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Linux/drivers/input/keyboard/gpio_keys_polled.c

  1 /*
  2  *  Driver for buttons on GPIO lines not capable of generating interrupts
  3  *
  4  *  Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
  5  *  Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
  6  *
  7  *  This file was based on: /drivers/input/misc/cobalt_btns.c
  8  *      Copyright (C) 2007 Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
  9  *
 10  *  also was based on: /drivers/input/keyboard/gpio_keys.c
 11  *      Copyright 2005 Phil Blundell
 12  *
 13  *  This program is free software; you can redistribute it and/or modify
 14  *  it under the terms of the GNU General Public License version 2 as
 15  *  published by the Free Software Foundation.
 16  */
 17 
 18 #include <linux/kernel.h>
 19 #include <linux/module.h>
 20 #include <linux/slab.h>
 21 #include <linux/input.h>
 22 #include <linux/input-polldev.h>
 23 #include <linux/ioport.h>
 24 #include <linux/platform_device.h>
 25 #include <linux/gpio.h>
 26 #include <linux/gpio_keys.h>
 27 #include <linux/of.h>
 28 #include <linux/of_platform.h>
 29 #include <linux/of_gpio.h>
 30 
 31 #define DRV_NAME        "gpio-keys-polled"
 32 
 33 struct gpio_keys_button_data {
 34         int last_state;
 35         int count;
 36         int threshold;
 37         int can_sleep;
 38 };
 39 
 40 struct gpio_keys_polled_dev {
 41         struct input_polled_dev *poll_dev;
 42         struct device *dev;
 43         const struct gpio_keys_platform_data *pdata;
 44         struct gpio_keys_button_data data[0];
 45 };
 46 
 47 static void gpio_keys_polled_check_state(struct input_dev *input,
 48                                          struct gpio_keys_button *button,
 49                                          struct gpio_keys_button_data *bdata)
 50 {
 51         int state;
 52 
 53         if (bdata->can_sleep)
 54                 state = !!gpio_get_value_cansleep(button->gpio);
 55         else
 56                 state = !!gpio_get_value(button->gpio);
 57 
 58         if (state != bdata->last_state) {
 59                 unsigned int type = button->type ?: EV_KEY;
 60 
 61                 input_event(input, type, button->code,
 62                             !!(state ^ button->active_low));
 63                 input_sync(input);
 64                 bdata->count = 0;
 65                 bdata->last_state = state;
 66         }
 67 }
 68 
 69 static void gpio_keys_polled_poll(struct input_polled_dev *dev)
 70 {
 71         struct gpio_keys_polled_dev *bdev = dev->private;
 72         const struct gpio_keys_platform_data *pdata = bdev->pdata;
 73         struct input_dev *input = dev->input;
 74         int i;
 75 
 76         for (i = 0; i < pdata->nbuttons; i++) {
 77                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 78 
 79                 if (bdata->count < bdata->threshold)
 80                         bdata->count++;
 81                 else
 82                         gpio_keys_polled_check_state(input, &pdata->buttons[i],
 83                                                      bdata);
 84         }
 85 }
 86 
 87 static void gpio_keys_polled_open(struct input_polled_dev *dev)
 88 {
 89         struct gpio_keys_polled_dev *bdev = dev->private;
 90         const struct gpio_keys_platform_data *pdata = bdev->pdata;
 91 
 92         if (pdata->enable)
 93                 pdata->enable(bdev->dev);
 94 }
 95 
 96 static void gpio_keys_polled_close(struct input_polled_dev *dev)
 97 {
 98         struct gpio_keys_polled_dev *bdev = dev->private;
 99         const struct gpio_keys_platform_data *pdata = bdev->pdata;
100 
101         if (pdata->disable)
102                 pdata->disable(bdev->dev);
103 }
104 
105 #ifdef CONFIG_OF
106 static struct gpio_keys_platform_data *gpio_keys_polled_get_devtree_pdata(struct device *dev)
107 {
108         struct device_node *node, *pp;
109         struct gpio_keys_platform_data *pdata;
110         struct gpio_keys_button *button;
111         int error;
112         int nbuttons;
113         int i;
114 
115         node = dev->of_node;
116         if (!node)
117                 return NULL;
118 
119         nbuttons = of_get_child_count(node);
120         if (nbuttons == 0)
121                 return NULL;
122 
123         pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
124                         GFP_KERNEL);
125         if (!pdata) {
