1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for buttons on GPIO lines not capable of generating interrupts
4 *
5 * Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
6 * Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
7 *
8 * This file was based on: /drivers/input/misc/cobalt_btns.c
9 * Copyright (C) 2007 Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
10 *
11 * also was based on: /drivers/input/keyboard/gpio_keys.c
12 * Copyright 2005 Phil Blundell
13 */
14
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/input.h>
19 #include <linux/ioport.h>
20 #include <linux/platform_device.h>
21 #include <linux/gpio.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/gpio_keys.h>
24 #include <linux/property.h>
25
26 #define DRV_NAME "gpio-keys-polled"
27
28 struct gpio_keys_button_data {
29 struct gpio_desc *gpiod;
30 int last_state;
31 int count;
32 int threshold;
33 };
34
35 struct gpio_keys_polled_dev {
36 struct input_dev *input;
37 struct device *dev;
38 const struct gpio_keys_platform_data *pdata;
39 unsigned long rel_axis_seen[BITS_TO_LONGS(REL_CNT)];
40 unsigned long abs_axis_seen[BITS_TO_LONGS(ABS_CNT)];
41 struct gpio_keys_button_data data[];
42 };
43
gpio_keys_button_event(struct input_dev * input,const struct gpio_keys_button * button,int state)44 static void gpio_keys_button_event(struct input_dev *input,
45 const struct gpio_keys_button *button,
46 int state)
47 {
48 struct gpio_keys_polled_dev *bdev = input_get_drvdata(input);
49 unsigned int type = button->type ?: EV_KEY;
50
51 if (type == EV_REL) {
52 if (state) {
53 input_event(input, type, button->code, button->value);
54 __set_bit(button->code, bdev->rel_axis_seen);
55 }
56 } else if (type == EV_ABS) {
57 if (state) {
58 input_event(input, type, button->code, button->value);
59 __set_bit(button->code, bdev->abs_axis_seen);
60 }
61 } else {
62 input_event(input, type, button->code, state);
63 input_sync(input);
64 }
65 }
66
gpio_keys_polled_check_state(struct input_dev * input,const struct gpio_keys_button * button,struct gpio_keys_button_data * bdata)67 static void gpio_keys_polled_check_state(struct input_dev *input,
68 const struct gpio_keys_button *button,
69 struct gpio_keys_button_data *bdata)
70 {
71 int state;
72
73 state = gpiod_get_value_cansleep(bdata->gpiod);
74 if (state < 0) {
75 dev_err(input->dev.parent,
76 "failed to get gpio state: %d\n", state);
77 } else {
78 gpio_keys_button_event(input, button, state);
79
80 if (state != bdata->last_state) {
81 bdata->count = 0;
82 bdata->last_state = state;
83 }
84 }
85 }
86
gpio_keys_polled_poll(struct input_dev * input)87 static void gpio_keys_polled_poll(struct input_dev *input)
88 {
89 struct gpio_keys_polled_dev *bdev = input_get_drvdata(input);
90 const struct gpio_keys_platform_data *pdata = bdev->pdata;
91 int i;
92
93 memset(bdev->rel_axis_seen, 0, sizeof(bdev->rel_axis_seen));
94 memset(bdev->abs_axis_seen, 0, sizeof(bdev->abs_axis_seen));
95
96 for (i = 0; i < pdata->nbuttons; i++) {
97 struct gpio_keys_button_data *bdata = &bdev->data[i];
98
99 if (bdata->count < bdata->threshold) {
100 bdata->count++;
101 gpio_keys_button_event(input, &pdata->buttons[i],
102 bdata->last_state);
103 } else {
104 gpio_keys_polled_check_state(input, &pdata->buttons[i],
105 bdata);
106 }
107 }
108
109 for_each_set_bit(i, input->relbit, REL_CNT) {
110 if (!test_bit(i, bdev->rel_axis_seen))
111 input_event(input, EV_REL, i, 0);
112 }
113
114 for_each_set_bit(i, input->absbit, ABS_CNT) {
115 if (!test_bit(i, bdev->abs_axis_seen))
116 input_event(input, EV_ABS, i, 0);
117 }
118
119 input_sync(input);
120 }
121
gpio_keys_polled_open(struct input_dev * input)122 static int gpio_keys_polled_open(struct input_dev *input)
