Input: add generic support for sparse keymaps

More and more devices choose to reimplement support for sparse keymaps
first introduced by wistron driver. Move it into a library module so it
can be easily used by interested parties.

Reviewed-by: Anisse Astier <anisse@astier.eu>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

4 files changed, 281 insertions, 12 deletions

diff --git a/drivers/input/Kconfig b/drivers/input/Kconfig
index cd50c00ab20f..50af91ebd075 100644
--- a/drivers/input/Kconfig
+++ b/drivers/input/Kconfig
@@ -8,7 +8,7 @@ menu "Input device support"
 config INPUT
         tristate "Generic input layer (needed for keyboard, mouse, ...)" if EMBEDDED
         default y
-        ---help---
+        help
           Say Y here if you have any input device (mouse, keyboard, tablet,
           joystick, steering wheel ...) connected to your system and want
           it to be available to applications. This includes standard PS/2
@@ -27,8 +27,7 @@ if INPUT
 
 config INPUT_FF_MEMLESS
         tristate "Support for memoryless force-feedback devices"
-        default n
-        ---help---
+        help
           Say Y here if you have memoryless force-feedback input device
           such as Logitech WingMan Force 3D, ThrustMaster FireStorm Dual
           Power 2, or similar. You will also need to enable hardware-specific
@@ -52,12 +51,25 @@ config INPUT_POLLDEV
           To compile this driver as a module, choose M here: the
           module will be called input-polldev.
 
+config INPUT_SPARSEKMAP
+        tristate "Sparse keymap support library"
+        help
+          Say Y here if you are using a driver for an input
+          device that uses sparse keymap. This option is only
+          useful for out-of-tree drivers since in-tree drivers
+          select it automatically.
+
+          If unsure, say N.
+
+          To compile this driver as a module, choose M here: the
+          module will be called sparse-keymap.
+
 comment "Userland interfaces"
 
 config INPUT_MOUSEDEV
         tristate "Mouse interface" if EMBEDDED
         default y
-        ---help---
+        help
           Say Y here if you want your mouse to be accessible as char devices
           13:32+ - /dev/input/mouseX and 13:63 - /dev/input/mice as an
           emulated IntelliMouse Explorer PS/2 mouse. That way, all user space
@@ -73,7 +85,7 @@ config INPUT_MOUSEDEV_PSAUX
         bool "Provide legacy /dev/psaux device"
         default y
         depends on INPUT_MOUSEDEV
-        ---help---
+        help
           Say Y here if you want your mouse also be accessible as char device
           10:1 - /dev/psaux. The data available through /dev/psaux is exactly
           the same as the data from /dev/input/mice.
@@ -103,7 +115,7 @@ config INPUT_MOUSEDEV_SCREEN_Y
 
 config INPUT_JOYDEV
         tristate "Joystick interface"
-        ---help---
+        help
           Say Y here if you want your joystick or gamepad to be
           accessible as char device 13:0+ - /dev/input/jsX device.
 
@@ -125,7 +137,7 @@ config INPUT_EVDEV
 
 config INPUT_EVBUG
         tristate "Event debugging"
-        ---help---
+        help
           Say Y here if you have a problem with the input subsystem and
           want all events (keypresses, mouse movements), to be output to
           the system log. While this is useful for debugging, it's also
@@ -140,7 +152,7 @@ config INPUT_EVBUG
 config INPUT_APMPOWER
         tristate "Input Power Event -> APM Bridge" if EMBEDDED
         depends on INPUT && APM_EMULATION
-        ---help---
+        help
           Say Y here if you want suspend key events to trigger a user
           requested suspend through APM. This is useful on embedded
           systems where such behaviour is desired without userspace
diff --git a/drivers/input/Makefile b/drivers/input/Makefile
index 4c9c745a7020..7ad212d31f99 100644
--- a/drivers/input/Makefile
+++ b/drivers/input/Makefile
@@ -9,6 +9,7 @@ input-core-objs := input.o input-compat.o ff-core.o
 
 obj-$(CONFIG_INPUT_FF_MEMLESS)  += ff-memless.o
 obj-$(CONFIG_INPUT_POLLDEV)     += input-polldev.o
+obj-$(CONFIG_INPUT_SPARSEKMAP)  += sparse-keymap.o
 
 obj-$(CONFIG_INPUT_MOUSEDEV)    += mousedev.o
 obj-$(CONFIG_INPUT_JOYDEV)      += joydev.o
diff --git a/drivers/input/input-polldev.c b/drivers/input/input-polldev.c
index 6a2eb399b988..aa6713b4a988 100644
--- a/drivers/input/input-polldev.c
+++ b/drivers/input/input-polldev.c
@@ -212,7 +212,7 @@ EXPORT_SYMBOL(input_allocate_polled_device);
  * @dev: device to free
  *
  * The function frees memory allocated for polling device and drops
- * reference to the associated input device (if present).
+ * reference to the associated input device.
  */
 void input_free_polled_device(struct input_polled_dev *dev)
 {
@@ -258,6 +258,15 @@ int input_register_polled_device(struct input_polled_dev *dev)
                 return error;
         }
 