126                 error = -ENOMEM;
127                 goto err_out;
128         }
129 
130         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
131         pdata->nbuttons = nbuttons;
132 
133         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
134         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
135 
136         i = 0;
137         for_each_child_of_node(node, pp) {
138                 int gpio;
139                 enum of_gpio_flags flags;
140 
141                 if (!of_find_property(pp, "gpios", NULL)) {
142                         pdata->nbuttons--;
143                         dev_warn(dev, "Found button without gpios\n");
144                         continue;
145                 }
146 
147                 gpio = of_get_gpio_flags(pp, 0, &flags);
148                 if (gpio < 0) {
149                         error = gpio;
150                         if (error != -EPROBE_DEFER)
151                                 dev_err(dev,
152                                         "Failed to get gpio flags, error: %d\n",
153                                         error);
154                         goto err_free_pdata;
155                 }
156 
157                 button = &pdata->buttons[i++];
158 
159                 button->gpio = gpio;
160                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
161 
162                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
163                         dev_err(dev, "Button without keycode: 0x%x\n",
164                                 button->gpio);
165                         error = -EINVAL;
166                         goto err_free_pdata;
167                 }
168 
169                 button->desc = of_get_property(pp, "label", NULL);
170 
171                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
172                         button->type = EV_KEY;
173 
174                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
175 
176                 if (of_property_read_u32(pp, "debounce-interval",
177                                          &button->debounce_interval))
178                         button->debounce_interval = 5;
179         }
180 
181         if (pdata->nbuttons == 0) {
182                 error = -EINVAL;
183                 goto err_free_pdata;
184         }
185 
186         return pdata;
187 
188 err_free_pdata:
189         kfree(pdata);
190 err_out:
191         return ERR_PTR(error);
192 }
193 
194 static struct of_device_id gpio_keys_polled_of_match[] = {
195         { .compatible = "gpio-keys-polled", },
196         { },
197 };
198 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
199 
200 #else
201 
202 static inline struct gpio_keys_platform_data *
203 gpio_keys_polled_get_devtree_pdata(struct device *dev)
204 {
205         return NULL;
206 }
207 #endif
208 
209 static int gpio_keys_polled_probe(struct platform_device *pdev)
210 {
211         struct device *dev = &pdev->dev;
212         const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
213         struct gpio_keys_polled_dev *bdev;
214         struct input_polled_dev *poll_dev;
215         struct input_dev *input;
216         int error;
217         int i;
218 
219         if (!pdata) {
220                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
221                 if (IS_ERR(pdata))
222                         return PTR_ERR(pdata);
223                 if (!pdata) {
224                         dev_err(dev, "missing platform data\n");
225                         return -EINVAL;
226                 }
227         }
228 
229         if (!pdata->poll_interval) {
230                 dev_err(dev, "missing poll_interval value\n");
231                 error = -EINVAL;
232                 goto err_free_pdata;
233         }
234 
235         bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
236                        pdata->nbuttons * sizeof(struct gpio_keys_button_data),
237                        GFP_KERNEL);
238         if (!bdev) {
239                 dev_err(dev, "no memory for private data\n");
240                 error = -ENOMEM;
241                 goto err_free_pdata;
242         }
243 
244         poll_dev = input_allocate_polled_device();
245         if (!poll_dev) {
246                 dev_err(dev, "no memory for polled device\n");
247                 error = -ENOMEM;
248                 goto err_free_bdev;
249         }
250 
251         poll_dev->private = bdev;
252         poll_dev->poll = gpio_keys_polled_poll;
