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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 = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * sizeof(*button),
124                              GFP_KERNEL);
125         if (!pdata)
126                 return ERR_PTR(-ENOMEM);
127 
128         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
129         pdata->nbuttons = nbuttons;
130 
131         pdata->rep = !!of_get_property(node, "autorepeat", NULL);
132         of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
133 
134         i = 0;
135         for_each_child_of_node(node, pp) {
136                 int gpio;
137                 enum of_gpio_flags flags;
138 
139                 if (!of_find_property(pp, "gpios", NULL)) {
140                         pdata->nbuttons--;
141                         dev_warn(dev, "Found button without gpios\n");
142                         continue;
143                 }
144 
145                 gpio = of_get_gpio_flags(pp, 0, &flags);
146                 if (gpio < 0) {
147                         error = gpio;
148                         if (error != -EPROBE_DEFER)
149                                 dev_err(dev,
150                                         "Failed to get gpio flags, error: %d\n",
151                                         error);
152                         return ERR_PTR(error);
153                 }
154 
155                 button = &pdata->buttons[i++];
156 
157                 button->gpio = gpio;
158                 button->active_low = flags & OF_GPIO_ACTIVE_LOW;
159 
160                 if (of_property_read_u32(pp, "linux,code", &button->code)) {
161                         dev_err(dev, "Button without keycode: 0x%x\n",
162                                 button->gpio);
163                         return ERR_PTR(-EINVAL);
164                 }
165 
166                 button->desc = of_get_property(pp, "label", NULL);
167 
168                 if (of_property_read_u32(pp, "linux,input-type", &button->type))
169                         button->type = EV_KEY;
170 
171                 button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
172 
173                 if (of_property_read_u32(pp, "debounce-interval",
174                                          &button->debounce_interval))
175                         button->debounce_interval = 5;
176         }
177 
178         if (pdata->nbuttons == 0)
179                 return ERR_PTR(-EINVAL);
180 
181         return pdata;
182 }
183 
184 static const struct of_device_id gpio_keys_polled_of_match[] = {
185         { .compatible = "gpio-keys-polled", },
186         { },
187 };
188 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
189 
190 #else
191 
192 static inline struct gpio_keys_platform_data *
193 gpio_keys_polled_get_devtree_pdata(struct device *dev)
194 {
195         return NULL;
196 }
197 #endif
198 
199 static int gpio_keys_polled_probe(struct platform_device *pdev)
200 {
201         struct device *dev = &pdev->dev;
202         const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
203         struct gpio_keys_polled_dev *bdev;
204         struct input_polled_dev *poll_dev;
205         struct input_dev *input;
206         size_t size;
207         int error;
208         int i;
209 
210         if (!pdata) {
211                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
212                 if (IS_ERR(pdata))
213                         return PTR_ERR(pdata);
214                 if (!pdata) {
215                         dev_err(dev, "missing platform data\n");
216                         return -EINVAL;
217                 }
218         }
219 
220         if (!pdata->poll_interval) {
221                 dev_err(dev, "missing poll_interval value\n");
222                 return -EINVAL;
223         }
224 
225         size = sizeof(struct gpio_keys_polled_dev) +
226                         pdata->nbuttons * sizeof(struct gpio_keys_button_data);
227         bdev = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
228         if (!bdev) {
229                 dev_err(dev, "no memory for private data\n");
230                 return -ENOMEM;
231         }
232 
233         poll_dev = devm_input_allocate_polled_device(&pdev->dev);
234         if (!poll_dev) {
235                 dev_err(dev, "no memory for polled device\n");
236                 return -ENOMEM;
237         }
238 
239         poll_dev->private = bdev;
240         poll_dev->poll = gpio_keys_polled_poll;
241         poll_dev->poll_interval = pdata->poll_interval;
242         poll_dev->open = gpio_keys_polled_open;
243         poll_dev->close = gpio_keys_polled_close;
244 
245         input = poll_dev->input;
246 
247         input->name = pdev->name;
248         input->phys = DRV_NAME"/input0";
249 
250         input->id.bustype = BUS_HOST;
251         input->id.vendor = 0x0001;
252         input->id.product = 0x0001;
253         input->id.version = 0x0100;
254 
255         __set_bit(EV_KEY, input->evbit);
256         if (pdata->rep)
257                 __set_bit(EV_REP, input->evbit);
258 
259         for (i = 0; i < pdata->nbuttons; i++) {
260                 struct gpio_keys_button *button = &pdata->buttons[i];
261                 struct gpio_keys_button_data *bdata = &bdev->data[i];
262                 unsigned int gpio = button->gpio;
263                 unsigned int type = button->type ?: EV_KEY;
264 
265                 if (button->wakeup) {
266                         dev_err(dev, DRV_NAME " does not support wakeup\n");
267                         return -EINVAL;
268                 }
269 
270                 error = devm_gpio_request_one(&pdev->dev, gpio, GPIOF_IN,
271                                               button->desc ? : DRV_NAME);
272                 if (error) {
273                         dev_err(dev, "unable to claim gpio %u, err=%d\n",
274                                 gpio, error);
275                         return error;
276                 }
277 
278                 bdata->can_sleep = gpio_cansleep(gpio);
279                 bdata->last_state = -1;
280                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
281                                                 pdata->poll_interval);
282 
283                 input_set_capability(input, type, button->code);
284         }
285 
286         bdev->poll_dev = poll_dev;
287         bdev->dev = dev;
288         bdev->pdata = pdata;
289         platform_set_drvdata(pdev, bdev);
290 
291         error = input_register_polled_device(poll_dev);
292         if (error) {
293                 dev_err(dev, "unable to register polled device, err=%d\n",
294                         error);
295                 return error;
296         }
297 
298         /* report initial state of the buttons */
299         for (i = 0; i < pdata->nbuttons; i++)
300                 gpio_keys_polled_check_state(input, &pdata->buttons[i],
301                                              &bdev->data[i]);
302 
303         return 0;
304 }
305 
306 static struct platform_driver gpio_keys_polled_driver = {
307         .probe  = gpio_keys_polled_probe,
308         .driver = {
309                 .name   = DRV_NAME,
310                 .owner  = THIS_MODULE,
311                 .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
312         },
313 };
314 module_platform_driver(gpio_keys_polled_driver);
315 
316 MODULE_LICENSE("GPL v2");
317 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
318 MODULE_DESCRIPTION("Polled GPIO Buttons driver");
319 MODULE_ALIAS("platform:" DRV_NAME);
320 

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