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/platform_device.h>
  20 #include <linux/pwm.h>
  21 #include <linux/slab.h>
  22 #include <linux/workqueue.h>
  23
  24 struct pwm_beeper {
  25         struct input_dev *input;
  26         struct pwm_device *pwm;
  27         struct work_struct work;
  28         unsigned long period;
  29 };
  30
  31 #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
  32
  33 static void __pwm_beeper_set(struct pwm_beeper *beeper)
  34 {
  35         unsigned long period = beeper->period;
  36
  37         if (period) {
  38                 pwm_config(beeper->pwm, period / 2, period);
  39                 pwm_enable(beeper->pwm);
  40         } else
  41                 pwm_disable(beeper->pwm);
  42 }
  43
  44 static void pwm_beeper_work(struct work_struct *work)
  45 {
  46         struct pwm_beeper *beeper =
  47                 container_of(work, struct pwm_beeper, work);
  48
  49         __pwm_beeper_set(beeper);
  50 }
  51
  52 static int pwm_beeper_event(struct input_dev *input,
  53                             unsigned int type, unsigned int code, int value)
  54 {
  55         struct pwm_beeper *beeper = input_get_drvdata(input);
  56
  57         if (type != EV_SND || value < 0)
  58                 return -EINVAL;
  59
  60         switch (code) {
  61         case SND_BELL:
  62                 value = value ? 1000 : 0;
  63                 break;
  64         case SND_TONE:
  65                 break;
  66         default:
  67                 return -EINVAL;
  68         }
  69
  70         if (value == 0)
  71                 beeper->period = 0;
  72         else
  73                 beeper->period = HZ_TO_NANOSECONDS(value);
  74
  75         schedule_work(&beeper->work);
  76
  77         return 0;
  78 }
  79
  80 static void pwm_beeper_stop(struct pwm_beeper *beeper)
  81 {
  82         cancel_work_sync(&beeper->work);
  83
  84         if (beeper->period)
  85                 pwm_disable(beeper->pwm);
  86 }
  87
  88 static void pwm_beeper_close(struct input_dev *input)
  89 {
  90         struct pwm_beeper *beeper = input_get_drvdata(input);
  91
  92         pwm_beeper_stop(beeper);
  93 }
  94
  95 static int __devinit pwm_beeper_probe(struct platform_device *pdev)
  96 {
  97         unsigned long pwm_id = (unsigned long)pdev->dev.platform_data;
  98         struct pwm_beeper *beeper;
  99         int error;
 100
 101         beeper = kzalloc(sizeof(*beeper), GFP_KERNEL);
 102         if (!beeper)
 103                 return -ENOMEM;
 104
 105         beeper->pwm = pwm_request(pwm_id, "pwm beeper");
 106
 107         if (IS_ERR(beeper->pwm)) {
 108                 error = PTR_ERR(beeper->pwm);
 109                 dev_err(&pdev->dev, "Failed to request pwm device: %d\n", error);
 110                 goto err_free;
 111         }
 112
 113         INIT_WORK(&beeper->work, pwm_beeper_work);
 114
 115         beeper->input = input_allocate_device();
 116         if (!beeper->input) {
 117                 dev_err(&pdev->dev, "Failed to allocate input device\n");
 118                 error = -ENOMEM;
 119                 goto err_pwm_free;
 120         }
 121         beeper->input->dev.parent = &pdev->dev;
 122
 123         beeper->input->name = "pwm-beeper";
 124         beeper->input->phys = "pwm/input0";
 125         beeper->input->id.bustype = BUS_HOST;
 126         beeper->input->id.vendor = 0x001f;
 127         beeper->input->id.product = 0x0001;
 128         beeper->input->id.version = 0x0100;
 129
 130         beeper->input->evbit[0] = BIT(EV_SND);
 131         beeper->input->sndbit[0] = BIT(SND_TONE) | BIT(SND_BELL);
 132
 133         beeper->input->event = pwm_beeper_event;
 134         beeper->input->close = pwm_beeper_close;
 135
 136         input_set_drvdata(beeper->input, beeper);
 137
 138         error = input_register_device(beeper->input);
 139         if (error) {
 140                 dev_err(&pdev->dev, "Failed to register input device: %d\n", error);
 141                 goto err_input_free;
 142         }
 143
 144         platform_set_drvdata(pdev, beeper);
 145
 146         return 0;
 147
 148 err_input_free:
 149         input_free_device(beeper->input);
 150 err_pwm_free:
 151         pwm_free(beeper->pwm);
 152 err_free:
 153         kfree(beeper);
 154
 155         return error;
 156 }
 157
 158 static int __devexit pwm_beeper_remove(struct platform_device *pdev)
 159 {
 160         struct pwm_beeper *beeper = platform_get_drvdata(pdev);
 161
 162         platform_set_drvdata(pdev, NULL);
 163         input_unregister_device(beeper->input);
 164
 165         pwm_free(beeper->pwm);
 166
 167         kfree(beeper);
 168
 169         return 0;
 170 }
 171
 172 #ifdef CONFIG_PM
 173 static int pwm_beeper_suspend(struct device *dev)
 174 {
 175         struct pwm_beeper *beeper = dev_get_drvdata(dev);
 176
 177         pwm_beeper_stop(beeper);
 178
 179         return 0;
 180 }
 181
 182 static int pwm_beeper_resume(struct device *dev)
 183 {
 184         struct pwm_beeper *beeper = dev_get_drvdata(dev);
 185
 186         if (beeper->period)
 187                 __pwm_beeper_set(beeper);
 188
 189         return 0;
 190 }
 191
 192 static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
 193                          pwm_beeper_suspend, pwm_beeper_resume);
 194
 195 #define PWM_BEEPER_PM_OPS (&pwm_beeper_pm_ops)
 196 #else
 197 #define PWM_BEEPER_PM_OPS NULL
 198 #endif
 199
 200 static struct platform_driver pwm_beeper_driver = {
 201         .probe  = pwm_beeper_probe,
 202         .remove = __devexit_p(pwm_beeper_remove),
 203         .driver = {
 204                 .name   = "pwm-beeper",
 205                 .owner  = THIS_MODULE,
 206                 .pm     = PWM_BEEPER_PM_OPS,
 207         },
 208 };
 209
 210 static int __init pwm_beeper_init(void)
 211 {
 212         return platform_driver_register(&pwm_beeper_driver);
 213 }
 214 module_init(pwm_beeper_init);
 215
 216 static void __exit pwm_beeper_exit(void)
 217 {
 218         platform_driver_unregister(&pwm_beeper_driver);
 219 }
 220 module_exit(pwm_beeper_exit);
 221
 222 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 223 MODULE_DESCRIPTION("PWM beeper driver");
 224 MODULE_LICENSE("GPL");
 225 MODULE_ALIAS("platform:pwm-beeper");