Staging: dream: add support for input on GPIO pins

Support for input devices connected to GPIO pins. This adds support
for HTC Dream's keyboard and its trackball. Generic support already
exists for keyboard on GPIO, but this one is more advanced because it
can detect shadow key presses (and actually works with Dream :-).

(It also contains Kconfig/Makefile changes, including some that were
missing from previous commit. Sorry.)

Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 343 insertions, 0 deletions

diff --git a/drivers/staging/dream/gpio_input.c b/drivers/staging/dream/gpio_input.c
new file mode 100644
index 00000000000..7e307f267a2
--- /dev/null
+++ b/drivers/staging/dream/gpio_input.c
@@ -0,0 +1,343 @@
+/* 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/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 input_dev *input_dev;
+	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;
+
+#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;
+	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));
+			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_dev, ds->info->type,
+			    key_entry->code, pressed);
+	}
+
+#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(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_dev, ds->info->type,
+			    key_entry->code, pressed);
+	}
+	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;
+		}
+		enable_irq_wake(irq);
+	}
+	return 0;
+
+	for (i = ds->info->keymap_size - 1; i >= 0; i--) {
+		free_irq(gpio_to_irq(ds->info->keymap[i].gpio),
+			 &ds->key_state[i]);
+err_request_irq_failed:
+err_gpio_get_irq_num_failed:
+		;
+	}
+	return err;
+}
+
+int gpio_event_input_func(struct input_dev *input_dev,
+			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) {
+		spin_lock_irqsave(&ds->irq_lock, irqflags);
+		if (ds->use_irq)
+			for (i = 0; i < di->keymap_size; i++)
+				disable_irq(gpio_to_irq(di->keymap[i].gpio));
+		spin_unlock_irqrestore(&ds->irq_lock, irqflags);
+		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_dev = input_dev;
+		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++) {
+			input_set_capability(input_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 in %s "
+			"mode\n",
+			input_dev->name, 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--) {
+			free_irq(gpio_to_irq(di->keymap[i].gpio),
+				 &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:
+		;
+	}
+	wake_lock_destroy(&ds->wake_lock);
+	kfree(ds);
+err_ds_alloc_failed:
+	return ret;
+}