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15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/slab.h>
18#include <linux/input.h>
19#include <linux/input-polldev.h>
20#include <linux/ioport.h>
21#include <linux/platform_device.h>
22#include <linux/gpio.h>
23#include <linux/gpio/consumer.h>
24#include <linux/gpio_keys.h>
25#include <linux/property.h>
26
27#define DRV_NAME "gpio-keys-polled"
28
29struct gpio_keys_button_data {
30 struct gpio_desc *gpiod;
31 int last_state;
32 int count;
33 int threshold;
34};
35
36struct gpio_keys_polled_dev {
37 struct input_polled_dev *poll_dev;
38 struct device *dev;
39 const struct gpio_keys_platform_data *pdata;
40 unsigned long rel_axis_seen[BITS_TO_LONGS(REL_CNT)];
41 unsigned long abs_axis_seen[BITS_TO_LONGS(ABS_CNT)];
42 struct gpio_keys_button_data data[0];
43};
44
45static void gpio_keys_button_event(struct input_polled_dev *dev,
46 const struct gpio_keys_button *button,
47 int state)
48{
49 struct gpio_keys_polled_dev *bdev = dev->private;
50 struct input_dev *input = dev->input;
51 unsigned int type = button->type ?: EV_KEY;
52
53 if (type == EV_REL) {
54 if (state) {
55 input_event(input, type, button->code, button->value);
56 __set_bit(button->code, bdev->rel_axis_seen);
57 }
58 } else if (type == EV_ABS) {
59 if (state) {
60 input_event(input, type, button->code, button->value);
61 __set_bit(button->code, bdev->abs_axis_seen);
62 }
63 } else {
64 input_event(input, type, button->code, state);
65 input_sync(input);
66 }
67}
68
69static void gpio_keys_polled_check_state(struct input_polled_dev *dev,
70 const struct gpio_keys_button *button,
71 struct gpio_keys_button_data *bdata)
72{
73 int state;
74
75 state = gpiod_get_value_cansleep(bdata->gpiod);
76 if (state < 0) {
77 dev_err(dev->input->dev.parent,
78 "failed to get gpio state: %d\n", state);
79 } else {
80 gpio_keys_button_event(dev, button, state);
81
82 if (state != bdata->last_state) {
83 bdata->count = 0;
84 bdata->last_state = state;
85 }
86 }
87}
88
89static void gpio_keys_polled_poll(struct input_polled_dev *dev)
90{
91 struct gpio_keys_polled_dev *bdev = dev->private;
92 const struct gpio_keys_platform_data *pdata = bdev->pdata;
93 struct input_dev *input = dev->input;
94 int i;
95
96 memset(bdev->rel_axis_seen, 0, sizeof(bdev->rel_axis_seen));
97 memset(bdev->abs_axis_seen, 0, sizeof(bdev->abs_axis_seen));
98
99 for (i = 0; i < pdata->nbuttons; i++) {
100 struct gpio_keys_button_data *bdata = &bdev->data[i];
101
102 if (bdata->count < bdata->threshold) {
103 bdata->count++;
104 gpio_keys_button_event(dev, &pdata->buttons[i],
105 bdata->last_state);
106 } else {
107 gpio_keys_polled_check_state(dev, &pdata->buttons[i],
108 bdata);
109 }
110 }
111
112 for_each_set_bit(i, input->relbit, REL_CNT) {
113 if (!test_bit(i, bdev->rel_axis_seen))
114 input_event(input, EV_REL, i, 0);
115 }
116
117 for_each_set_bit(i, input->absbit, ABS_CNT) {
118 if (!test_bit(i, bdev->abs_axis_seen))
119 input_event(input, EV_ABS, i, 0);
120 }
121
122 input_sync(input);
123}
124
125static void gpio_keys_polled_open(struct input_polled_dev *dev)
126{
127 struct gpio_keys_polled_dev *bdev = dev->private;
128 const struct gpio_keys_platform_data *pdata = bdev->pdata;
129
130 if (pdata->enable)
131 pdata->enable(bdev->dev);
132}
133
134static void gpio_keys_polled_close(struct input_polled_dev *dev)
135{
