文章目录

前言
一、根据硬件修改设备树
- 输入事件定义源码
二、Linux Kernel中的LRADC驱动源码
- 1、Kernel内置的LRADC驱动源码
- 2、驱动测试
- - 驱动测试软件使用信号量的方法
  - - 测试失败--键值错误
  - 驱动测试软件使用轮询方式
  - - 测试失败，键值显示错误
- 3、另一个测试方式
- 4、测试软件的编译方法
三、改进
四、重新开始一个
- 新编一个驱动.ko
- 测试程序

前言

LRADC全称“低分辨率模拟数字转换器”，分辨率很低，如下原理图就只有6位分辨率（0~64）通过一个ADC引脚识别多个按键，可以极大的节省引脚资源。

KEY_ADC0：112–LRADC0
当按键按下时对应电压：

按下的按键	S1按键按下	S2按键按下	S3按键按下	S4按键按下
ADC检测到的电压	0.2V	0.4V	0.6V	0.8V

参考：https://blog.csdn.net/lengyuefeng212/article/details/120033179
参考：https://dandelioncloud.cn/article/details/1419660822644854785/
参考：https://blog.csdn.net/u012577474/article/details/103166505

一、根据硬件修改设备树

1、添加pinctrl节点

&lradc {vref-supply = <&reg_vcc3v0>;status = "okay";button@200 {label = "Volume Up";linux,code = <KEY_VOLUMEUP>;channel = <0>;voltage = <200000>;};button@400 {label = "Volume Down";linux,code = <KEY_VOLUMEDOWN>;channel = <0>;voltage = <400000>;};button@600 {label = "Select";linux,code = <KEY_SELECT>;channel = <0>;voltage = <600000>;};button@800 {label = "Start";linux,code = <KEY_OK>;channel = <0>;voltage = <800000>;};
};

linux,cod对应键值：

物理按键		16进制键值	10进制键值
S1按键	KEY_VOLUMEUP	0x73	115
S2按键	KEY_VOLUMEDOWN	0x72	114
S3按键	KEY_SELECT	0x161	353
S4按键	KEY_OK	0x160	352

输入事件定义源码

在上面有一个属性：linux,code = <KEY_OK>这个KEY_OK是在哪里定义的呢？

linux-zero-4.10.y/include/dt-bindings/input/linux-event-codes.h
linux-zero-4.10.y/arch/arm/boot/dts/include/dt-bindings/input/linux-event-codes.h

