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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_state(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 error = PTR_ERR(beeper->pwm);
137 if (error != -EPROBE_DEFER)
138 dev_err(dev, "Failed to request PWM device: %d\n",
139 error);
140 return error;
141 }
142
143 /* Sync up PWM state and ensure it is off. */
144 pwm_init_state(beeper->pwm, &state);
145 state.enabled = false;
146 error = pwm_apply_state(beeper->pwm, &state);
147 if (error) {
148 dev_err(dev, "failed to apply initial PWM state: %d\n",
149 error);
150 return error;
151 }
152
153 beeper->amplifier = devm_regulator_get(dev, "amp");
154 if (IS_ERR(beeper->amplifier)) {
155 error = PTR_ERR(beeper->amplifier);
156 if (error != -EPROBE_DEFER)
157 dev_err(dev, "Failed to get 'amp' regulator: %d\n",
158 error);
159 return error;
160 }
161
162 INIT_WORK(&beeper->work, pwm_beeper_work);
163
164 error = device_property_read_u32(dev, "beeper-hz", &bell_frequency);
165 if (error) {
166 bell_frequency = 1000;
167 dev_dbg(dev,
168 "failed to parse 'beeper-hz' property, using default: %uHz\n",
169 bell_frequency);
170 }
171
172 beeper->bell_frequency = bell_frequency;
173
174 beeper->input = devm_input_allocate_device(dev);
175 if (!beeper->input) {
176 dev_err(dev, "Failed to allocate input device\n");
177 return -ENOMEM;
178 }
179
180 beeper->input->name = "pwm-beeper";
181 beeper->input->phys = "pwm/input0";
182 beeper->input->id.bustype = BUS_HOST;
183 beeper->input->id.vendor = 0x001f;
184 beeper->input->id.product = 0x0001;
185 beeper->input->id.version = 0x0100;
186
187 input_set_capability(beeper->input, EV_SND, SND_TONE);
188 input_set_capability(beeper->input, EV_SND, SND_BELL);
189
190 beeper->input->event = pwm_beeper_event;
191 beeper->input->close = pwm_beeper_close;
192
193 input_set_drvdata(beeper->input, beeper);
194
195 error = input_register_device(beeper->input);
196 if (error) {
197 dev_err(dev, "Failed to register input device: %d\n", error);
198 return error;
199 }
200
201 platform_set_drvdata(pdev, beeper);
202
203 return 0;
204}
205
206static int __maybe_unused pwm_beeper_suspend(struct device *dev)
207{
208 struct pwm_beeper *beeper = dev_get_drvdata(dev);
209
210 /*
211 * Spinlock is taken here is not to protect write to
212 * beeper->suspended, but to ensure that pwm_beeper_event
213 * does not re-submit work once flag is set.
214 */
215 spin_lock_irq(&beeper->input->event_lock);
216 beeper->suspended = true;
217 spin_unlock_irq(&beeper->input->event_lock);
218
219 pwm_beeper_stop(beeper);
220
221 return 0;
222}
223
224static int __maybe_unused pwm_beeper_resume(struct device *dev)
225{
226 struct pwm_beeper *beeper = dev_get_drvdata(dev);
227
228 spin_lock_irq(&beeper->input->event_lock);
229 beeper->suspended = false;
230 spin_unlock_irq(&beeper->input->event_lock);
231
232 /* Let worker figure out if we should resume beeping */
233 schedule_work(&beeper->work);
234
235 return 0;
236}
237
238static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
239 pwm_beeper_suspend, pwm_beeper_resume);
240
241#ifdef CONFIG_OF
242static const struct of_device_id pwm_beeper_match[] = {
243 { .compatible = "pwm-beeper", },
244 { },
245};
246MODULE_DEVICE_TABLE(of, pwm_beeper_match);
247#endif
248
249static struct platform_driver pwm_beeper_driver = {
250 .probe = pwm_beeper_probe,
251 .driver = {
252 .name = "pwm-beeper",
253 .pm = &pwm_beeper_pm_ops,
254 .of_match_table = of_match_ptr(pwm_beeper_match),
255 },
256};
257module_platform_driver(pwm_beeper_driver);
258
259MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
260MODULE_DESCRIPTION("PWM beeper driver");
261MODULE_LICENSE("GPL");