136 struct gpio_keys_polled_dev *bdev = dev->private;
137 const struct gpio_keys_platform_data *pdata = bdev->pdata;
138
139 if (pdata->disable)
140 pdata->disable(bdev->dev);
141}
142
143static struct gpio_keys_platform_data *
144gpio_keys_polled_get_devtree_pdata(struct device *dev)
145{
146 struct gpio_keys_platform_data *pdata;
147 struct gpio_keys_button *button;
148 struct fwnode_handle *child;
149 int nbuttons;
150
151 nbuttons = device_get_child_node_count(dev);
152 if (nbuttons == 0)
153 return ERR_PTR(-EINVAL);
154
155 pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * sizeof(*button),
156 GFP_KERNEL);
157 if (!pdata)
158 return ERR_PTR(-ENOMEM);
159
160 button = (struct gpio_keys_button *)(pdata + 1);
161
162 pdata->buttons = button;
163 pdata->nbuttons = nbuttons;
164
165 pdata->rep = device_property_present(dev, "autorepeat");
166 device_property_read_u32(dev, "poll-interval", &pdata->poll_interval);
167
168 device_for_each_child_node(dev, child) {
169 if (fwnode_property_read_u32(child, "linux,code",
170 &button->code)) {
171 dev_err(dev, "button without keycode\n");
172 fwnode_handle_put(child);
173 return ERR_PTR(-EINVAL);
174 }
175
176 fwnode_property_read_string(child, "label", &button->desc);
177
178 if (fwnode_property_read_u32(child, "linux,input-type",
179 &button->type))
180 button->type = EV_KEY;
181
182 if (fwnode_property_read_u32(child, "linux,input-value",
183 (u32 *)&button->value))
184 button->value = 1;
185
186 button->wakeup =
187 fwnode_property_read_bool(child, "wakeup-source") ||
188
189 fwnode_property_read_bool(child, "gpio-key,wakeup");
190
191 if (fwnode_property_read_u32(child, "debounce-interval",
192 &button->debounce_interval))
193 button->debounce_interval = 5;
194
195 button++;
196 }
197
198 return pdata;
199}
200
201static void gpio_keys_polled_set_abs_params(struct input_dev *input,
202 const struct gpio_keys_platform_data *pdata, unsigned int code)
203{
204 int i, min = 0, max = 0;
205
206 for (i = 0; i < pdata->nbuttons; i++) {
207 const struct gpio_keys_button *button = &pdata->buttons[i];
208
209 if (button->type != EV_ABS || button->code != code)
210 continue;
211
212 if (button->value < min)
213 min = button->value;
214 if (button->value > max)
215 max = button->value;
216 }
217
218 input_set_abs_params(input, code, min, max, 0, 0);
219}
220
221static const struct of_device_id gpio_keys_polled_of_match[] = {
222 { .compatible = "gpio-keys-polled", },
223 { },
224};
225MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
226
227static int gpio_keys_polled_probe(struct platform_device *pdev)
228{
229 struct device *dev = &pdev->dev;
230 struct fwnode_handle *child = NULL;
231 const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
232 struct gpio_keys_polled_dev *bdev;
233 struct input_polled_dev *poll_dev;
234 struct input_dev *input;
235 size_t size;
236 int error;
237 int i;
238
239 if (!pdata) {
240 pdata = gpio_keys_polled_get_devtree_pdata(dev);
241 if (IS_ERR(pdata))
242 return PTR_ERR(pdata);
243 }
244
245 if (!pdata->poll_interval) {
246 dev_err(dev, "missing poll_interval value\n");
247 return -EINVAL;
248 }
249
250 size = sizeof(struct gpio_keys_polled_dev) +
251 pdata->nbuttons * sizeof(struct gpio_keys_button_data);
252 bdev = devm_kzalloc(dev, size, GFP_KERNEL);
253 if (!bdev) {
254 dev_err(dev, "no memory for private data\n");