/** Input event codes**    *** IMPORTANT **** This file is not only included from C-code but also from devicetree source* files. As such this file MUST only contain comments and defines.** Copyright (c) 1999-2002 Vojtech Pavlik* Copyright (c) 2015 Hans de Goede <hdegoede@redhat.com>** 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.*/
#ifndef _UAPI_INPUT_EVENT_CODES_H
#define _UAPI_INPUT_EVENT_CODES_H/** Device properties and quirks*/#define INPUT_PROP_POINTER       0x00    /* needs a pointer */
#define INPUT_PROP_DIRECT       0x01    /* direct input devices */
#define INPUT_PROP_BUTTONPAD        0x02    /* has button(s) under pad */
#define INPUT_PROP_SEMI_MT      0x03    /* touch rectangle only */
#define INPUT_PROP_TOPBUTTONPAD     0x04    /* softbuttons at top of pad */
#define INPUT_PROP_POINTING_STICK   0x05    /* is a pointing stick */
#define INPUT_PROP_ACCELEROMETER    0x06    /* has accelerometer */#define INPUT_PROP_MAX           0x1f
#define INPUT_PROP_CNT          (INPUT_PROP_MAX + 1)/** Event types*/#define EV_SYN            0x00
#define EV_KEY          0x01
#define EV_REL          0x02
#define EV_ABS          0x03
#define EV_MSC          0x04
#define EV_SW           0x05
#define EV_LED          0x11
#define EV_SND          0x12
#define EV_REP          0x14
#define EV_FF           0x15
#define EV_PWR          0x16
#define EV_FF_STATUS        0x17
#define EV_MAX          0x1f
#define EV_CNT          (EV_MAX+1)/** Synchronization events.*/#define SYN_REPORT      0
#define SYN_CONFIG      1
#define SYN_MT_REPORT       2
#define SYN_DROPPED     3
#define SYN_MAX         0xf
#define SYN_CNT         (SYN_MAX+1)/** Keys and buttons** Most of the keys/buttons are modeled after USB HUT 1.12* (see http://www.usb.org/developers/hidpage).* Abbreviations in the comments:* AC - Application Control* AL - Application Launch Button* SC - System Control*/#define KEY_RESERVED       0
#define KEY_ESC         1
#define KEY_1           2
#define KEY_2           3
#define KEY_3           4
#define KEY_4           5
#define KEY_5           6
#define KEY_6           7
#define KEY_7           8
#define KEY_8           9
#define KEY_9           10
#define KEY_0           11
#define KEY_MINUS       12
#define KEY_EQUAL       13
#define KEY_BACKSPACE       14
#define KEY_TAB         15
#define KEY_Q           16
#define KEY_W           17
#define KEY_E           18
#define KEY_R           19
#define KEY_T           20
#define KEY_Y           21
#define KEY_U           22
#define KEY_I           23
#define KEY_O           24
#define KEY_P           25
#define KEY_LEFTBRACE       26
#define KEY_RIGHTBRACE      27
#define KEY_ENTER       28
#define KEY_LEFTCTRL        29
#define KEY_A           30
#define KEY_S           31
#define KEY_D           32
#define KEY_F           33
#define KEY_G           34
#define KEY_H           35
#define KEY_J           36
#define KEY_K           37
#define KEY_L           38
#define KEY_SEMICOLON       39
#define KEY_APOSTROPHE      40
#define KEY_GRAVE       41
#define KEY_LEFTSHIFT       42
#define KEY_BACKSLASH       43
#define KEY_Z           44
#define KEY_X           45
#define KEY_C           46
#define KEY_V           47
#define KEY_B           48
#define KEY_N           49
#define KEY_M           50
#define KEY_COMMA       51
#define KEY_DOT         52
#define KEY_SLASH       53
#define KEY_RIGHTSHIFT      54
#define KEY_KPASTERISK      55
#define KEY_LEFTALT     56
#define KEY_SPACE       57
#define KEY_CAPSLOCK        58
#define KEY_F1          59
#define KEY_F2          60
#define KEY_F3          61
#define KEY_F4          62
#define KEY_F5          63
#define KEY_F6          64
#define KEY_F7          65
#define KEY_F8          66
#define KEY_F9          67
#define KEY_F10         68
#define KEY_NUMLOCK     69
#define KEY_SCROLLLOCK      70
#define KEY_KP7         71
#define KEY_KP8         72
#define KEY_KP9         73
#define KEY_KPMINUS     74
#define KEY_KP4         75
#define KEY_KP5         76
#define KEY_KP6         77
#define KEY_KPPLUS      78
#define KEY_KP1         79
#define KEY_KP2         80
#define KEY_KP3         81
#define KEY_KP0         82
#define KEY_KPDOT       83#define KEY_ZENKAKUHANKAKU    85
#define KEY_102ND       86
#define KEY_F11         87
#define KEY_F12         88
#define KEY_RO          89
#define KEY_KATAKANA        90
#define KEY_HIRAGANA        91
#define KEY_HENKAN      92
#define KEY_KATAKANAHIRAGANA    93
#define KEY_MUHENKAN        94
#define KEY_KPJPCOMMA       95
#define KEY_KPENTER     96
#define KEY_RIGHTCTRL       97
#define KEY_KPSLASH     98
#define KEY_SYSRQ       99
#define KEY_RIGHTALT        100
#define KEY_LINEFEED        101
#define KEY_HOME        102
#define KEY_UP          103
#define KEY_PAGEUP      104
#define KEY_LEFT        105
#define KEY_RIGHT       106
#define KEY_END         107
#define KEY_DOWN        108
#define KEY_PAGEDOWN        109
#define KEY_INSERT      110
#define KEY_DELETE      111
#define KEY_MACRO       112
#define KEY_MUTE        113
#define KEY_VOLUMEDOWN      114
#define KEY_VOLUMEUP        115
#define KEY_POWER       116 /* SC System Power Down */
#define KEY_KPEQUAL     117
#define KEY_KPPLUSMINUS     118
#define KEY_PAUSE       119
#define KEY_SCALE       120 /* AL Compiz Scale (Expose) */#define KEY_KPCOMMA       121
#define KEY_HANGEUL     122
#define KEY_HANGUEL     KEY_HANGEUL
#define KEY_HANJA       123
#define KEY_YEN         124
#define KEY_LEFTMETA        125
#define KEY_RIGHTMETA       126
#define KEY_COMPOSE     127#define KEY_STOP     128 /* AC Stop */
#define KEY_AGAIN       129
#define KEY_PROPS       130 /* AC Properties */
#define KEY_UNDO        131 /* AC Undo */
#define KEY_FRONT       132
#define KEY_COPY        133 /* AC Copy */
#define KEY_OPEN        134 /* AC Open */
#define KEY_PASTE       135 /* AC Paste */
#define KEY_FIND        136 /* AC Search */
#define KEY_CUT         137 /* AC Cut */
#define KEY_HELP        138 /* AL Integrated Help Center */
#define KEY_MENU        139 /* Menu (show menu) */
#define KEY_CALC        140 /* AL Calculator */
#define KEY_SETUP       141
#define KEY_SLEEP       142 /* SC System Sleep */
#define KEY_WAKEUP      143 /* System Wake Up */
#define KEY_FILE        144 /* AL Local Machine Browser */
#define KEY_SENDFILE        145
#define KEY_DELETEFILE      146
#define KEY_XFER        147
#define KEY_PROG1       148
#define KEY_PROG2       149
#define KEY_WWW         150 /* AL Internet Browser */
#define KEY_MSDOS       151
#define KEY_COFFEE      152 /* AL Terminal Lock/Screensaver */
#define KEY_SCREENLOCK      KEY_COFFEE
#define KEY_ROTATE_DISPLAY  153 /* Display orientation for e.g. tablets */
#define KEY_DIRECTION       KEY_ROTATE_DISPLAY
#define KEY_CYCLEWINDOWS    154
#define KEY_MAIL        155
#define KEY_BOOKMARKS       156 /* AC Bookmarks */
#define KEY_COMPUTER        157
#define KEY_BACK        158 /* AC Back */
#define KEY_FORWARD     159 /* AC Forward */
#define KEY_CLOSECD     160
#define KEY_EJECTCD     161
#define KEY_EJECTCLOSECD    162
#define KEY_NEXTSONG        163
#define KEY_PLAYPAUSE       164
#define KEY_PREVIOUSSONG    165
#define KEY_STOPCD      166
#define KEY_RECORD      167
#define KEY_REWIND      168
#define KEY_PHONE       169 /* Media Select Telephone */
#define KEY_ISO         170
#define KEY_CONFIG      171 /* AL Consumer Control Configuration */
#define KEY_HOMEPAGE        172 /* AC Home */
#define KEY_REFRESH     173 /* AC Refresh */
#define KEY_EXIT        174 /* AC Exit */
#define KEY_MOVE        175
#define KEY_EDIT        176
#define KEY_SCROLLUP        177
#define KEY_SCROLLDOWN      178
#define KEY_KPLEFTPAREN     179
#define KEY_KPRIGHTPAREN    180
#define KEY_NEW         181 /* AC New */
#define KEY_REDO        182 /* AC Redo/Repeat */#define KEY_F13         183
#define KEY_F14         184
#define KEY_F15         185
#define KEY_F16         186
#define KEY_F17         187
#define KEY_F18         188
#define KEY_F19         189
#define KEY_F20         190
#define KEY_F21         191
#define KEY_F22         192
#define KEY_F23         193
#define KEY_F24         194#define KEY_PLAYCD       200
#define KEY_PAUSECD     201
#define KEY_PROG3       202
#define KEY_PROG4       203
#define KEY_DASHBOARD       204 /* AL Dashboard */
#define KEY_SUSPEND     205
#define KEY_CLOSE       206 /* AC Close */
#define KEY_PLAY        207
#define KEY_FASTFORWARD     208
#define KEY_BASSBOOST       209
#define KEY_PRINT       210 /* AC Print */
#define KEY_HP          211
#define KEY_CAMERA      212
#define KEY_SOUND       213
#define KEY_QUESTION        214
#define KEY_EMAIL       215
#define KEY_CHAT        216
#define KEY_SEARCH      217
#define KEY_CONNECT     218
#define KEY_FINANCE     219 /* AL Checkbook/Finance */
#define KEY_SPORT       220
#define KEY_SHOP        221
#define KEY_ALTERASE        222
#define KEY_CANCEL      223 /* AC Cancel */
#define KEY_BRIGHTNESSDOWN  224
#define KEY_BRIGHTNESSUP    225
#define KEY_MEDIA       226#define KEY_SWITCHVIDEOMODE  227 /* Cycle between available videooutputs (Monitor/LCD/TV-out/etc) */
