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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
24struct 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
32static 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
69static 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
123err_input_free:
124 input_free_device(beeper->input);
125err_pwm_free:
126 pwm_free(beeper->pwm);
127err_free:
128 kfree(beeper);
129
130 return error;
131}
132
133static 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
148static 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
158static 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
170static 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
179static const struct of_device_id pwm_beeper_match[] = {
180 { .compatible = "pwm-beeper", },
181 { },
182};
183#endif
184
185static 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};
195module_platform_driver(pwm_beeper_driver);
196
197MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
198MODULE_DESCRIPTION("PWM beeper driver");
199MODULE_LICENSE("GPL");
200MODULE_ALIAS("platform:pwm-beeper");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
4 * PWM beeper driver
5 */
6
7#include <linux/input.h>
8#include <linux/regulator/consumer.h>
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/property.h>
14#include <linux/pwm.h>
15#include <linux/slab.h>
16#include <linux/workqueue.h>
17
18struct pwm_beeper {
19 struct input_dev *input;
20 struct pwm_device *pwm;
21 struct regulator *amplifier;
22 struct work_struct work;
23 unsigned long period;
24 unsigned int bell_frequency;
25 bool suspended;
26 bool amplifier_on;
27};
28
29#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
30
31static int pwm_beeper_on(struct pwm_beeper *beeper, unsigned long period)
32{
33 struct pwm_state state;
34 int error;
35
36 pwm_get_state(beeper->pwm, &state);
37
38 state.enabled = true;
39 state.period = period;
40 pwm_set_relative_duty_cycle(&state, 50, 100);
41
42 error = pwm_apply_might_sleep(beeper->pwm, &state);
43 if (error)
44 return error;
45
46 if (!beeper->amplifier_on) {
47 error = regulator_enable(beeper->amplifier);
48 if (error) {
49 pwm_disable(beeper->pwm);
50 return error;
51 }
52
53 beeper->amplifier_on = true;
54 }
55
56 return 0;
57}
58
59static void pwm_beeper_off(struct pwm_beeper *beeper)
60{
61 if (beeper->amplifier_on) {
62 regulator_disable(beeper->amplifier);
63 beeper->amplifier_on = false;
64 }
65
66 pwm_disable(beeper->pwm);
67}
68
69static void pwm_beeper_work(struct work_struct *work)
70{
71 struct pwm_beeper *beeper = container_of(work, struct pwm_beeper, work);
72 unsigned long period = READ_ONCE(beeper->period);
73
74 if (period)
75 pwm_beeper_on(beeper, period);
76 else
77 pwm_beeper_off(beeper);
78}
79
80static int pwm_beeper_event(struct input_dev *input,
81 unsigned int type, unsigned int code, int value)
82{
83 struct pwm_beeper *beeper = input_get_drvdata(input);
84
85 if (type != EV_SND || value < 0)
86 return -EINVAL;
87
88 switch (code) {
89 case SND_BELL:
90 value = value ? beeper->bell_frequency : 0;
91 break;
92 case SND_TONE:
93 break;
94 default:
95 return -EINVAL;
96 }
97
98 if (value == 0)
99 beeper->period = 0;
100 else
101 beeper->period = HZ_TO_NANOSECONDS(value);
102
103 if (!beeper->suspended)
104 schedule_work(&beeper->work);
105
106 return 0;
107}
108
109static void pwm_beeper_stop(struct pwm_beeper *beeper)
110{
111 cancel_work_sync(&beeper->work);
112 pwm_beeper_off(beeper);
113}
114
115static void pwm_beeper_close(struct input_dev *input)
116{
117 struct pwm_beeper *beeper = input_get_drvdata(input);
118
119 pwm_beeper_stop(beeper);
120}
121
122static int pwm_beeper_probe(struct platform_device *pdev)