255 return -ENOMEM;
256 }
257
258 poll_dev = devm_input_allocate_polled_device(dev);
259 if (!poll_dev) {
260 dev_err(dev, "no memory for polled device\n");
261 return -ENOMEM;
262 }
263
264 poll_dev->private = bdev;
265 poll_dev->poll = gpio_keys_polled_poll;
266 poll_dev->poll_interval = pdata->poll_interval;
267 poll_dev->open = gpio_keys_polled_open;
268 poll_dev->close = gpio_keys_polled_close;
269
270 input = poll_dev->input;
271
272 input->name = pdev->name;
273 input->phys = DRV_NAME"/input0";
274
275 input->id.bustype = BUS_HOST;
276 input->id.vendor = 0x0001;
277 input->id.product = 0x0001;
278 input->id.version = 0x0100;
279
280 __set_bit(EV_KEY, input->evbit);
281 if (pdata->rep)
282 __set_bit(EV_REP, input->evbit);
283
284 for (i = 0; i < pdata->nbuttons; i++) {
285 const struct gpio_keys_button *button = &pdata->buttons[i];
286 struct gpio_keys_button_data *bdata = &bdev->data[i];
287 unsigned int type = button->type ?: EV_KEY;
288
289 if (button->wakeup) {
290 dev_err(dev, DRV_NAME " does not support wakeup\n");
291 fwnode_handle_put(child);
292 return -EINVAL;
293 }
294
295 if (!dev_get_platdata(dev)) {
296
297 child = device_get_next_child_node(dev, child);
298 if (!child) {
299 dev_err(dev, "missing child device node\n");
300 return -EINVAL;
301 }
302
303 bdata->gpiod = devm_fwnode_get_gpiod_from_child(dev,
304 NULL, child,
305 GPIOD_IN,
306 button->desc);
307 if (IS_ERR(bdata->gpiod)) {
308 error = PTR_ERR(bdata->gpiod);
309 if (error != -EPROBE_DEFER)
310 dev_err(dev,
311 "failed to get gpio: %d\n",
312 error);
313 fwnode_handle_put(child);
314 return error;
315 }
316 } else if (gpio_is_valid(button->gpio)) {
317
318
319
320
321 unsigned flags = GPIOF_IN;
322
323 if (button->active_low)
324 flags |= GPIOF_ACTIVE_LOW;
325
326 error = devm_gpio_request_one(dev, button->gpio,
327 flags, button->desc ? : DRV_NAME);
328 if (error) {
329 dev_err(dev,
330 "unable to claim gpio %u, err=%d\n",
331 button->gpio, error);
332 return error;
333 }
334
335 bdata->gpiod = gpio_to_desc(button->gpio);
336 if (!bdata->gpiod) {
337 dev_err(dev,
338 "unable to convert gpio %u to descriptor\n",
339 button->gpio);
340 return -EINVAL;
341 }
342 }
343
344 bdata->last_state = -1;
345 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
346 pdata->poll_interval);
347
348 input_set_capability(input, type, button->code);
349 if (type == EV_ABS)
350 gpio_keys_polled_set_abs_params(input, pdata,
351 button->code);
352 }
353
354 fwnode_handle_put(child);
355
356 bdev->poll_dev = poll_dev;
357 bdev->dev = dev;
358 bdev->pdata = pdata;
359
360 error = input_register_polled_device(poll_dev);
361 if (error) {
362 dev_err(dev, "unable to register polled device, err=%d\n",
363 error);
364 return error;
365 }
366
367
368 for (i = 0; i < pdata->nbuttons; i++)
369 gpio_keys_polled_check_state(poll_dev, &pdata->buttons[i],
370 &bdev->data[i]);
371
372 input_sync(input);
373
374 return 0;
375}
376
377static struct platform_driver gpio_keys_polled_driver = {
378 .probe = gpio_keys_polled_probe,
379 .driver = {
380 .name = DRV_NAME,
381 .of_match_table = gpio_keys_polled_of_match,
382 },
383};
384module_platform_driver(gpio_keys_polled_driver);
385
386MODULE_LICENSE("GPL v2");
387MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
388MODULE_DESCRIPTION("Polled GPIO Buttons driver");
389MODULE_ALIAS("platform:" DRV_NAME);
390