#define KEY_KBDILLUMTOGGLE  228
#define KEY_KBDILLUMDOWN    229
#define KEY_KBDILLUMUP      230#define KEY_SEND     231 /* AC Send */
#define KEY_REPLY       232 /* AC Reply */
#define KEY_FORWARDMAIL     233 /* AC Forward Msg */
#define KEY_SAVE        234 /* AC Save */
#define KEY_DOCUMENTS       235#define KEY_BATTERY      236#define KEY_BLUETOOTH        237
#define KEY_WLAN        238
#define KEY_UWB         239#define KEY_UNKNOWN      240#define KEY_VIDEO_NEXT       241 /* drive next video source */
#define KEY_VIDEO_PREV      242 /* drive previous video source */
#define KEY_BRIGHTNESS_CYCLE    243 /* brightness up, after max is min */
#define KEY_BRIGHTNESS_AUTO 244 /* Set Auto Brightness: manualbrightness control is off,rely on ambient */
#define KEY_BRIGHTNESS_ZERO KEY_BRIGHTNESS_AUTO
#define KEY_DISPLAY_OFF     245 /* display device to off state */#define KEY_WWAN       246 /* Wireless WAN (LTE, UMTS, GSM, etc.) */
#define KEY_WIMAX       KEY_WWAN
#define KEY_RFKILL      247 /* Key that controls all radios */#define KEY_MICMUTE       248 /* Mute / unmute the microphone *//* Code 255 is reserved for special needs of AT keyboard driver */#define BTN_MISC        0x100
#define BTN_0           0x100
#define BTN_1           0x101
#define BTN_2           0x102
#define BTN_3           0x103
#define BTN_4           0x104
#define BTN_5           0x105
#define BTN_6           0x106
#define BTN_7           0x107
#define BTN_8           0x108
#define BTN_9           0x109#define BTN_MOUSE      0x110
#define BTN_LEFT        0x110
#define BTN_RIGHT       0x111
#define BTN_MIDDLE      0x112
#define BTN_SIDE        0x113
#define BTN_EXTRA       0x114
#define BTN_FORWARD     0x115
#define BTN_BACK        0x116
#define BTN_TASK        0x117#define BTN_JOYSTICK       0x120
#define BTN_TRIGGER     0x120
#define BTN_THUMB       0x121
#define BTN_THUMB2      0x122
#define BTN_TOP         0x123
#define BTN_TOP2        0x124
#define BTN_PINKIE      0x125
#define BTN_BASE        0x126
#define BTN_BASE2       0x127
#define BTN_BASE3       0x128
#define BTN_BASE4       0x129
#define BTN_BASE5       0x12a
#define BTN_BASE6       0x12b
#define BTN_DEAD        0x12f#define BTN_GAMEPAD        0x130
#define BTN_SOUTH       0x130
#define BTN_A           BTN_SOUTH
#define BTN_EAST        0x131
#define BTN_B           BTN_EAST
#define BTN_C           0x132
#define BTN_NORTH       0x133
#define BTN_X           BTN_NORTH
#define BTN_WEST        0x134
#define BTN_Y           BTN_WEST
#define BTN_Z           0x135
#define BTN_TL          0x136
#define BTN_TR          0x137
#define BTN_TL2         0x138
#define BTN_TR2         0x139
#define BTN_SELECT      0x13a
#define BTN_START       0x13b
#define BTN_MODE        0x13c
#define BTN_THUMBL      0x13d
#define BTN_THUMBR      0x13e#define BTN_DIGI       0x140
#define BTN_TOOL_PEN        0x140
#define BTN_TOOL_RUBBER     0x141
#define BTN_TOOL_BRUSH      0x142
#define BTN_TOOL_PENCIL     0x143
#define BTN_TOOL_AIRBRUSH   0x144
#define BTN_TOOL_FINGER     0x145
#define BTN_TOOL_MOUSE      0x146
#define BTN_TOOL_LENS       0x147
#define BTN_TOOL_QUINTTAP   0x148   /* Five fingers on trackpad */
#define BTN_TOUCH       0x14a
#define BTN_STYLUS      0x14b
#define BTN_STYLUS2     0x14c
#define BTN_TOOL_DOUBLETAP  0x14d
#define BTN_TOOL_TRIPLETAP  0x14e
#define BTN_TOOL_QUADTAP    0x14f   /* Four fingers on trackpad */#define BTN_WHEEL     0x150
#define BTN_GEAR_DOWN       0x150
#define BTN_GEAR_UP     0x151#define KEY_OK         0x160
#define KEY_SELECT      0x161
#define KEY_GOTO        0x162
#define KEY_CLEAR       0x163
#define KEY_POWER2      0x164
#define KEY_OPTION      0x165
#define KEY_INFO        0x166   /* AL OEM Features/Tips/Tutorial */
#define KEY_TIME        0x167
#define KEY_VENDOR      0x168
#define KEY_ARCHIVE     0x169
#define KEY_PROGRAM     0x16a   /* Media Select Program Guide */
#define KEY_CHANNEL     0x16b
#define KEY_FAVORITES       0x16c
#define KEY_EPG         0x16d
#define KEY_PVR         0x16e   /* Media Select Home */
#define KEY_MHP         0x16f
#define KEY_LANGUAGE        0x170
#define KEY_TITLE       0x171
#define KEY_SUBTITLE        0x172
#define KEY_ANGLE       0x173
#define KEY_ZOOM        0x174
#define KEY_MODE        0x175
#define KEY_KEYBOARD        0x176
#define KEY_SCREEN      0x177
#define KEY_PC          0x178   /* Media Select Computer */
#define KEY_TV          0x179   /* Media Select TV */
#define KEY_TV2         0x17a   /* Media Select Cable */
#define KEY_VCR         0x17b   /* Media Select VCR */
#define KEY_VCR2        0x17c   /* VCR Plus */
#define KEY_SAT         0x17d   /* Media Select Satellite */
#define KEY_SAT2        0x17e
#define KEY_CD          0x17f   /* Media Select CD */
#define KEY_TAPE        0x180   /* Media Select Tape */
#define KEY_RADIO       0x181
#define KEY_TUNER       0x182   /* Media Select Tuner */
#define KEY_PLAYER      0x183
#define KEY_TEXT        0x184
#define KEY_DVD         0x185   /* Media Select DVD */
#define KEY_AUX         0x186
#define KEY_MP3         0x187
#define KEY_AUDIO       0x188   /* AL Audio Browser */
#define KEY_VIDEO       0x189   /* AL Movie Browser */
#define KEY_DIRECTORY       0x18a
#define KEY_LIST        0x18b
#define KEY_MEMO        0x18c   /* Media Select Messages */
#define KEY_CALENDAR        0x18d
#define KEY_RED         0x18e
#define KEY_GREEN       0x18f
#define KEY_YELLOW      0x190
#define KEY_BLUE        0x191
#define KEY_CHANNELUP       0x192   /* Channel Increment */
#define KEY_CHANNELDOWN     0x193   /* Channel Decrement */
#define KEY_FIRST       0x194
#define KEY_LAST        0x195   /* Recall Last */
#define KEY_AB          0x196
#define KEY_NEXT        0x197
#define KEY_RESTART     0x198
#define KEY_SLOW        0x199
#define KEY_SHUFFLE     0x19a
#define KEY_BREAK       0x19b
#define KEY_PREVIOUS        0x19c
#define KEY_DIGITS      0x19d
#define KEY_TEEN        0x19e
#define KEY_TWEN        0x19f
#define KEY_VIDEOPHONE      0x1a0   /* Media Select Video Phone */
#define KEY_GAMES       0x1a1   /* Media Select Games */
#define KEY_ZOOMIN      0x1a2   /* AC Zoom In */
#define KEY_ZOOMOUT     0x1a3   /* AC Zoom Out */
#define KEY_ZOOMRESET       0x1a4   /* AC Zoom */
#define KEY_WORDPROCESSOR   0x1a5   /* AL Word Processor */
#define KEY_EDITOR      0x1a6   /* AL Text Editor */
#define KEY_SPREADSHEET     0x1a7   /* AL Spreadsheet */
#define KEY_GRAPHICSEDITOR  0x1a8   /* AL Graphics Editor */
#define KEY_PRESENTATION    0x1a9   /* AL Presentation App */
#define KEY_DATABASE        0x1aa   /* AL Database App */
#define KEY_NEWS        0x1ab   /* AL Newsreader */
#define KEY_VOICEMAIL       0x1ac   /* AL Voicemail */
#define KEY_ADDRESSBOOK     0x1ad   /* AL Contacts/Address Book */
#define KEY_MESSENGER       0x1ae   /* AL Instant Messaging */
#define KEY_DISPLAYTOGGLE   0x1af   /* Turn display (LCD) on and off */
#define KEY_BRIGHTNESS_TOGGLE   KEY_DISPLAYTOGGLE
#define KEY_SPELLCHECK      0x1b0   /* AL Spell Check */
#define KEY_LOGOFF      0x1b1   /* AL Logoff */#define KEY_DOLLAR       0x1b2
#define KEY_EURO        0x1b3#define KEY_FRAMEBACK      0x1b4   /* Consumer - transport controls */
#define KEY_FRAMEFORWARD    0x1b5
#define KEY_CONTEXT_MENU    0x1b6   /* GenDesc - system context menu */
#define KEY_MEDIA_REPEAT    0x1b7   /* Consumer - transport control */
#define KEY_10CHANNELSUP    0x1b8   /* 10 channels up (10+) */
#define KEY_10CHANNELSDOWN  0x1b9   /* 10 channels down (10-) */
#define KEY_IMAGES      0x1ba   /* AL Image Browser */#define KEY_DEL_EOL       0x1c0
#define KEY_DEL_EOS     0x1c1
#define KEY_INS_LINE        0x1c2
#define KEY_DEL_LINE        0x1c3#define KEY_FN         0x1d0
#define KEY_FN_ESC      0x1d1
#define KEY_FN_F1       0x1d2
#define KEY_FN_F2       0x1d3
#define KEY_FN_F3       0x1d4
#define KEY_FN_F4       0x1d5
#define KEY_FN_F5       0x1d6
#define KEY_FN_F6       0x1d7
#define KEY_FN_F7       0x1d8
#define KEY_FN_F8       0x1d9
#define KEY_FN_F9       0x1da
#define KEY_FN_F10      0x1db
#define KEY_FN_F11      0x1dc
#define KEY_FN_F12      0x1dd
#define KEY_FN_1        0x1de
#define KEY_FN_2        0x1df
#define KEY_FN_D        0x1e0
#define KEY_FN_E        0x1e1
#define KEY_FN_F        0x1e2
#define KEY_FN_S        0x1e3
#define KEY_FN_B        0x1e4#define KEY_BRL_DOT1       0x1f1
#define KEY_BRL_DOT2        0x1f2
#define KEY_BRL_DOT3        0x1f3
#define KEY_BRL_DOT4        0x1f4
#define KEY_BRL_DOT5        0x1f5
#define KEY_BRL_DOT6        0x1f6
#define KEY_BRL_DOT7        0x1f7
#define KEY_BRL_DOT8        0x1f8
#define KEY_BRL_DOT9        0x1f9
#define KEY_BRL_DOT10       0x1fa#define KEY_NUMERIC_0      0x200   /* used by phones, remote controls, */
#define KEY_NUMERIC_1       0x201   /* and other keypads */
#define KEY_NUMERIC_2       0x202
#define KEY_NUMERIC_3       0x203
#define KEY_NUMERIC_4       0x204
#define KEY_NUMERIC_5       0x205
#define KEY_NUMERIC_6       0x206
#define KEY_NUMERIC_7       0x207
#define KEY_NUMERIC_8       0x208
#define KEY_NUMERIC_9       0x209
#define KEY_NUMERIC_STAR    0x20a
#define KEY_NUMERIC_POUND   0x20b
