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 <acpi/acpi_bus.h>
  22 #include <acpi/acpi_drivers.h>
  23
  24 #define MODULE_NAME "xo15-ebook"
  25
  26 #define XO15_EBOOK_CLASS                MODULE_NAME
  27 #define XO15_EBOOK_TYPE_UNKNOWN 0x00
  28 #define XO15_EBOOK_NOTIFY_STATUS        0x80
  29
  30 #define XO15_EBOOK_SUBCLASS             "ebook"
  31 #define XO15_EBOOK_HID                  "XO15EBK"
  32 #define XO15_EBOOK_DEVICE_NAME          "EBook Switch"
  33
  34 ACPI_MODULE_NAME(MODULE_NAME);
  35
  36 MODULE_DESCRIPTION("OLPC XO-1.5 ebook switch driver");
  37 MODULE_LICENSE("GPL");
  38
  39 static const struct acpi_device_id ebook_device_ids[] = {
  40         { XO15_EBOOK_HID, 0 },
  41         { "", 0 },
  42 };
  43 MODULE_DEVICE_TABLE(acpi, ebook_device_ids);
  44
  45 struct ebook_switch {
  46         struct input_dev *input;
  47         char phys[32];                  /* for input device */
  48 };
  49
  50 static int ebook_send_state(struct acpi_device *device)
  51 {
  52         struct ebook_switch *button = acpi_driver_data(device);
  53         unsigned long long state;
  54         acpi_status status;
  55
  56         status = acpi_evaluate_integer(device->handle, "EBK", NULL, &state);
  57         if (ACPI_FAILURE(status))
  58                 return -EIO;
  59
  60         /* input layer checks if event is redundant */
  61         input_report_switch(button->input, SW_TABLET_MODE, !state);
  62         input_sync(button->input);
  63         return 0;
  64 }
  65
  66 static void ebook_switch_notify(struct acpi_device *device, u32 event)
  67 {
  68         switch (event) {
  69         case ACPI_FIXED_HARDWARE_EVENT:
  70         case XO15_EBOOK_NOTIFY_STATUS:
  71                 ebook_send_state(device);
  72                 break;
  73         default:
  74                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  75                                   "Unsupported event [0x%x]\n", event));
  76                 break;
  77         }
  78 }
  79
  80 static int ebook_switch_resume(struct acpi_device *device)
  81 {
  82         return ebook_send_state(device);
  83 }
  84
  85 static int ebook_switch_add(struct acpi_device *device)
  86 {
  87         struct ebook_switch *button;
  88         struct input_dev *input;
  89         const char *hid = acpi_device_hid(device);
  90         char *name, *class;
  91         int error;
  92
  93         button = kzalloc(sizeof(struct ebook_switch), GFP_KERNEL);
  94         if (!button)
  95                 return -ENOMEM;
  96
  97         device->driver_data = button;
  98
  99         button->input = input = input_allocate_device();
 100         if (!input) {
 101                 error = -ENOMEM;
 102                 goto err_free_button;
 103         }
 104
 105         name = acpi_device_name(device);
 106         class = acpi_device_class(device);
 107
 108         if (strcmp(hid, XO15_EBOOK_HID)) {
 109                 pr_err("Unsupported hid [%s]\n", hid);
 110                 error = -ENODEV;
 111                 goto err_free_input;
 112         }
 113
 114         strcpy(name, XO15_EBOOK_DEVICE_NAME);
 115         sprintf(class, "%s/%s", XO15_EBOOK_CLASS, XO15_EBOOK_SUBCLASS);
 116
 117         snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
 118
 119         input->name = name;
 120         input->phys = button->phys;
 121         input->id.bustype = BUS_HOST;
 122         input->dev.parent = &device->dev;
 123
 124         input->evbit[0] = BIT_MASK(EV_SW);
 125         set_bit(SW_TABLET_MODE, input->swbit);
 126
 127         error = input_register_device(input);
 128         if (error)
 129                 goto err_free_input;
 130
 131         ebook_send_state(device);
 132
 133         if (device->wakeup.flags.valid) {
 134                 /* Button's GPE is run-wake GPE */
 135                 acpi_enable_gpe(device->wakeup.gpe_device,
 136                                 device->wakeup.gpe_number);
 137                 device_set_wakeup_enable(&device->dev, true);
 138         }
 139
 140         return 0;
 141
 142  err_free_input:
 143         input_free_device(input);
 144  err_free_button:
 145         kfree(button);
 146         return error;
 147 }
 148
 149 static int ebook_switch_remove(struct acpi_device *device, int type)
 150 {
 151         struct ebook_switch *button = acpi_driver_data(device);
 152
 153         input_unregister_device(button->input);
 154         kfree(button);
 155         return 0;
 156 }
 157
 158 static struct acpi_driver xo15_ebook_driver = {
 159         .name = MODULE_NAME,
 160         .class = XO15_EBOOK_CLASS,
 161         .ids = ebook_device_ids,
 162         .ops = {
 163                 .add = ebook_switch_add,
 164                 .resume = ebook_switch_resume,
 165                 .remove = ebook_switch_remove,
 166                 .notify = ebook_switch_notify,
 167         },
 168 };
 169
 170 static int __init xo15_ebook_init(void)
 171 {
 172         return acpi_bus_register_driver(&xo15_ebook_driver);
 173 }
 174
 175 static void __exit xo15_ebook_exit(void)
 176 {
 177         acpi_bus_unregister_driver(&xo15_ebook_driver);
 178 }
 179
 180 module_init(xo15_ebook_init);
 181 module_exit(xo15_ebook_exit);