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 unsigned long pwm_id = (unsigned long)dev_get_platdata(&pdev->dev); 99 struct pwm_beeper *beeper; 100 int error; 101 102 beeper = kzalloc(sizeof(*beeper), GFP_KERNEL); 103 if (!beeper) 104 return -ENOMEM; 105 106 beeper->pwm = pwm_get(&pdev->dev, NULL); 107 if (IS_ERR(beeper->pwm)) { 108 dev_dbg(&pdev->dev, "unable to request PWM, trying legacy API\n"); 109 beeper->pwm = pwm_request(pwm_id, "pwm beeper"); 110 } 111 112 if (IS_ERR(beeper->pwm)) { 113 error = PTR_ERR(beeper->pwm); 114 dev_err(&pdev->dev, "Failed to request pwm device: %d\n", error); 115 goto err_free; 116 } 117 118 /* 119 * FIXME: pwm_apply_args() should be removed when switching to 120 * the atomic PWM API. 121 */ 122 pwm_apply_args(beeper->pwm); 123 124 INIT_WORK(&beeper->work, pwm_beeper_work); 125 126 beeper->input = input_allocate_device(); 127 if (!beeper->input) { 128 dev_err(&pdev->dev, "Failed to allocate input device\n"); 129 error = -ENOMEM; 130 goto err_pwm_free; 131 } 132 beeper->input->dev.parent = &pdev->dev; 133 134 beeper->input->name = "pwm-beeper"; 135 beeper->input->phys = "pwm/input0"; 136 beeper->input->id.bustype = BUS_HOST; 137 beeper->input->id.vendor = 0x001f; 138 beeper->input->id.product = 0x0001; 139 beeper->input->id.version = 0x0100; 140 141 beeper->input->evbit[0] = BIT(EV_SND); 142 beeper->input->sndbit[0] = BIT(SND_TONE) | BIT(SND_BELL); 143 144 beeper->input->event = pwm_beeper_event; 145 beeper->input->close = pwm_beeper_close; 146 147 input_set_drvdata(beeper->input, beeper); 148 149 error = input_register_device(beeper->input); 150 if (error) { 151 dev_err(&pdev->dev, "Failed to register input device: %d\n", error); 152 goto err_input_free; 153 } 154 155 platform_set_drvdata(pdev, beeper); 156 157 return 0; 158 159 err_input_free: 160 input_free_device(beeper->input); 161 err_pwm_free: 162 pwm_free(beeper->pwm); 163 err_free: 164 kfree(beeper); 165 166 return error; 167 } 168 169 static int pwm_beeper_remove(struct platform_device *pdev) 170 { 171 struct pwm_beeper *beeper = platform_get_drvdata(pdev); 172 173 input_unregister_device(beeper->input); 174 175 pwm_free(beeper->pwm); 176 177 kfree(beeper); 178 179 return 0; 180 } 181 182 static int __maybe_unused pwm_beeper_suspend(struct device *dev) 183 { 184 struct pwm_beeper *beeper = dev_get_drvdata(dev); 185 186 pwm_beeper_stop(beeper); 187 188 return 0; 189 } 190 191 static int __maybe_unused pwm_beeper_resume(struct device *dev) 192 { 193 struct pwm_beeper *beeper = dev_get_drvdata(dev); 194 195 if (beeper->period) 196 __pwm_beeper_set(beeper); 197 198 return 0; 199 } 200 201 static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops, 202 pwm_beeper_suspend, pwm_beeper_resume); 203 204 #ifdef CONFIG_OF 205 static const struct of_device_id pwm_beeper_match[] = { 206 { .compatible = "pwm-beeper", }, 207 { }, 208 }; 209 MODULE_DEVICE_TABLE(of, pwm_beeper_match); 210 #endif 211 212 static struct platform_driver pwm_beeper_driver = { 213 .probe = pwm_beeper_probe, 214 .remove = pwm_beeper_remove, 215 .driver = { 216 .name = "pwm-beeper", 217 .pm = &pwm_beeper_pm_ops, 218 .of_match_table = of_match_ptr(pwm_beeper_match), 219 }, 220 }; 221 module_platform_driver(pwm_beeper_driver); 222 223 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 224 MODULE_DESCRIPTION("PWM beeper driver"); 225 MODULE_LICENSE("GPL"); 226 MODULE_ALIAS("platform:pwm-beeper"); 227