#define KEY_NUMERIC_A       0x20c   /* Phone key A - HUT Telephony 0xb9 */
#define KEY_NUMERIC_B       0x20d
#define KEY_NUMERIC_C       0x20e
#define KEY_NUMERIC_D       0x20f#define KEY_CAMERA_FOCUS   0x210
#define KEY_WPS_BUTTON      0x211   /* WiFi Protected Setup key */#define KEY_TOUCHPAD_TOGGLE   0x212   /* Request switch touchpad on or off */
#define KEY_TOUCHPAD_ON     0x213
#define KEY_TOUCHPAD_OFF    0x214#define KEY_CAMERA_ZOOMIN  0x215
#define KEY_CAMERA_ZOOMOUT  0x216
#define KEY_CAMERA_UP       0x217
#define KEY_CAMERA_DOWN     0x218
#define KEY_CAMERA_LEFT     0x219
#define KEY_CAMERA_RIGHT    0x21a#define KEY_ATTENDANT_ON   0x21b
#define KEY_ATTENDANT_OFF   0x21c
#define KEY_ATTENDANT_TOGGLE    0x21d   /* Attendant call on or off */
#define KEY_LIGHTS_TOGGLE   0x21e   /* Reading light on or off */#define BTN_DPAD_UP        0x220
#define BTN_DPAD_DOWN       0x221
#define BTN_DPAD_LEFT       0x222
#define BTN_DPAD_RIGHT      0x223#define KEY_ALS_TOGGLE     0x230   /* Ambient light sensor */#define KEY_BUTTONCONFIG      0x240   /* AL Button Configuration */
#define KEY_TASKMANAGER     0x241   /* AL Task/Project Manager */
#define KEY_JOURNAL     0x242   /* AL Log/Journal/Timecard */
#define KEY_CONTROLPANEL        0x243   /* AL Control Panel */
#define KEY_APPSELECT       0x244   /* AL Select Task/Application */
#define KEY_SCREENSAVER     0x245   /* AL Screen Saver */
#define KEY_VOICECOMMAND        0x246   /* Listening Voice Command */#define KEY_BRIGHTNESS_MIN     0x250   /* Set Brightness to Minimum */
#define KEY_BRIGHTNESS_MAX      0x251   /* Set Brightness to Maximum */#define KEY_KBDINPUTASSIST_PREV      0x260
#define KEY_KBDINPUTASSIST_NEXT     0x261
#define KEY_KBDINPUTASSIST_PREVGROUP        0x262
#define KEY_KBDINPUTASSIST_NEXTGROUP        0x263
#define KEY_KBDINPUTASSIST_ACCEPT       0x264
#define KEY_KBDINPUTASSIST_CANCEL       0x265/* Diagonal movement keys */
#define KEY_RIGHT_UP            0x266
#define KEY_RIGHT_DOWN          0x267
#define KEY_LEFT_UP         0x268
#define KEY_LEFT_DOWN           0x269#define KEY_ROOT_MENU          0x26a /* Show Device's Root Menu */
/* Show Top Menu of the Media (e.g. DVD) */
#define KEY_MEDIA_TOP_MENU      0x26b
#define KEY_NUMERIC_11          0x26c
#define KEY_NUMERIC_12          0x26d
/** Toggle Audio Description: refers to an audio service that helps blind and* visually impaired consumers understand the action in a program. Note: in* some countries this is referred to as "Video Description".*/
#define KEY_AUDIO_DESC          0x26e
#define KEY_3D_MODE         0x26f
#define KEY_NEXT_FAVORITE       0x270
#define KEY_STOP_RECORD         0x271
#define KEY_PAUSE_RECORD        0x272
#define KEY_VOD             0x273 /* Video on Demand */
#define KEY_UNMUTE          0x274
#define KEY_FASTREVERSE         0x275
#define KEY_SLOWREVERSE         0x276
/** Control a data application associated with the currently viewed channel,* e.g. teletext or data broadcast application (MHEG, MHP, HbbTV, etc.)*/
#define KEY_DATA            0x277#define BTN_TRIGGER_HAPPY      0x2c0
#define BTN_TRIGGER_HAPPY1      0x2c0
#define BTN_TRIGGER_HAPPY2      0x2c1
#define BTN_TRIGGER_HAPPY3      0x2c2
#define BTN_TRIGGER_HAPPY4      0x2c3
#define BTN_TRIGGER_HAPPY5      0x2c4
#define BTN_TRIGGER_HAPPY6      0x2c5
#define BTN_TRIGGER_HAPPY7      0x2c6
#define BTN_TRIGGER_HAPPY8      0x2c7
#define BTN_TRIGGER_HAPPY9      0x2c8
#define BTN_TRIGGER_HAPPY10     0x2c9
#define BTN_TRIGGER_HAPPY11     0x2ca
#define BTN_TRIGGER_HAPPY12     0x2cb
#define BTN_TRIGGER_HAPPY13     0x2cc
#define BTN_TRIGGER_HAPPY14     0x2cd
#define BTN_TRIGGER_HAPPY15     0x2ce
#define BTN_TRIGGER_HAPPY16     0x2cf
#define BTN_TRIGGER_HAPPY17     0x2d0
#define BTN_TRIGGER_HAPPY18     0x2d1
#define BTN_TRIGGER_HAPPY19     0x2d2
#define BTN_TRIGGER_HAPPY20     0x2d3
#define BTN_TRIGGER_HAPPY21     0x2d4
#define BTN_TRIGGER_HAPPY22     0x2d5
#define BTN_TRIGGER_HAPPY23     0x2d6
#define BTN_TRIGGER_HAPPY24     0x2d7
#define BTN_TRIGGER_HAPPY25     0x2d8
#define BTN_TRIGGER_HAPPY26     0x2d9
#define BTN_TRIGGER_HAPPY27     0x2da
#define BTN_TRIGGER_HAPPY28     0x2db
#define BTN_TRIGGER_HAPPY29     0x2dc
#define BTN_TRIGGER_HAPPY30     0x2dd
#define BTN_TRIGGER_HAPPY31     0x2de
#define BTN_TRIGGER_HAPPY32     0x2df
#define BTN_TRIGGER_HAPPY33     0x2e0
#define BTN_TRIGGER_HAPPY34     0x2e1
#define BTN_TRIGGER_HAPPY35     0x2e2
#define BTN_TRIGGER_HAPPY36     0x2e3
#define BTN_TRIGGER_HAPPY37     0x2e4
#define BTN_TRIGGER_HAPPY38     0x2e5
#define BTN_TRIGGER_HAPPY39     0x2e6
#define BTN_TRIGGER_HAPPY40     0x2e7/* We avoid low common keys in module aliases so they don't get huge. */
#define KEY_MIN_INTERESTING KEY_MUTE
#define KEY_MAX         0x2ff
#define KEY_CNT         (KEY_MAX+1)/** Relative axes*/#define REL_X            0x00
#define REL_Y           0x01
#define REL_Z           0x02
#define REL_RX          0x03
#define REL_RY          0x04
#define REL_RZ          0x05
#define REL_HWHEEL      0x06
#define REL_DIAL        0x07
#define REL_WHEEL       0x08
#define REL_MISC        0x09
#define REL_MAX         0x0f
#define REL_CNT         (REL_MAX+1)/** Absolute axes*/#define ABS_X            0x00
#define ABS_Y           0x01
#define ABS_Z           0x02
#define ABS_RX          0x03
#define ABS_RY          0x04
#define ABS_RZ          0x05
#define ABS_THROTTLE        0x06
#define ABS_RUDDER      0x07
#define ABS_WHEEL       0x08
#define ABS_GAS         0x09
#define ABS_BRAKE       0x0a
#define ABS_HAT0X       0x10
#define ABS_HAT0Y       0x11
#define ABS_HAT1X       0x12
#define ABS_HAT1Y       0x13
#define ABS_HAT2X       0x14
#define ABS_HAT2Y       0x15
#define ABS_HAT3X       0x16
#define ABS_HAT3Y       0x17
#define ABS_PRESSURE        0x18
#define ABS_DISTANCE        0x19
#define ABS_TILT_X      0x1a
#define ABS_TILT_Y      0x1b
#define ABS_TOOL_WIDTH      0x1c#define ABS_VOLUME      0x20#define ABS_MISC        0x28#define ABS_MT_SLOT     0x2f    /* MT slot being modified */
#define ABS_MT_TOUCH_MAJOR  0x30    /* Major axis of touching ellipse */
#define ABS_MT_TOUCH_MINOR  0x31    /* Minor axis (omit if circular) */
#define ABS_MT_WIDTH_MAJOR  0x32    /* Major axis of approaching ellipse */
#define ABS_MT_WIDTH_MINOR  0x33    /* Minor axis (omit if circular) */
#define ABS_MT_ORIENTATION  0x34    /* Ellipse orientation */
#define ABS_MT_POSITION_X   0x35    /* Center X touch position */
#define ABS_MT_POSITION_Y   0x36    /* Center Y touch position */
#define ABS_MT_TOOL_TYPE    0x37    /* Type of touching device */
#define ABS_MT_BLOB_ID      0x38    /* Group a set of packets as a blob */
#define ABS_MT_TRACKING_ID  0x39    /* Unique ID of initiated contact */
#define ABS_MT_PRESSURE     0x3a    /* Pressure on contact area */
#define ABS_MT_DISTANCE     0x3b    /* Contact hover distance */
#define ABS_MT_TOOL_X       0x3c    /* Center X tool position */
#define ABS_MT_TOOL_Y       0x3d    /* Center Y tool position */#define ABS_MAX         0x3f
#define ABS_CNT         (ABS_MAX+1)/** Switch events*/#define SW_LID           0x00  /* set = lid shut */
#define SW_TABLET_MODE      0x01  /* set = tablet mode */
#define SW_HEADPHONE_INSERT 0x02  /* set = inserted */
#define SW_RFKILL_ALL       0x03  /* rfkill master switch, type "any"set = radio enabled */
#define SW_RADIO        SW_RFKILL_ALL   /* deprecated */
#define SW_MICROPHONE_INSERT    0x04  /* set = inserted */
#define SW_DOCK         0x05  /* set = plugged into dock */
#define SW_LINEOUT_INSERT   0x06  /* set = inserted */
#define SW_JACK_PHYSICAL_INSERT 0x07  /* set = mechanical switch set */
#define SW_VIDEOOUT_INSERT  0x08  /* set = inserted */
#define SW_CAMERA_LENS_COVER    0x09  /* set = lens covered */
#define SW_KEYPAD_SLIDE     0x0a  /* set = keypad slide out */
#define SW_FRONT_PROXIMITY  0x0b  /* set = front proximity sensor active */
#define SW_ROTATE_LOCK      0x0c  /* set = rotate locked/disabled */
#define SW_LINEIN_INSERT    0x0d  /* set = inserted */
#define SW_MUTE_DEVICE      0x0e  /* set = device disabled */
#define SW_PEN_INSERTED     0x0f  /* set = pen inserted */
#define SW_MAX          0x0f
#define SW_CNT          (SW_MAX+1)/** Misc events*/#define MSC_SERIAL      0x00
#define MSC_PULSELED        0x01
#define MSC_GESTURE     0x02
#define MSC_RAW         0x03
#define MSC_SCAN        0x04
#define MSC_TIMESTAMP       0x05
#define MSC_MAX         0x07
#define MSC_CNT         (MSC_MAX+1)/** LEDs*/#define LED_NUML      0x00
#define LED_CAPSL       0x01
#define LED_SCROLLL     0x02
#define LED_COMPOSE     0x03
#define LED_KANA        0x04
#define LED_SLEEP       0x05
#define LED_SUSPEND     0x06
#define LED_MUTE        0x07
#define LED_MISC        0x08
#define LED_MAIL        0x09
#define LED_CHARGING        0x0a
#define LED_MAX         0x0f
#define LED_CNT         (LED_MAX+1)/** Autorepeat values*/#define REP_DELAY        0x00
#define REP_PERIOD      0x01
#define REP_MAX         0x01
#define REP_CNT         (REP_MAX+1)/** Sounds*/#define SND_CLICK       0x00
#define SND_BELL        0x01
#define SND_TONE        0x02
#define SND_MAX         0x07
#define SND_CNT         (SND_MAX+1)#endif