+        /*
+         * Take extra reference to the underlying input device so
+         * that it survives call to input_unregister_polled_device()
+         * and is deleted only after input_free_polled_device()
+         * has been invoked. This is needed to ease task of freeing
+         * sparse keymaps.
+         */
+        input_get_device(input);
+
         return 0;
 }
 EXPORT_SYMBOL(input_register_polled_device);
@@ -269,8 +278,6 @@ EXPORT_SYMBOL(input_register_polled_device);
  * The function unregisters previously registered polled input
  * device from input layer. Polling is stopped and device is
  * ready to be freed with call to input_free_polled_device().
- * Callers should not attempt to access dev->input pointer
- * after calling this function.
  */
 void input_unregister_polled_device(struct input_polled_dev *dev)
 {
@@ -278,7 +285,6 @@ void input_unregister_polled_device(struct input_polled_dev *dev)
                            &input_polldev_attribute_group);
 
         input_unregister_device(dev->input);
-        dev->input = NULL;
 }
 EXPORT_SYMBOL(input_unregister_polled_device);
 
diff --git a/drivers/input/sparse-keymap.c b/drivers/input/sparse-keymap.c
new file mode 100644
index 000000000000..fbd3987af57f
--- /dev/null
+++ b/drivers/input/sparse-keymap.c
@@ -0,0 +1,250 @@
+/*
+ * Generic support for sparse keymaps
+ *
+ * Copyright (c) 2009 Dmitry Torokhov
+ *
+ * Derived from wistron button driver:
+ * Copyright (C) 2005 Miloslav Trmac <mitr@volny.cz>
+ * Copyright (C) 2005 Bernhard Rosenkraenzer <bero@arklinux.org>
+ * Copyright (C) 2005 Dmitry Torokhov <dtor@mail.ru>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/input.h>
+#include <linux/input/sparse-keymap.h>
+
+MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
+MODULE_DESCRIPTION("Generic support for sparse keymaps");
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION("0.1");
+
+/**
+ * sparse_keymap_entry_from_scancode - perform sparse keymap lookup
+ * @dev: Input device using sparse keymap
+ * @code: Scan code
+ *
+ * This function is used to perform &struct key_entry lookup in an
+ * input device using sparse keymap.
+ */
+struct key_entry *sparse_keymap_entry_from_scancode(struct input_dev *dev,
+                                                    unsigned int code)
+{
+        struct key_entry *key;
+
+        for (key = dev->keycode; key->type != KE_END; key++)
+                if (code == key->code)
+                        return key;
+
+        return NULL;
+}
+EXPORT_SYMBOL(sparse_keymap_entry_from_scancode);
+
+/**
+ * sparse_keymap_entry_from_keycode - perform sparse keymap lookup
+ * @dev: Input device using sparse keymap
+ * @keycode: Key code
+ *
+ * This function is used to perform &struct key_entry lookup in an
+ * input device using sparse keymap.
+ */
+struct key_entry *sparse_keymap_entry_from_keycode(struct input_dev *dev,
+                                                   unsigned int keycode)
+{
+        struct key_entry *key;
+
+        for (key = dev->keycode; key->type != KE_END; key++)
+                if (key->type == KE_KEY && keycode == key->keycode)
+                        return key;
+
+        return NULL;
+}
+EXPORT_SYMBOL(sparse_keymap_entry_from_keycode);
+
+static int sparse_keymap_getkeycode(struct input_dev *dev,
+                                    int scancode, int *keycode)
+{
+        const struct key_entry *key =
+                        sparse_keymap_entry_from_scancode(dev, scancode);
+
+        if (key && key->type == KE_KEY) {
+                *keycode = key->keycode;
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
+static int sparse_keymap_setkeycode(struct input_dev *dev,
+                                    int scancode, int keycode)
+{
+        struct key_entry *key;
+        int old_keycode;
+
+        if (keycode < 0 || keycode > KEY_MAX)
+                return -EINVAL;
+
+        key = sparse_keymap_entry_from_scancode(dev, scancode);
+        if (key && key->type == KE_KEY) {
+                old_keycode = key->keycode;
+                key->keycode = keycode;
+                set_bit(keycode, dev->keybit);
+                if (!sparse_keymap_entry_from_keycode(dev, old_keycode))
+                        clear_bit(old_keycode, dev->keybit);
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
+/**
+ * sparse_keymap_setup - set up sparse keymap for an input device
+ * @dev: Input device
+ * @keymap: Keymap in form of array of &key_entry structures ending
+ *      with %KE_END type entry
+ * @setup: Function that can be used to adjust keymap entries
+ *      depending on device's deeds, may be %NULL
+ *
