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_matrix.c b/drivers/input/misc/gpio_matrix.c
new file mode 100644
index 0000000..441cc1c
--- /dev/null
+++ b/drivers/input/misc/gpio_matrix.c
@@ -0,0 +1,407 @@
+/* drivers/input/misc/gpio_matrix.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/interrupt.h>
+#include <linux/slab.h>
+#include <linux/wakelock.h>
+
+struct gpio_kp {
+ struct input_dev *input_dev;
+ struct gpio_event_matrix_info *keypad_info;
+ struct hrtimer timer;
+ struct wake_lock wake_lock;
+ int current_output;
+ unsigned int use_irq:1;
+ unsigned int key_state_changed:1;
+ unsigned int last_key_state_changed:1;
+ unsigned int some_keys_pressed:2;
+ unsigned long keys_pressed[0];
+};
+
+static void clear_phantom_key(struct gpio_kp *kp, int out, int in)
+{
+ struct gpio_event_matrix_info *mi = kp->keypad_info;
+ int key_index = out * mi->ninputs + in;
+ unsigned short keycode = mi->keymap[key_index];;
+
+ if (!test_bit(keycode, kp->input_dev->key)) {
+ if (mi->flags & GPIOKPF_PRINT_PHANTOM_KEYS)
+ pr_info("gpiomatrix: phantom key %x, %d-%d (%d-%d) "
+ "cleared\n", keycode, out, in,
+ mi->output_gpios[out], mi->input_gpios[in]);
+ __clear_bit(key_index, kp->keys_pressed);
+ } else {
+ if (mi->flags & GPIOKPF_PRINT_PHANTOM_KEYS)
+ pr_info("gpiomatrix: phantom key %x, %d-%d (%d-%d) "
+ "not cleared\n", keycode, out, in,
+ mi->output_gpios[out], mi->input_gpios[in]);
+ }
+}
+
+static int restore_keys_for_input(struct gpio_kp *kp, int out, int in)
+{
+ int rv = 0;
+ int key_index;
+
+ key_index = out * kp->keypad_info->ninputs + in;
+ while (out < kp->keypad_info->noutputs) {
+ if (test_bit(key_index, kp->keys_pressed)) {
+ rv = 1;
+ clear_phantom_key(kp, out, in);
+ }
+ key_index += kp->keypad_info->ninputs;
+ out++;
+ }
+ return rv;
+}
+
+static void remove_phantom_keys(struct gpio_kp *kp)
+{
+ int out, in, inp;
+ int key_index;
+
+ if (kp->some_keys_pressed < 3)
+ return;
+
+ for (out = 0; out < kp->keypad_info->noutputs; out++) {
+ inp = -1;
+ key_index = out * kp->keypad_info->ninputs;
+ for (in = 0; in < kp->keypad_info->ninputs; in++, key_index++) {
+ if (test_bit(key_index, kp->keys_pressed)) {
+ if (inp == -1) {
+ inp = in;
+ continue;
+ }
+ if (inp >= 0) {
+ if (!restore_keys_for_input(kp, out + 1,
+ inp))
+ break;
+ clear_phantom_key(kp, out, inp);
+ inp = -2;
+ }
+ restore_keys_for_input(kp, out, in);
+ }
+ }
+ }
+}
+
+static void report_key(struct gpio_kp *kp, int key_index, int out, int in)
+{
+ struct gpio_event_matrix_info *mi = kp->keypad_info;
+ int pressed = test_bit(key_index, kp->keys_pressed);
+ unsigned short keycode = mi->keymap[key_index];
+ if (pressed != test_bit(keycode, kp->input_dev->key)) {
+ if (keycode == KEY_RESERVED) {
+ if (mi->flags & GPIOKPF_PRINT_UNMAPPED_KEYS)
+ pr_info("gpiomatrix: unmapped key, %d-%d "
