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
28struct gpio_keys_button_data {
29 struct gpio_desc *gpiod;
30 int last_state;
31 int count;
32 int threshold;
33};
34
35struct 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
44static 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(dev: input);
49 unsigned int type = button->type ?: EV_KEY;
50
51 if (type == EV_REL) {
52 if (state) {
53 input_event(dev: input, type, code: button->code, value: button->value);
54 __set_bit(button->code, bdev->rel_axis_seen);
55 }
56 } else if (type == EV_ABS) {
57 if (state) {
58 input_event(dev: input, type, code: button->code, value: button->value);
59 __set_bit(button->code, bdev->abs_axis_seen);
60 }
61 } else {
62 input_event(dev: input, type, code: button->code, value: state);
63 input_sync(dev: input);
64 }
65}
66
67static 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(desc: 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
87static void gpio_keys_polled_poll(struct input_dev *input)
88{
89 struct gpio_keys_polled_dev *bdev = input_get_drvdata(dev: 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, button: &pdata->buttons[i],
102 state: bdata->last_state);
103 } else {
104 gpio_keys_polled_check_state(input, button: &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(dev: input, EV_REL, code: i, value: 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(dev: input, EV_ABS, code: i, value: 0);
117 }
118
119 input_sync(dev: input);
120}
121
122static int gpio_keys_polled_open(struct input_dev *input)
123{
124 struct gpio_keys_polled_dev *bdev = input_get_drvdata(dev: 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
133static void gpio_keys_polled_close(struct input_dev *input)
134{
135 struct gpio_keys_polled_dev *bdev = input_get_drvdata(dev: input);
136 const struct gpio_keys_platform_data *pdata = bdev->pdata;
137
138 if (pdata->disable)
139 pdata->disable(bdev->dev);
140}
141
142static struct gpio_keys_platform_data *
143gpio_keys_polled_get_devtree_pdata(struct device *dev)
144{
145 struct gpio_keys_platform_data *pdata;
146 struct gpio_keys_button *button;
147 struct fwnode_handle *child;
148 int nbuttons;
149
150 nbuttons = device_get_child_node_count(dev);
151 if (nbuttons == 0)
152 return ERR_PTR(error: -EINVAL);
153
154 pdata = devm_kzalloc(dev, size: sizeof(*pdata) + nbuttons * sizeof(*button),
155 GFP_KERNEL);
156 if (!pdata)
157 return ERR_PTR(error: -ENOMEM);
158
159 button = (struct gpio_keys_button *)(pdata + 1);
160
161 pdata->buttons = button;
162 pdata->nbuttons = nbuttons;
163
164 pdata->rep = device_property_present(dev, propname: "autorepeat");
165 device_property_read_u32(dev, propname: "poll-interval", val: &pdata->poll_interval);
166
167 device_property_read_string(dev, propname: "label", val: &pdata->name);
168
169 device_for_each_child_node(dev, child) {
170 if (fwnode_property_read_u32(fwnode: child, propname: "linux,code",
171 val: &button->code)) {
172 dev_err(dev, "button without keycode\n");
173 fwnode_handle_put(fwnode: child);
174 return ERR_PTR(error: -EINVAL);
175 }
176
177 fwnode_property_read_string(fwnode: child, propname: "label", val: &button->desc);
178
179 if (fwnode_property_read_u32(fwnode: child, propname: "linux,input-type",
180 val: &button->type))
181 button->type = EV_KEY;
182
183 if (fwnode_property_read_u32(fwnode: child, propname: "linux,input-value",
184 val: (u32 *)&button->value))
185 button->value = 1;
186
187 button->wakeup =
188 fwnode_property_read_bool(fwnode: child, propname: "wakeup-source") ||
189 /* legacy name */
190 fwnode_property_read_bool(fwnode: child, propname: "gpio-key,wakeup");
191
192 if (fwnode_property_read_u32(fwnode: child, propname: "debounce-interval",
193 val: &button->debounce_interval))
194 button->debounce_interval = 5;
195
196 button++;
197 }
198
199 return pdata;
200}
201
202static void gpio_keys_polled_set_abs_params(struct input_dev *input,
203 const struct gpio_keys_platform_data *pdata, unsigned int code)
204{
205 int i, min = 0, max = 0;
206
207 for (i = 0; i < pdata->nbuttons; i++) {
208 const struct gpio_keys_button *button = &pdata->buttons[i];
209
210 if (button->type != EV_ABS || button->code != code)
211 continue;
212
213 if (button->value < min)
214 min = button->value;
215 if (button->value > max)
216 max = button->value;
217 }
218
219 input_set_abs_params(dev: input, axis: code, min, max, fuzz: 0, flat: 0);
220}
221
222static const struct of_device_id gpio_keys_polled_of_match[] = {
223 { .compatible = "gpio-keys-polled", },
224 { },
225};
226MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
227
228static int gpio_keys_polled_probe(struct platform_device *pdev)
229{
230 struct device *dev = &pdev->dev;
231 struct fwnode_handle *child = NULL;
232 const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
233 struct gpio_keys_polled_dev *bdev;
234 struct input_dev *input;
235 int error;
236 int i;
237
238 if (!pdata) {
239 pdata = gpio_keys_polled_get_devtree_pdata(dev);
240 if (IS_ERR(ptr: pdata))
241 return PTR_ERR(ptr: pdata);
242 }
243
244 if (!pdata->poll_interval) {
245 dev_err(dev, "missing poll_interval value\n");
246 return -EINVAL;
247 }
248
249 bdev = devm_kzalloc(dev, struct_size(bdev, data, pdata->nbuttons),
250 GFP_KERNEL);
251 if (!bdev) {
252 dev_err(dev, "no memory for private data\n");
253 return -ENOMEM;
254 }
255
256 input = devm_input_allocate_device(dev);
257 if (!input) {
258 dev_err(dev, "no memory for input device\n");
259 return -ENOMEM;
260 }
261
262 input_set_drvdata(dev: input, data: bdev);
263
264 input->name = pdata->name ?: pdev->name;
265 input->phys = DRV_NAME"/input0";
266
267 input->id.bustype = BUS_HOST;
268 input->id.vendor = 0x0001;
269 input->id.product = 0x0001;
270 input->id.version = 0x0100;
271
272 input->open = gpio_keys_polled_open;
273 input->close = gpio_keys_polled_close;
274
275 __set_bit(EV_KEY, input->evbit);
276 if (pdata->rep)
277 __set_bit(EV_REP, input->evbit);
278
279 for (i = 0; i < pdata->nbuttons; i++) {
280 const struct gpio_keys_button *button = &pdata->buttons[i];
281 struct gpio_keys_button_data *bdata = &bdev->data[i];
282 unsigned int type = button->type ?: EV_KEY;
283
284 if (button->wakeup) {
285 dev_err(dev, DRV_NAME " does not support wakeup\n");
286 fwnode_handle_put(fwnode: child);
287 return -EINVAL;
288 }
289
290 if (!dev_get_platdata(dev)) {
291 /* No legacy static platform data */
292 child = device_get_next_child_node(dev, child);
293 if (!child) {
294 dev_err(dev, "missing child device node\n");
295 return -EINVAL;
296 }
297
298 bdata->gpiod = devm_fwnode_gpiod_get(dev, fwnode: child,
299 NULL, flags: GPIOD_IN,
300 label: button->desc);
301 if (IS_ERR(ptr: bdata->gpiod)) {
302 fwnode_handle_put(fwnode: child);
303 return dev_err_probe(dev, err: PTR_ERR(ptr: bdata->gpiod),
304 fmt: "failed to get gpio\n");
305 }
306 } else if (gpio_is_valid(number: button->gpio)) {
307 /*
308 * Legacy GPIO number so request the GPIO here and
309 * convert it to descriptor.
310 */
311 unsigned flags = GPIOF_IN;
312
313 if (button->active_low)
314 flags |= GPIOF_ACTIVE_LOW;
315
316 error = devm_gpio_request_one(dev, gpio: button->gpio,
317 flags, label: button->desc ? : DRV_NAME);
318 if (error) {
319 dev_err(dev,
320 "unable to claim gpio %u, err=%d\n",
321 button->gpio, error);
322 return error;
323 }
324
325 bdata->gpiod = gpio_to_desc(gpio: button->gpio);
326 if (!bdata->gpiod) {
327 dev_err(dev,
328 "unable to convert gpio %u to descriptor\n",
329 button->gpio);
330 return -EINVAL;
331 }
332 }
333
334 bdata->last_state = -1;
335 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
336 pdata->poll_interval);
337
338 input_set_capability(dev: input, type, code: button->code);
339 if (type == EV_ABS)
340 gpio_keys_polled_set_abs_params(input, pdata,
341 code: button->code);
342 }
343
344 fwnode_handle_put(fwnode: child);
345
346 bdev->input = input;
347 bdev->dev = dev;
348 bdev->pdata = pdata;
349
350 error = input_setup_polling(dev: input, poll_fn: gpio_keys_polled_poll);
351 if (error) {
352 dev_err(dev, "unable to set up polling, err=%d\n", error);
353 return error;
354 }
355
356 input_set_poll_interval(dev: input, interval: pdata->poll_interval);
357
358 error = input_register_device(input);
359 if (error) {
360 dev_err(dev, "unable to register polled device, err=%d\n",
361 error);
362 return error;
363 }
364
365 /* report initial state of the buttons */
366 for (i = 0; i < pdata->nbuttons; i++)
367 gpio_keys_polled_check_state(input, button: &pdata->buttons[i],
368 bdata: &bdev->data[i]);
369
370 input_sync(dev: input);
371
372 return 0;
373}
374
375static struct platform_driver gpio_keys_polled_driver = {
376 .probe = gpio_keys_polled_probe,
377 .driver = {
378 .name = DRV_NAME,
379 .of_match_table = gpio_keys_polled_of_match,
380 },
381};
382module_platform_driver(gpio_keys_polled_driver);
383
384MODULE_LICENSE("GPL v2");
385MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
386MODULE_DESCRIPTION("Polled GPIO Buttons driver");
387MODULE_ALIAS("platform:" DRV_NAME);
388

source code of linux/drivers/input/keyboard/gpio_keys_polled.c