Patch from Jim - refactor ACPI calls in AMW0 and WMID execute into one function

[acer_acpi.git] / acer_acpi.c

/*
 *  acer_acpi.c - Acer Laptop ACPI Extras
 *
 *
 *  Copyright (C) 2005      E.M. Smith
 *  Copyright (C) 2007      Carlos Corbacho <cathectic@gmail.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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
 *
 *
 *  The devolpment page for this driver is located at
 *  http://code.google.com/p/aceracpi
 *
 *  Credits:
 *
 *  John Belmonte - the Toshiba ACPI driver I've adapted for this module.
 *  Julien Lerouge & Karol Kozimor - ASUS Acpi driver authors.
 *  Olaf Tauber - developer of acerhk, the inspiration to solve the 64-bit
 *                driver problem for my Aspire 5024.
 *  Mathieu Segaud - solved the ACPI problem that needed a double-modprobe
 *                   in version 0.2 and below.
 *  Carlos Corbacho - added initial status support for wireless/ mail/
 *                    bluetooth, added module parameter support to turn
 *                    hardware/ LEDs on and off at module loading (thanks
 *                    again to acerhk for the inspiration)
 *  Jim Ramsay - Figured out and added support for WMID interface
 *
 */

#define ACER_ACPI_VERSION       "0.6"
#define PROC_INTERFACE_VERSION  1
#define PROC_ACER               "acer"

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/delay.h>
#include <linux/suspend.h>
#include <asm/uaccess.h>

#include <acpi/acpi_drivers.h>

MODULE_AUTHOR("Mark Smith");
MODULE_DESCRIPTION("Acer Laptop ACPI Extras Driver");
MODULE_LICENSE("GPL");

#define MY_LOGPREFIX "acer_acpi: "
#define MY_ERR KERN_ERR MY_LOGPREFIX
#define MY_NOTICE KERN_NOTICE MY_LOGPREFIX
#define MY_INFO KERN_INFO MY_LOGPREFIX

#define DEBUG(level, message...) { \
        if (debug >= level) \
                printk(KERN_DEBUG MY_LOGPREFIX message);\
}

/*
 * On the 5580, brightness values range from 0x0 to 0xf, inclusive.
 * This may vary on other machines.
 */
#define ACER_MAX_BRIGHTNESS 0xf

/*
 * Magic Number -
 * Meaning is unknown - this number is required for writing to ACPI
 * (it's also used in acerhk when directly accessing the EC)
 */
#define ACER_WRITE      0x9610

/*
 * Bit masks for the old AMW0 interface
 * These could vary between the particular interface
 */
#define ACER_AMW0_WIRELESS_MASK  0x35
#define ACER_AMW0_BLUETOOTH_MASK 0x34
#define ACER_AMW0_MAILLED_MASK   0x31

/*
 * Method IDs for new WMID interface
 * These could be different for other untested machines
 */
#define ACER_WMID_GET_WIRELESS_METHODID   1
#define ACER_WMID_GET_BLUETOOTH_METHODID  2
#define ACER_WMID_GET_BRIGHTNESS_METHODID 3
#define ACER_WMID_SET_WIRELESS_METHODID   4
#define ACER_WMID_SET_BLUETOOTH_METHODID  5
#define ACER_WMID_SET_BRIGHTNESS_METHODID 6
#define ACER_WMID_GET_THREEG_METHODID 10
#define ACER_WMID_SET_THREEG_METHODID 11

/*
 * Acer ACPI method paths 
 *
 * TODO: It may be possbile to autodetect these, since these are all at HID PNP0C14
 */
#define AMW0_METHOD             "\\_SB_.AMW0.WMAB"
#define AMW0_GETDATA            "\\_SB_.AMW0._WED"

#define WMID_METHOD             "\\_SB.WMID.WMBA"
#define WMID_GETDATA            "\\_SB.WMID._WED"

/*
 * Interface capability flags
 */
#define ACER_CAP_MAILLED    (1<<0)
#define ACER_CAP_WIRELESS   (1<<1)
#define ACER_CAP_BLUETOOTH  (1<<2)
#define ACER_CAP_BRIGHTNESS (1<<3)
#define ACER_CAP_THREEG     (1<<4)
#define ACER_CAP_ANY        (0xffffffff)

