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