 | char ev_name[5]; |
114 | |
115 | if (!chip->dev || !chip->to_irq) |
116 | return; |
117 | |
118 | handle = ACPI_HANDLE(chip->dev); |
119 | if (!handle) |
120 | return; |
121 | |
122 | status = acpi_get_event_resources(handle, &buf); |
123 | if (ACPI_FAILURE(status)) |
124 | return; |
125 | |
126 | status = acpi_get_handle(handle, "_EVT", &evt_handle); |
127 | if (ACPI_SUCCESS(status)) { |
128 | evt_pins = kzalloc(sizeof(*evt_pins), GFP_KERNEL); |
129 | if (evt_pins) { |
130 | INIT_LIST_HEAD(evt_pins); |
131 | status = acpi_attach_data(handle, acpi_gpio_evt_dh, |
132 | evt_pins); |
133 | if (ACPI_FAILURE(status)) { |
134 | kfree(evt_pins); |
135 | evt_pins = NULL; |
136 | } |
137 | } |
138 | } |
139 | |
140 | /* |
141 | * If a GPIO interrupt has an ACPI event handler method, or _EVT is |
142 | * present, set up an interrupt handler that calls the ACPI event |
143 | * handler. |
144 | */ |
145 | for (res = buf.pointer; |
146 | res && (res->type != ACPI_RESOURCE_TYPE_END_TAG); |
147 | res = ACPI_NEXT_RESOURCE(res)) { |
148 | irq_handler_t handler = NULL; |
149 | void *data; |
150 | |
151 | if (res->type != ACPI_RESOURCE_TYPE_GPIO || |
152 | res->data.gpio.connection_type != |
153 | ACPI_RESOURCE_GPIO_TYPE_INT) |
154 | continue; |
155 | |
156 | pin = res->data.gpio.pin_table[0]; |
157 | if (pin > chip->ngpio) |
158 | continue; |
159 | |
160 | irq = chip->to_irq(chip, pin); |
161 | if (irq < 0) |
162 | continue; |
163 | |
164 | if (pin <= 255) { |
165 | acpi_handle ev_handle; |
166 | |
167 | sprintf(ev_name, "_%c%02X", |
168 | res->data.gpio.triggering ? 'E' : 'L', pin); |
169 | status = acpi_get_handle(handle, ev_name, &ev_handle); |
170 | if (ACPI_SUCCESS(status)) { |
171 | handler = acpi_gpio_irq_handler; |
172 | data = ev_handle; |
173 | } |
174 | } |
175 | if (!handler && evt_pins) { |
176 | struct acpi_gpio_evt_pin *evt_pin; |
177 | |
178 | evt_pin = kzalloc(sizeof(*evt_pin), GFP_KERNEL); |
179 | if (!evt_pin) |
180 | continue; |
181 | |
182 | list_add_tail(&evt_pin->node, evt_pins); |
183 | evt_pin->evt_handle = evt_handle; |
184 | evt_pin->pin = pin; |
185 | evt_pin->irq = irq; |
186 | handler = acpi_gpio_irq_handler_evt; |
187 | data = evt_pin; |
188 | } |
189 | if (!handler) |
190 | continue; |
191 | |
192 | /* Assume BIOS sets the triggering, so no flags */ |
193 | ret = devm_request_threaded_irq(chip->dev, irq, NULL, handler, |
194 | 0, "GPIO-signaled-ACPI-event", |
195 | data); |
196 | if (ret) |
197 | dev_err(chip->dev, |
198 | "Failed to request IRQ %d ACPI event handler\n", |
199 | irq); |
200 | } |
201 | } |
202 | EXPORT_SYMBOL(acpi_gpiochip_request_interrupts); |
203 | |
204 | struct acpi_gpio_lookup { |
205 | struct acpi_gpio_info info; |
206 | int index; |
207 | int gpio; |
208 | int n; |
209 | }; |
210 | |
211 | static int acpi_find_gpio(struct acpi_resource *ares, void *data) |
212 | { |
213 | struct acpi_gpio_lookup *lookup = data; |
214 | |
215 | if (ares->type != ACPI_RESOURCE_TYPE_GPIO) |
216 | return 1; |
217 | |
218 | if (lookup->n++ == lookup->index && lookup->gpio < 0) { |
219 | const struct acpi_resource_gpio *agpio = &ares->data.gpio; |
220 | |
221 | lookup->gpio = acpi_get_gpio(agpio->resource_source.string_ptr, |
222 | agpio->pin_table[0]); |
