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/regulator/consumer.h>
18#include <linux/module.h>
19#include <linux/kernel.h>
20#include <linux/of.h>
21#include <linux/platform_device.h>
22#include <linux/property.h>
23#include <linux/pwm.h>
24#include <linux/slab.h>
25#include <linux/workqueue.h>
26
27struct pwm_beeper {
28 struct input_dev *input;
29 struct pwm_device *pwm;
30 struct regulator *amplifier;
31 struct work_struct work;
32 unsigned long period;
33 unsigned int bell_frequency;
34 bool suspended;
35 bool amplifier_on;
36};
37
38#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
39
40static int pwm_beeper_on(struct pwm_beeper *beeper, unsigned long period)
41{
42 struct pwm_state state;
43 int error;
44
45 pwm_get_state(beeper->pwm, &state);
46
47 state.enabled = true;
48 state.period = period;
49 pwm_set_relative_duty_cycle(&state, 50, 100);
50
51 error = pwm_apply_state(beeper->pwm, &state);
52 if (error)
53 return error;
54
55 if (!beeper->amplifier_on) {
56 error = regulator_enable(beeper->amplifier);
57 if (error) {
58 pwm_disable(beeper->pwm);
59 return error;
60 }
61
62 beeper->amplifier_on = true;
63 }
64
65 return 0;
66}
67
68static void pwm_beeper_off(struct pwm_beeper *beeper)
69{
70 if (beeper->amplifier_on) {
71 regulator_disable(beeper->amplifier);
72 beeper->amplifier_on = false;
73 }
74
75 pwm_disable(beeper->pwm);
76}
77
78static void pwm_beeper_work(struct work_struct *work)
79{
80 struct pwm_beeper *beeper = container_of(work, struct pwm_beeper, work);
81 unsigned long period = READ_ONCE(beeper->period);
82
83 if (period)
84 pwm_beeper_on(beeper, period);
85 else
86 pwm_beeper_off(beeper);
87}
88
89static int pwm_beeper_event(struct input_dev *input,
90 unsigned int type, unsigned int code, int value)
91{
92 struct pwm_beeper *beeper = input_get_drvdata(input);
93
94 if (type != EV_SND || value < 0)
95 return -EINVAL;
96
97 switch (code) {
98 case SND_BELL:
99 value = value ? beeper->bell_frequency : 0;
100 break;
101 case SND_TONE:
102 break;
103 default:
104 return -EINVAL;
105 }
106
107 if (value == 0)
108 beeper->period = 0;
109 else
110 beeper->period = HZ_TO_NANOSECONDS(value);
111
112 if (!beeper->suspended)
113 schedule_work(&beeper->work);
114
115 return 0;
116}
117
118static void pwm_beeper_stop(struct pwm_beeper *beeper)
119{
120 cancel_work_sync(&beeper->work);
121 pwm_beeper_off(beeper);
122}
123
124static void pwm_beeper_close(struct input_dev *input)
125{
126 struct pwm_beeper *beeper = input_get_drvdata(input);
127
128 pwm_beeper_stop(beeper);
129}
130
131static int pwm_beeper_probe(struct platform_device *pdev)
132{
133 struct device *dev = &pdev->dev;
134 struct pwm_beeper *beeper;
135 struct pwm_state state;
136 u32 bell_frequency;
137 int error;
138
139 beeper = devm_kzalloc(dev, sizeof(*beeper), GFP_KERNEL);
140 if (!beeper)
141 return -ENOMEM;
142
143 beeper->pwm = devm_pwm_get(dev, NULL);
144 if (IS_ERR(beeper->pwm)) {
145 error = PTR_ERR(beeper->pwm);
146 if (error != -EPROBE_DEFER)
147 dev_err(dev, "Failed to request PWM device: %d\n",
148 error);
149 return error;
150 }
151
152 /* Sync up PWM state and ensure it is off. */
153 pwm_init_state(beeper->pwm, &state);
154 state.enabled = false;
155 error = pwm_apply_state(beeper->pwm, &state);
