drivers/leds/leds-ot200.c

   1 /*
   2  * Bachmann ot200 leds driver.
   3  *
   4  * Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
   5  *         Christian Gmeiner <christian.gmeiner@gmail.com>
   6  *
   7  * License: GPL as published by the FSF.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/slab.h>
  14 #include <linux/leds.h>
  15 #include <linux/io.h>
  16 #include <linux/module.h>
  17
  18
  19 struct ot200_led {
  20         struct led_classdev cdev;
  21         const char *name;
  22         unsigned long port;
  23         u8 mask;
  24 };
  25
  26 /*
  27  * The device has three leds on the back panel (led_err, led_init and led_run)
  28  * and can handle up to seven leds on the front panel.
  29  */
  30
  31 static struct ot200_led leds[] = {
  32         {
  33                 .name = "led_run",
  34                 .port = 0x5a,
  35                 .mask = BIT(0),
  36         },
  37         {
  38                 .name = "led_init",
  39                 .port = 0x5a,
  40                 .mask = BIT(1),
  41         },
  42         {
  43                 .name = "led_err",
  44                 .port = 0x5a,
  45                 .mask = BIT(2),
  46         },
  47         {
  48                 .name = "led_1",
  49                 .port = 0x49,
  50                 .mask = BIT(6),
  51         },
  52         {
  53                 .name = "led_2",
  54                 .port = 0x49,
  55                 .mask = BIT(5),
  56         },
  57         {
  58                 .name = "led_3",
  59                 .port = 0x49,
  60                 .mask = BIT(4),
  61         },
  62         {
  63                 .name = "led_4",
  64                 .port = 0x49,
  65                 .mask = BIT(3),
  66         },
  67         {
  68                 .name = "led_5",
  69                 .port = 0x49,
  70                 .mask = BIT(2),
  71         },
  72         {
  73                 .name = "led_6",
  74                 .port = 0x49,
  75                 .mask = BIT(1),
  76         },
  77         {
  78                 .name = "led_7",
  79                 .port = 0x49,
  80                 .mask = BIT(0),
  81         }
  82 };
  83
  84 static DEFINE_SPINLOCK(value_lock);
  85
  86 /*
  87  * we need to store the current led states, as it is not
  88  * possible to read the current led state via inb().
  89  */
  90 static u8 leds_back;
  91 static u8 leds_front;
  92
  93 static void ot200_led_brightness_set(struct led_classdev *led_cdev,
  94                 enum led_brightness value)
  95 {
  96         struct ot200_led *led = container_of(led_cdev, struct ot200_led, cdev);
  97         u8 *val;
  98         unsigned long flags;
  99
 100         spin_lock_irqsave(&value_lock, flags);
 101
 102         if (led->port == 0x49)
 103                 val = &leds_front;
 104         else if (led->port == 0x5a)
 105                 val = &leds_back;
 106         else
 107                 BUG();
 108
 109         if (value == LED_OFF)
 110                 *val &= ~led->mask;
 111         else
 112                 *val |= led->mask;
 113
 114         outb(*val, led->port);
 115         spin_unlock_irqrestore(&value_lock, flags);
 116 }
 117
 118 static int ot200_led_probe(struct platform_device *pdev)
 119 {
 120         int i;
 121         int ret;
 122
 123         for (i = 0; i < ARRAY_SIZE(leds); i++) {
 124
 125                 leds[i].cdev.name = leds[i].name;
 126                 leds[i].cdev.brightness_set = ot200_led_brightness_set;
 127
 128                 ret = led_classdev_register(&pdev->dev, &leds[i].cdev);
 129                 if (ret < 0)
 130                         goto err;
 131         }
 132
 133         leds_front = 0;         /* turn off all front leds */
 134         leds_back = BIT(1);     /* turn on init led */
 135         outb(leds_front, 0x49);
 136         outb(leds_back, 0x5a);
 137
 138         return 0;
 139
 140 err:
 141         for (i = i - 1; i >= 0; i--)
 142                 led_classdev_unregister(&leds[i].cdev);
 143
 144         return ret;
 145 }
 146
 147 static int ot200_led_remove(struct platform_device *pdev)
 148 {
 149         int i;
 150
 151         for (i = 0; i < ARRAY_SIZE(leds); i++)
 152                 led_classdev_unregister(&leds[i].cdev);
 153
 154         return 0;
 155 }
 156
 157 static struct platform_driver ot200_led_driver = {
 158         .probe          = ot200_led_probe,
 159         .remove         = ot200_led_remove,
 160         .driver         = {
 161                 .name   = "leds-ot200",
 162                 .owner  = THIS_MODULE,
 163         },
 164 };
 165
 166 module_platform_driver(ot200_led_driver);
 167
 168 MODULE_AUTHOR("Sebastian A. Siewior <bigeasy@linutronix.de>");
 169 MODULE_DESCRIPTION("ot200 LED driver");
 170 MODULE_LICENSE("GPL");
 171 MODULE_ALIAS("platform:leds-ot200");