Android6.0 按键kl文件加载过程分析

在之前按键过程分析的几篇博客中，我分析过关于按键kl文件的加载，但是讲的不是非常详细，这篇博客主要把kl文件加载过程单独拉出来分析下。

1. 获取InputDeviceIdentifier的name 以及 Device的创建

InputDeviceIdentifier的name 非常重要，后面寻找idc kl kcm文件都需要这个name。

我们看下面的调用流程EventHub::getEvents -> EventHub::scanDevicesLocked -> EventHub::scanDirLocked -> EventHub::openDeviceLocked

我们来看EventHub::openDeviceLocked函数，先是打开devicePath，然后利用ioctl获取InputDeviceIdentifier的name

status_t EventHub::openDeviceLocked(const char *devicePath) {
char buffer[80];

ALOGE("Opening device: %s", devicePath);

int fd = open(devicePath, O_RDWR | O_CLOEXEC);
if(fd < 0) {
ALOGE("could not open %s, %s\n", devicePath, strerror(errno));
return -1;
}

InputDeviceIdentifier identifier;

// Get device name.
if(ioctl(fd, EVIOCGNAME(sizeof(buffer) - 1), &buffer) < 1) {
//fprintf(stderr, "could not get device name for %s, %s\n", devicePath, strerror(errno));
} else {
buffer[sizeof(buffer) - 1] = '\0';
identifier.name.setTo(buffer);
}

下面创建了Device，各种打印。

Device* device = new Device(fd, deviceId, String8(devicePath), identifier);

ALOGW("add device %d: %s\n", deviceId, devicePath);
ALOGW("  bus:        %04x\n"
"  vendor      %04x\n"
"  product     %04x\n"
"  version     %04x\n",
identifier.bus, identifier.vendor, identifier.product, identifier.version);
ALOGW("  name:       \"%s\"\n", identifier.name.string());
ALOGW("  location:   \"%s\"\n", identifier.location.string());
ALOGW("  unique id:  \"%s\"\n", identifier.uniqueId.string());
ALOGW("  descriptor: \"%s\"\n", identifier.descriptor.string());
ALOGW("  driver:     v%d.%d.%d\n",
driverVersion >> 16, (driverVersion >> 8) & 0xff, driverVersion & 0xff);

// Load the configuration file for the device.
loadConfigurationLocked(device);

先来看下打印

EventHub: Opening device: /dev/input/event4
EventHub: Created descriptor: raw=:0000:0000:name:comip_snd_soc Headset, cooked=2efc90e2a7d3beb2de2b795a507e8489f0acd57f
EventHub: add device 1: /dev/input/event4
EventHub:   bus:        0000
EventHub:   vendor      0000
EventHub:   product     0000
EventHub:   version     0000
EventHub:   name:       "comip_snd_soc Headset"
EventHub:   location:   "ALSA"
EventHub:   unique id:  ""
EventHub:   descriptor: "2efc90e2a7d3beb2de2b795a507e8489f0acd57f"
EventHub:   driver:     v1.0.1

2. 加载idc文件

在我们的设备中，一般没有定义自己的idc文件，也就找不到。一般定义idc文件，是在这个文件中定义kl 和kcm文件。

我们再来分析下loadConfigurationLocked函数，调用getInputDeviceConfigurationFilePathByDeviceIdentifier函数，当configurationFile不为空的时候，调用PropertyMap::load加载idc文件，这部分代码是在system/libutil下面的，当有这个idc文件的时候，device->configuration就不为空。

void EventHub::loadConfigurationLocked(Device* device) {
device->configurationFile = getInputDeviceConfigurationFilePathByDeviceIdentifier(
device->identifier, INPUT_DEVICE_CONFIGURATION_FILE_TYPE_CONFIGURATION);
if (device->configurationFile.isEmpty()) {//configurationFile为空
ALOGD("No input device configuration file found for device '%s'.",
device->identifier.name.string());
} else {//如果有configurationFile文件，那我们就调用PropertyMap::load函数
ALOGD("input device configuration file name '%s'.",
device->configurationFile.string());
status_t status = PropertyMap::load(device->configurationFile,
&device->configuration);
if (status) {
ALOGE("Error loading input device configuration file for device '%s'.  "
"Using default configuration.",
device->identifier.name.string());
}
}
}