156 if (error) {
157 dev_err(dev, "failed to apply initial PWM state: %d\n",
158 error);
159 return error;
160 }
161
162 beeper->amplifier = devm_regulator_get(dev, "amp");
163 if (IS_ERR(beeper->amplifier)) {
164 error = PTR_ERR(beeper->amplifier);
165 if (error != -EPROBE_DEFER)
166 dev_err(dev, "Failed to get 'amp' regulator: %d\n",
167 error);
168 return error;
169 }
170
171 INIT_WORK(&beeper->work, pwm_beeper_work);
172
173 error = device_property_read_u32(dev, "beeper-hz", &bell_frequency);
174 if (error) {
175 bell_frequency = 1000;
176 dev_dbg(dev,
177 "failed to parse 'beeper-hz' property, using default: %uHz\n",
178 bell_frequency);
179 }
180
181 beeper->bell_frequency = bell_frequency;
182
183 beeper->input = devm_input_allocate_device(dev);
184 if (!beeper->input) {
185 dev_err(dev, "Failed to allocate input device\n");
186 return -ENOMEM;
187 }
188
189 beeper->input->name = "pwm-beeper";
190 beeper->input->phys = "pwm/input0";
191 beeper->input->id.bustype = BUS_HOST;
192 beeper->input->id.vendor = 0x001f;
193 beeper->input->id.product = 0x0001;
194 beeper->input->id.version = 0x0100;
195
196 input_set_capability(beeper->input, EV_SND, SND_TONE);
197 input_set_capability(beeper->input, EV_SND, SND_BELL);
198
199 beeper->input->event = pwm_beeper_event;
200 beeper->input->close = pwm_beeper_close;
201
202 input_set_drvdata(beeper->input, beeper);
203
204 error = input_register_device(beeper->input);
205 if (error) {
206 dev_err(dev, "Failed to register input device: %d\n", error);
207 return error;
208 }
209
210 platform_set_drvdata(pdev, beeper);
211
212 return 0;
213}
214
215static int __maybe_unused pwm_beeper_suspend(struct device *dev)
216{
217 struct pwm_beeper *beeper = dev_get_drvdata(dev);
218
219 /*
220 * Spinlock is taken here is not to protect write to
221 * beeper->suspended, but to ensure that pwm_beeper_event
222 * does not re-submit work once flag is set.
223 */
224 spin_lock_irq(&beeper->input->event_lock);
225 beeper->suspended = true;
226 spin_unlock_irq(&beeper->input->event_lock);
227
228 pwm_beeper_stop(beeper);
229
230 return 0;
231}
232
233static int __maybe_unused pwm_beeper_resume(struct device *dev)
234{
235 struct pwm_beeper *beeper = dev_get_drvdata(dev);
236
237 spin_lock_irq(&beeper->input->event_lock);
238 beeper->suspended = false;
239 spin_unlock_irq(&beeper->input->event_lock);
240
241 /* Let worker figure out if we should resume beeping */
242 schedule_work(&beeper->work);
243
244 return 0;
245}
246
247static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
248 pwm_beeper_suspend, pwm_beeper_resume);
249
250#ifdef CONFIG_OF
251static const struct of_device_id pwm_beeper_match[] = {
252 { .compatible = "pwm-beeper", },
253 { },
254};
255MODULE_DEVICE_TABLE(of, pwm_beeper_match);
256#endif
257
258static struct platform_driver pwm_beeper_driver = {
259 .probe = pwm_beeper_probe,
260 .driver = {
261 .name = "pwm-beeper",
262 .pm = &pwm_beeper_pm_ops,
263 .of_match_table = of_match_ptr(pwm_beeper_match),
264 },
265};
266module_platform_driver(pwm_beeper_driver);
267
268MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
269MODULE_DESCRIPTION("PWM beeper driver");
270MODULE_LICENSE("GPL");
271MODULE_ALIAS("platform:pwm-beeper");
272