262MODULE_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_state(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 error = PTR_ERR(beeper->pwm);
137 if (error != -EPROBE_DEFER)
138 dev_err(dev, "Failed to request PWM device: %d\n",
139 error);
140 return error;
141 }
142
143 /* Sync up PWM state and ensure it is off. */
144 pwm_init_state(beeper->pwm, &state);
145 state.enabled = false;
146 error = pwm_apply_state(beeper->pwm, &state);
147 if (error) {
148 dev_err(dev, "failed to apply initial PWM state: %d\n",
149 error);
150 return error;
151 }
152
153 beeper->amplifier = devm_regulator_get(dev, "amp");
154 if (IS_ERR(beeper->amplifier)) {
155 error = PTR_ERR(beeper->amplifier);
156 if (error != -EPROBE_DEFER)
157 dev_err(dev, "Failed to get 'amp' regulator: %d\n",
158 error);
159 return error;
160 }
161
162 INIT_WORK(&beeper->work, pwm_beeper_work);
163
164 error = device_property_read_u32(dev, "beeper-hz", &bell_frequency);
165 if (error) {
166 bell_frequency = 1000;
167 dev_dbg(dev,
168 "failed to parse 'beeper-hz' property, using default: %uHz\n",
169 bell_frequency);
170 }
171
172 beeper->bell_frequency = bell_frequency;
173
174 beeper->input = devm_input_allocate_device(dev);
175 if (!beeper->input) {
176 dev_err(dev, "Failed to allocate input device\n");
177 return -ENOMEM;
178 }
179
180 beeper->input->name = "pwm-beeper";
181 beeper->input->phys = "pwm/input0";
182 beeper->input->id.bustype = BUS_HOST;
183 beeper->input->id.vendor = 0x001f;
184 beeper->input->id.product = 0x0001;
185 beeper->input->id.version = 0x0100;
186
187 input_set_capability(beeper->input, EV_SND, SND_TONE);
188 input_set_capability(beeper->input, EV_SND, SND_BELL);
189
190 beeper->input->event = pwm_beeper_event;
191 beeper->input->close = pwm_beeper_close;
192
193 input_set_drvdata(beeper->input, beeper);
194
195 error = input_register_device(beeper->input);
196 if (error) {
197 dev_err(dev, "Failed to register input device: %d\n", error);
198 return error;
199 }
200
201 platform_set_drvdata(pdev, beeper);
202
203 return 0;
204}
205
206static int __maybe_unused pwm_beeper_suspend(struct device *dev)
207{
208 struct pwm_beeper *beeper = dev_get_drvdata(dev);
209
210 /*
211 * Spinlock is taken here is not to protect write to
212 * beeper->suspended, but to ensure that pwm_beeper_event
213 * does not re-submit work once flag is set.
214 */
215 spin_lock_irq(&beeper->input->event_lock);
216 beeper->suspended = true;
217 spin_unlock_irq(&beeper->input->event_lock);
218
219 pwm_beeper_stop(beeper);
220
221 return 0;
222}
223
224static int __maybe_unused pwm_beeper_resume(struct device *dev)
225{
226 struct pwm_beeper *beeper = dev_get_drvdata(dev);
227
228 spin_lock_irq(&beeper->input->event_lock);
229 beeper->suspended = false;
230 spin_unlock_irq(&beeper->input->event_lock);
231
232 /* Let worker figure out if we should resume beeping */
233 schedule_work(&beeper->work);
234
235 return 0;
236}
237
238static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
239 pwm_beeper_suspend, pwm_beeper_resume);
240
241#ifdef CONFIG_OF
242static const struct of_device_id pwm_beeper_match[] = {
243 { .compatible = "pwm-beeper", },
244 { },
245};
246MODULE_DEVICE_TABLE(of, pwm_beeper_match);
247#endif
248
249static struct platform_driver pwm_beeper_driver = {
250 .probe = pwm_beeper_probe,
251 .driver = {
252 .name = "pwm-beeper",
253 .pm = &pwm_beeper_pm_ops,
254 .of_match_table = of_match_ptr(pwm_beeper_match),
255 },
256};
257module_platform_driver(pwm_beeper_driver);
258
259MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
260MODULE_DESCRIPTION("PWM beeper driver");
261MODULE_LICENSE("GPL");
262MODULE_ALIAS("platform:pwm-beeper");