kernel/drivers/platform/x86/xo15-ebook.c

   1 /*
   2  *  OLPC XO-1.5 ebook switch driver
   3  *  (based on generic ACPI button driver)
   4  *
   5  *  Copyright (C) 2009 Paul Fox <pgf@laptop.org>
   6  *  Copyright (C) 2010 One Laptop per Child
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or (at
  11  *  your option) any later version.
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/types.h>
  20 #include <linux/input.h>
  21 #include <linux/acpi.h>
  22
  23 #define MODULE_NAME "xo15-ebook"
  24
  25 #define XO15_EBOOK_CLASS                MODULE_NAME
  26 #define XO15_EBOOK_TYPE_UNKNOWN 0x00
  27 #define XO15_EBOOK_NOTIFY_STATUS        0x80
  28
  29 #define XO15_EBOOK_SUBCLASS             "ebook"
  30 #define XO15_EBOOK_HID                  "XO15EBK"
  31 #define XO15_EBOOK_DEVICE_NAME          "EBook Switch"
  32
  33 ACPI_MODULE_NAME(MODULE_NAME);
  34
  35 MODULE_DESCRIPTION("OLPC XO-1.5 ebook switch driver");
  36 MODULE_LICENSE("GPL");
  37
  38 static const struct acpi_device_id ebook_device_ids[] = {
  39         { XO15_EBOOK_HID, 0 },
  40         { "", 0 },
  41 };
  42 MODULE_DEVICE_TABLE(acpi, ebook_device_ids);
  43
  44 struct ebook_switch {
  45         struct input_dev *input;
  46         char phys[32];                  /* for input device */
  47 };
  48
  49 static int ebook_send_state(struct acpi_device *device)
  50 {
  51         struct ebook_switch *button = acpi_driver_data(device);
  52         unsigned long long state;
  53         acpi_status status;
  54
  55         status = acpi_evaluate_integer(device->handle, "EBK", NULL, &state);
  56         if (ACPI_FAILURE(status))
  57                 return -EIO;
  58
  59         /* input layer checks if event is redundant */
  60         input_report_switch(button->input, SW_TABLET_MODE, !state);
  61         input_sync(button->input);
  62         return 0;
  63 }
  64
  65 static void ebook_switch_notify(struct acpi_device *device, u32 event)
  66 {
  67         switch (event) {
  68         case ACPI_FIXED_HARDWARE_EVENT:
  69         case XO15_EBOOK_NOTIFY_STATUS:
  70                 ebook_send_state(device);
  71                 break;
  72         default:
  73                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  74                                   "Unsupported event [0x%x]\n", event));
  75                 break;
  76         }
  77 }
  78
  79 #ifdef CONFIG_PM_SLEEP
  80 static int ebook_switch_resume(struct device *dev)
  81 {
  82         return ebook_send_state(to_acpi_device(dev));
  83 }
  84 #endif
  85
  86 static SIMPLE_DEV_PM_OPS(ebook_switch_pm, NULL, ebook_switch_resume);
  87
  88 static int ebook_switch_add(struct acpi_device *device)
  89 {
  90         struct ebook_switch *button;
  91         struct input_dev *input;
  92         const char *hid = acpi_device_hid(device);
  93         char *name, *class;
  94         int error;
  95
  96         button = kzalloc(sizeof(struct ebook_switch), GFP_KERNEL);
  97         if (!button)
  98                 return -ENOMEM;
  99
 100         device->driver_data = button;
 101
 102         button->input = input = input_allocate_device();
 103         if (!input) {
 104                 error = -ENOMEM;
 105                 goto err_free_button;
 106         }
 107
 108         name = acpi_device_name(device);
 109         class = acpi_device_class(device);
 110
 111         if (strcmp(hid, XO15_EBOOK_HID)) {
 112                 pr_err("Unsupported hid [%s]\n", hid);
 113                 error = -ENODEV;
 114                 goto err_free_input;
 115         }
 116
 117         strcpy(name, XO15_EBOOK_DEVICE_NAME);
 118         sprintf(class, "%s/%s", XO15_EBOOK_CLASS, XO15_EBOOK_SUBCLASS);
 119
 120         snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
 121
 122         input->name = name;
 123         input->phys = button->phys;
 124         input->id.bustype = BUS_HOST;
 125         input->dev.parent = &device->dev;
 126
 127         input->evbit[0] = BIT_MASK(EV_SW);
 128         set_bit(SW_TABLET_MODE, input->swbit);
 129
 130         error = input_register_device(input);
 131         if (error)
 132                 goto err_free_input;
 133
 134         ebook_send_state(device);
 135
 136         if (device->wakeup.flags.valid) {
 137                 /* Button's GPE is run-wake GPE */
 138                 acpi_enable_gpe(device->wakeup.gpe_device,
 139                                 device->wakeup.gpe_number);
 140                 device_set_wakeup_enable(&device->dev, true);
 141         }
 142
 143         return 0;
 144
 145  err_free_input:
 146         input_free_device(input);
 147  err_free_button:
 148         kfree(button);
 149         return error;
 150 }
 151
 152 static int ebook_switch_remove(struct acpi_device *device)
 153 {
 154         struct ebook_switch *button = acpi_driver_data(device);
 155
 156         input_unregister_device(button->input);
 157         kfree(button);
 158         return 0;
 159 }
 160
 161 static struct acpi_driver xo15_ebook_driver = {
 162         .name = MODULE_NAME,
 163         .class = XO15_EBOOK_CLASS,
 164         .ids = ebook_device_ids,
 165         .ops = {
 166                 .add = ebook_switch_add,
 167                 .remove = ebook_switch_remove,
 168                 .notify = ebook_switch_notify,
 169         },
 170         .drv.pm = &ebook_switch_pm,
 171 };
 172 module_acpi_driver(xo15_ebook_driver);