/*
 *  Panasonic HotKey and LCD brightness control driver
 *  (C) 2004 Hiroshi Miura <miura@da-cha.org>
 *  (C) 2004 NTT DATA Intellilink Co. http://www.intellilink.co.jp/
 *  (C) YOKOTA Hiroshi <yokota (at) netlab. is. tsukuba. ac. jp>
 *  (C) 2004 David Bronaugh <dbronaugh>
 *  (C) 2006-2008 Harald Welte <laforge@gnumonks.org>
 *
 *  derived from toshiba_acpi.c, Copyright (C) 2002-2004 John Belmonte
 *
 *  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
 *  publicshed by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
 *
 *---------------------------------------------------------------------------
 *
 * ChangeLog:
 *      Sep.23, 2008    Harald Welte <laforge@gnumonks.org>
 *              -v0.95  rename driver from drivers/acpi/pcc_acpi.c to
 *                      drivers/misc/panasonic-laptop.c
 *
 *      Jul.04, 2008    Harald Welte <laforge@gnumonks.org>
 *              -v0.94  replace /proc interface with device attributes
 *                      support {set,get}keycode on th input device
 *
 *      Jun.27, 2008    Harald Welte <laforge@gnumonks.org>
 *              -v0.92  merge with 2.6.26-rc6 input API changes
 *                      remove broken <= 2.6.15 kernel support
 *                      resolve all compiler warnings
 *                      various coding style fixes (checkpatch.pl)
 *                      add support for backlight api
 *                      major code restructuring
 *
 *      Dac.28, 2007    Harald Welte <laforge@gnumonks.org>
 *              -v0.91  merge with 2.6.24-rc6 ACPI changes
 *
 *      Nov.04, 2006    Hiroshi Miura <miura@da-cha.org>
 *              -v0.9   remove warning about section reference.
 *                      remove acpi_os_free
 *                      add /proc/acpi/pcc/brightness interface for HAL access
 *                      merge dbronaugh's enhancement
 *                      Aug.17, 2004 David Bronaugh (dbronaugh)
 *                              - Added screen brightness setting interface
 *                                Thanks to FreeBSD crew (acpi_panasonic.c)
 *                                for the ideas I needed to accomplish it
 *
 *      May.29, 2006    Hiroshi Miura <miura@da-cha.org>
 *              -v0.8.4 follow to change keyinput structure
 *                      thanks Fabian Yamaguchi <fabs@cs.tu-berlin.de>,
 *                      Jacob Bower <jacob.bower@ic.ac.uk> and
 *                      Hiroshi Yokota for providing solutions.
 *
 *      Oct.02, 2004    Hiroshi Miura <miura@da-cha.org>
 *              -v0.8.2 merge code of YOKOTA Hiroshi
 *                                      <yokota@netlab.is.tsukuba.ac.jp>.
 *                      Add sticky key mode interface.
 *                      Refactoring acpi_pcc_generate_keyinput().
 *
 *      Sep.15, 2004    Hiroshi Miura <miura@da-cha.org>
 *              -v0.8   Generate key input event on input subsystem.
 *                      This is based on yet another driver written by
 *                                                      Ryuta Nakanishi.
 *
 *      Sep.10, 2004    Hiroshi Miura <miura@da-cha.org>
 *              -v0.7   Change proc interface functions using seq_file
 *                      facility as same as other ACPI drivers.
 *
 *      Aug.28, 2004    Hiroshi Miura <miura@da-cha.org>
 *              -v0.6.4 Fix a silly error with status checking
 *
 *      Aug.25, 2004    Hiroshi Miura <miura@da-cha.org>
 *              -v0.6.3 replace read_acpi_int by standard function
 *                                                      acpi_evaluate_integer
 *                      some clean up and make smart copyright notice.
 *                      fix return value of pcc_acpi_get_key()
 *                      fix checking return value of acpi_bus_register_driver()
 *
 *      Aug.22, 2004    David Bronaugh <dbronaugh@linuxboxen.org>
 *              -v0.6.2 Add check on ACPI data (num_sifr)
 *                      Coding style cleanups, better error messages/handling
 *                      Fixed an off-by-one error in memory allocation
 *
 *      Aug.21, 2004    David Bronaugh <dbronaugh@linuxboxen.org>
 *              -v0.6.1 Fix a silly error with status checking
 *
 *      Aug.20, 2004    David Bronaugh <dbronaugh@linuxboxen.org>
 *              - v0.6  Correct brightness controls to reflect reality
 *                      based on information gleaned by Hiroshi Miura
 *                      and discussions with Hiroshi Miura
 *
 *      Aug.10, 2004    Hiroshi Miura <miura@da-cha.org>
 *              - v0.5  support LCD brightness control
 *                      based on the disclosed information by MEI.
 *
 *      Jul.25, 2004    Hiroshi Miura <miura@da-cha.org>
 *              - v0.4  first post version
 *                      add function to retrive SIFR
 *
 *      Jul.24, 2004    Hiroshi Miura <miura@da-cha.org>
 *              - v0.3  get proper status of hotkey
 *
 *      Jul.22, 2004    Hiroshi Miura <miura@da-cha.org>
 *              - v0.2  add HotKey handler
 *
 *      Jul.17, 2004    Hiroshi Miura <miura@da-cha.org>
 *              - v0.1  start from toshiba_acpi driver written by John Belmonte
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/backlight.h>
#include <linux/ctype.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <linux/input.h>