+ "(%d-%d) changed to %d\n",
+ out, in, mi->output_gpios[out],
+ mi->input_gpios[in], pressed);
+ } else {
+ if (mi->flags & GPIOKPF_PRINT_MAPPED_KEYS)
+ pr_info("gpiomatrix: key %x, %d-%d (%d-%d) "
+ "changed to %d\n", keycode,
+ out, in, mi->output_gpios[out],
+ mi->input_gpios[in], pressed);
+ input_report_key(kp->input_dev, keycode, pressed);
+ }
+ }
+}
+
+static enum hrtimer_restart gpio_keypad_timer_func(struct hrtimer *timer)
+{
+ int out, in;
+ int key_index;
+ int gpio;
+ struct gpio_kp *kp = container_of(timer, struct gpio_kp, timer);
+ struct gpio_event_matrix_info *mi = kp->keypad_info;
+ unsigned gpio_keypad_flags = mi->flags;
+ unsigned polarity = !!(gpio_keypad_flags & GPIOKPF_ACTIVE_HIGH);
+
+ out = kp->current_output;
+ if (out == mi->noutputs) {
+ out = 0;
+ kp->last_key_state_changed = kp->key_state_changed;
+ kp->key_state_changed = 0;
+ kp->some_keys_pressed = 0;
+ } else {
+ key_index = out * mi->ninputs;
+ for (in = 0; in < mi->ninputs; in++, key_index++) {
+ gpio = mi->input_gpios[in];
+ if (gpio_get_value(gpio) ^ !polarity) {
+ if (kp->some_keys_pressed < 3)
+ kp->some_keys_pressed++;
+ kp->key_state_changed |= !__test_and_set_bit(
+ key_index, kp->keys_pressed);
+ } else
+ kp->key_state_changed |= __test_and_clear_bit(
+ key_index, kp->keys_pressed);
+ }
+ gpio = mi->output_gpios[out];
+ if (gpio_keypad_flags & GPIOKPF_DRIVE_INACTIVE)
+ gpio_set_value(gpio, !polarity);
+ else
+ gpio_direction_input(gpio);
+ out++;
+ }
+ kp->current_output = out;
+ if (out < mi->noutputs) {
+ gpio = mi->output_gpios[out];
+ if (gpio_keypad_flags & GPIOKPF_DRIVE_INACTIVE)
+ gpio_set_value(gpio, polarity);
+ else
+ gpio_direction_output(gpio, polarity);
+ hrtimer_start(timer, mi->settle_time, HRTIMER_MODE_REL);
+ return HRTIMER_NORESTART;
+ }
+ if (gpio_keypad_flags & GPIOKPF_DEBOUNCE) {
+ if (kp->key_state_changed) {
+ hrtimer_start(&kp->timer, mi->debounce_delay,
+ HRTIMER_MODE_REL);
+ return HRTIMER_NORESTART;
+ }
+ kp->key_state_changed = kp->last_key_state_changed;
+ }
+ if (kp->key_state_changed) {
+ if (gpio_keypad_flags & GPIOKPF_REMOVE_SOME_PHANTOM_KEYS)
+ remove_phantom_keys(kp);
+ key_index = 0;
+ for (out = 0; out < mi->noutputs; out++)
+ for (in = 0; in < mi->ninputs; in++, key_index++)
+ report_key(kp, key_index, out, in);
+ }
+ if (!kp->use_irq || kp->some_keys_pressed) {
+ hrtimer_start(timer, mi->poll_time, HRTIMER_MODE_REL);
+ return HRTIMER_NORESTART;
+ }
+
+ /* No keys are pressed, reenable interrupt */
+ for (out = 0; out < mi->noutputs; out++) {
+ if (gpio_keypad_flags & GPIOKPF_DRIVE_INACTIVE)
+ gpio_set_value(mi->output_gpios[out], polarity);
+ else
+ gpio_direction_output(mi->output_gpios[out], polarity);
+ }
+ for (in = 0; in < mi->ninputs; in++)
+ enable_irq(gpio_to_irq(mi->input_gpios[in]));
+ wake_unlock(&kp->wake_lock);
