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