#ifndef ACPI_HOTKEY_COMPONENT
#define ACPI_HOTKEY_COMPONENT   0x10000000
#endif

#define _COMPONENT              ACPI_HOTKEY_COMPONENT

MODULE_AUTHOR("Hiroshi Miura, David Bronaugh and Harald Welte");
MODULE_DESCRIPTION("ACPI HotKey driver for Panasonic Let's Note laptops");
MODULE_LICENSE("GPL");

#define LOGPREFIX "pcc_acpi: "

/* Define ACPI PATHs */
/* Lets note hotkeys */
#define METHOD_HKEY_QUERY       "HINF"
#define METHOD_HKEY_SQTY        "SQTY"
#define METHOD_HKEY_SINF        "SINF"
#define METHOD_HKEY_SSET        "SSET"
#define HKEY_NOTIFY              0x80

#define ACPI_PCC_DRIVER_NAME    "Panasonic Laptop Support"
#define ACPI_PCC_DEVICE_NAME    "Hotkey"
#define ACPI_PCC_CLASS          "pcc"

#define ACPI_PCC_INPUT_PHYS     "panasonic/hkey0"

/* LCD_TYPEs: 0 = Normal, 1 = Semi-transparent
   ENV_STATEs: Normal temp=0x01, High temp=0x81, N/A=0x00
*/
enum SINF_BITS { SINF_NUM_BATTERIES = 0,
                 SINF_LCD_TYPE,
                 SINF_AC_MAX_BRIGHT,
                 SINF_AC_MIN_BRIGHT,
                 SINF_AC_CUR_BRIGHT,
                 SINF_DC_MAX_BRIGHT,
                 SINF_DC_MIN_BRIGHT,
                 SINF_DC_CUR_BRIGHT,
                 SINF_MUTE,
                 SINF_RESERVED,
                 SINF_ENV_STATE,
                 SINF_STICKY_KEY = 0x80,
        };
/* R1 handles SINF_AC_CUR_BRIGHT as SINF_CUR_BRIGHT, doesn't know AC state */

static int acpi_pcc_hotkey_add(struct acpi_device *device);
static int acpi_pcc_hotkey_remove(struct acpi_device *device, int type);
static int acpi_pcc_hotkey_resume(struct acpi_device *device);
static void acpi_pcc_hotkey_notify(struct acpi_device *device, u32 event);

static const struct acpi_device_id pcc_device_ids[] = {
        { "MAT0012", 0},
        { "MAT0013", 0},
        { "MAT0018", 0},
        { "MAT0019", 0},
        { "", 0},
};
MODULE_DEVICE_TABLE(acpi, pcc_device_ids);

static struct acpi_driver acpi_pcc_driver = {
        .name =         ACPI_PCC_DRIVER_NAME,
        .class =        ACPI_PCC_CLASS,
        .ids =          pcc_device_ids,
        .ops =          {
                                .add =          acpi_pcc_hotkey_add,
                                .remove =       acpi_pcc_hotkey_remove,
                                .resume =       acpi_pcc_hotkey_resume,
                                .notify =       acpi_pcc_hotkey_notify,
                        },
};