+ return HRTIMER_NORESTART;
+}
+
+static irqreturn_t gpio_keypad_irq_handler(int irq_in, void *dev_id)
+{
+ int i;
+ struct gpio_kp *kp = dev_id;
+ struct gpio_event_matrix_info *mi = kp->keypad_info;
+ unsigned gpio_keypad_flags = mi->flags;
+
+ if (!kp->use_irq) /* ignore interrupt while registering the handler */
+ return IRQ_HANDLED;
+
+ for (i = 0; i < mi->ninputs; i++)
+ disable_irq(gpio_to_irq(mi->input_gpios[i]));
+ for (i = 0; i < mi->noutputs; i++) {
+ if (gpio_keypad_flags & GPIOKPF_DRIVE_INACTIVE)
+ gpio_set_value(mi->output_gpios[i],
+ !(gpio_keypad_flags & GPIOKPF_ACTIVE_HIGH));
+ else
+ gpio_direction_input(mi->output_gpios[i]);
+ }
+ wake_lock(&kp->wake_lock);
+ hrtimer_start(&kp->timer, ktime_set(0, 0), HRTIMER_MODE_REL);
+ return IRQ_HANDLED;
+}
+
+static int gpio_keypad_request_irqs(struct gpio_kp *kp)
+{
+ int i;
+ int err;
+ unsigned int irq;
+ unsigned long request_flags;
+ struct gpio_event_matrix_info *mi = kp->keypad_info;
+
+ switch (mi->flags & (GPIOKPF_ACTIVE_HIGH|GPIOKPF_LEVEL_TRIGGERED_IRQ)) {
+ default:
+ request_flags = IRQF_TRIGGER_FALLING;
+ break;
+ case GPIOKPF_ACTIVE_HIGH:
+ request_flags = IRQF_TRIGGER_RISING;
+ break;
+ case GPIOKPF_LEVEL_TRIGGERED_IRQ:
+ request_flags = IRQF_TRIGGER_LOW;
+ break;
+ case GPIOKPF_LEVEL_TRIGGERED_IRQ | GPIOKPF_ACTIVE_HIGH:
+ request_flags = IRQF_TRIGGER_HIGH;
+ break;
+ }
+
+ for (i = 0; i < mi->ninputs; i++) {
+ err = irq = gpio_to_irq(mi->input_gpios[i]);
+ if (err < 0)
+ goto err_gpio_get_irq_num_failed;
+ err = request_irq(irq, gpio_keypad_irq_handler, request_flags,
+ "gpio_kp", kp);
+ if (err) {
+ pr_err("gpiomatrix: request_irq failed for input %d, "
+ "irq %d\n", mi->input_gpios[i], irq);
+ goto err_request_irq_failed;
+ }
+ err = set_irq_wake(irq, 1);
+ if (err) {
+ pr_err("gpiomatrix: set_irq_wake failed for input %d, "
+ "irq %d\n", mi->input_gpios[i], irq);
+ }
+ disable_irq(irq);
+ }
+ return 0;
+
+ for (i = mi->noutputs - 1; i >= 0; i--) {
+ free_irq(gpio_to_irq(mi->input_gpios[i]), kp);
+err_request_irq_failed:
+err_gpio_get_irq_num_failed:
+ ;
+ }
+ return err;
+}
+
+int gpio_event_matrix_func(struct input_dev *input_dev,
+ struct gpio_event_info *info, void **data, int func)
+{
+ int i;
+ int err;
+ int key_count;
+ struct gpio_kp *kp;
+ struct gpio_event_matrix_info *mi;
+
+ mi = container_of(info, struct gpio_event_matrix_info, info);
+ if (func == GPIO_EVENT_FUNC_SUSPEND || func == GPIO_EVENT_FUNC_RESUME) {
+ /* TODO: disable scanning */
+ return 0;
+ }
+
+ if (func == GPIO_EVENT_FUNC_INIT) {
+ if (mi->keymap == NULL ||
+ mi->input_gpios == NULL ||
+ mi->output_gpios == NULL) {
+ err = -ENODEV;
+ pr_err("gpiomatrix: Incomplete pdata\n");
+ goto err_invalid_platform_data;
+ }
+ key_count = mi->ninputs * mi->noutputs;
+
+ *data = kp = kzalloc(sizeof(*kp) + sizeof(kp->keys_pressed[0]) *