253         poll_dev->poll_interval = pdata->poll_interval;
254         poll_dev->open = gpio_keys_polled_open;
255         poll_dev->close = gpio_keys_polled_close;
256 
257         input = poll_dev->input;
258 
259         input->name = pdev->name;
260         input->phys = DRV_NAME"/input0";
261         input->dev.parent = &pdev->dev;
262 
263         input->id.bustype = BUS_HOST;
264         input->id.vendor = 0x0001;
265         input->id.product = 0x0001;
266         input->id.version = 0x0100;
267 
268         __set_bit(EV_KEY, input->evbit);
269         if (pdata->rep)
270                 __set_bit(EV_REP, input->evbit);
271 
272         for (i = 0; i < pdata->nbuttons; i++) {
273                 struct gpio_keys_button *button = &pdata->buttons[i];
274                 struct gpio_keys_button_data *bdata = &bdev->data[i];
275                 unsigned int gpio = button->gpio;
276                 unsigned int type = button->type ?: EV_KEY;
277 
278                 if (button->wakeup) {
279                         dev_err(dev, DRV_NAME " does not support wakeup\n");
280                         error = -EINVAL;
281                         goto err_free_gpio;
282                 }
283 
284                 error = gpio_request_one(gpio, GPIOF_IN,
285                                          button->desc ?: DRV_NAME);
286                 if (error) {
287                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
288                                 gpio, error);
289                         goto err_free_gpio;
290                 }
291 
292                 bdata->can_sleep = gpio_cansleep(gpio);
293                 bdata->last_state = -1;
294                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
295                                                 pdata->poll_interval);
296 
297                 input_set_capability(input, type, button->code);
298         }
299 
300         bdev->poll_dev = poll_dev;
301         bdev->dev = dev;
302         bdev->pdata = pdata;
303         platform_set_drvdata(pdev, bdev);
304 
305         error = input_register_polled_device(poll_dev);
306         if (error) {
307                 dev_err(dev, "unable to register polled device, err=%d\n",
308                         error);
309                 goto err_free_gpio;
310         }
311 
312         /* report initial state of the buttons */
313         for (i = 0; i < pdata->nbuttons; i++)
314                 gpio_keys_polled_check_state(input, &pdata->buttons[i],
315                                              &bdev->data[i]);
316 
317         return 0;
318 
319 err_free_gpio:
320         while (--i >= 0)
321                 gpio_free(pdata->buttons[i].gpio);
322 
323         input_free_polled_device(poll_dev);
324 
325 err_free_bdev:
326         kfree(bdev);
327 
328 err_free_pdata:
329         /* If we have no platform_data, we allocated pdata dynamically.  */
330         if (!dev_get_platdata(&pdev->dev))
331                 kfree(pdata);
332 
333         return error;
334 }
335 
336 static int gpio_keys_polled_remove(struct platform_device *pdev)
337 {
338         struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
339         const struct gpio_keys_platform_data *pdata = bdev->pdata;
340         int i;
341 
342         input_unregister_polled_device(bdev->poll_dev);
343 
344         for (i = 0; i < pdata->nbuttons; i++)
345                 gpio_free(pdata->buttons[i].gpio);
346 
347         input_free_polled_device(bdev->poll_dev);
348 
349         /*
350          * If we had no platform_data, we allocated pdata dynamically and
351          * must free it here.
352          */
353         if (!dev_get_platdata(&pdev->dev))
354                 kfree(pdata);
355 
356         kfree(bdev);
357 
358         return 0;
359 }
360 
361 static struct platform_driver gpio_keys_polled_driver = {
362         .probe  = gpio_keys_polled_probe,
363         .remove = gpio_keys_polled_remove,
364         .driver = {
365                 .name   = DRV_NAME,
366                 .owner  = THIS_MODULE,
367                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
368         },
369 };
370 module_platform_driver(gpio_keys_polled_driver);
371 
372 MODULE_LICENSE("GPL v2");
373 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
374 MODULE_DESCRIPTION("Polled GPIO Buttons driver");
375 MODULE_ALIAS("platform:" DRV_NAME);
376 

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