// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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 <const@mimas.ru>
 * Copyright (C) 2011 Ed Wildgoose <kernel@wildgooses.com>
 *                and Philip Prindeville <philipp@redfish-solutions.com>
 *
 * TODO: There are large similarities with leds-net5501.c
 * by Alessandro Zummo <a.zummo@towertech.it>
 * In the future leds-net5501.c should be migrated over to platform
 */

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

#include <asm/geode.h>

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

/*
 * This driver is not modular, but to keep back compatibility
 * with existing use cases, continuing with module_param is
 * the easiest way forward.
 */
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",
                .default_trigger = "default-on",
        },
        {
                .name = "alix:2",
                .default_trigger = "default-off",
        },
        {
                .name = "alix:3",
                .default_trigger = "default-off",
        },
};

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

static struct gpiod_lookup_table alix_leds_gpio_table = {
        .dev_id = "leds-gpio",
        .table = {
                /* The Geode GPIOs should be on the CS5535 companion chip */
                GPIO_LOOKUP_IDX("cs5535-gpio", 6, NULL, 0, GPIO_ACTIVE_LOW),
                GPIO_LOOKUP_IDX("cs5535-gpio", 25, NULL, 1, GPIO_ACTIVE_LOW),
                GPIO_LOOKUP_IDX("cs5535-gpio", 27, NULL, 2, GPIO_ACTIVE_LOW),
                { }
        },
};

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

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

static void __init register_alix(void)
{
        /* Setup LED control through leds-gpio driver */
        gpiod_add_lookup_table(&alix_leds_gpio_table);
        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;
}
device_initcall(alix_init);