// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Fujitsu Lifebook Application Panel button drive
 *
 *  Copyright (C) 2007 Stephen Hemminger <shemminger@linux-foundation.org>
 *  Copyright (C) 2001-2003 Jochen Eisinger <jochen@penguin-breeder.org>
 *
 * Many Fujitsu Lifebook laptops have a small panel of buttons that are
 * accessible via the i2c/smbus interface. This driver polls those
 * buttons and generates input events.
 *
 * For more details see:
 *      http://apanel.sourceforge.net/tech.php
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/input.h>
#include <linux/i2c.h>
#include <linux/leds.h>

#define APANEL_NAME     "Fujitsu Application Panel"
#define APANEL          "apanel"

/* How often we poll keys - msecs */
#define POLL_INTERVAL_DEFAULT   1000

/* Magic constants in BIOS that tell about buttons */
enum apanel_devid {
        APANEL_DEV_NONE   = 0,
        APANEL_DEV_APPBTN = 1,
        APANEL_DEV_CDBTN  = 2,
        APANEL_DEV_LCD    = 3,
        APANEL_DEV_LED    = 4,

        APANEL_DEV_MAX,
};

enum apanel_chip {
        CHIP_NONE    = 0,
        CHIP_OZ992C  = 1,
        CHIP_OZ163T  = 2,
        CHIP_OZ711M3 = 4,
};

/* Result of BIOS snooping/probing -- what features are supported */
static enum apanel_chip device_chip[APANEL_DEV_MAX];

#define MAX_PANEL_KEYS  12

struct apanel {
        struct input_dev *idev;
        struct i2c_client *client;
        unsigned short keymap[MAX_PANEL_KEYS];
        u16 nkeys;
        struct led_classdev mail_led;
};

static const unsigned short apanel_keymap[MAX_PANEL_KEYS] = {
        [0] = KEY_MAIL,
        [1] = KEY_WWW,
        [2] = KEY_PROG2,
        [3] = KEY_PROG1,

        [8] = KEY_FORWARD,
        [9] = KEY_REWIND,
        [10] = KEY_STOPCD,
        [11] = KEY_PLAYPAUSE,
};

static void report_key(struct input_dev *input, unsigned keycode)
{
        dev_dbg(input->dev.parent, "report key %#x\n", keycode);
        input_report_key(input, keycode, 1);
        input_sync(input);

        input_report_key(input, keycode, 0);
        input_sync(input);
}

/* Poll for key changes
 *
 * Read Application keys via SMI
 *  A (0x4), B (0x8), Internet (0x2), Email (0x1).
 *
 * CD keys:
 * Forward (0x100), Rewind (0x200), Stop (0x400), Pause (0x800)
 */
static void apanel_poll(struct input_dev *idev)
{
        struct apanel *ap = input_get_drvdata(idev);
        u8 cmd = device_chip[APANEL_DEV_APPBTN] == CHIP_OZ992C ? 0 : 8;
        s32 data;
        int i;

        data = i2c_smbus_read_word_data(ap->client, cmd);
        if (data < 0)
                return; /* ignore errors (due to ACPI??) */

        /* write back to clear latch */
        i2c_smbus_write_word_data(ap->client, cmd, 0);

        if (!data)
                return;

        dev_dbg(&idev->dev, APANEL ": data %#x\n", data);
        for (i = 0; i < idev->keycodemax; i++)
                if ((1u << i) & data)
                        report_key(idev, ap->keymap[i]);
}

static int mail_led_set(struct led_classdev *led,
                         enum led_brightness value)
{
        struct apanel *ap = container_of(led, struct apanel, mail_led);
        u16 led_bits = value != LED_OFF ? 0x8000 : 0x0000;

        return i2c_smbus_write_word_data(ap->client, 0x10, led_bits);
}

static int apanel_probe(struct i2c_client *client)
{
        struct apanel *ap;
        struct input_dev *idev;
        u8 cmd = device_chip[APANEL_DEV_APPBTN] == CHIP_OZ992C ? 0 : 8;
        int i, err;

        ap = devm_kzalloc(&client->dev, sizeof(*ap), GFP_KERNEL);
        if (!ap)
                return -ENOMEM;

        idev = devm_input_allocate_device(&client->dev);
        if (!idev)
                return -ENOMEM;

        ap->idev = idev;
        ap->client = client;

        i2c_set_clientdata(client, ap);

        err = i2c_smbus_write_word_data(client, cmd, 0);
        if (err) {
                dev_warn(&client->dev, "smbus write error %d\n", err);
                return err;
        }

        input_set_drvdata(idev, ap);

        idev->name = APANEL_NAME " buttons";
        idev->phys = "apanel/input0";
        idev->id.bustype = BUS_HOST;

