drivers/staging/nvec/nvec_leds.c

   1 /*
   2  * nvec_leds: LED driver for a NVIDIA compliant embedded controller
   3  *
   4  * Copyright (C) 2011 The AC100 Kernel Team <ac100@lists.launchpad.net>
   5  *
   6  * Authors:  Ilya Petrov <ilya.muromec@gmail.com>
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  *
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/err.h>
  16 #include <linux/slab.h>
  17 #include <linux/leds.h>
  18 #include <linux/platform_device.h>
  19 #include "nvec.h"
  20
  21 #define to_nvec_led(led_cdev) \
  22         container_of(led_cdev, struct nvec_led, cdev)
  23
  24 #define NVEC_LED_REQ {'\x0d', '\x10', '\x45', '\x10', '\x00'}
  25
  26 #define NVEC_LED_MAX 8
  27
  28 struct nvec_led {
  29         struct led_classdev cdev;
  30         struct nvec_chip *nvec;
  31 };
  32
  33 static void nvec_led_brightness_set(struct led_classdev *led_cdev,
  34                                     enum led_brightness value)
  35 {
  36         struct nvec_led *led = to_nvec_led(led_cdev);
  37         unsigned char buf[] = NVEC_LED_REQ;
  38         buf[4] = value;
  39
  40         nvec_write_async(led->nvec, buf, sizeof(buf));
  41
  42         led->cdev.brightness = value;
  43
  44 }
  45
  46 static int __devinit nvec_led_probe(struct platform_device *pdev)
  47 {
  48         struct nvec_chip *nvec = dev_get_drvdata(pdev->dev.parent);
  49         struct nvec_led *led;
  50         int ret = 0;
  51
  52         led = kzalloc(sizeof(*led), GFP_KERNEL);
  53         if (led == NULL)
  54                 return -ENOMEM;
  55
  56         led->cdev.max_brightness = NVEC_LED_MAX;
  57
  58         led->cdev.brightness_set = nvec_led_brightness_set;
  59         led->cdev.name = "nvec-led";
  60         led->cdev.flags |= LED_CORE_SUSPENDRESUME;
  61         led->nvec = nvec;
  62
  63         platform_set_drvdata(pdev, led);
  64
  65         ret = led_classdev_register(&pdev->dev, &led->cdev);
  66         if (ret < 0)
  67                 goto err_led;
  68
  69         /* to expose the default value to userspace */
  70         led->cdev.brightness = 0;
  71
  72         return 0;
  73
  74 err_led:
  75         kfree(led);
  76         return ret;
  77 }
  78
  79 static int __devexit nvec_led_remove(struct platform_device *pdev)
  80 {
  81         struct nvec_led *led = platform_get_drvdata(pdev);
  82
  83         led_classdev_unregister(&led->cdev);
  84         kfree(led);
  85         return 0;
  86 }
  87
  88 static struct platform_driver nvec_led_driver = {
  89         .probe  = nvec_led_probe,
  90         .remove = __devexit_p(nvec_led_remove),
  91         .driver = {
  92                    .name  = "nvec-leds",
  93                    .owner = THIS_MODULE,
  94         },
  95 };
  96
  97 static int __init nvec_led_init(void)
  98 {
  99         return platform_driver_register(&nvec_led_driver);
 100 }
 101
 102 module_init(nvec_led_init);
 103
 104 static void __exit nvec_led_exit(void)
 105 {
 106         platform_driver_unregister(&nvec_led_driver);
 107 }
 108
 109 module_exit(nvec_led_exit);
 110
 111 MODULE_AUTHOR("Ilya Petrov <ilya.muromec@gmail.com>");
 112 MODULE_DESCRIPTION("Tegra NVEC LED driver");
 113 MODULE_LICENSE("GPL");
 114 MODULE_ALIAS("platform:nvec-leds");