/*
 * Presumed start states -
 * For the old-style interfaces, there is no way to know for certain what the start state
 * is for any of the parameters (ACPI does not provide any methods or store this
 * anywhere). We therefore start with an unknown state (this is also how acerhk
 * does it); we then change the status so that we are in a known state (I
 * suspect LaunchManager on Windows does something similar, since the  wireless
 * appears to turn off as soon as it launches).
 *
 * Plus, we can't tell which features are enabled or disabled on a specific
 * model, just ranges - e.g. The 5020 series can _support_ bluetooth; but the
 * 5021 has no bluetooth, whilst the 5024 does.  However, the BIOS identifies
 * both laptops as 5020 - we can't tell them apart!
 *
 * Basically the code works like this:
 *   - On init, any values specified on the commandline are set.
 *   - For interfaces where the current values cannot be detected and which
 *     have not been set on the commandline, we set them to some sane default
 *     (disabled)
 *
 * See AMW0_init and acer_commandline_init
 */

#define ACER_DEFAULT_WIRELESS  0
#define ACER_DEFAULT_BLUETOOTH 0
#define ACER_DEFAULT_MAILLED   0
#define ACER_DEFAULT_THREEG    0
#define ACER_DEFAULT_BRIGHTNESS ACER_MAX_BRIGHTNESS

static int wireless = -1;
static int bluetooth = -1;
static int mailled = -1;
static int brightness = -1;
static int threeg = -1;
static int debug = 0;

module_param(mailled, int, 0444);
module_param(wireless, int, 0444);
module_param(bluetooth, int, 0444);
module_param(brightness, int, 0444);
module_param(threeg, int, 0444);
module_param(debug, int, 0664);
MODULE_PARM_DESC(wireless, "Set initial state of Wireless hardware");
MODULE_PARM_DESC(bluetooth, "Set initial state of Bluetooth hardware");
MODULE_PARM_DESC(mailled, "Set initial state of Mail LED");
MODULE_PARM_DESC(brightness, "Set initial LCD backlight brightness");
MODULE_PARM_DESC(threeg, "Set initial state of 3G hardware");
MODULE_PARM_DESC(debug, "Debugging verbosity level (0=least 2=most)");

typedef struct _ProcItem {
        const char *name;
        char *(*read_func) (char *, uint32_t);
        unsigned long (*write_func) (const char *, unsigned long, uint32_t);
        unsigned int capability;
} ProcItem;

struct acer_hotk {
        struct acpi_device *device;
        acpi_handle handle;
};

static struct proc_dir_entry *acer_proc_dir;

static int is_valid_acpi_path(const char *methodName)
{
        acpi_handle handle;
        acpi_status status;

        status = acpi_get_handle(NULL, (char *)methodName, &handle);
        return ACPI_SUCCESS(status);
}

/* Each low-level interface must define at least some of the following */
typedef struct _Interface {
        /*
         * The capabilities this interface provides
         * In the future, these can be removed/added at runtime when we have a
         * way of detecting what capabilities are /actually/ present on an
         * interface
         */
        uint32_t capability;

        /*
         * Initializes an interface, should allocate the interface-specific
         * data
         */
        acpi_status (*init) (struct _Interface*);

        /*
         * Frees an interface, should free the interface-specific data
         */
        void (*free) (struct _Interface*);

        /*
         * Gets and sets various data types.
         *   First paramater:  Value to set, or pointer to place got value into
         *   Second parameter: Specific capability being requested
         *   Third paramater: Pointer to this interface
         */
        acpi_status (*get_bool) (bool*, uint32_t, struct _Interface*);
        acpi_status (*set_bool) (bool, uint32_t, struct _Interface*);
        acpi_status (*get_u8) (uint8_t*, uint32_t, struct _Interface*);
        acpi_status (*set_u8) (uint8_t, uint32_t, struct _Interface*);

        /*
         * Interface-specific private data member.  Must *not* be touched by
         * anyone outside of this struct
         */
        void *data;
} Interface;

/* The static interface pointer, points to the currently detected interface */
static Interface *interface;

