drivers/input/misc/gpio_input.c

   1 /* drivers/input/misc/gpio_input.c
   2  *
   3  * Copyright (C) 2007 Google, Inc.
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/gpio.h>
  18 #include <linux/gpio_event.h>
  19 #include <linux/hrtimer.h>
  20 #include <linux/input.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/slab.h>
  23 #include <linux/wakelock.h>
  24
  25 enum {
  26         DEBOUNCE_UNSTABLE     = BIT(0), /* Got irq, while debouncing */
  27         DEBOUNCE_PRESSED      = BIT(1),
  28         DEBOUNCE_NOTPRESSED   = BIT(2),
  29         DEBOUNCE_WAIT_IRQ     = BIT(3), /* Stable irq state */
  30         DEBOUNCE_POLL         = BIT(4), /* Stable polling state */
  31
  32         DEBOUNCE_UNKNOWN =
  33                 DEBOUNCE_PRESSED | DEBOUNCE_NOTPRESSED,
  34 };
  35
  36 struct gpio_key_state {
  37         struct gpio_input_state *ds;
  38         uint8_t debounce;
  39 };
  40
  41 struct gpio_input_state {
  42         struct gpio_event_input_devs *input_devs;
  43         const struct gpio_event_input_info *info;
  44         struct hrtimer timer;
  45         int use_irq;
  46         int debounce_count;
  47         spinlock_t irq_lock;
  48         struct wake_lock wake_lock;
  49         struct gpio_key_state key_state[0];
  50 };
  51
  52 static enum hrtimer_restart gpio_event_input_timer_func(struct hrtimer *timer)
  53 {
  54         int i;
  55         int pressed;
  56         struct gpio_input_state *ds =
  57                 container_of(timer, struct gpio_input_state, timer);
  58         unsigned gpio_flags = ds->info->flags;
  59         unsigned npolarity;
  60         int nkeys = ds->info->keymap_size;
  61         const struct gpio_event_direct_entry *key_entry;
  62         struct gpio_key_state *key_state;
  63         unsigned long irqflags;
  64         uint8_t debounce;
  65
  66 #if 0
  67         key_entry = kp->keys_info->keymap;
  68         key_state = kp->key_state;
  69         for (i = 0; i < nkeys; i++, key_entry++, key_state++)
  70                 pr_info("gpio_read_detect_status %d %d\n", key_entry->gpio,
  71                         gpio_read_detect_status(key_entry->gpio));
  72 #endif
  73         key_entry = ds->info->keymap;
  74         key_state = ds->key_state;
  75         spin_lock_irqsave(&ds->irq_lock, irqflags);
  76         for (i = 0; i < nkeys; i++, key_entry++, key_state++) {
  77                 debounce = key_state->debounce;
  78                 if (debounce & DEBOUNCE_WAIT_IRQ)
  79                         continue;
  80                 if (key_state->debounce & DEBOUNCE_UNSTABLE) {
  81                         debounce = key_state->debounce = DEBOUNCE_UNKNOWN;
  82                         enable_irq(gpio_to_irq(key_entry->gpio));
  83                         pr_info("gpio_keys_scan_keys: key %x-%x, %d "
  84                                 "(%d) continue debounce\n",
  85                                 ds->info->type, key_entry->code,
  86                                 i, key_entry->gpio);
  87                 }
  88                 npolarity = !(gpio_flags & GPIOEDF_ACTIVE_HIGH);
  89                 pressed = gpio_get_value(key_entry->gpio) ^ npolarity;
  90                 if (debounce & DEBOUNCE_POLL) {
  91                         if (pressed == !(debounce & DEBOUNCE_PRESSED)) {
  92                                 ds->debounce_count++;
  93                                 key_state->debounce = DEBOUNCE_UNKNOWN;
  94                                 if (gpio_flags & GPIOEDF_PRINT_KEY_DEBOUNCE)
  95                                         pr_info("gpio_keys_scan_keys: key %x-"
  96                                                 "%x, %d (%d) start debounce\n",
  97                                                 ds->info->type, key_entry->code,
  98                                                 i, key_entry->gpio);
  99                         }
 100                         continue;
 101                 }
 102                 if (pressed && (debounce & DEBOUNCE_NOTPRESSED)) {
