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         struct gpio_keys_button_data data[0];
  44 };
  45
  46 static void gpio_keys_polled_check_state(struct input_dev *input,
  47                                          struct gpio_keys_button *button,
  48                                          struct gpio_keys_button_data *bdata)
  49 {
  50         int state;
  51
  52         if (bdata->can_sleep)
  53                 state = !!gpiod_get_value_cansleep(button->gpiod);
  54         else
  55                 state = !!gpiod_get_value(button->gpiod);
  56
  57         if (state != bdata->last_state) {
  58                 unsigned int type = button->type ?: EV_KEY;
  59
  60                 input_event(input, type, button->code, state);
  61                 input_sync(input);
  62                 bdata->count = 0;
  63                 bdata->last_state = state;
  64         }
  65 }
  66
  67 static void gpio_keys_polled_poll(struct input_polled_dev *dev)
  68 {
  69         struct gpio_keys_polled_dev *bdev = dev->private;
  70         const struct gpio_keys_platform_data *pdata = bdev->pdata;
  71         struct input_dev *input = dev->input;
  72         int i;
  73
  74         for (i = 0; i < pdata->nbuttons; i++) {
  75                 struct gpio_keys_button_data *bdata = &bdev->data[i];
  76
  77                 if (bdata->count < bdata->threshold)
  78                         bdata->count++;
  79                 else
  80                         gpio_keys_polled_check_state(input, &pdata->buttons[i],
  81                                                      bdata);
  82         }
  83 }
  84
  85 static void gpio_keys_polled_open(struct input_polled_dev *dev)
  86 {
  87         struct gpio_keys_polled_dev *bdev = dev->private;
  88         const struct gpio_keys_platform_data *pdata = bdev->pdata;
  89
  90         if (pdata->enable)
  91                 pdata->enable(bdev->dev);
  92 }
  93
  94 static void gpio_keys_polled_close(struct input_polled_dev *dev)
  95 {
  96         struct gpio_keys_polled_dev *bdev = dev->private;
  97         const struct gpio_keys_platform_data *pdata = bdev->pdata;
  98
  99         if (pdata->disable)
 100                 pdata->disable(bdev->dev);
 101 }
 102
 103 static struct gpio_keys_platform_data *gpio_keys_polled_get_devtree_pdata(struct device *dev)
 104 {
 105         struct gpio_keys_platform_data *pdata;
 106         struct gpio_keys_button *button;
 107         struct fwnode_handle *child;
 108         int error;
 109         int nbuttons;
 110
 111         nbuttons = device_get_child_node_count(dev);
 112         if (nbuttons == 0)
 113                 return NULL;
 114
 115         pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * sizeof(*button),
 116                              GFP_KERNEL);
 117         if (!pdata)
 118                 return ERR_PTR(-ENOMEM);
 119
 120         pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
 121
 122         pdata->rep = device_property_present(dev, "autorepeat");
 123         device_property_read_u32(dev, "poll-interval", &pdata->poll_interval);
 124
 125         device_for_each_child_node(dev, child) {
 126                 struct gpio_desc *desc;
 127
 128                 desc = devm_get_gpiod_from_child(dev, NULL, child);
 129                 if (IS_ERR(desc)) {
 130                         error = PTR_ERR(desc);
 131                         if (error != -EPROBE_DEFER)
 132                                 dev_err(dev,
 133                                         "Failed to get gpio flags, error: %d\n",
 134                                         error);
 135                         fwnode_handle_put(child);
 136                         return ERR_PTR(error);
 137                 }
 138
 139                 button = &pdata->buttons[pdata->nbuttons++];
 140                 button->gpiod = desc;
 141
 142                 if (fwnode_property_read_u32(child, "linux,code", &button->code)) {
 143                         dev_err(dev, "Button without keycode: %d\n",
 144                                 pdata->nbuttons - 1);
 145                         fwnode_handle_put(child);
 146                         return ERR_PTR(-EINVAL);
 147                 }
 148
 149                 fwnode_property_read_string(child, "label", &button->desc);
 150
 151                 if (fwnode_property_read_u32(child, "linux,input-type",
 152                                              &button->type))
 153                         button->type = EV_KEY;
 154
 155                 button->wakeup = fwnode_property_present(child, "gpio-key,wakeup");
 156
 157                 if (fwnode_property_read_u32(child, "debounce-interval",
 158                                              &button->debounce_interval))
 159                         button->debounce_interval = 5;
 160         }
 161
 162         if (pdata->nbuttons == 0)
 163                 return ERR_PTR(-EINVAL);
 164
 165         return pdata;
 166 }
 167
 168 static const struct of_device_id gpio_keys_polled_of_match[] = {
 169         { .compatible = "gpio-keys-polled", },
 170         { },
 171 };
 172 MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
 173
 174 static int gpio_keys_polled_probe(struct platform_device *pdev)
 175 {