123{
124 struct device *dev = &pdev->dev;
125 struct pwm_beeper *beeper;
126 struct pwm_state state;
127 u32 bell_frequency;
128 int error;
129
130 beeper = devm_kzalloc(dev, sizeof(*beeper), GFP_KERNEL);
131 if (!beeper)
132 return -ENOMEM;
133
134 beeper->pwm = devm_pwm_get(dev, NULL);
135 if (IS_ERR(beeper->pwm))
136 return dev_err_probe(dev, PTR_ERR(beeper->pwm), "Failed to request PWM device\n");
137
138 /* Sync up PWM state and ensure it is off. */
139 pwm_init_state(beeper->pwm, &state);
140 state.enabled = false;
141 error = pwm_apply_might_sleep(beeper->pwm, &state);
142 if (error) {
143 dev_err(dev, "failed to apply initial PWM state: %d\n",
144 error);
145 return error;
146 }
147
148 beeper->amplifier = devm_regulator_get(dev, "amp");
149 if (IS_ERR(beeper->amplifier))
150 return dev_err_probe(dev, PTR_ERR(beeper->amplifier),
151 "Failed to get 'amp' regulator\n");
152
153 INIT_WORK(&beeper->work, pwm_beeper_work);
154
155 error = device_property_read_u32(dev, "beeper-hz", &bell_frequency);
156 if (error) {
157 bell_frequency = 1000;
158 dev_dbg(dev,
159 "failed to parse 'beeper-hz' property, using default: %uHz\n",
160 bell_frequency);
161 }
162
163 beeper->bell_frequency = bell_frequency;
164
165 beeper->input = devm_input_allocate_device(dev);
166 if (!beeper->input) {
167 dev_err(dev, "Failed to allocate input device\n");
168 return -ENOMEM;
169 }
170
171 beeper->input->name = "pwm-beeper";
172 beeper->input->phys = "pwm/input0";
173 beeper->input->id.bustype = BUS_HOST;
174 beeper->input->id.vendor = 0x001f;
175 beeper->input->id.product = 0x0001;
176 beeper->input->id.version = 0x0100;
177
178 input_set_capability(beeper->input, EV_SND, SND_TONE);
179 input_set_capability(beeper->input, EV_SND, SND_BELL);
180
181 beeper->input->event = pwm_beeper_event;
182 beeper->input->close = pwm_beeper_close;
183
184 input_set_drvdata(beeper->input, beeper);
185
186 error = input_register_device(beeper->input);
187 if (error) {
188 dev_err(dev, "Failed to register input device: %d\n", error);
189 return error;
190 }
191
192 platform_set_drvdata(pdev, beeper);
193
194 return 0;
195}
196
197static int pwm_beeper_suspend(struct device *dev)
198{
199 struct pwm_beeper *beeper = dev_get_drvdata(dev);
200
201 /*
202 * Spinlock is taken here is not to protect write to
203 * beeper->suspended, but to ensure that pwm_beeper_event
204 * does not re-submit work once flag is set.
205 */
206 scoped_guard(spinlock_irq, &beeper->input->event_lock) {
207 beeper->suspended = true;
208 }
209
210 pwm_beeper_stop(beeper);
211
212 return 0;
213}
214
215static int pwm_beeper_resume(struct device *dev)
216{
217 struct pwm_beeper *beeper = dev_get_drvdata(dev);
218
219 scoped_guard(spinlock_irq, &beeper->input->event_lock) {
220 beeper->suspended = false;
221 }
222
223 /* Let worker figure out if we should resume beeping */
224 schedule_work(&beeper->work);
225
226 return 0;
227}
228
229static DEFINE_SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
230 pwm_beeper_suspend, pwm_beeper_resume);
231
232#ifdef CONFIG_OF
233static const struct of_device_id pwm_beeper_match[] = {
234 { .compatible = "pwm-beeper", },
235 { },
236};
237MODULE_DEVICE_TABLE(of, pwm_beeper_match);
238#endif
239
240static struct platform_driver pwm_beeper_driver = {
241 .probe = pwm_beeper_probe,
242 .driver = {
243 .name = "pwm-beeper",
244 .pm = pm_sleep_ptr(&pwm_beeper_pm_ops),
245 .of_match_table = of_match_ptr(pwm_beeper_match),
246 },
247};
248module_platform_driver(pwm_beeper_driver);
249
250MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
251MODULE_DESCRIPTION("PWM beeper driver");
252MODULE_LICENSE("GPL");
253MODULE_ALIAS("platform:pwm-beeper");