/*
 * General interface convenience methods
 */

/* These *_via_u8 use the interface's *_u8 methods to emulate other gets/sets */
static acpi_status get_bool_via_u8(bool *value, uint32_t cap, Interface *iface) {
        acpi_status status;
        uint8_t result;

        status = iface->get_u8(&result, cap, iface);

        if (ACPI_SUCCESS(status))
                *value = (result != 0);

        return status;
}

static acpi_status set_bool_via_u8(bool value, uint32_t cap, Interface *iface) {
        uint8_t v = value ? 1 : 0;

        return iface->set_u8(v, cap, iface);
}

/* General wrapper around the ACPI call */
static acpi_status
WMI_execute(char *methodPath, uint32_t methodId, const struct acpi_buffer *in, struct acpi_buffer *out) {
        struct acpi_object_list input;
        union acpi_object params[3];
        acpi_status status = AE_OK;

        /* WMI calling convention:
         *  methodPath( instance, methodId, input_buffer )
         *    - instance is always 1, since there's only this module
         *    - methodId is the method number within the current method group.
         *    - Input buffer is ignored for read-only commands
         *    - May return a buffer of results (optional)
         */
        input.count = 3;
        input.pointer = params;
        params[0].type = ACPI_TYPE_INTEGER;
        params[0].integer.value = 0x01;
        params[1].type = ACPI_TYPE_INTEGER;
        params[1].integer.value = methodId;
        params[2].type = ACPI_TYPE_BUFFER;
        params[2].buffer.length = in->length;
        params[2].buffer.pointer = in->pointer;

        DEBUG(2, "Doing %s( 1, %u, [%llu-byte buffer] )\n", methodPath, methodId, in->length);

        status = acpi_evaluate_object(NULL, methodPath, &input, out);

        DEBUG(2, "  Execution status: %d\n", status);
        DEBUG(2, "  Result: %llu bytes\n", out ? out->length : 0 );

        return status;
}


/*
 * Old interface (now known as the AMW0 interface)
 */
typedef struct _WMAB_args {
        u32 eax;
        u32 ebx;
        u32 ecx;
        u32 edx;
} WMAB_args;

typedef struct _AMW0_Data {
        int mailled;
        int wireless;
        int bluetooth;
} AMW0_Data;

static acpi_status WMAB_execute(WMAB_args * regbuf, struct acpi_buffer *result)
{
        struct acpi_buffer input;
        acpi_status status;
        input.length = sizeof(WMAB_args);
        input.pointer = (u8*)regbuf;

        status = WMI_execute( AMW0_METHOD, 1, &input, result);
        DEBUG(2, "  Args: 0x%08x 0x%08x 0x%08x 0x%08x\n", regbuf->eax, regbuf->ebx, regbuf->ecx, regbuf->edx );

        return status;
}

static acpi_status AMW0_init(Interface *iface) {
        WMAB_args args;
        acpi_status status;
        AMW0_Data *data;

        /* Allocate our private data structure */
        iface->data = kmalloc(sizeof(AMW0_Data), GFP_KERNEL);
        data = (AMW0_Data*)iface->data;

        /* 
         * Call the interface once so the BIOS knows it's to notify us of
         * events via PNP0C14
         */
        memset(&args, 0, sizeof(WMAB_args));
        args.eax = ACER_WRITE;
        args.ebx = 0;
        status = WMAB_execute(&args, NULL);

        /* 
         * If the commandline doesn't specify these, we need to force them to
         * the default values
         */
        if (mailled == -1)
                mailled = ACER_DEFAULT_MAILLED;
        if (wireless == -1)
                wireless = ACER_DEFAULT_WIRELESS;
        if (bluetooth == -1)
                bluetooth = ACER_DEFAULT_BLUETOOTH;

        /*
         * Set the cached "current" values to impossible ones so that
         * acer_commandline_init will definitely set them.
         */
        data->wireless = data->mailled = data->bluetooth = -1;

        return status;
}

static void AMW0_free(Interface *iface) {
        /* Free our private data structure */
        kfree(iface->data);
}

static acpi_status AMW0_get_bool(bool *value, uint32_t cap, Interface *iface)
{
        AMW0_Data *data = iface->data;

        /* Currently no way to query the state, so just return the cached value */
        switch (cap) {
                case ACER_CAP_MAILLED:
                        *value = data->mailled;
                        break;
                case ACER_CAP_WIRELESS:
                        *value = data->wireless;
                        break;
                case ACER_CAP_BLUETOOTH:
                        *value = data->bluetooth;
                        break;
                default:
                        return AE_BAD_ADDRESS;
        }
        return AE_OK;
}

static acpi_status AMW0_set_bool(bool value, uint32_t cap, Interface *iface)
{
        WMAB_args args;
        acpi_status status;

        args.eax = ACER_WRITE;
        args.ebx = value ? (1<<8) : 0;

        switch (cap) {
                case ACER_CAP_MAILLED:
                        args.ebx |= ACER_AMW0_MAILLED_MASK;
                        break;
                case ACER_CAP_WIRELESS:
                        args.ebx |= ACER_AMW0_WIRELESS_MASK;
                        break;
                case ACER_CAP_BLUETOOTH:
                        args.ebx |= ACER_AMW0_BLUETOOTH_MASK;
                        break;
                default:
                        return AE_BAD_ADDRESS;
        }