#define KEYMAP_SIZE             11
static const int initial_keymap[KEYMAP_SIZE] = {
        /*  0 */ KEY_RESERVED,
        /*  1 */ KEY_BRIGHTNESSDOWN,
        /*  2 */ KEY_BRIGHTNESSUP,
        /*  3 */ KEY_DISPLAYTOGGLE,
        /*  4 */ KEY_MUTE,
        /*  5 */ KEY_VOLUMEDOWN,
        /*  6 */ KEY_VOLUMEUP,
        /*  7 */ KEY_SLEEP,
        /*  8 */ KEY_PROG1, /* Change CPU boost */
        /*  9 */ KEY_BATTERY,
        /* 10 */ KEY_SUSPEND,
};

struct pcc_acpi {
        acpi_handle             handle;
        unsigned long           num_sifr;
        int                     sticky_mode;
        u32                     *sinf;
        struct acpi_device      *device;
        struct input_dev        *input_dev;
        struct backlight_device *backlight;
        int                     keymap[KEYMAP_SIZE];
};

struct pcc_keyinput {
        struct acpi_hotkey      *hotkey;
};

/* method access functions */
static int acpi_pcc_write_sset(struct pcc_acpi *pcc, int func, int val)
{
        union acpi_object in_objs[] = {
                { .integer.type  = ACPI_TYPE_INTEGER,
                  .integer.value = func, },
                { .integer.type  = ACPI_TYPE_INTEGER,
                  .integer.value = val, },
        };
        struct acpi_object_list params = {
                .count   = ARRAY_SIZE(in_objs),
                .pointer = in_objs,
        };
        acpi_status status = AE_OK;

        status = acpi_evaluate_object(pcc->handle, METHOD_HKEY_SSET,
                                      &params, NULL);

        return status == AE_OK;
}

static inline int acpi_pcc_get_sqty(struct acpi_device *device)
{
        unsigned long long s;
        acpi_status status;

        status = acpi_evaluate_integer(device->handle, METHOD_HKEY_SQTY,
                                       NULL, &s);
        if (ACPI_SUCCESS(status))
                return s;
        else {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                  "evaluation error HKEY.SQTY\n"));
                return -EINVAL;
        }
}

static int acpi_pcc_retrieve_biosdata(struct pcc_acpi *pcc, u32 *sinf)
{
        acpi_status status;
        struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
        union acpi_object *hkey = NULL;
        int i;

        status = acpi_evaluate_object(pcc->handle, METHOD_HKEY_SINF, NULL,
                                      &buffer);
        if (ACPI_FAILURE(status)) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                  "evaluation error HKEY.SINF\n"));
                return 0;
        }

        hkey = buffer.pointer;
        if (!hkey || (hkey->type != ACPI_TYPE_PACKAGE)) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid HKEY.SINF\n"));
                goto end;
        }

        if (pcc->num_sifr < hkey->package.count) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                 "SQTY reports bad SINF length\n"));
                status = AE_ERROR;
                goto end;
        }

        for (i = 0; i < hkey->package.count; i++) {
                union acpi_object *element = &(hkey->package.elements[i]);
                if (likely(element->type == ACPI_TYPE_INTEGER)) {
                        sinf[i] = element->integer.value;
                } else
                        ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                         "Invalid HKEY.SINF data\n"));
        }
        sinf[hkey->package.count] = -1;

end:
        kfree(buffer.pointer);
        return status == AE_OK;
}

/* backlight API interface functions */

/* This driver currently treats AC and DC brightness identical,
 * since we don't need to invent an interface to the core ACPI
 * logic to receive events in case a power supply is plugged in
 * or removed */

static int bl_get(struct backlight_device *bd)
{
        struct pcc_acpi *pcc = bl_get_data(bd);

        if (!acpi_pcc_retrieve_biosdata(pcc, pcc->sinf))
                return -EIO;

        return pcc->sinf[SINF_AC_CUR_BRIGHT];
}

static int bl_set_status(struct backlight_device *bd)
{
        struct pcc_acpi *pcc = bl_get_data(bd);
        int bright = bd->props.brightness;
        int rc;

