Input: Generic GPIO Input device.
Supports keyboard matrixces, direct inputs, direct outputs and axes connected to gpios.
Change-Id: I5e921e6e3a1cc169316ee3b665f4cc21b5735114
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Nick Pelly <npelly@google.com>
diff --git a/drivers/input/misc/gpio_input.c b/drivers/input/misc/gpio_input.c
new file mode 100644
index 0000000..6a0c315
--- /dev/null
+++ b/drivers/input/misc/gpio_input.c
@@ -0,0 +1,376 @@
+/* drivers/input/misc/gpio_input.c
+ *
+ * Copyright (C) 2007 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/gpio.h>
+#include <linux/gpio_event.h>
+#include <linux/hrtimer.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/wakelock.h>
+
+enum {
+ DEBOUNCE_UNSTABLE = BIT(0), /* Got irq, while debouncing */
+ DEBOUNCE_PRESSED = BIT(1),
+ DEBOUNCE_NOTPRESSED = BIT(2),
+ DEBOUNCE_WAIT_IRQ = BIT(3), /* Stable irq state */
+ DEBOUNCE_POLL = BIT(4), /* Stable polling state */
+
+ DEBOUNCE_UNKNOWN =
+ DEBOUNCE_PRESSED | DEBOUNCE_NOTPRESSED,
+};
+
+struct gpio_key_state {
+ struct gpio_input_state *ds;
+ uint8_t debounce;
+};
+
+struct gpio_input_state {
+ struct gpio_event_input_devs *input_devs;
+ const struct gpio_event_input_info *info;
+ struct hrtimer timer;
+ int use_irq;
+ int debounce_count;
+ spinlock_t irq_lock;
+ struct wake_lock wake_lock;
+ struct gpio_key_state key_state[0];
+};
+
+static enum hrtimer_restart gpio_event_input_timer_func(struct hrtimer *timer)
+{
+ int i;
+ int pressed;
+ struct gpio_input_state *ds =
+ container_of(timer, struct gpio_input_state, timer);
+ unsigned gpio_flags = ds->info->flags;
+ unsigned npolarity;
+ int nkeys = ds->info->keymap_size;
+ const struct gpio_event_direct_entry *key_entry;
+ struct gpio_key_state *key_state;
+ unsigned long irqflags;
+ uint8_t debounce;
+ bool sync_needed;
+
+#if 0
+ key_entry = kp->keys_info->keymap;
+ key_state = kp->key_state;
+ for (i = 0; i < nkeys; i++, key_entry++, key_state++)
+ pr_info("gpio_read_detect_status %d %d\n", key_entry->gpio,
+ gpio_read_detect_status(key_entry->gpio));
+#endif
+ key_entry = ds->info->keymap;
+ key_state = ds->key_state;
+ sync_needed = false;
+ spin_lock_irqsave(&ds->irq_lock, irqflags);
+ for (i = 0; i < nkeys; i++, key_entry++, key_state++) {
+ debounce = key_state->debounce;
+ if (debounce & DEBOUNCE_WAIT_IRQ)
+ continue;
+ if (key_state->debounce & DEBOUNCE_UNSTABLE) {
+ debounce = key_state->debounce = DEBOUNCE_UNKNOWN;
+ enable_irq(gpio_to_irq(key_entry->gpio));
+ if (gpio_flags & GPIOEDF_PRINT_KEY_UNSTABLE)
+ pr_info("gpio_keys_scan_keys: key %x-%x, %d "
+ "(%d) continue debounce\n",
+ ds->info->type, key_entry->code,
+ i, key_entry->gpio);
+ }
+ npolarity = !(gpio_flags & GPIOEDF_ACTIVE_HIGH);
+ pressed = gpio_get_value(key_entry->gpio) ^ npolarity;
