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