123 {
124 struct gpio_keys_polled_dev *bdev = input_get_drvdata(input);
125 const struct gpio_keys_platform_data *pdata = bdev->pdata;
126
127 if (pdata->enable)
128 pdata->enable(bdev->dev);
129
130 return 0;
131 }
132
gpio_keys_polled_close(struct input_dev * input)133 static void gpio_keys_polled_close(struct input_dev *input)
134 {
135 struct gpio_keys_polled_dev *bdev = input_get_drvdata(input);
136 const struct gpio_keys_platform_data *pdata = bdev->pdata;
137
138 if (pdata->disable)
139 pdata->disable(bdev->dev);
140 }
141
142 static struct gpio_keys_platform_data *
gpio_keys_polled_get_devtree_pdata(struct device * dev)143 gpio_keys_polled_get_devtree_pdata(struct device *dev)
144 {
145 struct gpio_keys_platform_data *pdata;
146 struct gpio_keys_button *button;
147 int nbuttons;
148
149 nbuttons = device_get_child_node_count(dev);
150 if (nbuttons == 0)
151 return ERR_PTR(-EINVAL);
152
153 pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * sizeof(*button),
154 GFP_KERNEL);
155 if (!pdata)
156 return ERR_PTR(-ENOMEM);
157
158 button = (struct gpio_keys_button *)(pdata + 1);
159
160 pdata->buttons = button;
161 pdata->nbuttons = nbuttons;
162
163 pdata->rep = device_property_present(dev, "autorepeat");
164 device_property_read_u32(dev, "poll-interval", &pdata->poll_interval);
165
166 device_property_read_string(dev, "label", &pdata->name);
167
168 device_for_each_child_node_scoped(dev, child) {
169 if (fwnode_property_read_u32(child, "linux,code",
170 &button->code)) {
171 dev_err(dev, "button without keycode\n");
172 return ERR_PTR(-EINVAL);
173 }
174
175 fwnode_property_read_string(child, "label", &button->desc);
176
177 if (fwnode_property_read_u32(child, "linux,input-type",
178 &button->type))
179 button->type = EV_KEY;
180
181 if (fwnode_property_read_u32(child, "linux,input-value",
182 (u32 *)&button->value))
183 button->value = 1;
184
185 button->wakeup =
186 fwnode_property_read_bool(child, "wakeup-source") ||
187 /* legacy name */
188 fwnode_property_read_bool(child, "gpio-key,wakeup");
189
190 if (fwnode_property_read_u32(child, "debounce-interval",
191 &button->debounce_interval))
192 button->debounce_interval = 5;
193
194 button++;
195 }
196
197 return pdata;
198 }
199
gpio_keys_polled_set_abs_params(struct input_dev * input,const struct gpio_keys_platform_data * pdata,unsigned int code)200 static void gpio_keys_polled_set_abs_params(struct input_dev *input,
201 const struct gpio_keys_platform_data *pdata, unsigned int code)
202 {
203 int i, min = 0, max = 0;
204
205 for (i = 0; i < pdata->nbuttons; i++) {
206 const struct gpio_keys_button *button = &pdata->buttons[i];
207
208 if (button->type != EV_ABS || button->code != code)
209 continue;
210
211 if (button->value < min)
212 min = button->value;
213 if (button->value > max)
214 max = button->value;
215 }
216
217 input_set_abs_params(input, code, min, max, 0, 0);
218 }
219
220 static const struct of_device_id gpio_keys_polled_of_match[] = {
221 { .compatible = "gpio-keys-polled", },
222 { },
223 };
224 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
225
gpio_keys_polled_probe(struct platform_device * pdev)226 static int gpio_keys_polled_probe(struct platform_device *pdev)
227 {
228 struct device *dev = &pdev->dev;
229 struct fwnode_handle *child = NULL;
230 const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
231 struct gpio_keys_polled_dev *bdev;
232 struct input_dev *input;
233 int error;
234 int i;
235
236 if (!pdata) {
237 pdata = gpio_keys_polled_get_devtree_pdata(dev);
238 if (IS_ERR(pdata))
239 return PTR_ERR(pdata);
240 }
241
242 if (!pdata->poll_interval) {
243 dev_err(dev, "missing poll_interval value\n");
244 return -EINVAL;