+ * The function calculates size and allocates copy of the original
+ * keymap after which sets up input device event bits appropriately.
+ * Before destroying input device allocated keymap should be freed
+ * with a call to sparse_keymap_free().
+ */
+int sparse_keymap_setup(struct input_dev *dev,
+                        const struct key_entry *keymap,
+                        int (*setup)(struct input_dev *, struct key_entry *))
+{
+        size_t map_size = 1; /* to account for the last KE_END entry */
+        const struct key_entry *e;
+        struct key_entry *map, *entry;
+        int i;
+        int error;
+
+        for (e = keymap; e->type != KE_END; e++)
+                map_size++;
+
+        map = kcalloc(map_size, sizeof (struct key_entry), GFP_KERNEL);
+        if (!map)
+                return -ENOMEM;
+
+        memcpy(map, keymap, map_size * sizeof (struct key_entry));
+
+        for (i = 0; i < map_size; i++) {
+                entry = &map[i];
+
+                if (setup) {
+                        error = setup(dev, entry);
+                        if (error)
+                                goto err_out;
+                }
+
+                switch (entry->type) {
+                case KE_KEY:
+                        __set_bit(EV_KEY, dev->evbit);
+                        __set_bit(entry->keycode, dev->keybit);
+                        break;
+
+                case KE_SW:
+                        __set_bit(EV_SW, dev->evbit);
+                        __set_bit(entry->sw.code, dev->swbit);
+                        break;
+                }
+        }
+
+        dev->keycode = map;
+        dev->keycodemax = map_size;
+        dev->getkeycode = sparse_keymap_getkeycode;
+        dev->setkeycode = sparse_keymap_setkeycode;
+
+        return 0;
+
+ err_out:
+        kfree(keymap);
+        return error;
+
+}
+EXPORT_SYMBOL(sparse_keymap_setup);
+
+/**
+ * sparse_keymap_free - free memory allocated for sparse keymap
+ * @dev: Input device using sparse keymap
+ *
+ * This function is used to free memory allocated by sparse keymap
+ * in an input device that was set up by sparse_keymap_setup().
+ */
+void sparse_keymap_free(struct input_dev *dev)
+{
+        kfree(dev->keycode);
+        dev->keycode = NULL;
+        dev->keycodemax = 0;
+        dev->getkeycode = NULL;
+        dev->setkeycode = NULL;
+}
+EXPORT_SYMBOL(sparse_keymap_free);
+
+/**
+ * sparse_keymap_report_entry - report event corresponding to given key entry
+ * @dev: Input device for which event should be reported
+ * @ke: key entry describing event
+ * @value: Value that should be reported (ignored by %KE_SW entries)
+ * @autorelease: Signals whether release event should be emitted for %KE_KEY
+ *      entries right after reporting press event, ignored by all other
+ *      entries
+ *
+ * This function is used to report input event described by given
+ * &struct key_entry.
+ */
+void sparse_keymap_report_entry(struct input_dev *dev, const struct key_entry *ke,
+                                unsigned int value, bool autorelease)
+{
+        switch (ke->type) {
+        case KE_KEY:
+                input_report_key(dev, ke->keycode, value);
+                input_sync(dev);
+                if (value && autorelease) {
+                        input_report_key(dev, ke->keycode, 0);
+                        input_sync(dev);
+                }
+                break;
+
+        case KE_SW:
+                value = ke->sw.value;
+                /* fall through */
+
+        case KE_VSW:
+                input_report_switch(dev, ke->sw.code, value);
+                break;
+        }
+}
+EXPORT_SYMBOL(sparse_keymap_report_entry);
+
+/**
+ * sparse_keymap_report_event - report event corresponding to given scancode
+ * @dev: Input device using sparse keymap
+ * @code: Scan code
+ * @value: Value that should be reported (ignored by %KE_SW entries)
+ * @autorelease: Signals whether release event should be emitted for %KE_KEY
+ *      entries right after reporting press event, ignored by all other
+ *      entries
+ *
+ * This function is used to perform lookup in an input device using sparse
+ * keymap and report corresponding event. Returns %true if lookup was
+ * successful and %false otherwise.
+ */
+bool sparse_keymap_report_event(struct input_dev *dev, unsigned int code,
+                                unsigned int value, bool autorelease)
+{
+        const struct key_entry *ke =
+                sparse_keymap_entry_from_scancode(dev, code);
+
+        if (ke) {
+                sparse_keymap_report_entry(dev, ke, value, autorelease);
+                return true;
+        }
+
+        return false;
+}
+EXPORT_SYMBOL(sparse_keymap_report_event);
+