Quelle  xo15-ebook.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  OLPC XO-1.5 ebook switch driver
 *  (based on generic ACPI button driver)
 *
 *  Copyright (C) 2009 Paul Fox <pgf@laptop.org>
 *  Copyright (C) 2010 One Laptop per Child
 */

#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 <linux/acpi.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"

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_handle_debug(device->handle,
      "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)
{
 const struct acpi_device_id *id;
 struct ebook_switch *button;
 struct input_dev *input;
 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;
 }

 id = acpi_match_acpi_device(ebook_device_ids, device);
 if (!id) {
  dev_err(&device->dev, "Unsupported hid\n");
  error = -ENODEV;
  goto err_free_input;
 }

 strscpy(acpi_device_name(device), XO15_EBOOK_DEVICE_NAME);
 strscpy(acpi_device_class(device), XO15_EBOOK_CLASS "/" XO15_EBOOK_SUBCLASS);

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

 input->name = acpi_device_name(device);
 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 void ebook_switch_remove(struct acpi_device *device)
{
 struct ebook_switch *button = acpi_driver_data(device);

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

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);