        /* Actually do the set */
        status = WMAB_execute(&args, NULL);

        /* 
         * Currently no way to query the state, so cache the new value on
         * success
         */
        if (ACPI_SUCCESS(status)) {
                AMW0_Data *data = iface->data;
                switch (cap) {
                        case ACER_CAP_MAILLED:
                                data->mailled = value;
                                break;
                        case ACER_CAP_WIRELESS:
                                data->wireless = value;
                                break;
                        case ACER_CAP_BLUETOOTH:
                                data->bluetooth = value;
                                break;
                }
        }

        return status;
}

static Interface AMW0_interface = {
        .capability = (
                ACER_CAP_MAILLED |
                ACER_CAP_WIRELESS |
                ACER_CAP_BLUETOOTH
        ),
        .init = AMW0_init,
        .free = AMW0_free,
        .get_bool = AMW0_get_bool,
        .set_bool = AMW0_set_bool,
};

/*
 * New interface (The WMID interface)
 */

static acpi_status
WMI_execute_uint32(uint32_t methodId, uint32_t in, uint32_t *out)
{       
        struct acpi_buffer input = { (acpi_size)sizeof(uint32_t), (void*)(&in) };
        struct acpi_buffer result = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *obj;
        uint32_t tmp;
        acpi_status status;

        status = WMI_execute(WMID_METHOD, methodId, &input, &result);
        DEBUG(2, "  In: 0x%08x\n", in);

        if (ACPI_FAILURE(status))
                return status;

        obj = (union acpi_object *)result.pointer;
        if (obj && obj->type == ACPI_TYPE_BUFFER && obj->buffer.length == sizeof(uint32_t)) {
                tmp = *((uint32_t*)obj->buffer.pointer);
                DEBUG(2, "  Out: 0x%08x\n", tmp);
        } else {
                tmp = 0;
                if (obj) {
                        DEBUG(2, "  Got unexpected result of type %d\n", obj->type);
                } else {
                        DEBUG(2, "  Got unexpected null result\n");
                }
        }

        if (out)
                *out = tmp;

        if (result.length > 0 && result.pointer)
                kfree(result.pointer);

        return status;
}

static acpi_status WMID_get_u8(uint8_t *value, uint32_t cap, Interface *iface) {
        acpi_status status;
        uint32_t result;
        uint32_t methodId = 0;

        switch (cap) {
                case ACER_CAP_WIRELESS:
                        methodId = ACER_WMID_GET_WIRELESS_METHODID;
                        break;
                case ACER_CAP_BLUETOOTH:
                        methodId = ACER_WMID_GET_BLUETOOTH_METHODID;
                        break;
                case ACER_CAP_BRIGHTNESS:
                        methodId = ACER_WMID_GET_BRIGHTNESS_METHODID;
                        break;
                case ACER_CAP_THREEG:
                        methodId = ACER_WMID_GET_THREEG_METHODID;
                        break;
                default:
                        return AE_BAD_ADDRESS;
        }
        status = WMI_execute_uint32(methodId, 0, &result);

        if (ACPI_SUCCESS(status))
                *value = (uint8_t)result;

        return status;
}

static acpi_status WMID_set_u8(uint8_t value, uint32_t cap, Interface *iface) {
        uint32_t methodId = 0;

        switch (cap) {
                case ACER_CAP_BRIGHTNESS:
                        methodId = ACER_WMID_SET_BRIGHTNESS_METHODID;
                        break;
                case ACER_CAP_WIRELESS:
                        methodId = ACER_WMID_SET_WIRELESS_METHODID;
                        break;
                case ACER_CAP_BLUETOOTH:
                        methodId = ACER_WMID_SET_BLUETOOTH_METHODID;
                case ACER_CAP_THREEG:
                        methodId = ACER_WMID_SET_THREEG_METHODID;
                        break;
                default:
                        return AE_BAD_ADDRESS;
        }
        return WMI_execute_uint32(methodId, (uint32_t)value, NULL);
}


static Interface WMID_interface = {
        .capability = (
                ACER_CAP_WIRELESS |
                ACER_CAP_BLUETOOTH |
                ACER_CAP_BRIGHTNESS |
                ACER_CAP_THREEG
        ),
        .get_bool = get_bool_via_u8,
        .set_bool = set_bool_via_u8,
        .get_u8 = WMID_get_u8,
        .set_u8 = WMID_set_u8,
        .data = NULL,
};