调用了getInputDeviceConfigurationFilePathByDeviceIdentifier函数，其中type为0，代表是idc文件

String8 getInputDeviceConfigurationFilePathByDeviceIdentifier(
const InputDeviceIdentifier& deviceIdentifier,
InputDeviceConfigurationFileType type) {
if (deviceIdentifier.vendor !=0 && deviceIdentifier.product != 0) {//不进入这个分支
if (deviceIdentifier.version != 0) {
// Try vendor product version.
String8 versionPath(getInputDeviceConfigurationFilePathByName(
String8::format("Vendor_%04x_Product_%04x_Version_%04x",
deviceIdentifier.vendor, deviceIdentifier.product,
deviceIdentifier.version),
type));
if (!versionPath.isEmpty()) {
return versionPath;
}
}

// Try vendor product.
String8 productPath(getInputDeviceConfigurationFilePathByName(
String8::format("Vendor_%04x_Product_%04x",
deviceIdentifier.vendor, deviceIdentifier.product),
type));
if (!productPath.isEmpty()) {
return productPath;
}
}

// Try device name.
return getInputDeviceConfigurationFilePathByName(deviceIdentifier.name, type);
}

于是我们再来看getInputDeviceConfigurationFilePathByName函数：

String8 getInputDeviceConfigurationFilePathByName(
const String8& name, InputDeviceConfigurationFileType type) {
// Search system repository.
String8 path;
path.setTo(getenv("ANDROID_ROOT"));
path.append("/usr/");
appendInputDeviceConfigurationFileRelativePath(path, name, type);
ALOGD("Probing for system provided input device configuration file: path='%s'", path.string());
if (!access(path.string(), R_OK)) {
ALOGD("Found");
return path;
}

// Search user repository.
// TODO Should only look here if not in safe mode.
path.setTo(getenv("ANDROID_DATA"));
path.append("/system/devices/");
appendInputDeviceConfigurationFileRelativePath(path, name, type);
ALOGD("Probing for system user input device configuration file: path='%s'", path.string());
if (!access(path.string(), R_OK)) {
ALOGD("Found");
return path;
}

// Not found.
ALOGD("Probe failed to find input device configuration file: name='%s', type=%d",
name.string(), type);
return String8();
}

这个函数就是寻找各种匹配的idc文件，最后没找到就返回一个空的String。我们来看下appendInputDeviceConfigurationFileRelativePath函数

static void appendInputDeviceConfigurationFileRelativePath(String8& path,
const String8& name, InputDeviceConfigurationFileType type) {
path.append(CONFIGURATION_FILE_DIR[type]);
for (size_t i = 0; i < name.length(); i++) {
char ch = name[i];
if (!isValidNameChar(ch)) {
ch = '_';
}
path.append(&ch, 1);
}
path.append(CONFIGURATION_FILE_EXTENSION[type]);
}

static const char* CONFIGURATION_FILE_DIR[] = {
"idc/",
"keylayout/",
"keychars/",
};

static const char* CONFIGURATION_FILE_EXTENSION[] = {
".idc",
".kl",
".kcm",
};

这个函数就是用传进来的路径和名字，组成一个idc文件。然后在getInputDeviceConfigurationFilePathByName文件中看用appendInputDeviceConfigurationFileRelativePath文件组成的idc文件是否有这个文件，有那就找到了返回idc的文件路径，如果没有最后返回一个空的string。我们看我们的这段log。

InputDevice: Probing for system provided input device configuration file: path='/system/usr/idc/comip_snd_soc_Headset.idc'
InputDevice: Probing for system user input device configuration file: path='/data/system/devices/idc/comip_snd_soc_Headset.idc'
InputDevice: Probe failed to find input device configuration file: name='comip_snd_soc Headset', type=0
EventHub: No input device configuration file found for device 'comip_snd_soc Headset'.