 103                         if (gpio_flags & GPIOEDF_PRINT_KEY_DEBOUNCE)
 104                                 pr_info("gpio_keys_scan_keys: key %x-%x, %d "
 105                                         "(%d) debounce pressed 1\n",
 106                                         ds->info->type, key_entry->code,
 107                                         i, key_entry->gpio);
 108                         key_state->debounce = DEBOUNCE_PRESSED;
 109                         continue;
 110                 }
 111                 if (!pressed && (debounce & DEBOUNCE_PRESSED)) {
 112                         if (gpio_flags & GPIOEDF_PRINT_KEY_DEBOUNCE)
 113                                 pr_info("gpio_keys_scan_keys: key %x-%x, %d "
 114                                         "(%d) debounce pressed 0\n",
 115                                         ds->info->type, key_entry->code,
 116                                         i, key_entry->gpio);
 117                         key_state->debounce = DEBOUNCE_NOTPRESSED;
 118                         continue;
 119                 }
 120                 /* key is stable */
 121                 ds->debounce_count--;
 122                 if (ds->use_irq)
 123                         key_state->debounce |= DEBOUNCE_WAIT_IRQ;
 124                 else
 125                         key_state->debounce |= DEBOUNCE_POLL;
 126                 if (gpio_flags & GPIOEDF_PRINT_KEYS)
 127                         pr_info("gpio_keys_scan_keys: key %x-%x, %d (%d) "
 128                                 "changed to %d\n", ds->info->type,
 129                                 key_entry->code, i, key_entry->gpio, pressed);
 130                 input_event(ds->input_devs->dev[key_entry->dev], ds->info->type,
 131                             key_entry->code, pressed);
 132         }
 133
 134 #if 0
 135         key_entry = kp->keys_info->keymap;
 136         key_state = kp->key_state;
 137         for (i = 0; i < nkeys; i++, key_entry++, key_state++) {
 138                 pr_info("gpio_read_detect_status %d %d\n", key_entry->gpio,
 139                         gpio_read_detect_status(key_entry->gpio));
 140         }
 141 #endif
 142
 143         if (ds->debounce_count)
 144                 hrtimer_start(timer, ds->info->debounce_time, HRTIMER_MODE_REL);
 145         else if (!ds->use_irq)
 146                 hrtimer_start(timer, ds->info->poll_time, HRTIMER_MODE_REL);
 147         else
 148                 wake_unlock(&ds->wake_lock);
 149
 150         spin_unlock_irqrestore(&ds->irq_lock, irqflags);
 151
 152         return HRTIMER_NORESTART;
 153 }
 154
 155 static irqreturn_t gpio_event_input_irq_handler(int irq, void *dev_id)
 156 {
 157         struct gpio_key_state *ks = dev_id;
 158         struct gpio_input_state *ds = ks->ds;
 159         int keymap_index = ks - ds->key_state;
 160         const struct gpio_event_direct_entry *key_entry;
 161         unsigned long irqflags;
 162         int pressed;
 163
 164         if (!ds->use_irq)
 165                 return IRQ_HANDLED;
 166
 167         key_entry = &ds->info->keymap[keymap_index];
 168
 169         if (ds->info->debounce_time.tv64) {
 170                 spin_lock_irqsave(&ds->irq_lock, irqflags);
 171                 if (ks->debounce & DEBOUNCE_WAIT_IRQ) {
 172                         ks->debounce = DEBOUNCE_UNKNOWN;
 173                         if (ds->debounce_count++ == 0) {
 174                                 wake_lock(&ds->wake_lock);
 175                                 hrtimer_start(
 176                                         &ds->timer, ds->info->debounce_time,
 177                                         HRTIMER_MODE_REL);
 178                         }
 179                         if (ds->info->flags & GPIOEDF_PRINT_KEY_DEBOUNCE)
 180                                 pr_info("gpio_event_input_irq_handler: "
 181                                         "key %x-%x, %d (%d) start debounce\n",
 182                                         ds->info->type, key_entry->code,
