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(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
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(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(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
122static 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
133static 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
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(-EINVAL);
153
154	pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * sizeof(*button),
155			     GFP_KERNEL);
156	if (!pdata)
157		return ERR_PTR(-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, "autorepeat");
165	device_property_read_u32(dev, "poll-interval", &pdata->poll_interval);
166
167	device_property_read_string(dev, "label", &pdata->name);
168
169	device_for_each_child_node(dev, child) {
170		if (fwnode_property_read_u32(child, "linux,code",
171					     &button->code)) {
172			dev_err(dev, "button without keycode\n");
173			fwnode_handle_put(child);
174			return ERR_PTR(-EINVAL);
175		}
176
177		fwnode_property_read_string(child, "label", &button->desc);
178
179		if (fwnode_property_read_u32(child, "linux,input-type",
180					     &button->type))
181			button->type = EV_KEY;
182
183		if (fwnode_property_read_u32(child, "linux,input-value",
184					     (u32 *)&button->value))
185			button->value = 1;
186
187		button->wakeup =
188			fwnode_property_read_bool(child, "wakeup-source") ||
189			/* legacy name */
190			fwnode_property_read_bool(child, "gpio-key,wakeup");
191
192		if (fwnode_property_read_u32(child, "debounce-interval",
193					     &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(input, code, min, max, 0, 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(pdata))
241			return PTR_ERR(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(input, 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(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, child,
299							     NULL, GPIOD_IN,
300							     button->desc);
301			if (IS_ERR(bdata->gpiod)) {
302				fwnode_handle_put(child);
303				return dev_err_probe(dev, PTR_ERR(bdata->gpiod),
304						     "failed to get gpio\n");
305			}
306		} else if (gpio_is_valid(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, button->gpio,
317					flags, button->desc ? : DRV_NAME);
318			if (error)
319				return dev_err_probe(dev, error,
320						     "unable to claim gpio %u\n",
321						     button->gpio);
322
323			bdata->gpiod = gpio_to_desc(button->gpio);
324			if (!bdata->gpiod) {
325				dev_err(dev,
326					"unable to convert gpio %u to descriptor\n",
327					button->gpio);
328				return -EINVAL;
329			}
330		}
331
332		bdata->last_state = -1;
333		bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
334						pdata->poll_interval);
335
336		input_set_capability(input, type, button->code);
337		if (type == EV_ABS)
338			gpio_keys_polled_set_abs_params(input, pdata,
339							button->code);
340	}
341
342	fwnode_handle_put(child);
343
344	bdev->input = input;
345	bdev->dev = dev;
346	bdev->pdata = pdata;
347
348	error = input_setup_polling(input, gpio_keys_polled_poll);
349	if (error) {
350		dev_err(dev, "unable to set up polling, err=%d\n", error);
351		return error;
352	}
353
354	input_set_poll_interval(input, pdata->poll_interval);
355
356	error = input_register_device(input);
357	if (error) {
358		dev_err(dev, "unable to register polled device, err=%d\n",
359			error);
360		return error;
361	}
362
363	/* report initial state of the buttons */
364	for (i = 0; i < pdata->nbuttons; i++)
365		gpio_keys_polled_check_state(input, &pdata->buttons[i],
366					     &bdev->data[i]);
367
368	input_sync(input);
369
370	return 0;
371}
372
373static struct platform_driver gpio_keys_polled_driver = {
374	.probe	= gpio_keys_polled_probe,
375	.driver	= {
376		.name	= DRV_NAME,
377		.of_match_table = gpio_keys_polled_of_match,
378	},
379};
380module_platform_driver(gpio_keys_polled_driver);
381
382MODULE_LICENSE("GPL v2");
383MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
384MODULE_DESCRIPTION("Polled GPIO Buttons driver");
385MODULE_ALIAS("platform:" DRV_NAME);
386