/*
 * High-level Procfs file handlers 
 */

static int
dispatch_read(char *page, char **start, off_t off, int count, int *eof,
              ProcItem * item)
{
        char *p = page;
        int len;

        if (off == 0)
                p = item->read_func(p, item->capability);

        /*
         * ISSUE: I don't understand this code 
         */
        len = (p - page);
        if (len <= off + count)
                *eof = 1;
        *start = page + off;
        len -= off;
        if (len > count)
                len = count;
        if (len < 0)
                len = 0;
        return len;
}

static int
dispatch_write(struct file *file, const char __user * buffer,
               unsigned long count, ProcItem * item)
{
        int result;
        char *tmp_buffer;

        /*
         * Arg buffer points to userspace memory, which can't be accessed
         * directly.  Since we're making a copy, zero-terminate the
         * destination so that sscanf can be used on it safely. 
         */
        tmp_buffer = kmalloc(count + 1, GFP_KERNEL);
        if (copy_from_user(tmp_buffer, buffer, count)) {
                result = -EFAULT;
        } else {
                tmp_buffer[count] = 0;
                result = item->write_func(tmp_buffer, count, item->capability);
        }
        kfree(tmp_buffer);
        return result;
}

/*
 * Generic Device (interface-independent)
 */

static acpi_status get_bool(bool *value, uint32_t cap) {
        acpi_status status = AE_BAD_ADDRESS;
        if (interface->get_bool)
                status = interface->get_bool(value, cap, interface);
        return status;
}

static acpi_status set_bool(int value, uint32_t cap) {
        acpi_status status = AE_BAD_PARAMETER;
        if ((value == 0 || value == 1) &&
                        (interface->capability & cap)) {
                if (interface->get_bool) {
                        /* If possible, only set if the value has changed */
                        bool actual;
                        status = interface->get_bool(&actual, cap, interface);
                        if (ACPI_SUCCESS(status) && actual == (bool)value)
                                return status;
                }
                if (interface->set_bool) 
                        status = interface->set_bool(value == 1, cap, interface);
        }
        return status;

}

static acpi_status get_u8(uint8_t *value, uint32_t cap) {
        acpi_status status = AE_BAD_ADDRESS;
        if (interface->get_u8)
                status = interface->get_u8(value, cap, interface);
        return status;
}

static acpi_status set_u8(uint8_t value, uint8_t min, uint8_t max, uint32_t cap) {
        acpi_status status = AE_BAD_PARAMETER;
        if ((value >= min && value <= max) &&
                        (interface->capability & cap) ) {
                if (interface->get_u8) {
                        /* If possible, only set if the value has changed */
                        uint8_t actual;
                        status = interface->get_u8(&actual, cap, interface);
                        if (ACPI_SUCCESS(status) && actual == value)
                                return status;
                }
                if (interface->set_u8) 
                        status = interface->set_u8(value, cap, interface);
        }
        return status;
}

/* Each _u8 needs a small wrapper that sets the boundary values */
static acpi_status set_brightness(uint8_t value)
{
        return set_u8(value, 0, ACER_MAX_BRIGHTNESS, ACER_CAP_BRIGHTNESS);
}

static void acpi_commandline_init(void)
{
        DEBUG(1, "Commandline args: mailled(%d) wireless(%d) bluetooth(%d) brightness(%d)\n",
                mailled, wireless, bluetooth, brightness);

        /* 
         * These will all fail silently if the value given is invalid, or the
         * capability isn't available on the given interface
         */
        set_bool(mailled, ACER_CAP_MAILLED);
        set_bool(wireless, ACER_CAP_WIRELESS);
        set_bool(bluetooth, ACER_CAP_BLUETOOTH);
        set_bool(threeg, ACER_CAP_THREEG);
        set_brightness((uint8_t)brightness);
}

