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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 
 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 #ifdef CONFIG_PM_SLEEP
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");
201 

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