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