        memcpy(ap->keymap, apanel_keymap, sizeof(apanel_keymap));
        idev->keycode = ap->keymap;
        idev->keycodesize = sizeof(ap->keymap[0]);
        idev->keycodemax = (device_chip[APANEL_DEV_CDBTN] != CHIP_NONE) ? 12 : 4;

        set_bit(EV_KEY, idev->evbit);
        for (i = 0; i < idev->keycodemax; i++)
                if (ap->keymap[i])
                        set_bit(ap->keymap[i], idev->keybit);

        err = input_setup_polling(idev, apanel_poll);
        if (err)
                return err;

        input_set_poll_interval(idev, POLL_INTERVAL_DEFAULT);

        err = input_register_device(idev);
        if (err)
                return err;

        if (device_chip[APANEL_DEV_LED] != CHIP_NONE) {
                ap->mail_led.name = "mail:blue";
                ap->mail_led.brightness_set_blocking = mail_led_set;
                err = devm_led_classdev_register(&client->dev, &ap->mail_led);
                if (err)
                        return err;
        }

        return 0;
}

static void apanel_shutdown(struct i2c_client *client)
{
        struct apanel *ap = i2c_get_clientdata(client);

        if (device_chip[APANEL_DEV_LED] != CHIP_NONE)
                led_set_brightness(&ap->mail_led, LED_OFF);
}

static const struct i2c_device_id apanel_id[] = {
        { "fujitsu_apanel" },
        { }
};
MODULE_DEVICE_TABLE(i2c, apanel_id);

static struct i2c_driver apanel_driver = {
        .driver = {
                .name = APANEL,
        },
        .probe          = apanel_probe,
        .shutdown       = apanel_shutdown,
        .id_table       = apanel_id,
};

/* Scan the system ROM for the signature "FJKEYINF" */
static __init const void __iomem *bios_signature(const void __iomem *bios)
{
        ssize_t offset;
        const unsigned char signature[] = "FJKEYINF";

        for (offset = 0; offset < 0x10000; offset += 0x10) {
                if (check_signature(bios + offset, signature,
                                    sizeof(signature)-1))
                        return bios + offset;
        }
        pr_notice(APANEL ": Fujitsu BIOS signature '%s' not found...\n",
                  signature);
        return NULL;
}

static int __init apanel_init(void)
{
        void __iomem *bios;
        const void __iomem *p;
        u8 devno;
        unsigned char i2c_addr;
        int found = 0;

        bios = ioremap(0xF0000, 0x10000); /* Can't fail */

        p = bios_signature(bios);
        if (!p) {
                iounmap(bios);
                return -ENODEV;
        }

        /* just use the first address */
        p += 8;
        i2c_addr = readb(p + 3) >> 1;

        for ( ; (devno = readb(p)) & 0x7f; p += 4) {
                unsigned char method, slave, chip;

                method = readb(p + 1);
                chip = readb(p + 2);
                slave = readb(p + 3) >> 1;

                if (slave != i2c_addr) {
                        pr_notice(APANEL ": only one SMBus slave "
                                  "address supported, skipping device...\n");
                        continue;
                }

                /* translate alternative device numbers */
                switch (devno) {
                case 6:
                        devno = APANEL_DEV_APPBTN;
                        break;
                case 7:
                        devno = APANEL_DEV_LED;
                        break;
                }

                if (devno >= APANEL_DEV_MAX)
                        pr_notice(APANEL ": unknown device %u found\n", devno);
                else if (device_chip[devno] != CHIP_NONE)
                        pr_warn(APANEL ": duplicate entry for devno %u\n",
                                devno);

                else if (method != 1 && method != 2 && method != 4) {
                        pr_notice(APANEL ": unknown method %u for devno %u\n",
                                  method, devno);
                } else {
                        device_chip[devno] = (enum apanel_chip) chip;
                        ++found;
                }
        }
        iounmap(bios);

        if (found == 0) {
                pr_info(APANEL ": no input devices reported by BIOS\n");
                return -EIO;
        }

        return i2c_add_driver(&apanel_driver);
}
module_init(apanel_init);

static void __exit apanel_cleanup(void)
{
        i2c_del_driver(&apanel_driver);
}
module_exit(apanel_cleanup);

MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>");
MODULE_DESCRIPTION(APANEL_NAME " driver");
MODULE_LICENSE("GPL");

MODULE_ALIAS("dmi:*:svnFUJITSU:pnLifeBook*:pvr*:rvnFUJITSU:*");
MODULE_ALIAS("dmi:*:svnFUJITSU:pnLifebook*:pvr*:rvnFUJITSU:*");