223 | lookup->info.gpioint = |
224 | agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT; |
225 | } |
226 | |
227 | return 1; |
228 | } |
229 | |
230 | /** |
231 | * acpi_get_gpio_by_index() - get a GPIO number from device resources |
232 | * @dev: pointer to a device to get GPIO from |
233 | * @index: index of GpioIo/GpioInt resource (starting from %0) |
234 | * @info: info pointer to fill in (optional) |
235 | * |
236 | * Function goes through ACPI resources for @dev and based on @index looks |
237 | * up a GpioIo/GpioInt resource, translates it to the Linux GPIO number, |
238 | * and returns it. @index matches GpioIo/GpioInt resources only so if there |
239 | * are total %3 GPIO resources, the index goes from %0 to %2. |
240 | * |
241 | * If the GPIO cannot be translated or there is an error, negative errno is |
242 | * returned. |
243 | * |
244 | * Note: if the GPIO resource has multiple entries in the pin list, this |
245 | * function only returns the first. |
246 | */ |
247 | int acpi_get_gpio_by_index(struct device *dev, int index, |
248 | struct acpi_gpio_info *info) |
249 | { |
250 | struct acpi_gpio_lookup lookup; |
251 | struct list_head resource_list; |
252 | struct acpi_device *adev; |
253 | acpi_handle handle; |
254 | int ret; |
255 | |
256 | if (!dev) |
257 | return -EINVAL; |
258 | |
259 | handle = ACPI_HANDLE(dev); |
260 | if (!handle || acpi_bus_get_device(handle, &adev)) |
261 | return -ENODEV; |
262 | |
263 | memset(&lookup, 0, sizeof(lookup)); |
264 | lookup.index = index; |
265 | lookup.gpio = -ENODEV; |
266 | |
267 | INIT_LIST_HEAD(&resource_list); |
268 | ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio, |
269 | &lookup); |
270 | if (ret < 0) |
271 | return ret; |
272 | |
273 | acpi_dev_free_resource_list(&resource_list); |
274 | |
275 | if (lookup.gpio >= 0 && info) |
276 | *info = lookup.info; |
277 | |
278 | return lookup.gpio; |
279 | } |
280 | EXPORT_SYMBOL_GPL(acpi_get_gpio_by_index); |
281 | |
282 | /** |
283 | * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts. |
284 | * @chip: gpio chip |
285 | * |
286 | * Free interrupts associated with the _EVT method for the given GPIO chip. |
287 | * |
288 | * The remaining ACPI event interrupts associated with the chip are freed |
289 | * automatically. |
290 | */ |
291 | void acpi_gpiochip_free_interrupts(struct gpio_chip *chip) |
292 | { |
293 | acpi_handle handle; |
294 | acpi_status status; |
295 | struct list_head *evt_pins; |
296 | struct acpi_gpio_evt_pin *evt_pin, *ep; |
297 | |
298 | if (!chip->dev || !chip->to_irq) |
299 | return; |
300 | |
301 | handle = ACPI_HANDLE(chip->dev); |
302 | if (!handle) |
303 | return; |
304 | |
305 | status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins); |
306 | if (ACPI_FAILURE(status)) |
307 | return; |
308 | |
309 | list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) { |
310 | devm_free_irq(chip->dev, evt_pin->irq, evt_pin); |
311 | list_del(&evt_pin->node); |
312 | kfree(evt_pin); |
313 | } |
314 | |
315 | acpi_detach_data(handle, acpi_gpio_evt_dh); |
316 | kfree(evt_pins); |
317 | } |
318 | EXPORT_SYMBOL(acpi_gpiochip_free_interrupts); |
319 |
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