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