二、Linux Kernel中的LRADC驱动源码

1、Kernel内置的LRADC驱动源码

源码地址：https://github.com/Lichee-Pi/linux/blob/zero-4.10.y/drivers/input/keyboard/sun4i-lradc-keys.c

#include <linux/err.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>#define LRADC_CTRL     0x00
#define LRADC_INTC      0x04
#define LRADC_INTS      0x08
#define LRADC_DATA0     0x0c
#define LRADC_DATA1     0x10/* LRADC_CTRL bits */
#define FIRST_CONVERT_DLY(x)    ((x) << 24) /* 8 bits */
#define CHAN_SELECT(x)          ((x) << 22) /* 2 bits */
#define CONTINUE_TIME_SEL(x)    ((x) << 16) /* 4 bits */
#define KEY_MODE_SEL(x)         ((x) << 12) /* 2 bits */
#define LEVELA_B_CNT(x)         ((x) << 8)  /* 4 bits */
#define HOLD_KEY_EN(x)          ((x) << 7)
#define HOLD_EN(x)              ((x) << 6)
#define LEVELB_VOL(x)           ((x) << 4)  /* 2 bits */
#define SAMPLE_RATE(x)          ((x) << 2)  /* 2 bits */
#define ENABLE(x)               ((x) << 0)/* LRADC_INTC and LRADC_INTS bits */
#define CHAN1_KEYUP_IRQ         BIT(12)
#define CHAN1_ALRDY_HOLD_IRQ    BIT(11)
#define CHAN1_HOLD_IRQ          BIT(10)
#define CHAN1_KEYDOWN_IRQ       BIT(9)
#define CHAN1_DATA_IRQ          BIT(8)
#define CHAN0_KEYUP_IRQ         BIT(4)
#define CHAN0_ALRDY_HOLD_IRQ    BIT(3)
#define CHAN0_HOLD_IRQ          BIT(2)
#define CHAN0_KEYDOWN_IRQ       BIT(1)
#define CHAN0_DATA_IRQ          BIT(0)/* struct lradc_variant - Describe sun4i-a10-lradc-keys hardware variant* @divisor_numerator:        The numerator of lradc Vref internally divisor* @divisor_denominator:  The denominator of lradc Vref internally divisor*/
struct lradc_variant {u8 divisor_numerator;u8 divisor_denominator;
};static const struct lradc_variant lradc_variant_a10 = {.divisor_numerator = 2,.divisor_denominator = 3
};static const struct lradc_variant r_lradc_variant_a83t = {.divisor_numerator = 3,.divisor_denominator = 4
};struct sun4i_lradc_keymap {u32 voltage;u32 keycode;
};
/*sun4i_lradc_data结构体*/
struct sun4i_lradc_data {struct device *dev;struct input_dev *input;void __iomem *base;struct regulator *vref_supply;struct sun4i_lradc_keymap *chan0_map;const struct lradc_variant *variant;u32 chan0_map_count;u32 chan0_keycode;u32 vref;
};
/*lradc中断*/
static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
{struct sun4i_lradc_data *lradc = dev_id;u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;ints  = readl(lradc->base + LRADC_INTS);  //读取中断类型/** lradc supports only one keypress at a time, release does not give* any info as to which key was released, so we cache the keycode.*///中断类型为按键释放if (ints & CHAN0_KEYUP_IRQ) {input_report_key(lradc->input, lradc->chan0_keycode, 0); /*向输入子系统报告产生按键事件*/lradc->chan0_keycode = 0;  //按键编码置零}//中断类型为按键按下，并且当前按键编码为0if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {val = readl(lradc->base + LRADC_DATA0) & 0x3f;  //读取adc值voltage = val * lradc->vref / 63;  //计算电压值（vref/63 是电压分辨率，采样位数6bit）//根据电压，匹配按键值for (i = 0; i < lradc->chan0_map_count; i++) {diff = abs(lradc->chan0_map[i].voltage - voltage);//匹配电压差值最小的键值if (diff < closest) {closest = diff;keycode = lradc->chan0_map[i].keycode;  //确定当前按下的键值}}lradc->chan0_keycode = keycode;input_report_key(lradc->input, lradc->chan0_keycode, 1);  /*向输入子系统报告产生按键事件*/}input_sync(lradc->input);   /*通知接收者,一个报告发送完毕*/writel(ints, lradc->base + LRADC_INTS); //写回寄存器（还未查阅芯片手册，应该是清除中断吧）return IRQ_HANDLED;
}static int sun4i_lradc_open(struct input_dev *dev)
{struct sun4i_lradc_data *lradc = input_get_drvdata(dev); /* 从设备的私有数据区获取设备描述结构体，可通过nput_set_drvdata 保存数据*/int error;/*regulator 是驱动中电源管理的基础设施。要先注册到内核中，然后使用这些电压输出的模块get其regulator,在驱动中的init里，在适当时间中进行电压电流的设置.与 gpio 差不多？　一样是基础设施？一种称为校准器（regulator）的动态电压和电流控制的方法，很有参考意义和实际使用价值。*/error = regulator_enable(lradc->vref_supply);  //打开校准器if (error)return error;//通过此接口获取当前电源电压。lradc->vref = regulator_get_voltage(lradc->vref_supply) *lradc->variant->divisor_numerator /lradc->variant->divisor_denominator;/**配置LRADC_INTC寄存器，设定采样时间为4ms / 250hz。等待2 * 4 ms的key to*稳定按下，等待(1 + 1)* 4毫秒后释放按键*/writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |SAMPLE_RATE(0) | ENABLE(1), lradc->base + LRADC_CTRL);writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);return 0;
}static void sun4i_lradc_close(struct input_dev *dev)
{struct sun4i_lradc_data *lradc = input_get_drvdata(dev);/* Disable lradc, leave other settings unchanged */writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |SAMPLE_RATE(2), lradc->base + LRADC_CTRL);writel(0, lradc->base + LRADC_INTC);regulator_disable(lradc->vref_supply);
}
//加载设备树资源
static int sun4i_lradc_load_dt_keymap(struct device *dev,struct sun4i_lradc_data *lradc)
{struct device_node *np, *pp;int i;int error;np = dev->of_node;if (!np)return -EINVAL;lradc->chan0_map_count = of_get_child_count(np);if (lradc->chan0_map_count == 0) {dev_err(dev, "keymap is missing in device tree\n");return -EINVAL;}lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count,sizeof(struct sun4i_lradc_keymap),GFP_KERNEL);if (!lradc->chan0_map)return -ENOMEM;i = 0;for_each_child_of_node(np, pp) {struct sun4i_lradc_keymap *map = &lradc->chan0_map[i];u32 channel;error = of_property_read_u32(pp, "channel", &channel);if (error || channel != 0) {dev_err(dev, "%pOFn: Inval channel prop\n", pp);return -EINVAL;}error = of_property_read_u32(pp, "voltage", &map->voltage);if (error) {dev_err(dev, "%pOFn: Inval voltage prop\n", pp);return -EINVAL;}error = of_property_read_u32(pp, "linux,code", &map->keycode);if (error) {dev_err(dev, "%pOFn: Inval linux,code prop\n", pp);return -EINVAL;}i++;}return 0;
}static int sun4i_lradc_probe(struct platform_device *pdev)
{struct sun4i_lradc_data *lradc;struct device *dev = &pdev->dev;int i;int error;lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);if (!lradc)return -ENOMEM;error = sun4i_lradc_load_dt_keymap(dev, lradc);if (error)return error;lradc->variant = of_device_get_match_data(&pdev->dev);if (!lradc->variant) {dev_err(&pdev->dev, "Missing sun4i-a10-lradc-keys variant\n");return -EINVAL;}lradc->vref_supply = devm_regulator_get(dev, "vref");if (IS_ERR(lradc->vref_supply))return PTR_ERR(lradc->vref_supply);lradc->dev = dev;lradc->input = devm_input_allocate_device(dev);if (!lradc->input)return -ENOMEM;lradc->input->name = pdev->name;lradc->input->phys = "sun4i_lradc/input0";lradc->input->open = sun4i_lradc_open;lradc->input->close = sun4i_lradc_close;lradc->input->id.bustype = BUS_HOST;lradc->input->id.vendor = 0x0001;lradc->input->id.product = 0x0001;lradc->input->id.version = 0x0100;__set_bit(EV_KEY, lradc->input->evbit);for (i = 0; i < lradc->chan0_map_count; i++)__set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit);input_set_drvdata(lradc->input, lradc);lradc->base = devm_ioremap_resource(dev,platform_get_resource(pdev, IORESOURCE_MEM, 0));if (IS_ERR(lradc->base))return PTR_ERR(lradc->base);error = devm_request_irq(dev, platform_get_irq(pdev, 0),sun4i_lradc_irq, 0,"sun4i-a10-lradc-keys", lradc);if (error)return error;error = input_register_device(lradc->input);if (error)return error;return 0;
}static const struct of_device_id sun4i_lradc_of_match[] = {{ .compatible = "allwinner,sun4i-a10-lradc-keys",.data = &lradc_variant_a10 },{ .compatible = "allwinner,sun8i-a83t-r-lradc",.data = &r_lradc_variant_a83t },{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);static struct platform_driver sun4i_lradc_driver = {.driver = {.name    = "sun4i-a10-lradc-keys",.of_match_table = of_match_ptr(sun4i_lradc_of_match),},.probe  = sun4i_lradc_probe,
};module_platform_driver(sun4i_lradc_driver);MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");

