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path: root/drivers/input/misc/pwm-beeper.c
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Diffstat (limited to 'drivers/input/misc/pwm-beeper.c')
-rw-r--r--drivers/input/misc/pwm-beeper.c262
1 files changed, 262 insertions, 0 deletions
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
new file mode 100644
index 000000000..d6b124777
--- /dev/null
+++ b/drivers/input/misc/pwm-beeper.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ * PWM beeper driver
+ */
+
+#include <linux/input.h>
+#include <linux/regulator/consumer.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+struct pwm_beeper {
+ struct input_dev *input;
+ struct pwm_device *pwm;
+ struct regulator *amplifier;
+ struct work_struct work;
+ unsigned long period;
+ unsigned int bell_frequency;
+ bool suspended;
+ bool amplifier_on;
+};
+
+#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
+
+static int pwm_beeper_on(struct pwm_beeper *beeper, unsigned long period)
+{
+ struct pwm_state state;
+ int error;
+
+ pwm_get_state(beeper->pwm, &state);
+
+ state.enabled = true;
+ state.period = period;
+ pwm_set_relative_duty_cycle(&state, 50, 100);
+
+ error = pwm_apply_state(beeper->pwm, &state);
+ if (error)
+ return error;
+
+ if (!beeper->amplifier_on) {
+ error = regulator_enable(beeper->amplifier);
+ if (error) {
+ pwm_disable(beeper->pwm);
+ return error;
+ }
+
+ beeper->amplifier_on = true;
+ }
+
+ return 0;
+}
+
+static void pwm_beeper_off(struct pwm_beeper *beeper)
+{
+ if (beeper->amplifier_on) {
+ regulator_disable(beeper->amplifier);
+ beeper->amplifier_on = false;
+ }
+
+ pwm_disable(beeper->pwm);
+}
+
+static void pwm_beeper_work(struct work_struct *work)
+{
+ struct pwm_beeper *beeper = container_of(work, struct pwm_beeper, work);
+ unsigned long period = READ_ONCE(beeper->period);
+
+ if (period)
+ pwm_beeper_on(beeper, period);
+ else
+ pwm_beeper_off(beeper);
+}
+
+static int pwm_beeper_event(struct input_dev *input,
+ unsigned int type, unsigned int code, int value)
+{
+ struct pwm_beeper *beeper = input_get_drvdata(input);
+
+ if (type != EV_SND || value < 0)
+ return -EINVAL;
+
+ switch (code) {
+ case SND_BELL:
+ value = value ? beeper->bell_frequency : 0;
+ break;
+ case SND_TONE:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (value == 0)
+ beeper->period = 0;
+ else
+ beeper->period = HZ_TO_NANOSECONDS(value);
+
+ if (!beeper->suspended)
+ schedule_work(&beeper->work);
+
+ return 0;
+}
+
+static void pwm_beeper_stop(struct pwm_beeper *beeper)
+{
+ cancel_work_sync(&beeper->work);
+ pwm_beeper_off(beeper);
+}
+
+static void pwm_beeper_close(struct input_dev *input)
+{
+ struct pwm_beeper *beeper = input_get_drvdata(input);
+
+ pwm_beeper_stop(beeper);
+}
+
+static int pwm_beeper_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct pwm_beeper *beeper;
+ struct pwm_state state;
+ u32 bell_frequency;
+ int error;
+
+ beeper = devm_kzalloc(dev, sizeof(*beeper), GFP_KERNEL);
+ if (!beeper)
+ return -ENOMEM;
+
+ beeper->pwm = devm_pwm_get(dev, NULL);
+ if (IS_ERR(beeper->pwm)) {
+ error = PTR_ERR(beeper->pwm);
+ if (error != -EPROBE_DEFER)
+ dev_err(dev, "Failed to request PWM device: %d\n",
+ error);
+ return error;
+ }
+
+ /* Sync up PWM state and ensure it is off. */
+ pwm_init_state(beeper->pwm, &state);
+ state.enabled = false;
+ error = pwm_apply_state(beeper->pwm, &state);
+ if (error) {
+ dev_err(dev, "failed to apply initial PWM state: %d\n",
+ error);
+ return error;
+ }
+
+ beeper->amplifier = devm_regulator_get(dev, "amp");
+ if (IS_ERR(beeper->amplifier)) {
+ error = PTR_ERR(beeper->amplifier);
+ if (error != -EPROBE_DEFER)
+ dev_err(dev, "Failed to get 'amp' regulator: %d\n",
+ error);
+ return error;
+ }
+
+ INIT_WORK(&beeper->work, pwm_beeper_work);
+
+ error = device_property_read_u32(dev, "beeper-hz", &bell_frequency);
+ if (error) {
+ bell_frequency = 1000;
+ dev_dbg(dev,
+ "failed to parse 'beeper-hz' property, using default: %uHz\n",
+ bell_frequency);
+ }
+
+ beeper->bell_frequency = bell_frequency;
+
+ beeper->input = devm_input_allocate_device(dev);
+ if (!beeper->input) {
+ dev_err(dev, "Failed to allocate input device\n");
+ return -ENOMEM;
+ }
+
+ beeper->input->name = "pwm-beeper";
+ beeper->input->phys = "pwm/input0";
+ beeper->input->id.bustype = BUS_HOST;
+ beeper->input->id.vendor = 0x001f;
+ beeper->input->id.product = 0x0001;
+ beeper->input->id.version = 0x0100;
+
+ input_set_capability(beeper->input, EV_SND, SND_TONE);
+ input_set_capability(beeper->input, EV_SND, SND_BELL);
+
+ beeper->input->event = pwm_beeper_event;
+ beeper->input->close = pwm_beeper_close;
+
+ input_set_drvdata(beeper->input, beeper);
+
+ error = input_register_device(beeper->input);
+ if (error) {
+ dev_err(dev, "Failed to register input device: %d\n", error);
+ return error;
+ }
+
+ platform_set_drvdata(pdev, beeper);
+
+ return 0;
+}
+
+static int __maybe_unused pwm_beeper_suspend(struct device *dev)
+{
+ struct pwm_beeper *beeper = dev_get_drvdata(dev);
+
+ /*
+ * Spinlock is taken here is not to protect write to
+ * beeper->suspended, but to ensure that pwm_beeper_event
+ * does not re-submit work once flag is set.
+ */
+ spin_lock_irq(&beeper->input->event_lock);
+ beeper->suspended = true;
+ spin_unlock_irq(&beeper->input->event_lock);
+
+ pwm_beeper_stop(beeper);
+
+ return 0;
+}
+
+static int __maybe_unused pwm_beeper_resume(struct device *dev)
+{
+ struct pwm_beeper *beeper = dev_get_drvdata(dev);
+
+ spin_lock_irq(&beeper->input->event_lock);
+ beeper->suspended = false;
+ spin_unlock_irq(&beeper->input->event_lock);
+
+ /* Let worker figure out if we should resume beeping */
+ schedule_work(&beeper->work);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
+ pwm_beeper_suspend, pwm_beeper_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id pwm_beeper_match[] = {
+ { .compatible = "pwm-beeper", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, pwm_beeper_match);
+#endif
+
+static struct platform_driver pwm_beeper_driver = {
+ .probe = pwm_beeper_probe,
+ .driver = {
+ .name = "pwm-beeper",
+ .pm = &pwm_beeper_pm_ops,
+ .of_match_table = of_match_ptr(pwm_beeper_match),
+ },
+};
+module_platform_driver(pwm_beeper_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("PWM beeper driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pwm-beeper");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-07 13:00:57 +0000