 176         struct device *dev = &pdev->dev;
 177         const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
 178         struct gpio_keys_polled_dev *bdev;
 179         struct input_polled_dev *poll_dev;
 180         struct input_dev *input;
 181         size_t size;
 182         int error;
 183         int i;
 184
 185         if (!pdata) {
 186                 pdata = gpio_keys_polled_get_devtree_pdata(dev);
 187                 if (IS_ERR(pdata))
 188                         return PTR_ERR(pdata);
 189                 if (!pdata) {
 190                         dev_err(dev, "missing platform data\n");
 191                         return -EINVAL;
 192                 }
 193         }
 194
 195         if (!pdata->poll_interval) {
 196                 dev_err(dev, "missing poll_interval value\n");
 197                 return -EINVAL;
 198         }
 199
 200         size = sizeof(struct gpio_keys_polled_dev) +
 201                         pdata->nbuttons * sizeof(struct gpio_keys_button_data);
 202         bdev = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
 203         if (!bdev) {
 204                 dev_err(dev, "no memory for private data\n");
 205                 return -ENOMEM;
 206         }
 207
 208         poll_dev = devm_input_allocate_polled_device(&pdev->dev);
 209         if (!poll_dev) {
 210                 dev_err(dev, "no memory for polled device\n");
 211                 return -ENOMEM;
 212         }
 213
 214         poll_dev->private = bdev;
 215         poll_dev->poll = gpio_keys_polled_poll;
 216         poll_dev->poll_interval = pdata->poll_interval;
 217         poll_dev->open = gpio_keys_polled_open;
 218         poll_dev->close = gpio_keys_polled_close;
 219
 220         input = poll_dev->input;
 221
 222         input->name = pdev->name;
 223         input->phys = DRV_NAME"/input0";
 224
 225         input->id.bustype = BUS_HOST;
 226         input->id.vendor = 0x0001;
 227         input->id.product = 0x0001;
 228         input->id.version = 0x0100;
 229
 230         __set_bit(EV_KEY, input->evbit);
 231         if (pdata->rep)
 232                 __set_bit(EV_REP, input->evbit);
 233
 234         for (i = 0; i < pdata->nbuttons; i++) {
 235                 struct gpio_keys_button *button = &pdata->buttons[i];
 236                 struct gpio_keys_button_data *bdata = &bdev->data[i];
 237                 unsigned int type = button->type ?: EV_KEY;
 238
 239                 if (button->wakeup) {
 240                         dev_err(dev, DRV_NAME " does not support wakeup\n");
 241                         return -EINVAL;
 242                 }
 243
 244                 /*
 245                  * Legacy GPIO number so request the GPIO here and
 246                  * convert it to descriptor.
 247                  */
 248                 if (!button->gpiod && gpio_is_valid(button->gpio)) {
 249                         unsigned flags = GPIOF_IN;
 250
 251                         if (button->active_low)
 252                                 flags |= GPIOF_ACTIVE_LOW;
 253
 254                         error = devm_gpio_request_one(&pdev->dev, button->gpio,
 255                                         flags, button->desc ? : DRV_NAME);
 256                         if (error) {
 257                                 dev_err(dev, "unable to claim gpio %u, err=%d\n",
 258                                         button->gpio, error);
 259                                 return error;
 260                         }
 261
 262                         button->gpiod = gpio_to_desc(button->gpio);
 263                 }
 264
 265                 if (IS_ERR(button->gpiod))
 266                         return PTR_ERR(button->gpiod);
 267
 268                 bdata->can_sleep = gpiod_cansleep(button->gpiod);
 269                 bdata->last_state = -1;
 270                 bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
 271                                                 pdata->poll_interval);
 272
 273                 input_set_capability(input, type, button->code);
 274         }
 275
 276         bdev->poll_dev = poll_dev;
 277         bdev->dev = dev;
 278         bdev->pdata = pdata;
 279         platform_set_drvdata(pdev, bdev);
 280
 281         error = input_register_polled_device(poll_dev);
 282         if (error) {
 283                 dev_err(dev, "unable to register polled device, err=%d\n",
 284                         error);
 285                 return error;
 286         }
 287
 288         /* report initial state of the buttons */
 289         for (i = 0; i < pdata->nbuttons; i++)
 290                 gpio_keys_polled_check_state(input, &pdata->buttons[i],
 291                                              &bdev->data[i]);
 292
 293         return 0;
 294 }
 295
 296 static struct platform_driver gpio_keys_polled_driver = {
 297         .probe  = gpio_keys_polled_probe,
 298         .driver = {
 299                 .name   = DRV_NAME,
 300                 .of_match_table = gpio_keys_polled_of_match,
 301         },
 302 };
 303 module_platform_driver(gpio_keys_polled_driver);
 304
 305 MODULE_LICENSE("GPL v2");
 306 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 307 MODULE_DESCRIPTION("Polled GPIO Buttons driver");
 308 MODULE_ALIAS("platform:" DRV_NAME);