245 }
246
247 bdev = devm_kzalloc(dev, struct_size(bdev, data, pdata->nbuttons),
248 GFP_KERNEL);
249 if (!bdev) {
250 dev_err(dev, "no memory for private data\n");
251 return -ENOMEM;
252 }
253
254 input = devm_input_allocate_device(dev);
255 if (!input) {
256 dev_err(dev, "no memory for input device\n");
257 return -ENOMEM;
258 }
259
260 input_set_drvdata(input, bdev);
261
262 input->name = pdata->name ?: pdev->name;
263 input->phys = DRV_NAME"/input0";
264
265 input->id.bustype = BUS_HOST;
266 input->id.vendor = 0x0001;
267 input->id.product = 0x0001;
268 input->id.version = 0x0100;
269
270 input->open = gpio_keys_polled_open;
271 input->close = gpio_keys_polled_close;
272
273 __set_bit(EV_KEY, input->evbit);
274 if (pdata->rep)
275 __set_bit(EV_REP, input->evbit);
276
277 for (i = 0; i < pdata->nbuttons; i++) {
278 const struct gpio_keys_button *button = &pdata->buttons[i];
279 struct gpio_keys_button_data *bdata = &bdev->data[i];
280 unsigned int type = button->type ?: EV_KEY;
281
282 if (button->wakeup) {
283 dev_err(dev, DRV_NAME " does not support wakeup\n");
284 fwnode_handle_put(child);
285 return -EINVAL;
286 }
287
288 if (!dev_get_platdata(dev)) {
289 /* No legacy static platform data */
290 child = device_get_next_child_node(dev, child);
291 if (!child) {
292 dev_err(dev, "missing child device node\n");
293 return -EINVAL;
294 }
295
296 bdata->gpiod = devm_fwnode_gpiod_get(dev, child,
297 NULL, GPIOD_IN,
298 button->desc);
299 if (IS_ERR(bdata->gpiod)) {
300 fwnode_handle_put(child);
301 return dev_err_probe(dev, PTR_ERR(bdata->gpiod),
302 "failed to get gpio\n");
303 }
304 } else if (gpio_is_valid(button->gpio)) {
305 /*
306 * Legacy GPIO number so request the GPIO here and
307 * convert it to descriptor.
308 */
309 unsigned flags = GPIOF_IN;
310
311 if (button->active_low)
312 flags |= GPIOF_ACTIVE_LOW;
313
314 error = devm_gpio_request_one(dev, button->gpio,
315 flags, button->desc ? : DRV_NAME);
316 if (error)
317 return dev_err_probe(dev, error,
318 "unable to claim gpio %u\n",
319 button->gpio);
320
321 bdata->gpiod = gpio_to_desc(button->gpio);
322 if (!bdata->gpiod) {
323 dev_err(dev,
324 "unable to convert gpio %u to descriptor\n",
325 button->gpio);
326 return -EINVAL;
327 }
328 }
329
330 bdata->last_state = -1;
331 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
332 pdata->poll_interval);
333
334 input_set_capability(input, type, button->code);
335 if (type == EV_ABS)
336 gpio_keys_polled_set_abs_params(input, pdata,
337 button->code);
338 }
339
340 fwnode_handle_put(child);
341
342 bdev->input = input;
343 bdev->dev = dev;
344 bdev->pdata = pdata;
345
346 error = input_setup_polling(input, gpio_keys_polled_poll);
347 if (error) {
348 dev_err(dev, "unable to set up polling, err=%d\n", error);
349 return error;
350 }
351
352 input_set_poll_interval(input, pdata->poll_interval);
353
354 error = input_register_device(input);
355 if (error) {
356 dev_err(dev, "unable to register polled device, err=%d\n",
357 error);
358 return error;
359 }
360
361 /* report initial state of the buttons */
362 for (i = 0; i < pdata->nbuttons; i++)
363 gpio_keys_polled_check_state(input, &pdata->buttons[i],
364 &bdev->data[i]);
365
366 input_sync(input);
367
368 return 0;
369 }
370
371 static struct platform_driver gpio_keys_polled_driver = {
372 .probe = gpio_keys_polled_probe,
373 .driver = {
374 .name = DRV_NAME,
375 .of_match_table = gpio_keys_polled_of_match,
376 },
377 };
378 module_platform_driver(gpio_keys_polled_driver);
379
380 MODULE_LICENSE("GPL v2");
381 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
382 MODULE_DESCRIPTION("Polled GPIO Buttons driver");
383 MODULE_ALIAS("platform:" DRV_NAME);
384