/*
 * Procfs interface
 */
static char *read_bool(char *p, uint32_t cap)
{
        bool result;
        acpi_status status = get_bool(&result, cap);
        if (ACPI_SUCCESS(status))
                p += sprintf(p, "%d\n", result);
        else
                p += sprintf(p, "Read error" );
        return p;
}

static unsigned long write_bool(const char *buffer, unsigned long count, uint32_t cap)
{
        int value;

        /*
         * For now, we are still supporting the "enabled: %i" - this _will_ be deprecated in 0.7
         */
        if ((sscanf(buffer, " enabled : %i", &value) == 1
                                || sscanf(buffer, "%i", &value) == 1)) {
                acpi_status status = set_bool(value, cap);
                if (ACPI_FAILURE(status))
                        return -EINVAL;
        } else {
                return -EINVAL;
        }
        return count;
}

static char *read_u8(char *p, uint32_t cap)
{
        uint8_t result;
        acpi_status status = get_u8(&result, cap);
        if (ACPI_SUCCESS(status))
                p += sprintf(p, "%u\n", result);
        else
                p += sprintf(p, "Read error" );
        return p;
}

static unsigned long write_u8(const char *buffer, unsigned long count, uint32_t cap)
{
        int value;
        acpi_status (*set_method)(uint8_t);

        /* Choose the appropriate set_u8 wrapper here, based on the capability */
        switch (cap) {
                case ACER_CAP_BRIGHTNESS:
                        set_method = set_brightness;
                        break;
                default:
                        return -EINVAL;
        };

        if (sscanf(buffer, "%i", &value) == 1) {
                acpi_status status = (*set_method)(value);
                if (ACPI_FAILURE(status))
                        return -EINVAL;
        } else {
                return -EINVAL;
        }
        return count;
}

static char *read_version(char *p, uint32_t cap)
{
        p += sprintf(p, "driver:                  %s\n", ACER_ACPI_VERSION);
        p += sprintf(p, "proc_interface:          %d\n",
                        PROC_INTERFACE_VERSION);
        return p;
}

ProcItem proc_items[] = {
        {"mailled", read_bool, write_bool, ACER_CAP_MAILLED},
        {"bluetooth", read_bool, write_bool, ACER_CAP_BLUETOOTH},
        {"wireless", read_bool, write_bool, ACER_CAP_WIRELESS},
        {"brightness", read_u8, write_u8, ACER_CAP_BRIGHTNESS},
        {"threeg", read_bool, write_bool, ACER_CAP_THREEG},
        {"version", read_version, NULL, ACER_CAP_ANY},
        {NULL}
};

static acpi_status __init add_proc_entries(void)
{
        struct proc_dir_entry *proc;
        ProcItem *item;

        for (item = proc_items; item->name; ++item) {
                /* 
                 * Only add the proc file if the current interface actually
                 * supports it
                 */
                if (interface->capability & item->capability) {
                        proc = create_proc_read_entry(item->name,
                                        S_IFREG | S_IRUGO | S_IWUSR,
                                        acer_proc_dir,
                                        (read_proc_t *) dispatch_read,
                                        item);
                        if (proc)
                                proc->owner = THIS_MODULE;
                        if (proc && item->write_func)
                                proc->write_proc = (write_proc_t *) dispatch_write;
                }
        }

        return AE_OK;
}

static acpi_status __exit remove_proc_entries(void)
{
        ProcItem *item;

        for (item = proc_items; item->name; ++item)
                remove_proc_entry(item->name, acer_proc_dir);
        return AE_OK;
}

/*
 * TODO: make this actually do useful stuff, if we ever see events 
 */
static void acer_acerkeys_notify(acpi_handle handle, u32 event, void *data)
{
        struct acer_hotk *hotk = (struct acer_hotk *)data;

        if (!hotk)
                return;
        printk(MY_ERR "Got an event!! %X", event);

        return;
}

static int acpi_acerkeys_add(struct acpi_device *device)
{
        struct acer_hotk *hotk = NULL;
        acpi_status status = AE_OK;

        if (!device)
                return -EINVAL;

        hotk =
                (struct acer_hotk *)kmalloc(sizeof(struct acer_hotk), GFP_KERNEL);
        if (!hotk)
                return -ENOMEM;
        memset(hotk, 0, sizeof(struct acer_hotk));
        hotk->handle = device->handle;
        strcpy(acpi_device_name(device), "Acer Laptop ACPI Extras");
        strcpy(acpi_device_class(device), "hkey");
        acpi_driver_data(device) = hotk;
        hotk->device = device;