这段log说明没有这样的idc文件。

root@lte26007:/system/usr/idc # ls
AVRCP.idc
qwerty.idc
qwerty2.idc

我们看我们手机上的idc目录，都是原生的，也就是framework/base/data下面的文件，都是原生的也就肯定找不到匹配的idc文件。idc文件中保存这kl kcm文件的名字。

下面是qwerty.idc文件，下面是它的内容，keyboard.layout代表kl的文件名，keyboard.characterMap代表kcm的文件名。

touch.deviceType = touchScreen
touch.orientationAware = 1

keyboard.layout = qwerty
keyboard.characterMap = qwerty
keyboard.orientationAware = 1
keyboard.builtIn = 1

cursor.mode = navigation
cursor.orientationAware = 1

3. 加载kl文件

加载kl 和 kcm文件是在openDeviceLocked函数中调用loadKeyMapLocked函数完成的。

那我们继续分析openDeviceLocked函数，关于加载kl文件的那部分代码：

status_t keyMapStatus = NAME_NOT_FOUND;
if (device->classes & (INPUT_DEVICE_CLASS_KEYBOARD | INPUT_DEVICE_CLASS_JOYSTICK)) {
// Load the keymap for the device.
keyMapStatus = loadKeyMapLocked(device);
}loadKeyMapLocked函数

status_t EventHub::loadKeyMapLocked(Device* device) {
return device->keyMap.load(device->identifier, device->configuration);
}

我们再来看load函数，前面我们的idc文件没有找到匹配的，因此第一个分支可以直接跳过，可以直接看probeKeyMap函数。

status_t KeyMap::load(const InputDeviceIdentifier& deviceIdenfifier,
const PropertyMap* deviceConfiguration) {
// Use the configured key layout if available.
if (deviceConfiguration) {
String8 keyLayoutName;
if (deviceConfiguration->tryGetProperty(String8("keyboard.layout"),
keyLayoutName)) {
status_t status = loadKeyLayout(deviceIdenfifier, keyLayoutName);
if (status == NAME_NOT_FOUND) {
ALOGE("Configuration for keyboard device '%s' requested keyboard layout '%s' but "
"it was not found.",
deviceIdenfifier.name.string(), keyLayoutName.string());
}
}

String8 keyCharacterMapName;
if (deviceConfiguration->tryGetProperty(String8("keyboard.characterMap"),
keyCharacterMapName)) {
status_t status = loadKeyCharacterMap(deviceIdenfifier, keyCharacterMapName);
if (status == NAME_NOT_FOUND) {
ALOGE("Configuration for keyboard device '%s' requested keyboard character "
"map '%s' but it was not found.",
deviceIdenfifier.name.string(), keyLayoutName.string());
}
}

if (isComplete()) {
return OK;
}
}

// Try searching by device identifier.
if (probeKeyMap(deviceIdenfifier, String8::empty())) {
return OK;
}

// Fall back on the Generic key map.
// TODO Apply some additional heuristics here to figure out what kind of
//      generic key map to use (US English, etc.) for typical external keyboards.
if (probeKeyMap(deviceIdenfifier, String8("Generic"))) {
return OK;
}

// Try the Virtual key map as a last resort.
if (probeKeyMap(deviceIdenfifier, String8("Virtual"))) {
return OK;
}

// Give up!
ALOGE("Could not determine key map for device '%s' and no default key maps were found!",
deviceIdenfifier.name.string());
return NAME_NOT_FOUND;
}

3.1 没有找到匹配InputDeviceIdentifier的name的kl文件 使用原生的Generic.kl文件

第一种情况是没有找到匹配InputDeviceIdentifier的name的kl文件，这个时候我们一般就用Generic.kl文件代替。

下面我们直接看probeKeyMap函数：

bool KeyMap::probeKeyMap(const InputDeviceIdentifier& deviceIdentifier,
const String8& keyMapName) {
if (!haveKeyLayout()) {//是否有kl文件
loadKeyLayout(deviceIdentifier, keyMapName);
}
if (!haveKeyCharacterMap()) {//是否有kcm文件
loadKeyCharacterMap(deviceIdentifier, keyMapName);
}
return isComplete();
}

先来看下isComplete函数，kl文件和kcm文件都有了才返回true，看load函数，当isComplete返回true，就直接return了，因为kl 和 kcm文件都找到了。

inline bool isComplete() const {
return haveKeyLayout() && haveKeyCharacterMap();
}

下面我们看下加载kl文件的过程，kcm文件的加载过程和kl类似我们就不看了。

status_t KeyMap::loadKeyLayout(const InputDeviceIdentifier& deviceIdentifier,
const String8& name) {
String8 path(getPath(deviceIdentifier, name,
INPUT_DEVICE_CONFIGURATION_FILE_TYPE_KEY_LAYOUT));
if (path.isEmpty()) {
return NAME_NOT_FOUND;
}
ALOGE("loadKeyLayout path '%s'.",
path.string());

status_t status = KeyLayoutMap::load(path, &keyLayoutMap);
if (status) {
return status;
}

keyLayoutFile.setTo(path);
return OK;
}

先看下getPath函数，第一个在load函数中调用loadKeyLayout的name是空的，所以这里就是用了getInputDeviceConfigurationFilePathByDeviceIdentifier函数。