+ if (debounce & DEBOUNCE_POLL) {
+ if (pressed == !(debounce & DEBOUNCE_PRESSED)) {
+ ds->debounce_count++;
+ key_state->debounce = DEBOUNCE_UNKNOWN;
+ if (gpio_flags & GPIOEDF_PRINT_KEY_DEBOUNCE)
+ pr_info("gpio_keys_scan_keys: key %x-"
+ "%x, %d (%d) start debounce\n",
+ ds->info->type, key_entry->code,
+ i, key_entry->gpio);
+ }
+ continue;
+ }
+ if (pressed && (debounce & DEBOUNCE_NOTPRESSED)) {
+ if (gpio_flags & GPIOEDF_PRINT_KEY_DEBOUNCE)
+ pr_info("gpio_keys_scan_keys: key %x-%x, %d "
+ "(%d) debounce pressed 1\n",
+ ds->info->type, key_entry->code,
+ i, key_entry->gpio);
+ key_state->debounce = DEBOUNCE_PRESSED;
+ continue;
+ }
+ if (!pressed && (debounce & DEBOUNCE_PRESSED)) {
+ if (gpio_flags & GPIOEDF_PRINT_KEY_DEBOUNCE)
+ pr_info("gpio_keys_scan_keys: key %x-%x, %d "
+ "(%d) debounce pressed 0\n",
+ ds->info->type, key_entry->code,
+ i, key_entry->gpio);
+ key_state->debounce = DEBOUNCE_NOTPRESSED;
+ continue;
+ }
+ /* key is stable */
+ ds->debounce_count--;
+ if (ds->use_irq)
+ key_state->debounce |= DEBOUNCE_WAIT_IRQ;
+ else
+ key_state->debounce |= DEBOUNCE_POLL;
+ if (gpio_flags & GPIOEDF_PRINT_KEYS)
+ pr_info("gpio_keys_scan_keys: key %x-%x, %d (%d) "
+ "changed to %d\n", ds->info->type,
+ key_entry->code, i, key_entry->gpio, pressed);
+ input_event(ds->input_devs->dev[key_entry->dev], ds->info->type,
+ key_entry->code, pressed);
+ sync_needed = true;
+ }
+ if (sync_needed) {
+ for (i = 0; i < ds->input_devs->count; i++)
+ input_sync(ds->input_devs->dev[i]);
+ }
+
+#if 0
+ key_entry = kp->keys_info->keymap;
+ key_state = kp->key_state;
+ for (i = 0; i < nkeys; i++, key_entry++, key_state++) {
+ pr_info("gpio_read_detect_status %d %d\n", key_entry->gpio,
+ gpio_read_detect_status(key_entry->gpio));
+ }
+#endif
+
+ if (ds->debounce_count)
+ hrtimer_start(timer, ds->info->debounce_time, HRTIMER_MODE_REL);
+ else if (!ds->use_irq)
+ hrtimer_start(timer, ds->info->poll_time, HRTIMER_MODE_REL);
+ else
+ wake_unlock(&ds->wake_lock);
+
+ spin_unlock_irqrestore(&ds->irq_lock, irqflags);
+
+ return HRTIMER_NORESTART;
+}
+
+static irqreturn_t gpio_event_input_irq_handler(int irq, void *dev_id)
+{
+ struct gpio_key_state *ks = dev_id;
+ struct gpio_input_state *ds = ks->ds;
+ int keymap_index = ks - ds->key_state;
+ const struct gpio_event_direct_entry *key_entry;
+ unsigned long irqflags;
+ int pressed;
+
+ if (!ds->use_irq)
+ return IRQ_HANDLED;
+
+ key_entry = &ds->info->keymap[keymap_index];
+
+ if (ds->info->debounce_time.tv64) {
+ spin_lock_irqsave(&ds->irq_lock, irqflags);
+ if (ks->debounce & DEBOUNCE_WAIT_IRQ) {
+ ks->debounce = DEBOUNCE_UNKNOWN;
+ if (ds->debounce_count++ == 0) {
+ wake_lock(&ds->wake_lock);
+ hrtimer_start(
+ &ds->timer, ds->info->debounce_time,
