xo15-ebook.c

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/*
 *  OLPC XO-1.5 ebook switch driver
 *  (based on generic ACPI button driver)
 *
 *  Copyright (C) 2009 Paul Fox <[email protected]>
 *  Copyright (C) 2010 One Laptop per Child
 *
 *  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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

#define MODULE_NAME "xo15-ebook"

#define XO15_EBOOK_CLASS        MODULE_NAME
#define XO15_EBOOK_TYPE_UNKNOWN 0x00
#define XO15_EBOOK_NOTIFY_STATUS    0x80

#define XO15_EBOOK_SUBCLASS     "ebook"
#define XO15_EBOOK_HID          "XO15EBK"
#define XO15_EBOOK_DEVICE_NAME      "EBook Switch"

ACPI_MODULE_NAME(MODULE_NAME);

MODULE_DESCRIPTION("OLPC XO-1.5 ebook switch driver");
MODULE_LICENSE("GPL");

static const struct acpi_device_id ebook_device_ids[] = {
    { XO15_EBOOK_HID, 0 },
    { "", 0 },
};
MODULE_DEVICE_TABLE(acpi, ebook_device_ids);

struct ebook_switch {
    struct input_dev *input;
    char phys[32];          /* for input device */
};

static int ebook_send_state(struct acpi_device *device)
{
    struct ebook_switch *button = acpi_driver_data(device);
    unsigned long long state;
    acpi_status status;

    status = acpi_evaluate_integer(device->handle, "EBK", NULL, &state);
    if (ACPI_FAILURE(status))
        return -EIO;

    /* input layer checks if event is redundant */
    input_report_switch(button->input, SW_TABLET_MODE, !state);
    input_sync(button->input);
    return 0;
}

static void ebook_switch_notify(struct acpi_device *device, u32 event)
{
    switch (event) {
    case ACPI_FIXED_HARDWARE_EVENT:
    case XO15_EBOOK_NOTIFY_STATUS:
        ebook_send_state(device);
        break;
    default:
        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                  "Unsupported event [0x%x]\n", event));
        break;
    }
}

#ifdef CONFIG_PM_SLEEP
static int ebook_switch_resume(struct device *dev)
{
    return ebook_send_state(to_acpi_device(dev));
}
#endif

static SIMPLE_DEV_PM_OPS(ebook_switch_pm, NULL, ebook_switch_resume);

static int ebook_switch_add(struct acpi_device *device)
{
    struct ebook_switch *button;
    struct input_dev *input;
    const char *hid = acpi_device_hid(device);
    char *name, *class;
    int error;

    button = kzalloc(sizeof(struct ebook_switch), GFP_KERNEL);
    if (!button)
        return -ENOMEM;

    device->driver_data = button;

    button->input = input = input_allocate_device();
    if (!input) {
        error = -ENOMEM;
        goto err_free_button;
    }

    name = acpi_device_name(device);
    class = acpi_device_class(device);

    if (strcmp(hid, XO15_EBOOK_HID)) {
        pr_err("Unsupported hid [%s]\n", hid);
        error = -ENODEV;
        goto err_free_input;
    }

    strcpy(name, XO15_EBOOK_DEVICE_NAME);
    sprintf(class, "%s/%s", XO15_EBOOK_CLASS, XO15_EBOOK_SUBCLASS);

    snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);

    input->name = name;
    input->phys = button->phys;
    input->id.bustype = BUS_HOST;
    input->dev.parent = &device->dev;

    input->evbit[0] = BIT_MASK(EV_SW);
    set_bit(SW_TABLET_MODE, input->swbit);

    error = input_register_device(input);
    if (error)
        goto err_free_input;

    ebook_send_state(device);

    if (device->wakeup.flags.valid) {
        /* Button's GPE is run-wake GPE */
        acpi_enable_gpe(device->wakeup.gpe_device,
                device->wakeup.gpe_number);
        device_set_wakeup_enable(&device->dev, true);
    }

    return 0;

 err_free_input:
    input_free_device(input);
 err_free_button:
    kfree(button);
    return error;
}

static int ebook_switch_remove(struct acpi_device *device, int type)
{
    struct ebook_switch *button = acpi_driver_data(device);

    input_unregister_device(button->input);
    kfree(button);
    return 0;
}

static struct acpi_driver xo15_ebook_driver = {
    .name = MODULE_NAME,
    .class = XO15_EBOOK_CLASS,
    .ids = ebook_device_ids,
    .ops = {
        .add = ebook_switch_add,
        .remove = ebook_switch_remove,
        .notify = ebook_switch_notify,
    },
    .drv.pm = &ebook_switch_pm,
};
module_acpi_driver(xo15_ebook_driver);