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");