arch/x86/platform/geode/alix.c

   1 /*
   2  * System Specific setup for PCEngines ALIX.
   3  * At the moment this means setup of GPIO control of LEDs
   4  * on Alix.2/3/6 boards.
   5  *
   6  *
   7  * Copyright (C) 2008 Constantin Baranov <const@mimas.ru>
   8  * Copyright (C) 2011 Ed Wildgoose <kernel@wildgooses.com>
   9  *
  10  * TODO: There are large similarities with leds-net5501.c
  11  * by Alessandro Zummo <a.zummo@towertech.it>
  12  * In the future leds-net5501.c should be migrated over to platform
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License version 2
  16  * as published by the Free Software Foundation.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/init.h>
  21 #include <linux/io.h>
  22 #include <linux/string.h>
  23 #include <linux/module.h>
  24 #include <linux/leds.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/gpio.h>
  27
  28 #include <asm/geode.h>
  29
  30 static int force = 0;
  31 module_param(force, bool, 0444);
  32 /* FIXME: Award bios is not automatically detected as Alix platform */
  33 MODULE_PARM_DESC(force, "Force detection as ALIX.2/ALIX.3 platform");
  34
  35 static struct gpio_led alix_leds[] = {
  36         {
  37                 .name = "alix:1",
  38                 .gpio = 6,
  39                 .default_trigger = "default-on",
  40                 .active_low = 1,
  41         },
  42         {
  43                 .name = "alix:2",
  44                 .gpio = 25,
  45                 .default_trigger = "default-off",
  46                 .active_low = 1,
  47         },
  48         {
  49                 .name = "alix:3",
  50                 .gpio = 27,
  51                 .default_trigger = "default-off",
  52                 .active_low = 1,
  53         },
  54 };
  55
  56 static struct gpio_led_platform_data alix_leds_data = {
  57         .num_leds = ARRAY_SIZE(alix_leds),
  58         .leds = alix_leds,
  59 };
  60
  61 static struct platform_device alix_leds_dev = {
  62         .name = "leds-gpio",
  63         .id = -1,
  64         .dev.platform_data = &alix_leds_data,
  65 };
  66
  67 static void __init register_alix(void)
  68 {
  69         /* Setup LED control through leds-gpio driver */
  70         platform_device_register(&alix_leds_dev);
  71 }
  72
  73 static int __init alix_present(unsigned long bios_phys,
  74                                 const char *alix_sig,
  75                                 size_t alix_sig_len)
  76 {
  77         const size_t bios_len = 0x00010000;
  78         const char *bios_virt;
  79         const char *scan_end;
  80         const char *p;
  81         char name[64];
  82
  83         if (force) {
  84                 printk(KERN_NOTICE "%s: forced to skip BIOS test, "
  85                        "assume system is ALIX.2/ALIX.3\n",
  86                        KBUILD_MODNAME);
  87                 return 1;
  88         }
  89
  90         bios_virt = phys_to_virt(bios_phys);
  91         scan_end = bios_virt + bios_len - (alix_sig_len + 2);
  92         for (p = bios_virt; p < scan_end; p++) {
  93                 const char *tail;
  94                 char *a;
  95
  96                 if (memcmp(p, alix_sig, alix_sig_len) != 0)
  97                         continue;
  98
  99                 memcpy(name, p, sizeof(name));
 100
 101                 /* remove the first \0 character from string */
 102                 a = strchr(name, '\0');
 103                 if (a)
 104                         *a = ' ';
 105
 106                 /* cut the string at a newline */
 107                 a = strchr(name, '\r');
 108                 if (a)
 109                         *a = '\0';
 110
 111                 tail = p + alix_sig_len;
 112                 if ((tail[0] == '2' || tail[0] == '3')) {
 113                         printk(KERN_INFO
 114                                "%s: system is recognized as \"%s\"\n",
 115                                KBUILD_MODNAME, name);
 116                         return 1;
 117                 }
 118         }
 119
 120         return 0;
 121 }
 122
 123 static int __init alix_init(void)
 124 {
 125         const char tinybios_sig[] = "PC Engines ALIX.";
 126         const char coreboot_sig[] = "PC Engines\0ALIX.";
 127
 128         if (!is_geode())
 129                 return 0;
 130
 131         if (alix_present(0xf0000, tinybios_sig, sizeof(tinybios_sig) - 1) ||
 132             alix_present(0x500, coreboot_sig, sizeof(coreboot_sig) - 1))
 133                 register_alix();
 134
 135         return 0;
 136 }
 137
 138 module_init(alix_init);
 139
 140 MODULE_AUTHOR("Ed Wildgoose <kernel@wildgooses.com>");
 141 MODULE_DESCRIPTION("PCEngines ALIX System Setup");
 142 MODULE_LICENSE("GPL");