xref: /linux/drivers/input/keyboard/gpio_keys_polled.c (revision 7f71507851fc7764b36a3221839607d3a45c2025) 
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 
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 
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 
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 
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 
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 *
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 
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 
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 			error = devm_gpio_request_one(dev, button->gpio, GPIOF_IN,
310 						      button->desc ? : DRV_NAME);
311 			if (error)
312 				return dev_err_probe(dev, error,
313 						     "unable to claim gpio %u\n",
314 						     button->gpio);
315 
316 			bdata->gpiod = gpio_to_desc(button->gpio);
317 			if (!bdata->gpiod) {
318 				dev_err(dev,
319 					"unable to convert gpio %u to descriptor\n",
320 					button->gpio);
321 				return -EINVAL;
322 			}
323 
324 			if (button->active_low ^ gpiod_is_active_low(bdata->gpiod))
325 				gpiod_toggle_active_low(bdata->gpiod);
326 		}
327 
328 		bdata->last_state = -1;
329 		bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
330 						pdata->poll_interval);
331 
332 		input_set_capability(input, type, button->code);
333 		if (type == EV_ABS)
334 			gpio_keys_polled_set_abs_params(input, pdata,
335 							button->code);
336 	}
337 
338 	fwnode_handle_put(child);
339 
340 	bdev->input = input;
341 	bdev->dev = dev;
342 	bdev->pdata = pdata;
343 
344 	error = input_setup_polling(input, gpio_keys_polled_poll);
345 	if (error) {
346 		dev_err(dev, "unable to set up polling, err=%d\n", error);
347 		return error;
348 	}
349 
350 	input_set_poll_interval(input, pdata->poll_interval);
351 
352 	error = input_register_device(input);
353 	if (error) {
354 		dev_err(dev, "unable to register polled device, err=%d\n",
355 			error);
356 		return error;
357 	}
358 
359 	/* report initial state of the buttons */
360 	for (i = 0; i < pdata->nbuttons; i++)
361 		gpio_keys_polled_check_state(input, &pdata->buttons[i],
362 					     &bdev->data[i]);
363 
364 	input_sync(input);
365 
366 	return 0;
367 }
368 
369 static struct platform_driver gpio_keys_polled_driver = {
370 	.probe	= gpio_keys_polled_probe,
371 	.driver	= {
372 		.name	= DRV_NAME,
373 		.of_match_table = gpio_keys_polled_of_match,
374 	},
375 };
376 module_platform_driver(gpio_keys_polled_driver);
377 
378 MODULE_LICENSE("GPL v2");
379 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
380 MODULE_DESCRIPTION("Polled GPIO Buttons driver");
381 MODULE_ALIAS("platform:" DRV_NAME);
382