drivers/leds/leds-alix2.c

   1 /*
   2  * LEDs driver for PCEngines ALIX.2 and ALIX.3
   3  *
   4  * Copyright (C) 2008 Constantin Baranov <const@mimas.ru>
   5  */
   6
   7 #include <linux/err.h>
   8 #include <linux/io.h>
   9 #include <linux/kernel.h>
  10 #include <linux/leds.h>
  11 #include <linux/module.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/string.h>
  14
  15 static int force = 0;
  16 module_param(force, bool, 0444);
  17 MODULE_PARM_DESC(force, "Assume system has ALIX.2/ALIX.3 style LEDs");
  18
  19 struct alix_led {
  20         struct led_classdev cdev;
  21         unsigned short port;
  22         unsigned int on_value;
  23         unsigned int off_value;
  24 };
  25
  26 static void alix_led_set(struct led_classdev *led_cdev,
  27                          enum led_brightness brightness)
  28 {
  29         struct alix_led *led_dev =
  30                 container_of(led_cdev, struct alix_led, cdev);
  31
  32         if (brightness)
  33                 outl(led_dev->on_value, led_dev->port);
  34         else
  35                 outl(led_dev->off_value, led_dev->port);
  36 }
  37
  38 static struct alix_led alix_leds[] = {
  39         {
  40                 .cdev = {
  41                         .name = "alix:1",
  42                         .brightness_set = alix_led_set,
  43                 },
  44                 .port = 0x6100,
  45                 .on_value = 1 << 22,
  46                 .off_value = 1 << 6,
  47         },
  48         {
  49                 .cdev = {
  50                         .name = "alix:2",
  51                         .brightness_set = alix_led_set,
  52                 },
  53                 .port = 0x6180,
  54                 .on_value = 1 << 25,
  55                 .off_value = 1 << 9,
  56         },
  57         {
  58                 .cdev = {
  59                         .name = "alix:3",
  60                         .brightness_set = alix_led_set,
  61                 },
  62                 .port = 0x6180,
  63                 .on_value = 1 << 27,
  64                 .off_value = 1 << 11,
  65         },
  66 };
  67
  68 static int __init alix_led_probe(struct platform_device *pdev)
  69 {
  70         int i;
  71         int ret;
  72
  73         for (i = 0; i < ARRAY_SIZE(alix_leds); i++) {
  74                 alix_leds[i].cdev.flags |= LED_CORE_SUSPENDRESUME;
  75                 ret = led_classdev_register(&pdev->dev, &alix_leds[i].cdev);
  76                 if (ret < 0)
  77                         goto fail;
  78         }
  79         return 0;
  80
  81 fail:
  82         while (--i >= 0)
  83                 led_classdev_unregister(&alix_leds[i].cdev);
  84         return ret;
  85 }
  86
  87 static int alix_led_remove(struct platform_device *pdev)
  88 {
  89         int i;
  90
  91         for (i = 0; i < ARRAY_SIZE(alix_leds); i++)
  92                 led_classdev_unregister(&alix_leds[i].cdev);
  93         return 0;
  94 }
  95
  96 static struct platform_driver alix_led_driver = {
  97         .remove = alix_led_remove,
  98         .driver = {
  99                 .name = KBUILD_MODNAME,
 100                 .owner = THIS_MODULE,
 101         },
 102 };
 103
 104 static int __init alix_present(void)
 105 {
 106         const unsigned long bios_phys = 0x000f0000;
 107         const size_t bios_len = 0x00010000;
 108         const char alix_sig[] = "PC Engines ALIX.";
 109         const size_t alix_sig_len = sizeof(alix_sig) - 1;
 110
 111         const char *bios_virt;
 112         const char *scan_end;
 113         const char *p;
 114         int ret = 0;
 115
 116         if (force) {
 117                 printk(KERN_NOTICE "%s: forced to skip BIOS test, "
 118                        "assume system has ALIX.2 style LEDs\n",
 119                        KBUILD_MODNAME);
 120                 ret = 1;
 121                 goto out;
 122         }
 123
 124         bios_virt = phys_to_virt(bios_phys);
 125         scan_end = bios_virt + bios_len - (alix_sig_len + 2);
 126         for (p = bios_virt; p < scan_end; p++) {
 127                 const char *tail;
 128
 129                 if (memcmp(p, alix_sig, alix_sig_len) != 0) {
 130                         continue;
 131                 }
 132
 133                 tail = p + alix_sig_len;
 134                 if ((tail[0] == '2' || tail[0] == '3') && tail[1] == '\0') {
 135                         printk(KERN_INFO
 136                                "%s: system is recognized as \"%s\"\n",
 137                                KBUILD_MODNAME, p);
 138                         ret = 1;
 139                         break;
 140                 }
 141         }
 142
 143 out:
 144         return ret;
 145 }
 146
 147 static struct platform_device *pdev;
 148
 149 static int __init alix_led_init(void)
 150 {
 151         int ret;
 152
 153         if (!alix_present()) {
 154                 ret = -ENODEV;
 155                 goto out;
 156         }
 157
 158         /* enable output on GPIO for LED 1,2,3 */
 159         outl(1 << 6, 0x6104);
 160         outl(1 << 9, 0x6184);
 161         outl(1 << 11, 0x6184);
 162
 163         pdev = platform_device_register_simple(KBUILD_MODNAME, -1, NULL, 0);
 164         if (!IS_ERR(pdev)) {
 165                 ret = platform_driver_probe(&alix_led_driver, alix_led_probe);
 166                 if (ret)
 167                         platform_device_unregister(pdev);
 168         } else
 169                 ret = PTR_ERR(pdev);
 170
 171 out:
 172         return ret;
 173 }
 174
 175 static void __exit alix_led_exit(void)
 176 {
 177         platform_device_unregister(pdev);
 178         platform_driver_unregister(&alix_led_driver);
 179 }
 180
 181 module_init(alix_led_init);
 182 module_exit(alix_led_exit);
 183
 184 MODULE_AUTHOR("Constantin Baranov <const@mimas.ru>");
 185 MODULE_DESCRIPTION("PCEngines ALIX.2 and ALIX.3 LED driver");
 186 MODULE_LICENSE("GPL");