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