alix.c

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/*
 * System Specific setup for PCEngines ALIX.
 * At the moment this means setup of GPIO control of LEDs
 * on Alix.2/3/6 boards.
 *
 *
 * Copyright (C) 2008 Constantin Baranov <[email protected]>
 * Copyright (C) 2011 Ed Wildgoose <[email protected]>
 *                and Philip Prindeville <[email protected]>
 *
 * TODO: There are large similarities with leds-net5501.c
 * by Alessandro Zummo <[email protected]>
 * In the future leds-net5501.c should be migrated over to platform
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/leds.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/input.h>
#include <linux/gpio_keys.h>
#include <linux/dmi.h>

#include <asm/geode.h>

#define BIOS_SIGNATURE_TINYBIOS     0xf0000
#define BIOS_SIGNATURE_COREBOOT     0x500
#define BIOS_REGION_SIZE        0x10000

static bool force = 0;
module_param(force, bool, 0444);
/* FIXME: Award bios is not automatically detected as Alix platform */
MODULE_PARM_DESC(force, "Force detection as ALIX.2/ALIX.3 platform");

static struct gpio_keys_button alix_gpio_buttons[] = {
    {
        .code           = KEY_RESTART,
        .gpio           = 24,
        .active_low     = 1,
        .desc           = "Reset button",
        .type           = EV_KEY,
        .wakeup         = 0,
        .debounce_interval  = 100,
        .can_disable        = 0,
    }
};
static struct gpio_keys_platform_data alix_buttons_data = {
    .buttons            = alix_gpio_buttons,
    .nbuttons           = ARRAY_SIZE(alix_gpio_buttons),
    .poll_interval          = 20,
};

static struct platform_device alix_buttons_dev = {
    .name               = "gpio-keys-polled",
    .id             = 1,
    .dev = {
        .platform_data      = &alix_buttons_data,
    }
};

static struct gpio_led alix_leds[] = {
    {
        .name = "alix:1",
        .gpio = 6,
        .default_trigger = "default-on",
        .active_low = 1,
    },
    {
        .name = "alix:2",
        .gpio = 25,
        .default_trigger = "default-off",
        .active_low = 1,
    },
    {
        .name = "alix:3",
        .gpio = 27,
        .default_trigger = "default-off",
        .active_low = 1,
    },
};

static struct gpio_led_platform_data alix_leds_data = {
    .num_leds = ARRAY_SIZE(alix_leds),
    .leds = alix_leds,
};

static struct platform_device alix_leds_dev = {
    .name = "leds-gpio",
    .id = -1,
    .dev.platform_data = &alix_leds_data,
};

static struct __initdata platform_device *alix_devs[] = {
    &alix_buttons_dev,
    &alix_leds_dev,
};

static void __init register_alix(void)
{
    /* Setup LED control through leds-gpio driver */
    platform_add_devices(alix_devs, ARRAY_SIZE(alix_devs));
}

static bool __init alix_present(unsigned long bios_phys,
                const char *alix_sig,
                size_t alix_sig_len)
{
    const size_t bios_len = BIOS_REGION_SIZE;
    const char *bios_virt;
    const char *scan_end;
    const char *p;
    char name[64];

    if (force) {
        printk(KERN_NOTICE "%s: forced to skip BIOS test, "
               "assume system is ALIX.2/ALIX.3\n",
               KBUILD_MODNAME);
        return true;
    }

    bios_virt = phys_to_virt(bios_phys);
    scan_end = bios_virt + bios_len - (alix_sig_len + 2);
    for (p = bios_virt; p < scan_end; p++) {
        const char *tail;
        char *a;

        if (memcmp(p, alix_sig, alix_sig_len) != 0)
            continue;

        memcpy(name, p, sizeof(name));

        /* remove the first \0 character from string */
        a = strchr(name, '\0');
        if (a)
            *a = ' ';

        /* cut the string at a newline */
        a = strchr(name, '\r');
        if (a)
            *a = '\0';

        tail = p + alix_sig_len;
        if ((tail[0] == '2' || tail[0] == '3' || tail[0] == '6')) {
            printk(KERN_INFO
                   "%s: system is recognized as \"%s\"\n",
                   KBUILD_MODNAME, name);
            return true;
        }
    }

    return false;
}

static bool __init alix_present_dmi(void)
{
    const char *vendor, *product;

    vendor = dmi_get_system_info(DMI_SYS_VENDOR);
    if (!vendor || strcmp(vendor, "PC Engines"))
        return false;

    product = dmi_get_system_info(DMI_PRODUCT_NAME);
    if (!product || (strcmp(product, "ALIX.2D") && strcmp(product, "ALIX.6")))
        return false;

    printk(KERN_INFO "%s: system is recognized as \"%s %s\"\n",
           KBUILD_MODNAME, vendor, product);

    return true;
}

static int __init alix_init(void)
{
    const char tinybios_sig[] = "PC Engines ALIX.";
    const char coreboot_sig[] = "PC Engines\0ALIX.";

    if (!is_geode())
        return 0;

    if (alix_present(BIOS_SIGNATURE_TINYBIOS, tinybios_sig, sizeof(tinybios_sig) - 1) ||
        alix_present(BIOS_SIGNATURE_COREBOOT, coreboot_sig, sizeof(coreboot_sig) - 1) ||
        alix_present_dmi())
        register_alix();

    return 0;
}

module_init(alix_init);

MODULE_AUTHOR("Ed Wildgoose <[email protected]>");
MODULE_DESCRIPTION("PCEngines ALIX System Setup");
MODULE_LICENSE("GPL");