String8 KeyMap::getPath(const InputDeviceIdentifier& deviceIdentifier,
const String8& name, InputDeviceConfigurationFileType type) {
return name.isEmpty()
? getInputDeviceConfigurationFilePathByDeviceIdentifier(deviceIdentifier, type)
: getInputDeviceConfigurationFilePathByName(name, type);
}

看下getInputDeviceConfigurationFilePathByDeviceIdentifier函数，第一部分就是各种Vendor之类的kl，我们没有走进这个分支。

String8 getInputDeviceConfigurationFilePathByDeviceIdentifier(
const InputDeviceIdentifier& deviceIdentifier,
InputDeviceConfigurationFileType type) {
if (deviceIdentifier.vendor !=0 && deviceIdentifier.product != 0) {
if (deviceIdentifier.version != 0) {
// Try vendor product version.
String8 versionPath(getInputDeviceConfigurationFilePathByName(
String8::format("Vendor_%04x_Product_%04x_Version_%04x",
deviceIdentifier.vendor, deviceIdentifier.product,
deviceIdentifier.version),
type));
if (!versionPath.isEmpty()) {
return versionPath;
}
}

// Try vendor product.
String8 productPath(getInputDeviceConfigurationFilePathByName(
String8::format("Vendor_%04x_Product_%04x",
deviceIdentifier.vendor, deviceIdentifier.product),
type));
if (!productPath.isEmpty()) {
return productPath;
}
}

// Try device name.
return getInputDeviceConfigurationFilePathByName(deviceIdentifier.name, type);
}

因此我们直接看下getInputDeviceConfigurationFilePathByName函数，和之前找idc那个函数一样，只是这里是用来找kl文件了

String8 getInputDeviceConfigurationFilePathByName(
const String8& name, InputDeviceConfigurationFileType type) {
// Search system repository.
String8 path;
path.setTo(getenv("ANDROID_ROOT"));
path.append("/usr/");
appendInputDeviceConfigurationFileRelativePath(path, name, type);
ALOGD("Probing for system provided input device configuration file: path='%s'", path.string());
if (!access(path.string(), R_OK)) {
ALOGD("Found");
return path;
}

// Search user repository.
// TODO Should only look here if not in safe mode.
path.setTo(getenv("ANDROID_DATA"));
path.append("/system/devices/");
appendInputDeviceConfigurationFileRelativePath(path, name, type);
ALOGD("Probing for system user input device configuration file: path='%s'", path.string());
if (!access(path.string(), R_OK)) {
ALOGD("Found");
return path;
}

// Not found.
ALOGD("Probe failed to find input device configuration file: name='%s', type=%d",
name.string(), type);
return String8();
}

之前我们的log中，这个name就是comip_snd_soc Headset，也没有找到。

EventHub:   name:       "comip_snd_soc Headset"

我们看下设备有哪些kl文件，确实没有comip_snd_soc Headset这个文件。

AVRCP.kl
Generic.kl
Vendor_0079_Product_0011.kl
Vendor_045e_Product_028e.kl
Vendor_046d_Product_b501.kl
Vendor_046d_Product_c216.kl
Vendor_046d_Product_c219.kl
Vendor_046d_Product_c21d.kl
Vendor_046d_Product_c21f.kl
Vendor_046d_Product_c294.kl
Vendor_046d_Product_c299.kl
Vendor_046d_Product_c532.kl
Vendor_054c_Product_0268.kl
Vendor_0583_Product_2060.kl
Vendor_05ac_Product_0239.kl
Vendor_0b05_Product_4500.kl
Vendor_1038_Product_1412.kl
Vendor_12bd_Product_d015.kl
Vendor_1532_Product_0900.kl
Vendor_1689_Product_fd00.kl
Vendor_1689_Product_fd01.kl
Vendor_1689_Product_fe00.kl
Vendor_18d1_Product_2c40.kl
Vendor_18d1_Product_5018.kl
Vendor_1949_Product_0401.kl
Vendor_1bad_Product_f016.kl
Vendor_1bad_Product_f023.kl
Vendor_1bad_Product_f027.kl
Vendor_1bad_Product_f036.kl
Vendor_1d79_Product_0009.kl
Vendor_22b8_Product_093d.kl
Vendor_2378_Product_1008.kl
Vendor_2378_Product_100a.kl
comip-gpio-keys.kl
comip-keypad.kl
ft5x06.kl
h2w_headset.kl
qwerty.kl
sensor00fn11.kl

