![Lars-Peter Clausen](/assets/img/avatar_default.png)
This patch adds a simple driver which allows to use pwm based beepers (for example piezo elements) as a pcspkr-like device. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
200 lines
4.4 KiB
C
200 lines
4.4 KiB
C
/*
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* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
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* PWM beeper driver
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/input.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/slab.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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unsigned long period;
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};
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#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
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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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int ret = 0;
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struct pwm_beeper *beeper = input_get_drvdata(input);
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unsigned long period;
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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 ? 1000 : 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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pwm_config(beeper->pwm, 0, 0);
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pwm_disable(beeper->pwm);
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} else {
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period = HZ_TO_NANOSECONDS(value);
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ret = pwm_config(beeper->pwm, period / 2, period);
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if (ret)
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return ret;
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ret = pwm_enable(beeper->pwm);
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if (ret)
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return ret;
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beeper->period = period;
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}
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return 0;
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}
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static int __devinit pwm_beeper_probe(struct platform_device *pdev)
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{
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unsigned long pwm_id = (unsigned long)pdev->dev.platform_data;
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struct pwm_beeper *beeper;
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int error;
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beeper = kzalloc(sizeof(*beeper), GFP_KERNEL);
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if (!beeper)
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return -ENOMEM;
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beeper->pwm = pwm_request(pwm_id, "pwm beeper");
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if (IS_ERR(beeper->pwm)) {
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error = PTR_ERR(beeper->pwm);
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dev_err(&pdev->dev, "Failed to request pwm device: %d\n", error);
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goto err_free;
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}
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beeper->input = input_allocate_device();
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if (!beeper->input) {
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dev_err(&pdev->dev, "Failed to allocate input device\n");
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error = -ENOMEM;
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goto err_pwm_free;
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}
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beeper->input->dev.parent = &pdev->dev;
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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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beeper->input->evbit[0] = BIT(EV_SND);
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beeper->input->sndbit[0] = BIT(SND_TONE) | BIT(SND_BELL);
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beeper->input->event = pwm_beeper_event;
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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(&pdev->dev, "Failed to register input device: %d\n", error);
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goto err_input_free;
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}
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platform_set_drvdata(pdev, beeper);
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return 0;
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err_input_free:
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input_free_device(beeper->input);
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err_pwm_free:
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pwm_free(beeper->pwm);
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err_free:
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kfree(beeper);
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return error;
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}
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static int __devexit pwm_beeper_remove(struct platform_device *pdev)
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{
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struct pwm_beeper *beeper = platform_get_drvdata(pdev);
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platform_set_drvdata(pdev, NULL);
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input_unregister_device(beeper->input);
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pwm_disable(beeper->pwm);
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pwm_free(beeper->pwm);
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kfree(beeper);
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return 0;
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}
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#ifdef CONFIG_PM
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static int 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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if (beeper->period)
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pwm_disable(beeper->pwm);
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return 0;
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}
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static int 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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if (beeper->period) {
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pwm_config(beeper->pwm, beeper->period / 2, beeper->period);
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pwm_enable(beeper->pwm);
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}
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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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#define PWM_BEEPER_PM_OPS (&pwm_beeper_pm_ops)
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#else
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#define PWM_BEEPER_PM_OPS NULL
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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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.remove = __devexit_p(pwm_beeper_remove),
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.driver = {
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.name = "pwm-beeper",
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.owner = THIS_MODULE,
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.pm = PWM_BEEPER_PM_OPS,
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},
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};
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static int __init pwm_beeper_init(void)
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{
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return platform_driver_register(&pwm_beeper_driver);
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}
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module_init(pwm_beeper_init);
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static void __exit pwm_beeper_exit(void)
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{
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platform_driver_unregister(&pwm_beeper_driver);
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}
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module_exit(pwm_beeper_exit);
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MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
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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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