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