我们回过头在来看load函数调用的第二个probeKeyMap函数，是传入了Generic参数，

if (probeKeyMap(deviceIdenfifier, String8("Generic"))) {
return OK;
}

我们再来看看probeKeyMap函数，还是调用了loadKeyLayout函数

bool KeyMap::probeKeyMap(const InputDeviceIdentifier& deviceIdentifier,
const String8& keyMapName) {
if (!haveKeyLayout()) {
loadKeyLayout(deviceIdentifier, keyMapName);
}
if (!haveKeyCharacterMap()) {
loadKeyCharacterMap(deviceIdentifier, keyMapName);
}
return isComplete();
}

status_t KeyMap::loadKeyLayout(const InputDeviceIdentifier& deviceIdentifier,
const String8& name) {
String8 path(getPath(deviceIdentifier, name,
INPUT_DEVICE_CONFIGURATION_FILE_TYPE_KEY_LAYOUT));
if (path.isEmpty()) {
return NAME_NOT_FOUND;
}
ALOGE("kangchen  loadKeyLayout path '%s'.",
path.string());

status_t status = KeyLayoutMap::load(path, &keyLayoutMap);
if (status) {
return status;
}

keyLayoutFile.setTo(path);
return OK;
}

同样我们来看getPath函数，这个时候name不是空了，就调用getInputDeviceConfigurationFilePathByName函数

String8 KeyMap::getPath(const InputDeviceIdentifier& deviceIdentifier,
const String8& name, InputDeviceConfigurationFileType type) {
return name.isEmpty()
? getInputDeviceConfigurationFilePathByDeviceIdentifier(deviceIdentifier, type)
: getInputDeviceConfigurationFilePathByName(name, type);
}

getInputDeviceConfigurationFilePathByName函数，最后就在这个函数中找到了Generic.kl文件。

String8 getInputDeviceConfigurationFilePathByName(
const String8& name, InputDeviceConfigurationFileType type) {
// Search system repository.
String8 path;
path.setTo(getenv("ANDROID_ROOT"));
path.append("/usr/");
appendInputDeviceConfigurationFileRelativePath(path, name, type);
ALOGD("Probing for system provided input device configuration file: path='%s'", path.string());
if (!access(path.string(), R_OK)) {
ALOGD("Found");
return path;
}

// Search user repository.
// TODO Should only look here if not in safe mode.
path.setTo(getenv("ANDROID_DATA"));
path.append("/system/devices/");
appendInputDeviceConfigurationFileRelativePath(path, name, type);
ALOGD("Probing for system user input device configuration file: path='%s'", path.string());
if (!access(path.string(), R_OK)) {
ALOGD("Found");
return path;
}

// Not found.
ALOGD("Probe failed to find input device configuration file: name='%s', type=%d",
name.string(), type);
return String8();
}

找到kl文件后，我们会对这个文件在load函数中进行解析，这个我们就不分析了，就是把扫描码转换成按键码之类。

status_t KeyLayoutMap::load(const String8& filename, sp<KeyLayoutMap>* outMap) {
outMap->clear();

Tokenizer* tokenizer;
status_t status = Tokenizer::open(filename, &tokenizer);
if (status) {
ALOGE("Error %d opening key layout map file %s.", status, filename.string());
} else {
sp<KeyLayoutMap> map = new KeyLayoutMap();
if (!map.get()) {
ALOGE("Error allocating key layout map.");
status = NO_MEMORY;
} else {
#if DEBUG_PARSER_PERFORMANCE
nsecs_t startTime = systemTime(SYSTEM_TIME_MONOTONIC);
#endif
Parser parser(map.get(), tokenizer);
status = parser.parse();
#if DEBUG_PARSER_PERFORMANCE
nsecs_t elapsedTime = systemTime(SYSTEM_TIME_MONOTONIC) - startTime;
ALOGD("Parsed key layout map file '%s' %d lines in %0.3fms.",
tokenizer->getFilename().string(), tokenizer->getLineNumber(),
elapsedTime / 1000000.0);
#endif
if (!status) {
*outMap = map;
}
}
delete tokenizer;
}
return status;
}