2、驱动测试

驱动测试软件使用信号量的方法

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <poll.h>
#include <signal.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>#include <linux/input.h>int fd;void my_signal_fun(int signum)
{struct input_event buttons_event, leds_event;/* [cgw]: 异步通知产生时返回的数据 */read(fd, &buttons_event, sizeof(struct input_event));/* [cgw]: 打印事件类型，事件码，事件值 */printf("type: 0x%x code: 0x%x value: 0x%x\n",buttons_event.type,buttons_event.code,  buttons_event.value);// /* [cgw]: 返回的是KEY_L或KEY_S值 */// if (buttons_event.code == KEY_L || buttons_event.code == KEY_S) {//     /* [cgw]: 按键弹起 */ //     if (buttons_event.value == 0) {//         /* [cgw]: 构造一个EV_LED事件 *///         //leds_event.type = EV_SND;//         leds_event.type = EV_LED;//         //leds_event.code = SND_BELL;//         leds_event.code = LED_MUTE;//         /* [cgw]: KEY_L和KEY_S控制LED的亮灭 *///         if (buttons_event.code == KEY_L) {//             leds_event.value = 0xAA;//         } else if (buttons_event.code == KEY_S) {//             leds_event.value = 0xEE;    //         }//         /* [cgw]: 发送LED控制事件 *///         write(fd, &leds_event, sizeof(struct input_event));//         printf("led write!\n");//     }// }
}int main(int argc, char **argv)
{int Oflags;/* [cgw]: 设置需要处理的信号SIGIO，即输入文件会请求一个SIGIO* 信号，当有新数据到来这个信号会发给filp->f_owner进程*/signal(SIGIO, my_signal_fun);fd = open("/dev/input/event0", O_RDWR | O_NONBLOCK);//printf("fd = 0x%x\n", fd);if (fd < 0){printf("can't open!\n");}/* [cgw]: 根据文件标识符fd，设置能够获得这个文件的进程(owner) * getpid()获得当前进程ID*/fcntl(fd, F_SETOWN, getpid());/* [cgw]: 获得file->f_flags标志 */Oflags = fcntl(fd, F_GETFL);/* [cgw]: 置位FASYNC使能异步通知 */fcntl(fd, F_SETFL, Oflags | FASYNC);while (1){/* [cgw]: 休眠 */sleep(1000);}return 0;
}

测试失败–键值错误

依次按上述原理图中的按键：S1-S2-S3-S4，如下显示，好像并不能通过键值识别出来。

S1按键：KEY_VOLUMEUP：0x73 = 115
S2按键：KEY_VOLUMEDOWN：0x72 = 114
S3按键：KEY_SELECT：0x161 = 353
S4按键：KEY_OK：0x160 = 352


# ./signalkeyinputApp
type: 0x1 code: 0x72 value: 0x1    # S1按键
type: 0x0 code: 0x0 value: 0x0
type: 0x1 code: 0x72 value: 0x0    # S2按键
type: 0x0 code: 0x0 value: 0x0
type: 0x1 code: 0x160 value: 0x1   # S3按键
type: 0x0 code: 0x0 value: 0x0
type: 0x1 code: 0x160 value: 0x0   # S4按键
type: 0x0 code: 0x0 value: 0x0

可以看出，只有S2按键和S4按键的键值是对的，其他两个是错误的键值。

驱动测试软件使用轮询方式

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>#include <linux/input.h>/*** file name：keyinputApp* date: 2022-3-5 11:08:53* version：1.0* author:liefyuan* describe：input系统测试APP* 执行命令：./keyinputApp /dev/input/event0*//* 定义一个input_event变量 存放输入事件信息 */
static struct input_event inputevent;/* 主程序 */
int main(int argc, char *argv[])
{char *filename;  // 可执行文件名int fd,ret =0 ;  //  fd: 文件句柄 ret:函数操作返回值/* 先判断输入的参数 */if(argc !=  2){  // 本身文件名带1个 执行文件1个  printf("parameter error!\r\n");return -1;}/* 分析参数 ，提取有用的信息 */filename = argv[1];  // 可执行文件名 /* 打开key文件 */fd = open(filename, O_RDWR);  // 可读可写 if(fd < 0){printf("can't open file:%s\r\n",filename);return -1;}/* 循环读取按键值 */while(1){ret = read(fd, &inputevent, sizeof(inputevent));if(ret  >  0 ){   /* 数据有效   */switch (inputevent.type){  // 判断事件的类型 case EV_KEY:if(inputevent.code < BTN_MISC){  // 是键盘键值// 输入按键代码 并且判断按键是按下还是松开printf("key %d %s \r\n", \inputevent.code, \inputevent.value ? "press" : "release");  }else{// 输入按键代码 并且判断按键是按下还是松开printf("button %d %s \r\n", \inputevent.code, \inputevent.value ? "press" : "release");  }break;/* 其他类型事件 根据需要自行处理 */case EV_REL:break;case EV_ABS:break;case EV_MSC:break;case EV_SW:break;}}else{  // 数据无效 printf("read data error\r\n");}}/* 关闭文件 */ret = close(fd);if(ret < 0){printf("can't close file %s \r\n", filename);return -1;}return 0;
}

测试失败，键值显示错误

依次按上述原理图中的按键：S1-S2-S3-S4，如下显示，只能显示两个按键值。

# ./keyinputApp /dev/input/event0
key 114 press      # S1按键
key 114 release
key 352 press      # S2按键
key 352 release
key 352 press      # S3按键
key 352 release
key 352 press      # S4按键
key 352 release

可能原因：
设备树里面的电压值和电阻网络是不是匹配，

3、另一个测试方式

源码：https://elinux.org/images/9/93/Evtest.c

# ./evtest /dev/input/event0
Input driver version is 1.0.1
Input device ID: bus 0x19 vendor 0x1 product 0x1 version 0x100
Input device name: "1c22800.lradc"
Supported events:Event type 0 (Sync)Event type 1 (Key)Event code 114 (VolumeDown)Event code 115 (VolumeUp)Event code 352 (Ok)Event code 353 (Select)
Testing ... (interrupt to exit)
Event: time 357.242358, type 1 (Key), code 114 (VolumeDown), value 1
Event: time 357.242358, -------------- Report Sync ------------
Event: time 357.484543, type 1 (Key), code 114 (VolumeDown), value 0
Event: time 357.484543, -------------- Report Sync ------------
Event: time 360.066660, type 1 (Key), code 352 (Ok), value 1
Event: time 360.066660, -------------- Report Sync ------------
Event: time 360.304947, type 1 (Key), code 352 (Ok), value 0
Event: time 360.304947, -------------- Report Sync ------------

键值与按键的关系是不对的！

查看中断列表：

# cat /proc/interruptsCPU019:        576     GIC-0  27 Level     arch_timer21:          0     GIC-0  50 Level     sun4i_timer022:          0     GIC-0  82 Level     1c02000.dma-controller23:       5039     GIC-0  92 Level     sunxi-mmc24:        159     GIC-0  93 Level     sunxi-mmc25:          1     GIC-0 103 Level     musb-hdrc.1.auto26:          0     GIC-0  72 Level     1c20400.rtc32:          2     GIC-0  62 Level     sun4i-a10-lradc-keys34:        226     GIC-0  32 Level     serial35:         63     GIC-0  38 Level     mv64xxx_i2c
IPI0:          0  CPU wakeup interrupts
IPI1:          0  Timer broadcast interrupts
IPI2:          0  Rescheduling interrupts
IPI3:          0  Function call interrupts
IPI4:          0  CPU stop interrupts
IPI5:          0  IRQ work interrupts
IPI6:          0  completion interrupts
Err:          0

