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