下面的数字代表扫描码，而旁边的代码键值码。

key 113 VOLUME_MUTE
key 114 VOLUME_DOWN
key 115 VOLUME_UP
key 116 POWER这样就完成了kl文件的加载解析。我们看下这段的log

InputDevice: Probing for system provided input device configuration file: path='/system/usr/keylayout/comip_snd_soc_Headset.kl'
InputDevice: Probing for system user input device configuration file: path='/data/system/devices/keylayout/comip_snd_soc_Headset.kl'
InputDevice: Probe failed to find input device configuration file: name='comip_snd_soc Headset', type=1
InputDevice: Probing for system provided input device configuration file: path='/system/usr/keychars/comip_snd_soc_Headset.kcm'
InputDevice: Probing for system user input device configuration file: path='/data/system/devices/keychars/comip_snd_soc_Headset.kcm'
InputDevice: Probe failed to find input device configuration file: name='comip_snd_soc Headset', type=2
InputDevice: Probing for system provided input device configuration file: path='/system/usr/keylayout/Generic.kl'
InputDevice: Found
Keyboard: loadKeyLayout path '/system/usr/keylayout/Generic.kl'.
InputDevice: Probing for system provided input device configuration file: path='/system/usr/keychars/Generic.kcm'
InputDevice: Found
EventHub: Unable to disable kernel key repeat for /dev/input/event4: Function not implemented
EventHub: New device: id=1, fd=70, path='/dev/input/event4', name='comip_snd_soc Headset', classes=0x81, configuration='', keyLayout='/system/usr/keylayout/Generic.kl', keyCharacterMap='/system/usr/keychars/Generic.kcm', builtinKeyboard=false, wakeMechanism=EPOLLWAKEUP, usingClockIoctl=true

上面的例子是加载了Generic.kl文件，是因为在system/usr/keylayout下面没有找到合适的。

3.2 找到匹配InputDeviceIdentifier的name的kl文件

下面我们的例子是找到合适的kl文件的，我们来看下log，注意name是ft5x06

EventHub: Opening device: /dev/input/event3
EventHub: Created descriptor: raw=:0000:0000:name:ft5x06, cooked=f2706364e2849110ed562db0c53423b5027a6cc5
EventHub: add device 2: /dev/input/event3
EventHub:   bus:        0000
EventHub:   vendor      0000
EventHub:   product     0000
EventHub:   version     0000
EventHub:   name:       "ft5x06"
EventHub:   location:   ""
EventHub:   unique id:  ""
EventHub:   descriptor: "f2706364e2849110ed562db0c53423b5027a6cc5"
EventHub:   driver:     v1.0.1
InputDevice: Probing for system provided input device configuration file: path='/system/usr/idc/ft5x06.idc'
InputDevice: Probing for system user input device configuration file: path='/data/system/devices/idc/ft5x06.idc'
InputDevice: Probe failed to find input device configuration file: name='ft5x06', type=0
EventHub: No input device configuration file found for device 'ft5x06'.
InputDevice: Probing for system provided input device configuration file: path='/system/usr/keylayout/ft5x06.kl'
InputDevice: Found
Keyboard: loadKeyLayout path '/system/usr/keylayout/ft5x06.kl'.
InputDevice: Probing for system provided input device configuration file: path='/system/usr/keychars/ft5x06.kcm'
InputDevice: Probing for system user input device configuration file: path='/data/system/devices/keychars/ft5x06.kcm'
InputDevice: Probe failed to find input device configuration file: name='ft5x06', type=2
InputDevice: Probing for system provided input device configuration file: path='/system/usr/keychars/Generic.kcm'
InputDevice: Found
EventHub: Unable to disable kernel key repeat for /dev/input/event3: Function not implemented
EventHub: New device: id=2, fd=71, path='/dev/input/event3', name='ft5x06', classes=0x15, configuration='', keyLayout='/system/usr/keylayout/ft5x06.kl', keyCharacterMap='/system/usr/keychars/Generic.kcm', builtinKeyboard=false, wakeMechanism=EPOLLWAKEUP, usingClockIoctl=true