+ BITS_TO_LONGS(key_count), GFP_KERNEL);
+ if (kp == NULL) {
+ err = -ENOMEM;
+ pr_err("gpiomatrix: Failed to allocate private data\n");
+ goto err_kp_alloc_failed;
+ }
+ kp->input_dev = input_dev;
+ kp->keypad_info = mi;
+ set_bit(EV_KEY, input_dev->evbit);
+ for (i = 0; i < key_count; i++) {
+ if (mi->keymap[i])
+ set_bit(mi->keymap[i] & KEY_MAX,
+ input_dev->keybit);
+ }
+
+ for (i = 0; i < mi->noutputs; i++) {
+ if (gpio_cansleep(mi->output_gpios[i])) {
+ pr_err("gpiomatrix: unsupported output gpio %d,"
+ " can sleep\n", mi->output_gpios[i]);
+ err = -EINVAL;
+ goto err_request_output_gpio_failed;
+ }
+ err = gpio_request(mi->output_gpios[i], "gpio_kp_out");
+ if (err) {
+ pr_err("gpiomatrix: gpio_request failed for "
+ "output %d\n", mi->output_gpios[i]);
+ goto err_request_output_gpio_failed;
+ }
+ if (mi->flags & GPIOKPF_DRIVE_INACTIVE)
+ err = gpio_direction_output(mi->output_gpios[i],
+ !(mi->flags & GPIOKPF_ACTIVE_HIGH));
+ else
+ err = gpio_direction_input(mi->output_gpios[i]);
+ if (err) {
+ pr_err("gpiomatrix: gpio_configure failed for "
+ "output %d\n", mi->output_gpios[i]);
+ goto err_output_gpio_configure_failed;
+ }
+ }
+ for (i = 0; i < mi->ninputs; i++) {
+ err = gpio_request(mi->input_gpios[i], "gpio_kp_in");
+ if (err) {
+ pr_err("gpiomatrix: gpio_request failed for "
+ "input %d\n", mi->input_gpios[i]);
+ goto err_request_input_gpio_failed;
+ }
+ err = gpio_direction_input(mi->input_gpios[i]);
+ if (err) {
+ pr_err("gpiomatrix: gpio_direction_input failed"
+ " for input %d\n", mi->input_gpios[i]);
+ goto err_gpio_direction_input_failed;
+ }
+ }
+ kp->current_output = mi->noutputs;
+ kp->key_state_changed = 1;
+
+ hrtimer_init(&kp->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ kp->timer.function = gpio_keypad_timer_func;
+ wake_lock_init(&kp->wake_lock, WAKE_LOCK_SUSPEND, "gpio_kp");
+ err = gpio_keypad_request_irqs(kp);
+ kp->use_irq = err == 0;
+
+ pr_info("GPIO Matrix Keypad Driver: Start keypad matrix for %s "
+ "in %s mode\n", input_dev->name,
+ kp->use_irq ? "interrupt" : "polling");
+
+ if (kp->use_irq)
+ wake_lock(&kp->wake_lock);
+ hrtimer_start(&kp->timer, ktime_set(0, 0), HRTIMER_MODE_REL);
+
+ return 0;
+ }
+
+ err = 0;
+ kp = *data;
+
+ if (kp->use_irq)
+ for (i = mi->noutputs - 1; i >= 0; i--)
+ free_irq(gpio_to_irq(mi->input_gpios[i]), kp);
+
+ hrtimer_cancel(&kp->timer);
+ wake_lock_destroy(&kp->wake_lock);
+ for (i = mi->noutputs - 1; i >= 0; i--) {
+err_gpio_direction_input_failed:
+ gpio_free(mi->input_gpios[i]);
+err_request_input_gpio_failed:
+ ;
+ }
+ for (i = mi->noutputs - 1; i >= 0; i--) {
+err_output_gpio_configure_failed:
+ gpio_free(mi->output_gpios[i]);
+err_request_output_gpio_failed:
+ ;
+ }
+ kfree(kp);
+err_kp_alloc_failed:
+err_invalid_platform_data:
+ return err;
+}