32: 2 GIC-0 62 Level sun4i-a10-lradc-keys LRADC KEY是存在的。

可能还是硬件问题！

4、测试软件的编译方法

编译测试应用：

$ arm-linux-gnueabihf-gcc keyinputApp.c -o keyinputApp

拷贝编译出来的文件到开发板上去：

/dev/input/event0

# ./keyinputApp /dev/input/event0
key 114 press
key 114 release
key 114 press
key 114 release
key 114 press

只能识别一个按键？

三、改进

参考一个linux3.4的源码里面可以正常识别如下：

/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
*
* Copyright (c) 2011
*
* ChangeLog
*
*
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/keyboard.h>
#include <linux/ioport.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/timer.h>
#include <linux/clk.h>
#include <mach/sys_config.h>
#undef CONFIG_HAS_EARLYSUSPEND
#ifdef CONFIG_ARCH_SUN9IW1P1
#include <linux/clk/clk-sun9iw1.h>
#endif
#ifdef CONFIG_HAS_EARLYSUSPEND
#include <linux/earlysuspend.h>
#endif
#if defined(CONFIG_HAS_EARLYSUSPEND) || defined(CONFIG_PM)
#include <linux/pm.h>
#endif
#include "sun8i-keyboard.h"
#include <linux/power/scenelock.h>#ifdef MODE_0V2
#ifndef CONFIG_ARCH_SUN9IW1P1
static unsigned char keypad_mapindex[64] = {0,0,0,0,0,0,0,0,                /* key 1, 8���� 0-7 */1,1,1,1,1,1,1,                  /* key 2, 7���� 8-14 */2,2,2,2,2,2,2,                  /* key 3, 7���� 15-21 */3,3,3,3,3,3,                    /* key 4, 6���� 22-27 */4,4,4,4,4,4,                    /* key 5, 6���� 28-33 */5,5,5,5,5,5,                    /* key 6, 6���� 34-39 */6,6,6,6,6,6,6,6,6,6,            /* key 7, 10����40-49 */7,7,7,7,7,7,7,7,7,7,7,7,7,7     /* key 8, 17����50-63 */
};
#else
static unsigned char keypad_mapindex[64] = {0,0,0,0,0,0,0,0,0,              /* key 1, 0-8 */1,1,1,1,1,                      /* key 2, 9-13 */2,2,2,2,2,2,                    /* key 3, 14-19 */3,3,3,3,3,3,                    /* key 4, 20-25 */4,4,4,4,4,4,4,4,4,4,4,          /* key 5, 26-36 */5,5,5,5,5,5,5,5,5,5,5,          /* key 6, 37-39 */6,6,6,6,6,6,6,6,6,              /* key 7, 40-49 */7,7,7,7,7,7,7                   /* key 8, 50-63 */
};
#endif
#endif#ifdef MODE_0V15
/* 0.15V mode */
static unsigned char keypad_mapindex[64] = {0,0,0,                          /* key1 */1,1,1,1,1,                      /* key2 */2,2,2,2,2,3,3,3,3,4,4,4,4,4,5,5,5,5,5,6,6,6,6,6,7,7,7,7,8,8,8,8,8,9,9,9,9,9,10,10,10,10,11,11,11,11,12,12,12,12,12,12,12,12,12,12   /*key13 */
};
#endif#ifdef CONFIG_HAS_EARLYSUSPEND
struct sunxi_keyboard_data {struct early_suspend early_suspend;
};
#else
#ifdef CONFIG_PM
static struct dev_pm_domain keyboard_pm_domain;
#endif
#endif#if defined(CONFIG_ARCH_SUN8IW6P1)||defined(CONFIG_ARCH_SUN9IW1P1)
#define ADC_MEASURE     (1350)
#define ADC_RESOL       (21)
#else
#define ADC_MEASURE     (2000)
#define ADC_RESOL       (31)
#endif
#define VOL_NUM 16static int key_vol[VOL_NUM];
static int key_num = 0;
static volatile u32 key_val;
static struct input_dev *sunxikbd_dev;
static unsigned char scancode;static unsigned char key_cnt = 0;
static unsigned char compare_buffer[REPORT_START_NUM] = {0};
static unsigned char transfer_code = INITIAL_VALUE;
#ifdef CONFIG_ARCH_SUN9IW1P1
static struct clk *key_clk;
static struct clk *key_clk_source;
#endif
enum {DEBUG_INIT = 1U << 0,DEBUG_INT = 1U << 1,DEBUG_DATA_INFO = 1U << 2,DEBUG_SUSPEND = 1U << 3,
};
static u32 debug_mask = 0;
#define dprintk(level_mask, fmt, arg...)        if (unlikely(debug_mask & level_mask)) \printk(fmt , ## arg)module_param_named(debug_mask, debug_mask, int, 0644);#ifdef CONFIG_HAS_EARLYSUSPEND
static struct sunxi_keyboard_data *keyboard_data;
#endif#ifdef CONFIG_ARCH_SUN9IW1P1
static void sunxikbd_clk_cfg(void)
{unsigned long rate = 0; /* 3Mhz */key_clk_source = clk_get(NULL, APB0_CLK);if (!key_clk_source || IS_ERR(key_clk_source)) {pr_err("try to get key_clk_source failed!\n");return;}rate = clk_get_rate(key_clk_source);dprintk(DEBUG_INIT, "%s: get key_clk_source rate %dHZ\n", __func__, (__u32)rate);key_clk = clk_get(NULL, LRADC_CLK);if (!key_clk || IS_ERR(key_clk)) {pr_err("try to get key clock failed!\n");return;}if(clk_set_parent(key_clk, key_clk_source))pr_err("%s: set key_clk parent to key_clk_source failed!\n", __func__);if (clk_prepare_enable(key_clk)) {pr_err("try to enable key_clk failed!\n");}return;
}static void sunxikbd_clk_uncfg(void)
{if(NULL == key_clk || IS_ERR(key_clk)) {pr_err("key_clk handle is invalid, just return!\n");return;} else {clk_disable_unprepare(key_clk);clk_put(key_clk);key_clk = NULL;}if(NULL == key_clk_source || IS_ERR(key_clk_source)) {pr_err("key_clk_source handle is invalid, just return!\n");return;} else {clk_put(key_clk_source);key_clk_source = NULL;}return;
}
#endifstatic void sunxi_keyboard_ctrl_set(enum key_mode key_mode, u32 para)
{u32 ctrl_reg = 0;if (0 != para)ctrl_reg = readl((const volatile void __iomem *)(KEY_BASSADDRESS + LRADC_CTRL));if (CONCERT_DLY_SET & key_mode)ctrl_reg |= (FIRST_CONCERT_DLY & para);if (ADC_CHAN_SET & key_mode)ctrl_reg |= (ADC_CHAN_SELECT & para);if (KEY_MODE_SET & key_mode)ctrl_reg |= (KEY_MODE_SELECT & para);if (LRADC_HOLD_SET & key_mode)ctrl_reg |= (LRADC_HOLD_EN & para);if (LEVELB_VOL_SET & key_mode)ctrl_reg |= (LEVELB_VOL & para);if (LRADC_SAMPLE_SET & key_mode)ctrl_reg |= (LRADC_SAMPLE_250HZ & para);if (LRADC_EN_SET & key_mode)ctrl_reg |= (LRADC_EN & para);writel(ctrl_reg, (volatile void __iomem *)(KEY_BASSADDRESS + LRADC_CTRL));
}static void sunxi_keyboard_int_set(enum int_mode int_mode, u32 para)
{u32 ctrl_reg = 0;if (0 != para)ctrl_reg = readl((const volatile void __iomem *)(KEY_BASSADDRESS + LRADC_INTC));if (ADC0_DOWN_INT_SET & int_mode)ctrl_reg |= (LRADC_ADC0_DOWN_EN & para);if (ADC0_UP_INT_SET & int_mode)ctrl_reg |= (LRADC_ADC0_UP_EN & para);if (ADC0_DATA_INT_SET & int_mode)ctrl_reg |= (LRADC_ADC0_DATA_EN & para);writel(ctrl_reg, (volatile void __iomem *)(KEY_BASSADDRESS + LRADC_INTC));
}static u32 sunxi_keyboard_read_ints(void)
{u32 reg_val;reg_val  = readl((const volatile void __iomem *)(KEY_BASSADDRESS + LRADC_INT_STA));return reg_val;
}static void sunxi_keyboard_clr_ints(u32 reg_val)
{writel(reg_val, (volatile void __iomem *)(KEY_BASSADDRESS + LRADC_INT_STA));
}static u32 sunxi_keyboard_read_data(unsigned long addr)
{u32 reg_val;reg_val = readl((const volatile void __iomem *)(addr));return reg_val;
}#ifdef CONFIG_HAS_EARLYSUSPEND
/* ͣ���豸 */
static void sunxi_keyboard_early_suspend(struct early_suspend *h)