        status = acpi_install_notify_handler(hotk->handle, ACPI_SYSTEM_NOTIFY,
                        acer_acerkeys_notify, hotk);
        if (ACPI_FAILURE(status))
                printk(MY_ERR "Error installing notify handler.\n");
        return 0;
}

static int acpi_acerkeys_remove(struct acpi_device *device, int type)
{
        acpi_status status = 0;
        struct acer_hotk *hotk = NULL;

        if (!device || !acpi_driver_data(device))
                return -EINVAL;
        hotk = (struct acer_hotk *)acpi_driver_data(device);

        status = acpi_remove_notify_handler(hotk->handle, ACPI_SYSTEM_NOTIFY,
                        acer_acerkeys_notify);
        if (ACPI_FAILURE(status))
                printk(MY_ERR "Error removing notify handler.\n");
        kfree(hotk);

        return 0;
}

static struct acpi_driver acpi_acerkeys = {
        .name = "acer_acpi",
        .class = "hotkey",
        .ids = "PNP0C14",
        .ops = {
                .add = acpi_acerkeys_add,
                .remove = acpi_acerkeys_remove,
        },
};

static int __init acer_acpi_init(void)
{
        acpi_status status = AE_OK;

        printk(MY_INFO "Acer Laptop ACPI Extras version %s\n",
                        ACER_ACPI_VERSION);
        if (acpi_disabled) {
                printk(MY_ERR "ACPI Disabled, unable to load.\n");
                return -ENODEV;
        }

        /*
         * Detect which WMI interface we're using.
         *
         * TODO: This could be more dynamic, and perhaps done in part by the
         *       acpi_bus driver?
         */
        if (is_valid_acpi_path(AMW0_METHOD)) {
                DEBUG(0, "Detected ACER AMW0 interface\n");
                interface = &AMW0_interface;
        } else if (is_valid_acpi_path(WMID_METHOD)) {
                DEBUG(0, "Detected ACER WMID interface\n");
                interface = &WMID_interface;
        } else {
                printk(MY_ERR "No or unsupported WMI interface, unable to load.\n");
                goto error_no_interface;
        }

        /* Now that we have a known interface, initialize it */
        if (interface->init) {
                status = interface->init(interface);
                if (ACPI_FAILURE(status)) {
                        printk(MY_ERR "Interface initialization failed.\n");
                        goto error_interface_init;
                }
        }

        /* Create the proc entries */
        acer_proc_dir = proc_mkdir(PROC_ACER, acpi_root_dir);
        if (!acer_proc_dir) {
                printk(MY_ERR "Unable to create /proc entries, aborting.\n");
                goto error_proc_mkdir;
        }

        acer_proc_dir->owner = THIS_MODULE;
        status = add_proc_entries();
        if (ACPI_FAILURE(status)) {
                printk(MY_ERR "Unable to create /proc entries, aborting.\n");
                goto error_proc_add;
        }

        /*
         * Register the hotkeys driver
         *
         * TODO: Does this do anything?  Can we use the bus detection code to
         *       check for the interface or all or part of the method ID path?
         */
        status = acpi_bus_register_driver(&acpi_acerkeys);
        if (ACPI_FAILURE(status)) {
                printk(MY_ERR "Unable to register driver, aborting.\n");
                goto error_acpi_bus_register;
        }

        /* Finally, override any initial settings with values from the commandline */
        acpi_commandline_init();

        return 0;

error_acpi_bus_register:
        remove_proc_entries();
error_proc_add:
        if (acer_proc_dir)
                remove_proc_entry(PROC_ACER, acpi_root_dir);
error_proc_mkdir:
        if (interface->free)
                interface->free(interface);
error_interface_init:
error_no_interface:
        return -ENODEV;
}

static void __exit acer_acpi_exit(void)
{
        acpi_bus_unregister_driver(&acpi_acerkeys);

        remove_proc_entries();

        if (acer_proc_dir)
                remove_proc_entry(PROC_ACER, acpi_root_dir);

        if (interface->free)
                interface->free(interface);

        printk(MY_INFO "Acer Laptop ACPI Extras unloaded\n");
        return;
}

module_init(acer_acpi_init);
module_exit(acer_acpi_exit);