+ HRTIMER_MODE_REL);
+ }
+ if (ds->info->flags & GPIOEDF_PRINT_KEY_DEBOUNCE)
+ pr_info("gpio_event_input_irq_handler: "
+ "key %x-%x, %d (%d) start debounce\n",
+ ds->info->type, key_entry->code,
+ keymap_index, key_entry->gpio);
+ } else {
+ disable_irq_nosync(irq);
+ ks->debounce = DEBOUNCE_UNSTABLE;
+ }
+ spin_unlock_irqrestore(&ds->irq_lock, irqflags);
+ } else {
+ pressed = gpio_get_value(key_entry->gpio) ^
+ !(ds->info->flags & GPIOEDF_ACTIVE_HIGH);
+ if (ds->info->flags & GPIOEDF_PRINT_KEYS)
+ pr_info("gpio_event_input_irq_handler: key %x-%x, %d "
+ "(%d) changed to %d\n",
+ ds->info->type, key_entry->code, keymap_index,
+ key_entry->gpio, pressed);
+ input_event(ds->input_devs->dev[key_entry->dev], ds->info->type,
+ key_entry->code, pressed);
+ input_sync(ds->input_devs->dev[key_entry->dev]);
+ }
+ return IRQ_HANDLED;
+}
+
+static int gpio_event_input_request_irqs(struct gpio_input_state *ds)
+{
+ int i;
+ int err;
+ unsigned int irq;
+ unsigned long req_flags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
+
+ for (i = 0; i < ds->info->keymap_size; i++) {
+ err = irq = gpio_to_irq(ds->info->keymap[i].gpio);
+ if (err < 0)
+ goto err_gpio_get_irq_num_failed;
+ err = request_irq(irq, gpio_event_input_irq_handler,
+ req_flags, "gpio_keys", &ds->key_state[i]);
+ if (err) {
+ pr_err("gpio_event_input_request_irqs: request_irq "
+ "failed for input %d, irq %d\n",
+ ds->info->keymap[i].gpio, irq);
+ goto err_request_irq_failed;
+ }
+ if (ds->info->info.no_suspend) {
+ err = enable_irq_wake(irq);
+ if (err) {
+ pr_err("gpio_event_input_request_irqs: "
+ "enable_irq_wake failed for input %d, "
+ "irq %d\n",
+ ds->info->keymap[i].gpio, irq);
+ goto err_enable_irq_wake_failed;
+ }
+ }
+ }
+ return 0;
+
+ for (i = ds->info->keymap_size - 1; i >= 0; i--) {
+ irq = gpio_to_irq(ds->info->keymap[i].gpio);
+ if (ds->info->info.no_suspend)
+ disable_irq_wake(irq);
+err_enable_irq_wake_failed:
+ free_irq(irq, &ds->key_state[i]);
+err_request_irq_failed:
+err_gpio_get_irq_num_failed:
+ ;
+ }
+ return err;
+}
+
+int gpio_event_input_func(struct gpio_event_input_devs *input_devs,
+ struct gpio_event_info *info, void **data, int func)
+{
+ int ret;
+ int i;
+ unsigned long irqflags;
+ struct gpio_event_input_info *di;
+ struct gpio_input_state *ds = *data;
+
+ di = container_of(info, struct gpio_event_input_info, info);
+
+ if (func == GPIO_EVENT_FUNC_SUSPEND) {
+ if (ds->use_irq)
+ for (i = 0; i < di->keymap_size; i++)
+ disable_irq(gpio_to_irq(di->keymap[i].gpio));
+ hrtimer_cancel(&ds->timer);
+ return 0;
+ }
+ if (func == GPIO_EVENT_FUNC_RESUME) {
+ spin_lock_irqsave(&ds->irq_lock, irqflags);
+ if (ds->use_irq)
+ for (i = 0; i < di->keymap_size; i++)
+ enable_irq(gpio_to_irq(di->keymap[i].gpio));
