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);