        if (!acpi_pcc_retrieve_biosdata(pcc, pcc->sinf))
                return -EIO;

        if (bright < pcc->sinf[SINF_AC_MIN_BRIGHT])
                bright = pcc->sinf[SINF_AC_MIN_BRIGHT];

        if (bright < pcc->sinf[SINF_DC_MIN_BRIGHT])
                bright = pcc->sinf[SINF_DC_MIN_BRIGHT];

        if (bright < pcc->sinf[SINF_AC_MIN_BRIGHT] ||
            bright > pcc->sinf[SINF_AC_MAX_BRIGHT])
                return -EINVAL;

        rc = acpi_pcc_write_sset(pcc, SINF_AC_CUR_BRIGHT, bright);
        if (rc < 0)
                return rc;

        return acpi_pcc_write_sset(pcc, SINF_DC_CUR_BRIGHT, bright);
}

static struct backlight_ops pcc_backlight_ops = {
        .get_brightness = bl_get,
        .update_status  = bl_set_status,
};


/* sysfs user interface functions */

static ssize_t show_numbatt(struct device *dev, struct device_attribute *attr,
                            char *buf)
{
        struct acpi_device *acpi = to_acpi_device(dev);
        struct pcc_acpi *pcc = acpi_driver_data(acpi);

        if (!acpi_pcc_retrieve_biosdata(pcc, pcc->sinf))
                return -EIO;

        return snprintf(buf, PAGE_SIZE, "%u\n", pcc->sinf[SINF_NUM_BATTERIES]);
}

static ssize_t show_lcdtype(struct device *dev, struct device_attribute *attr,
                            char *buf)
{
        struct acpi_device *acpi = to_acpi_device(dev);
        struct pcc_acpi *pcc = acpi_driver_data(acpi);

        if (!acpi_pcc_retrieve_biosdata(pcc, pcc->sinf))
                return -EIO;

        return snprintf(buf, PAGE_SIZE, "%u\n", pcc->sinf[SINF_LCD_TYPE]);
}

static ssize_t show_mute(struct device *dev, struct device_attribute *attr,
                         char *buf)
{
        struct acpi_device *acpi = to_acpi_device(dev);
        struct pcc_acpi *pcc = acpi_driver_data(acpi);

        if (!acpi_pcc_retrieve_biosdata(pcc, pcc->sinf))
                return -EIO;

        return snprintf(buf, PAGE_SIZE, "%u\n", pcc->sinf[SINF_MUTE]);
}

static ssize_t show_sticky(struct device *dev, struct device_attribute *attr,
                           char *buf)
{
        struct acpi_device *acpi = to_acpi_device(dev);
        struct pcc_acpi *pcc = acpi_driver_data(acpi);

        if (!acpi_pcc_retrieve_biosdata(pcc, pcc->sinf))
                return -EIO;

        return snprintf(buf, PAGE_SIZE, "%u\n", pcc->sinf[SINF_STICKY_KEY]);
}

static ssize_t set_sticky(struct device *dev, struct device_attribute *attr,
                          const char *buf, size_t count)
{
        struct acpi_device *acpi = to_acpi_device(dev);
        struct pcc_acpi *pcc = acpi_driver_data(acpi);
        int val;

        if (count && sscanf(buf, "%i", &val) == 1 &&
            (val == 0 || val == 1)) {
                acpi_pcc_write_sset(pcc, SINF_STICKY_KEY, val);
                pcc->sticky_mode = val;
        }

        return count;
}

static DEVICE_ATTR(numbatt, S_IRUGO, show_numbatt, NULL);
static DEVICE_ATTR(lcdtype, S_IRUGO, show_lcdtype, NULL);
static DEVICE_ATTR(mute, S_IRUGO, show_mute, NULL);
static DEVICE_ATTR(sticky_key, S_IRUGO | S_IWUSR, show_sticky, set_sticky);

static struct attribute *pcc_sysfs_entries[] = {
        &dev_attr_numbatt.attr,
        &dev_attr_lcdtype.attr,
        &dev_attr_mute.attr,
        &dev_attr_sticky_key.attr,
        NULL,
};

static struct attribute_group pcc_attr_group = {
        .name   = NULL,         /* put in device directory */
        .attrs  = pcc_sysfs_entries,
};


