1 /* 2 * linux/drivers/leds-pwm.c 3 * 4 * simple PWM based LED control 5 * 6 * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de) 7 * 8 * based on leds-gpio.c by Raphael Assenat <raph@8d.com> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14 15 #include <linux/module.h> 16 #include <linux/kernel.h> 17 #include <linux/init.h> 18 #include <linux/platform_device.h> 19 #include <linux/fb.h> 20 #include <linux/leds.h> 21 #include <linux/err.h> 22 #include <linux/pwm.h> 23 #include <linux/leds_pwm.h> 24 25 struct led_pwm_data { 26 struct led_classdev cdev; 27 struct pwm_device *pwm; 28 unsigned int active_low; 29 unsigned int period; 30 }; 31 32 static void led_pwm_set(struct led_classdev *led_cdev, 33 enum led_brightness brightness) 34 { 35 struct led_pwm_data *led_dat = 36 container_of(led_cdev, struct led_pwm_data, cdev); 37 unsigned int max = led_dat->cdev.max_brightness; 38 unsigned int period = led_dat->period; 39 40 if (brightness == 0) { 41 pwm_config(led_dat->pwm, 0, period); 42 pwm_disable(led_dat->pwm); 43 } else { 44 pwm_config(led_dat->pwm, brightness * period / max, period); 45 pwm_enable(led_dat->pwm); 46 } 47 } 48 49 static int led_pwm_probe(struct platform_device *pdev) 50 { 51 struct led_pwm_platform_data *pdata = pdev->dev.platform_data; 52 struct led_pwm *cur_led; 53 struct led_pwm_data *leds_data, *led_dat; 54 int i, ret = 0; 55 56 if (!pdata) 57 return -EBUSY; 58 59 leds_data = kzalloc(sizeof(struct led_pwm_data) * pdata->num_leds, 60 GFP_KERNEL); 61 if (!leds_data) 62 return -ENOMEM; 63 64 for (i = 0; i < pdata->num_leds; i++) { 65 cur_led = &pdata->leds[i]; 66 led_dat = &leds_data[i]; 67 68 led_dat->pwm = pwm_request(cur_led->pwm_id, 69 cur_led->name); 70 if (IS_ERR(led_dat->pwm)) { 71 dev_err(&pdev->dev, "unable to request PWM %d\n", 72 cur_led->pwm_id); 73 goto err; 74 } 75 76 led_dat->cdev.name = cur_led->name; 77 led_dat->cdev.default_trigger = cur_led->default_trigger; 78 led_dat->active_low = cur_led->active_low; 79 led_dat->period = cur_led->pwm_period_ns; 80 led_dat->cdev.brightness_set = led_pwm_set; 81 led_dat->cdev.brightness = LED_OFF; 82 led_dat->cdev.max_brightness = cur_led->max_brightness; 83 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; 84 85 ret = led_classdev_register(&pdev->dev, &led_dat->cdev); 86 if (ret < 0) { 87 pwm_free(led_dat->pwm); 88 goto err; 89 } 90 } 91 92 platform_set_drvdata(pdev, leds_data); 93 94 return 0; 95 96 err: 97 if (i > 0) { 98 for (i = i - 1; i >= 0; i--) { 99 led_classdev_unregister(&leds_data[i].cdev); 100 pwm_free(leds_data[i].pwm); 101 } 102 } 103 104 kfree(leds_data); 105 106 return ret; 107 } 108 109 static int __devexit led_pwm_remove(struct platform_device *pdev) 110 { 111 int i; 112 struct led_pwm_platform_data *pdata = pdev->dev.platform_data; 113 struct led_pwm_data *leds_data; 114 115 leds_data = platform_get_drvdata(pdev); 116 117 for (i = 0; i < pdata->num_leds; i++) { 118 led_classdev_unregister(&leds_data[i].cdev); 119 pwm_free(leds_data[i].pwm); 120 } 121 122 kfree(leds_data); 123 124 return 0; 125 } 126 127 static struct platform_driver led_pwm_driver = { 128 .probe = led_pwm_probe, 129 .remove = __devexit_p(led_pwm_remove), 130 .driver = { 131 .name = "leds_pwm", 132 .owner = THIS_MODULE, 133 }, 134 }; 135 136 static int __init led_pwm_init(void) 137 { 138 return platform_driver_register(&led_pwm_driver); 139 } 140 141 static void __exit led_pwm_exit(void) 142 { 143 platform_driver_unregister(&led_pwm_driver); 144 } 145 146 module_init(led_pwm_init); 147 module_exit(led_pwm_exit); 148 149 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>"); 150 MODULE_DESCRIPTION("PWM LED driver for PXA"); 151 MODULE_LICENSE("GPL"); 152 MODULE_ALIAS("platform:leds-pwm"); 153