 183                                         keymap_index, key_entry->gpio);
 184                 } else {
 185                         disable_irq_nosync(irq);
 186                         ks->debounce = DEBOUNCE_UNSTABLE;
 187                 }
 188                 spin_unlock_irqrestore(&ds->irq_lock, irqflags);
 189         } else {
 190                 pressed = gpio_get_value(key_entry->gpio) ^
 191                         !(ds->info->flags & GPIOEDF_ACTIVE_HIGH);
 192                 if (ds->info->flags & GPIOEDF_PRINT_KEYS)
 193                         pr_info("gpio_event_input_irq_handler: key %x-%x, %d "
 194                                 "(%d) changed to %d\n",
 195                                 ds->info->type, key_entry->code, keymap_index,
 196                                 key_entry->gpio, pressed);
 197                 input_event(ds->input_devs->dev[key_entry->dev], ds->info->type,
 198                             key_entry->code, pressed);
 199         }
 200         return IRQ_HANDLED;
 201 }
 202
 203 static int gpio_event_input_request_irqs(struct gpio_input_state *ds)
 204 {
 205         int i;
 206         int err;
 207         unsigned int irq;
 208         unsigned long req_flags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
 209
 210         for (i = 0; i < ds->info->keymap_size; i++) {
 211                 err = irq = gpio_to_irq(ds->info->keymap[i].gpio);
 212                 if (err < 0)
 213                         goto err_gpio_get_irq_num_failed;
 214                 err = request_irq(irq, gpio_event_input_irq_handler,
 215                                   req_flags, "gpio_keys", &ds->key_state[i]);
 216                 if (err) {
 217                         pr_err("gpio_event_input_request_irqs: request_irq "
 218                                 "failed for input %d, irq %d\n",
 219                                 ds->info->keymap[i].gpio, irq);
 220                         goto err_request_irq_failed;
 221                 }
 222                 enable_irq_wake(irq);
 223         }
 224         return 0;
 225
 226         for (i = ds->info->keymap_size - 1; i >= 0; i--) {
 227                 free_irq(gpio_to_irq(ds->info->keymap[i].gpio),
 228                          &ds->key_state[i]);
 229 err_request_irq_failed:
 230 err_gpio_get_irq_num_failed:
 231                 ;
 232         }
 233         return err;
 234 }
 235
 236 int gpio_event_input_func(struct gpio_event_input_devs *input_devs,
 237                         struct gpio_event_info *info, void **data, int func)
 238 {
 239         int ret;
 240         int i;
 241         unsigned long irqflags;
 242         struct gpio_event_input_info *di;
 243         struct gpio_input_state *ds = *data;
 244
 245         di = container_of(info, struct gpio_event_input_info, info);
 246
 247         if (func == GPIO_EVENT_FUNC_SUSPEND) {
 248                 if (ds->use_irq)
 249                         for (i = 0; i < di->keymap_size; i++)
 250                                 disable_irq(gpio_to_irq(di->keymap[i].gpio));
 251                 hrtimer_cancel(&ds->timer);
 252                 return 0;
 253         }
 254         if (func == GPIO_EVENT_FUNC_RESUME) {
 255                 spin_lock_irqsave(&ds->irq_lock, irqflags);
 256                 if (ds->use_irq)
 257                         for (i = 0; i < di->keymap_size; i++)
 258                                 enable_irq(gpio_to_irq(di->keymap[i].gpio));
 259                 hrtimer_start(&ds->timer, ktime_set(0, 0), HRTIMER_MODE_REL);
 260                 spin_unlock_irqrestore(&ds->irq_lock, irqflags);
 261                 return 0;
 262         }
 263
 264         if (func == GPIO_EVENT_FUNC_INIT) {
 265                 if (ktime_to_ns(di->poll_time) <= 0)
 266                         di->poll_time = ktime_set(0, 20 * NSEC_PER_MSEC);
 267
 268                 *data = ds = kzalloc(sizeof(*ds) + sizeof(ds->key_state[0]) *
 269                                         di->keymap_size, GFP_KERNEL);
 270                 if (ds == NULL) {