+ hrtimer_start(&ds->timer, ktime_set(0, 0), HRTIMER_MODE_REL);
+ spin_unlock_irqrestore(&ds->irq_lock, irqflags);
+ return 0;
+ }
+
+ if (func == GPIO_EVENT_FUNC_INIT) {
+ if (ktime_to_ns(di->poll_time) <= 0)
+ di->poll_time = ktime_set(0, 20 * NSEC_PER_MSEC);
+
+ *data = ds = kzalloc(sizeof(*ds) + sizeof(ds->key_state[0]) *
+ di->keymap_size, GFP_KERNEL);
+ if (ds == NULL) {
+ ret = -ENOMEM;
+ pr_err("gpio_event_input_func: "
+ "Failed to allocate private data\n");
+ goto err_ds_alloc_failed;
+ }
+ ds->debounce_count = di->keymap_size;
+ ds->input_devs = input_devs;
+ ds->info = di;
+ wake_lock_init(&ds->wake_lock, WAKE_LOCK_SUSPEND, "gpio_input");
+ spin_lock_init(&ds->irq_lock);
+
+ for (i = 0; i < di->keymap_size; i++) {
+ int dev = di->keymap[i].dev;
+ if (dev >= input_devs->count) {
+ pr_err("gpio_event_input_func: bad device "
+ "index %d >= %d for key code %d\n",
+ dev, input_devs->count,
+ di->keymap[i].code);
+ ret = -EINVAL;
+ goto err_bad_keymap;
+ }
+ input_set_capability(input_devs->dev[dev], di->type,
+ di->keymap[i].code);
+ ds->key_state[i].ds = ds;
+ ds->key_state[i].debounce = DEBOUNCE_UNKNOWN;
+ }
+
+ for (i = 0; i < di->keymap_size; i++) {
+ ret = gpio_request(di->keymap[i].gpio, "gpio_kp_in");
+ if (ret) {
+ pr_err("gpio_event_input_func: gpio_request "
+ "failed for %d\n", di->keymap[i].gpio);
+ goto err_gpio_request_failed;
+ }
+ ret = gpio_direction_input(di->keymap[i].gpio);
+ if (ret) {
+ pr_err("gpio_event_input_func: "
+ "gpio_direction_input failed for %d\n",
+ di->keymap[i].gpio);
+ goto err_gpio_configure_failed;
+ }
+ }
+
+ ret = gpio_event_input_request_irqs(ds);
+
+ spin_lock_irqsave(&ds->irq_lock, irqflags);
+ ds->use_irq = ret == 0;
+
+ pr_info("GPIO Input Driver: Start gpio inputs for %s%s in %s "
+ "mode\n", input_devs->dev[0]->name,
+ (input_devs->count > 1) ? "..." : "",
+ ret == 0 ? "interrupt" : "polling");
+
+ hrtimer_init(&ds->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ ds->timer.function = gpio_event_input_timer_func;
+ hrtimer_start(&ds->timer, ktime_set(0, 0), HRTIMER_MODE_REL);
+ spin_unlock_irqrestore(&ds->irq_lock, irqflags);
+ return 0;
+ }
+
+ ret = 0;
+ spin_lock_irqsave(&ds->irq_lock, irqflags);
+ hrtimer_cancel(&ds->timer);
+ if (ds->use_irq) {
+ for (i = di->keymap_size - 1; i >= 0; i--) {
+ int irq = gpio_to_irq(di->keymap[i].gpio);
+ if (ds->info->info.no_suspend)
+ disable_irq_wake(irq);
+ free_irq(irq, &ds->key_state[i]);
+ }
+ }
+ spin_unlock_irqrestore(&ds->irq_lock, irqflags);
+
+ for (i = di->keymap_size - 1; i >= 0; i--) {
+err_gpio_configure_failed:
+ gpio_free(di->keymap[i].gpio);
+err_gpio_request_failed:
+ ;
+ }
+err_bad_keymap:
+ wake_lock_destroy(&ds->wake_lock);
+ kfree(ds);
+err_ds_alloc_failed:
+ return ret;
+}