我们再来看设备中的kl文件，有ft5x06.kl文件，这样就找到了匹配的kl文件，而不用原生的Generic.kl了。

AVRCP.kl
Generic.kl
Vendor_0079_Product_0011.kl
Vendor_045e_Product_028e.kl
Vendor_046d_Product_b501.kl
Vendor_046d_Product_c216.kl
Vendor_046d_Product_c219.kl
Vendor_046d_Product_c21d.kl
Vendor_046d_Product_c21f.kl
Vendor_046d_Product_c294.kl
Vendor_046d_Product_c299.kl
Vendor_046d_Product_c532.kl
Vendor_054c_Product_0268.kl
Vendor_0583_Product_2060.kl
Vendor_05ac_Product_0239.kl
Vendor_0b05_Product_4500.kl
Vendor_1038_Product_1412.kl
Vendor_12bd_Product_d015.kl
Vendor_1532_Product_0900.kl
Vendor_1689_Product_fd00.kl
Vendor_1689_Product_fd01.kl
Vendor_1689_Product_fe00.kl
Vendor_18d1_Product_2c40.kl
Vendor_18d1_Product_5018.kl
Vendor_1949_Product_0401.kl
Vendor_1bad_Product_f016.kl
Vendor_1bad_Product_f023.kl
Vendor_1bad_Product_f027.kl
Vendor_1bad_Product_f036.kl
Vendor_1d79_Product_0009.kl
Vendor_22b8_Product_093d.kl
Vendor_2378_Product_1008.kl
Vendor_2378_Product_100a.kl
comip-gpio-keys.kl
comip-keypad.kl
ft5x06.kl
h2w_headset.kl
qwerty.kl
sensor00fn11.kl

4. 使用kl文件，将扫描码，转换成按键码：

之前我们在按键流程（一），已经讲解了按键最后到各个InputMapper中的process函数中处理，下面我们看这个函数，我们调用EventHub的mapKey来将扫描码转换成按键码。

void KeyboardInputMapper::process(const RawEvent* rawEvent) {
switch (rawEvent->type) {

case EV_KEY: {
int32_t scanCode = rawEvent->code;
int32_t usageCode = mCurrentHidUsage;
mCurrentHidUsage = 0;

if (isKeyboardOrGamepadKey(scanCode)) {
int32_t keyCode;
uint32_t flags;
if (getEventHub()->mapKey(getDeviceId(), scanCode, usageCode, &keyCode, &flags)) {//扫描码对应成按键码
keyCode = AKEYCODE_UNKNOWN;
flags = 0;
}
processKey(rawEvent->when, rawEvent->value != 0, keyCode, scanCode, flags);
}
break;
}
case EV_MSC: {
if (rawEvent->code == MSC_SCAN) {
mCurrentHidUsage = rawEvent->value;
}
break;
}
case EV_SYN: {
if (rawEvent->code == SYN_REPORT) {
mCurrentHidUsage = 0;
}
}
}
}

最后在processKey函数中，将发送到InputDispatch中做后续处理。这个我们在之前的博客中也分析过了。

我们再来看看mapKey函数，先处理的kcm，再处理kl的。

status_t EventHub::mapKey(int32_t deviceId,
int32_t scanCode, int32_t usageCode, int32_t metaState,
int32_t* outKeycode, int32_t* outMetaState, uint32_t* outFlags) const {
AutoMutex _l(mLock);
Device* device = getDeviceLocked(deviceId);
status_t status = NAME_NOT_FOUND;

if (device) {
// Check the key character map first.
sp<KeyCharacterMap> kcm = device->getKeyCharacterMap();
if (kcm != NULL) {
if (!kcm->mapKey(scanCode, usageCode, outKeycode)) {
*outFlags = 0;
status = NO_ERROR;
}
}

// Check the key layout next.
if (status != NO_ERROR && device->keyMap.haveKeyLayout()) {
if (!device->keyMap.keyLayoutMap->mapKey(
scanCode, usageCode, outKeycode, outFlags)) {
status = NO_ERROR;
}
}

if (status == NO_ERROR) {
if (kcm != NULL) {
kcm->tryRemapKey(*outKeycode, metaState, outKeycode, outMetaState);
} else {
*outMetaState = metaState;
}
}
}

if (status != NO_ERROR) {
*outKeycode = 0;
*outFlags = 0;
*outMetaState = metaState;
}

return status;
}至于详细分析kcm的mapKey和kl的mapKey放在以后分析了