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Linux/drivers/input/misc/pwm-beeper.c

  1 /*
  2  *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
  3  *  PWM beeper driver
  4  *
  5  *  This program is free software; you can redistribute it and/or modify it
  6  *  under  the terms of the GNU General  Public License as published by the
  7  *  Free Software Foundation;  either version 2 of the License, or (at your
  8  *  option) any later version.
  9  *
 10  *  You should have received a copy of the GNU General Public License along
 11  *  with this program; if not, write to the Free Software Foundation, Inc.,
 12  *  675 Mass Ave, Cambridge, MA 02139, USA.
 13  *
 14  */
 15 
 16 #include <linux/input.h>
 17 #include <linux/module.h>
 18 #include <linux/kernel.h>
 19 #include <linux/of.h>
 20 #include <linux/platform_device.h>
 21 #include <linux/pwm.h>
 22 #include <linux/slab.h>
 23 #include <linux/workqueue.h>
 24 
 25 struct pwm_beeper {
 26         struct input_dev *input;
 27         struct pwm_device *pwm;
 28         struct work_struct work;
 29         unsigned long period;
 30 };
 31 
 32 #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
 33 
 34 static void __pwm_beeper_set(struct pwm_beeper *beeper)
 35 {
 36         unsigned long period = beeper->period;
 37 
 38         if (period) {
 39                 pwm_config(beeper->pwm, period / 2, period);
 40                 pwm_enable(beeper->pwm);
 41         } else
 42                 pwm_disable(beeper->pwm);
 43 }
 44 
 45 static void pwm_beeper_work(struct work_struct *work)
 46 {
 47         struct pwm_beeper *beeper =
 48                 container_of(work, struct pwm_beeper, work);
 49 
 50         __pwm_beeper_set(beeper);
 51 }
 52 
 53 static int pwm_beeper_event(struct input_dev *input,
 54                             unsigned int type, unsigned int code, int value)
 55 {
 56         struct pwm_beeper *beeper = input_get_drvdata(input);
 57 
 58         if (type != EV_SND || value < 0)
 59                 return -EINVAL;
 60 
 61         switch (code) {
 62         case SND_BELL:
 63                 value = value ? 1000 : 0;
 64                 break;
 65         case SND_TONE:
 66                 break;
 67         default:
 68                 return -EINVAL;
 69         }
 70 
 71         if (value == 0)
 72                 beeper->period = 0;
 73         else
 74                 beeper->period = HZ_TO_NANOSECONDS(value);
 75 
 76         schedule_work(&beeper->work);
 77 
 78         return 0;
 79 }
 80 
 81 static void pwm_beeper_stop(struct pwm_beeper *beeper)
 82 {
 83         cancel_work_sync(&beeper->work);
 84 
 85         if (beeper->period)
 86                 pwm_disable(beeper->pwm);
 87 }
 88 
 89 static void pwm_beeper_close(struct input_dev *input)
 90 {
 91         struct pwm_beeper *beeper = input_get_drvdata(input);
 92 
 93         pwm_beeper_stop(beeper);
 94 }
 95 
 96 static int pwm_beeper_probe(struct platform_device *pdev)
 97 {
 98         unsigned long pwm_id = (unsigned long)dev_get_platdata(&pdev->dev);
 99         struct pwm_beeper *beeper;
100         int error;
101 
102         beeper = kzalloc(sizeof(*beeper), GFP_KERNEL);
103         if (!beeper)
104                 return -ENOMEM;
105 
106         beeper->pwm = pwm_get(&pdev->dev, NULL);
107         if (IS_ERR(beeper->pwm)) {
108                 dev_dbg(&pdev->dev, "unable to request PWM, trying legacy API\n");
109                 beeper->pwm = pwm_request(pwm_id, "pwm beeper");
110         }
111 
112         if (IS_ERR(beeper->pwm)) {
113                 error = PTR_ERR(beeper->pwm);
114                 dev_err(&pdev->dev, "Failed to request pwm device: %d\n", error);
115                 goto err_free;
116         }
117 
118         /*
119          * FIXME: pwm_apply_args() should be removed when switching to
120          * the atomic PWM API.
121          */
122         pwm_apply_args(beeper->pwm);
123 
124         INIT_WORK(&beeper->work, pwm_beeper_work);
125 
126         beeper->input = input_allocate_device();
127         if (!beeper->input) {
128                 dev_err(&pdev->dev, "Failed to allocate input device\n");
129                 error = -ENOMEM;
130                 goto err_pwm_free;
131         }
132         beeper->input->dev.parent = &pdev->dev;
133 
134         beeper->input->name = "pwm-beeper";
135         beeper->input->phys = "pwm/input0";
136         beeper->input->id.bustype = BUS_HOST;
137         beeper->input->id.vendor = 0x001f;
138         beeper->input->id.product = 0x0001;
139         beeper->input->id.version = 0x0100;
140 
141         beeper->input->evbit[0] = BIT(EV_SND);
142         beeper->input->sndbit[0] = BIT(SND_TONE) | BIT(SND_BELL);
143 
144         beeper->input->event = pwm_beeper_event;
145         beeper->input->close = pwm_beeper_close;
146 
147         input_set_drvdata(beeper->input, beeper);
148 
149         error = input_register_device(beeper->input);
150         if (error) {
151                 dev_err(&pdev->dev, "Failed to register input device: %d\n", error);
152                 goto err_input_free;
153         }
154 
155         platform_set_drvdata(pdev, beeper);
156 
157         return 0;
158 
159 err_input_free:
160         input_free_device(beeper->input);
161 err_pwm_free:
162         pwm_free(beeper->pwm);
163 err_free:
164         kfree(beeper);
165 
166         return error;
167 }
168 
169 static int pwm_beeper_remove(struct platform_device *pdev)
170 {
171         struct pwm_beeper *beeper = platform_get_drvdata(pdev);
172 
173         input_unregister_device(beeper->input);
174 
175         pwm_free(beeper->pwm);
176 
177         kfree(beeper);
178 
179         return 0;
180 }
181 
182 static int __maybe_unused pwm_beeper_suspend(struct device *dev)
183 {
184         struct pwm_beeper *beeper = dev_get_drvdata(dev);
185 
186         pwm_beeper_stop(beeper);
187 
188         return 0;
189 }
190 
191 static int __maybe_unused pwm_beeper_resume(struct device *dev)
192 {
193         struct pwm_beeper *beeper = dev_get_drvdata(dev);
194 
195         if (beeper->period)
196                 __pwm_beeper_set(beeper);
197 
198         return 0;
199 }
200 
201 static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
202                          pwm_beeper_suspend, pwm_beeper_resume);
203 
204 #ifdef CONFIG_OF
205 static const struct of_device_id pwm_beeper_match[] = {
206         { .compatible = "pwm-beeper", },
207         { },
208 };
209 MODULE_DEVICE_TABLE(of, pwm_beeper_match);
210 #endif
211 
212 static struct platform_driver pwm_beeper_driver = {
213         .probe  = pwm_beeper_probe,
214         .remove = pwm_beeper_remove,
215         .driver = {
216                 .name   = "pwm-beeper",
217                 .pm     = &pwm_beeper_pm_ops,
218                 .of_match_table = of_match_ptr(pwm_beeper_match),
219         },
220 };
221 module_platform_driver(pwm_beeper_driver);
222 
223 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
224 MODULE_DESCRIPTION("PWM beeper driver");
225 MODULE_LICENSE("GPL");
226 MODULE_ALIAS("platform:pwm-beeper");
227 

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