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 }; 31 32 #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x)) 33 34 static void __pwm_beeper_set(struct pwm_beeper *beeper) 35 { 36 unsigned long period = beeper->period; 37 38 if (period) { 39 pwm_config(beeper->pwm, period / 2, period); 40 pwm_enable(beeper->pwm); 41 } else 42 pwm_disable(beeper->pwm); 43 } 44 45 static void pwm_beeper_work(struct work_struct *work) 46 { 47 struct pwm_beeper *beeper = 48 container_of(work, struct pwm_beeper, work); 49 50 __pwm_beeper_set(beeper); 51 } 52 53 static int pwm_beeper_event(struct input_dev *input, 54 unsigned int type, unsigned int code, int value) 55 { 56 struct pwm_beeper *beeper = input_get_drvdata(input); 57 58 if (type != EV_SND || value < 0) 59 return -EINVAL; 60 61 switch (code) { 62 case SND_BELL: 63 value = value ? 1000 : 0; 64 break; 65 case SND_TONE: 66 break; 67 default: 68 return -EINVAL; 69 } 70 71 if (value == 0) 72 beeper->period = 0; 73 else 74 beeper->period = HZ_TO_NANOSECONDS(value); 75 76 schedule_work(&beeper->work); 77 78 return 0; 79 } 80 81 static void pwm_beeper_stop(struct pwm_beeper *beeper) 82 { 83 cancel_work_sync(&beeper->work); 84 85 if (beeper->period) 86 pwm_disable(beeper->pwm); 87 } 88 89 static void pwm_beeper_close(struct input_dev *input) 90 { 91 struct pwm_beeper *beeper = input_get_drvdata(input); 92 93 pwm_beeper_stop(beeper); 94 } 95 96 static int pwm_beeper_probe(struct platform_device *pdev) 97 { 98 struct device *dev = &pdev->dev; 99 struct pwm_beeper *beeper; 100 int error; 101 102 beeper = devm_kzalloc(dev, sizeof(*beeper), GFP_KERNEL); 103 if (!beeper) 104 return -ENOMEM; 105 106 beeper->pwm = devm_pwm_get(dev, NULL); 107 if (IS_ERR(beeper->pwm)) { 108 error = PTR_ERR(beeper->pwm); 109 dev_err(dev, "Failed to request PWM device: %d\n", error); 110 return error; 111 } 112 113 /* 114 * FIXME: pwm_apply_args() should be removed when switching to 115 * the atomic PWM API. 116 */ 117 pwm_apply_args(beeper->pwm); 118 119 INIT_WORK(&beeper->work, pwm_beeper_work); 120 121 beeper->input = devm_input_allocate_device(dev); 122 if (!beeper->input) { 123 dev_err(dev, "Failed to allocate input device\n"); 124 return -ENOMEM; 125 } 126 127 beeper->input->name = "pwm-beeper"; 128 beeper->input->phys = "pwm/input0"; 129 beeper->input->id.bustype = BUS_HOST; 130 beeper->input->id.vendor = 0x001f; 131 beeper->input->id.product = 0x0001; 132 beeper->input->id.version = 0x0100; 133 134 input_set_capability(beeper->input, EV_SND, SND_TONE); 135 input_set_capability(beeper->input, EV_SND, SND_BELL); 136 137 beeper->input->event = pwm_beeper_event; 138 beeper->input->close = pwm_beeper_close; 139 140 input_set_drvdata(beeper->input, beeper); 141 142 error = input_register_device(beeper->input); 143 if (error) { 144 dev_err(dev, "Failed to register input device: %d\n", error); 145 return error; 146 } 147 148 platform_set_drvdata(pdev, beeper); 149 150 return 0; 151 } 152 153 static int __maybe_unused pwm_beeper_suspend(struct device *dev) 154 { 155 struct pwm_beeper *beeper = dev_get_drvdata(dev); 156 157 pwm_beeper_stop(beeper); 158 159 return 0; 160 } 161 162 static int __maybe_unused pwm_beeper_resume(struct device *dev) 163 { 164 struct pwm_beeper *beeper = dev_get_drvdata(dev); 165 166 if (beeper->period) 167 __pwm_beeper_set(beeper); 168 169 return 0; 170 } 171 172 static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops, 173 pwm_beeper_suspend, pwm_beeper_resume); 174 175 #ifdef CONFIG_OF 176 static const struct of_device_id pwm_beeper_match[] = { 177 { .compatible = "pwm-beeper", }, 178 { }, 179 }; 180 MODULE_DEVICE_TABLE(of, pwm_beeper_match); 181 #endif 182 183 static struct platform_driver pwm_beeper_driver = { 184 .probe = pwm_beeper_probe, 185 .driver = { 186 .name = "pwm-beeper", 187 .pm = &pwm_beeper_pm_ops, 188 .of_match_table = of_match_ptr(pwm_beeper_match), 189 }, 190 }; 191 module_platform_driver(pwm_beeper_driver); 192 193 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 194 MODULE_DESCRIPTION("PWM beeper driver"); 195 MODULE_LICENSE("GPL"); 196 MODULE_ALIAS("platform:pwm-beeper"); 197