/* hotkey input device driver */

static int pcc_getkeycode(struct input_dev *dev, int scancode, int *keycode)
{
        struct pcc_acpi *pcc = input_get_drvdata(dev);

        if (scancode >= ARRAY_SIZE(pcc->keymap))
                return -EINVAL;

        *keycode = pcc->keymap[scancode];

        return 0;
}

static int keymap_get_by_keycode(struct pcc_acpi *pcc, int keycode)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(pcc->keymap); i++) {
                if (pcc->keymap[i] == keycode)
                        return i+1;
        }

        return 0;
}

static int pcc_setkeycode(struct input_dev *dev, int scancode, int keycode)
{
        struct pcc_acpi *pcc = input_get_drvdata(dev);
        int oldkeycode;

        if (scancode >= ARRAY_SIZE(pcc->keymap))
                return -EINVAL;

        if (keycode < 0 || keycode > KEY_MAX)
                return -EINVAL;

        oldkeycode = pcc->keymap[scancode];
        pcc->keymap[scancode] = keycode;

        set_bit(keycode, dev->keybit);

        if (!keymap_get_by_keycode(pcc, oldkeycode))
                clear_bit(oldkeycode, dev->keybit);

        return 0;
}

static void acpi_pcc_generate_keyinput(struct pcc_acpi *pcc)
{
        struct input_dev *hotk_input_dev = pcc->input_dev;
        int rc;
        int key_code, hkey_num;
        unsigned long long result;

        rc = acpi_evaluate_integer(pcc->handle, METHOD_HKEY_QUERY,
                                   NULL, &result);
        if (!ACPI_SUCCESS(rc)) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                 "error getting hotkey status\n"));
                return;
        }

        acpi_bus_generate_proc_event(pcc->device, HKEY_NOTIFY, result);

        hkey_num = result & 0xf;

        if (hkey_num < 0 || hkey_num >= ARRAY_SIZE(pcc->keymap)) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                  "hotkey number out of range: %d\n",
                                  hkey_num));
                return;
        }

        key_code = pcc->keymap[hkey_num];

        if (key_code != KEY_RESERVED) {
                int pushed = (result & 0x80) ? TRUE : FALSE;

                input_report_key(hotk_input_dev, key_code, pushed);
                input_sync(hotk_input_dev);
        }

        return;
}

static void acpi_pcc_hotkey_notify(struct acpi_device *device, u32 event)
{
        struct pcc_acpi *pcc = acpi_driver_data(device);

        switch (event) {
        case HKEY_NOTIFY:
                acpi_pcc_generate_keyinput(pcc);
                break;
        default:
                /* nothing to do */
                break;
        }
}

static int acpi_pcc_init_input(struct pcc_acpi *pcc)
{
        int i, rc;

        pcc->input_dev = input_allocate_device();
        if (!pcc->input_dev) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                  "Couldn't allocate input device for hotkey"));
                return -ENOMEM;
        }

        pcc->input_dev->evbit[0] = BIT(EV_KEY);

        pcc->input_dev->name = ACPI_PCC_DRIVER_NAME;
        pcc->input_dev->phys = ACPI_PCC_INPUT_PHYS;
        pcc->input_dev->id.bustype = BUS_HOST;
        pcc->input_dev->id.vendor = 0x0001;
        pcc->input_dev->id.product = 0x0001;
        pcc->input_dev->id.version = 0x0100;
        pcc->input_dev->getkeycode = pcc_getkeycode;
        pcc->input_dev->setkeycode = pcc_setkeycode;

        /* load initial keymap */
        memcpy(pcc->keymap, initial_keymap, sizeof(pcc->keymap));

        for (i = 0; i < ARRAY_SIZE(pcc->keymap); i++)
                __set_bit(pcc->keymap[i], pcc->input_dev->keybit);
        __clear_bit(KEY_RESERVED, pcc->input_dev->keybit);

        input_set_drvdata(pcc->input_dev, pcc);

        rc = input_register_device(pcc->input_dev);
        if (rc < 0)
                input_free_device(pcc->input_dev);

        return rc;
}

/* kernel module interface */

static int acpi_pcc_hotkey_resume(struct acpi_device *device)
{
        struct pcc_acpi *pcc = acpi_driver_data(device);
        acpi_status status = AE_OK;

        if (device == NULL || pcc == NULL)
                return -EINVAL;

        ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Sticky mode restore: %d\n",
                          pcc->sticky_mode));

        status = acpi_pcc_write_sset(pcc, SINF_STICKY_KEY, pcc->sticky_mode);

        return status == AE_OK ? 0 : -EINVAL;
}

static int acpi_pcc_hotkey_add(struct acpi_device *device)
{
        struct pcc_acpi *pcc;
        int num_sifr, result;

        if (!device)
                return -EINVAL;

        num_sifr = acpi_pcc_get_sqty(device);

        if (num_sifr > 255) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "num_sifr too large"));
                return -ENODEV;
        }

        pcc = kzalloc(sizeof(struct pcc_acpi), GFP_KERNEL);
        if (!pcc) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                  "Couldn't allocate mem for pcc"));
                return -ENOMEM;
        }

        pcc->sinf = kzalloc(sizeof(u32) * (num_sifr + 1), GFP_KERNEL);
        if (!pcc->sinf) {
                result = -ENOMEM;
                goto out_hotkey;
        }

        pcc->device = device;
        pcc->handle = device->handle;
        pcc->num_sifr = num_sifr;
        device->driver_data = pcc;
        strcpy(acpi_device_name(device), ACPI_PCC_DEVICE_NAME);
        strcpy(acpi_device_class(device), ACPI_PCC_CLASS);

        result = acpi_pcc_init_input(pcc);
        if (result) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                  "Error installing keyinput handler\n"));
                goto out_sinf;
        }

        /* initialize backlight */
        pcc->backlight = backlight_device_register("panasonic", NULL, pcc,
                                                   &pcc_backlight_ops);
        if (IS_ERR(pcc->backlight))
                goto out_input;

        if (!acpi_pcc_retrieve_biosdata(pcc, pcc->sinf)) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                 "Couldn't retrieve BIOS data\n"));
                goto out_backlight;
        }

        /* read the initial brightness setting from the hardware */
        pcc->backlight->props.max_brightness =
                                        pcc->sinf[SINF_AC_MAX_BRIGHT];
        pcc->backlight->props.brightness = pcc->sinf[SINF_AC_CUR_BRIGHT];

        /* read the initial sticky key mode from the hardware */
        pcc->sticky_mode = pcc->sinf[SINF_STICKY_KEY];

        /* add sysfs attributes */
        result = sysfs_create_group(&device->dev.kobj, &pcc_attr_group);
        if (result)
                goto out_backlight;

        return 0;

out_backlight:
        backlight_device_unregister(pcc->backlight);
out_input:
        input_unregister_device(pcc->input_dev);
        /* no need to input_free_device() since core input API refcount and
         * free()s the device */
out_sinf:
        kfree(pcc->sinf);
out_hotkey:
        kfree(pcc);

        return result;
}

static int __init acpi_pcc_init(void)
{
        int result = 0;

        if (acpi_disabled)
                return -ENODEV;

        result = acpi_bus_register_driver(&acpi_pcc_driver);
        if (result < 0) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                  "Error registering hotkey driver\n"));
                return -ENODEV;
        }

        return 0;
}

static int acpi_pcc_hotkey_remove(struct acpi_device *device, int type)
{
        struct pcc_acpi *pcc = acpi_driver_data(device);

        if (!device || !pcc)
                return -EINVAL;

        sysfs_remove_group(&device->dev.kobj, &pcc_attr_group);

        backlight_device_unregister(pcc->backlight);

        input_unregister_device(pcc->input_dev);
        /* no need to input_free_device() since core input API refcount and
         * free()s the device */

        kfree(pcc->sinf);
        kfree(pcc);

        return 0;
}

static void __exit acpi_pcc_exit(void)
{
        acpi_bus_unregister_driver(&acpi_pcc_driver);
}

module_init(acpi_pcc_init);
module_exit(acpi_pcc_exit);