 271                         ret = -ENOMEM;
 272                         pr_err("gpio_event_input_func: "
 273                                 "Failed to allocate private data\n");
 274                         goto err_ds_alloc_failed;
 275                 }
 276                 ds->debounce_count = di->keymap_size;
 277                 ds->input_devs = input_devs;
 278                 ds->info = di;
 279                 wake_lock_init(&ds->wake_lock, WAKE_LOCK_SUSPEND, "gpio_input");
 280                 spin_lock_init(&ds->irq_lock);
 281
 282                 for (i = 0; i < di->keymap_size; i++) {
 283                         int dev = di->keymap[i].dev;
 284                         if (dev >= input_devs->count) {
 285                                 pr_err("gpio_event_input_func: bad device "
 286                                         "index %d >= %d for key code %d\n",
 287                                         dev, input_devs->count,
 288                                         di->keymap[i].code);
 289                                 ret = -EINVAL;
 290                                 goto err_bad_keymap;
 291                         }
 292                         input_set_capability(input_devs->dev[dev], di->type,
 293                                              di->keymap[i].code);
 294                         ds->key_state[i].ds = ds;
 295                         ds->key_state[i].debounce = DEBOUNCE_UNKNOWN;
 296                 }
 297
 298                 for (i = 0; i < di->keymap_size; i++) {
 299                         ret = gpio_request(di->keymap[i].gpio, "gpio_kp_in");
 300                         if (ret) {
 301                                 pr_err("gpio_event_input_func: gpio_request "
 302                                         "failed for %d\n", di->keymap[i].gpio);
 303                                 goto err_gpio_request_failed;
 304                         }
 305                         ret = gpio_direction_input(di->keymap[i].gpio);
 306                         if (ret) {
 307                                 pr_err("gpio_event_input_func: "
 308                                         "gpio_direction_input failed for %d\n",
 309                                         di->keymap[i].gpio);
 310                                 goto err_gpio_configure_failed;
 311                         }
 312                 }
 313
 314                 ret = gpio_event_input_request_irqs(ds);
 315
 316                 spin_lock_irqsave(&ds->irq_lock, irqflags);
 317                 ds->use_irq = ret == 0;
 318
 319                 pr_info("GPIO Input Driver: Start gpio inputs for %s%s in %s "
 320                         "mode\n", input_devs->dev[0]->name,
 321                         (input_devs->count > 1) ? "..." : "",
 322                         ret == 0 ? "interrupt" : "polling");
 323
 324                 hrtimer_init(&ds->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 325                 ds->timer.function = gpio_event_input_timer_func;
 326                 hrtimer_start(&ds->timer, ktime_set(0, 0), HRTIMER_MODE_REL);
 327                 spin_unlock_irqrestore(&ds->irq_lock, irqflags);
 328                 return 0;
 329         }
 330
 331         ret = 0;
 332         spin_lock_irqsave(&ds->irq_lock, irqflags);
 333         hrtimer_cancel(&ds->timer);
 334         if (ds->use_irq) {
 335                 for (i = di->keymap_size - 1; i >= 0; i--) {
 336                         free_irq(gpio_to_irq(di->keymap[i].gpio),
 337                                  &ds->key_state[i]);
 338                 }
 339         }
 340         spin_unlock_irqrestore(&ds->irq_lock, irqflags);
 341
 342         for (i = di->keymap_size - 1; i >= 0; i--) {
 343 err_gpio_configure_failed:
 344                 gpio_free(di->keymap[i].gpio);
 345 err_gpio_request_failed:
 346                 ;
 347         }
 348 err_bad_keymap:
 349         wake_lock_destroy(&ds->wake_lock);
 350         kfree(ds);
 351 err_ds_alloc_failed:
 352         return ret;
 353 }