{//int ret;//struct sunxi_keyboard_data *ts = container_of(h, struct sunxi_keyboard_data, early_suspend);dprintk(DEBUG_SUSPEND, "[%s] enter standby state: %d. \n", __FUNCTION__, (int)standby_type);disable_irq_nosync(SW_INT_IRQNO_LRADC);if (NORMAL_STANDBY == standby_type) {sunxi_keyboard_ctrl_set(0, 0);
#ifdef CONFIG_ARCH_SUN9IW1P1clk_disable_unprepare(key_clk);
#endif/* process for super standby */ } else if (SUPER_STANDBY == standby_type) {if (check_scene_locked(SCENE_TALKING_STANDBY) == 0) {printk("lradc-key: talking standby, enable wakeup source lradc!!\n");enable_wakeup_src(CPUS_LRADC_SRC, 0);} else {sunxi_keyboard_ctrl_set(0, 0);
#ifdef CONFIG_ARCH_SUN9IW1P1clk_disable_unprepare(key_clk);
#endif}}return ;
}/* ���»��� */
static void sunxi_keyboard_late_resume(struct early_suspend *h)
{unsigned long mode, para;//int ret;//struct sunxi_keyboard_data *ts = container_of(h, struct sunxi_keyboard_data, early_suspend);dprintk(DEBUG_SUSPEND, "[%s] return from standby state: %d. \n", __FUNCTION__, (int)standby_type);#ifdef CONFIG_ARCH_SUN9IW1P1clk_prepare_enable(key_clk);
#endif/* process for normal standby */if (NORMAL_STANDBY == standby_type) {mode = CONCERT_DLY_SET | ADC_CHAN_SET | KEY_MODE_SET | LRADC_HOLD_SET | LEVELB_VOL_SET \| LRADC_SAMPLE_SET | LRADC_EN_SET;para = FIRST_CONCERT_DLY|LEVELB_VOL|KEY_MODE_SELECT|LRADC_HOLD_EN|ADC_CHAN_SELECT \|LRADC_SAMPLE_250HZ|LRADC_EN;sunxi_keyboard_ctrl_set(mode, para);/* process for super standby */ } else if (SUPER_STANDBY == standby_type) {if (check_scene_locked(SCENE_TALKING_STANDBY) != 0) {#ifdef ONE_CHANNELmode = ADC0_DOWN_INT_SET | ADC0_UP_INT_SET | ADC0_DATA_INT_SET;para = LRADC_ADC0_DOWN_EN | LRADC_ADC0_UP_EN | LRADC_ADC0_DATA_EN;sunxi_keyboard_int_set(mode, para);mode = CONCERT_DLY_SET | ADC_CHAN_SET | KEY_MODE_SET | LRADC_HOLD_SET | LEVELB_VOL_SET \| LRADC_SAMPLE_SET | LRADC_EN_SET;para = FIRST_CONCERT_DLY|LEVELB_VOL|KEY_MODE_SELECT|LRADC_HOLD_EN|ADC_CHAN_SELECT \|LRADC_SAMPLE_250HZ|LRADC_EN;sunxi_keyboard_ctrl_set(mode, para);
#else
#endif} else {disable_wakeup_src(CPUS_LRADC_SRC, 0);printk("lradc-key: resume from talking standby!!\n");}}enable_irq(SW_INT_IRQNO_LRADC);return ;
}
#else
#ifdef CONFIG_PM
static int sunxi_keyboard_suspend(struct device *dev)
{//int ret;//struct sunxi_keyboard_data *ts = container_of(h, struct sunxi_keyboard_data, early_suspend);dprintk(DEBUG_SUSPEND, "[%s] enter standby state: %d. \n", __FUNCTION__, (int)standby_type);disable_irq_nosync(SW_INT_IRQNO_LRADC);if (NORMAL_STANDBY == standby_type) {sunxi_keyboard_ctrl_set(0, 0);
#ifdef CONFIG_ARCH_SUN9IW1P1clk_disable_unprepare(key_clk);
#endif/* process for super standby */ } else if (SUPER_STANDBY == standby_type) {if (check_scene_locked(SCENE_TALKING_STANDBY) == 0) {printk("lradc-key: talking standby, enable wakeup source lradc!!\n");enable_wakeup_src(CPUS_LRADC_SRC, 0);} else {sunxi_keyboard_ctrl_set(0, 0);
#ifdef CONFIG_ARCH_SUN9IW1P1clk_disable_unprepare(key_clk);
#endif}}return 0;
}/* ���»��� */
static int sunxi_keyboard_resume(struct device *dev)
{unsigned long mode, para;//int ret;//struct sunxi_keyboard_data *ts = container_of(h, struct sunxi_keyboard_data, early_suspend);dprintk(DEBUG_SUSPEND, "[%s] return from standby state: %d. \n", __FUNCTION__, (int)standby_type);#ifdef CONFIG_ARCH_SUN9IW1P1clk_prepare_enable(key_clk);
#endif/* process for normal standby */if (NORMAL_STANDBY == standby_type) {mode = CONCERT_DLY_SET | ADC_CHAN_SET | KEY_MODE_SET | LRADC_HOLD_SET | LEVELB_VOL_SET \| LRADC_SAMPLE_SET | LRADC_EN_SET;para = FIRST_CONCERT_DLY|LEVELB_VOL|KEY_MODE_SELECT|LRADC_HOLD_EN|ADC_CHAN_SELECT \|LRADC_SAMPLE_250HZ|LRADC_EN;sunxi_keyboard_ctrl_set(mode, para);/* process for super standby */} else if (SUPER_STANDBY == standby_type) {if (check_scene_locked(SCENE_TALKING_STANDBY) != 0) {#ifdef ONE_CHANNELmode = ADC0_DOWN_INT_SET | ADC0_UP_INT_SET | ADC0_DATA_INT_SET;para = LRADC_ADC0_DOWN_EN | LRADC_ADC0_UP_EN | LRADC_ADC0_DATA_EN;sunxi_keyboard_int_set(mode, para);mode = CONCERT_DLY_SET | ADC_CHAN_SET | KEY_MODE_SET | LRADC_HOLD_SET | LEVELB_VOL_SET \| LRADC_SAMPLE_SET | LRADC_EN_SET;para = FIRST_CONCERT_DLY|LEVELB_VOL|KEY_MODE_SELECT|LRADC_HOLD_EN|ADC_CHAN_SELECT \|LRADC_SAMPLE_250HZ|LRADC_EN;sunxi_keyboard_ctrl_set(mode, para);
#else
#endif} else {disable_wakeup_src(CPUS_LRADC_SRC, 0);printk("lradc-key: resume from talking standby!!\n");}}enable_irq(SW_INT_IRQNO_LRADC);return 0;
}
#endif
#endifstatic irqreturn_t sunxi_isr_key(int irq, void *dummy)
{u32  reg_val = 0;int judge_flag = 0;dprintk(DEBUG_INT, "Key Interrupt\n");reg_val = sunxi_keyboard_read_ints();//writel(reg_val,KEY_BASSADDRESS + LRADC_INT_STA);if (reg_val & LRADC_ADC0_DOWNPEND) {dprintk(DEBUG_INT, "key down\n");}if (reg_val & LRADC_ADC0_DATAPEND) {key_val = sunxi_keyboard_read_data(KEY_BASSADDRESS+LRADC_DATA0);if (key_val < 0x3f) {compare_buffer[key_cnt] = key_val&0x3f;}if ((key_cnt + 1) < REPORT_START_NUM) {key_cnt++;/* do not report key message */} else {if(compare_buffer[0] == compare_buffer[1]){key_val = compare_buffer[1];scancode = keypad_mapindex[key_val&0x3f];judge_flag = 1;key_cnt = 0;} else {key_cnt = 0;judge_flag = 0;}if (1 == judge_flag) {dprintk(DEBUG_INT, "report data: key_val :%8d transfer_code: %8d , scancode: %8d\n", \key_val, transfer_code, scancode);if (transfer_code == scancode) {/* report repeat key value */
#ifdef REPORT_REPEAT_KEY_FROM_HWinput_report_key(sunxikbd_dev, sunxi_scankeycodes[scancode], 0);input_sync(sunxikbd_dev);input_report_key(sunxikbd_dev, sunxi_scankeycodes[scancode], 1);input_sync(sunxikbd_dev);
#else/* do not report key value */
#endif} else if (INITIAL_VALUE != transfer_code) {     /* report previous key value up signal + report current key value down */input_report_key(sunxikbd_dev, sunxi_scankeycodes[transfer_code], 0);input_sync(sunxikbd_dev);input_report_key(sunxikbd_dev, sunxi_scankeycodes[scancode], 1);input_sync(sunxikbd_dev);transfer_code = scancode;} else {/* INITIAL_VALUE == transfer_code, first time to report key event */input_report_key(sunxikbd_dev, sunxi_scankeycodes[scancode], 1);input_sync(sunxikbd_dev);transfer_code = scancode;}}}}if (reg_val & LRADC_ADC0_UPPEND) {if(INITIAL_VALUE != transfer_code) {dprintk(DEBUG_INT, "report data: key_val :%8d transfer_code: %8d \n",key_val, transfer_code);input_report_key(sunxikbd_dev, sunxi_scankeycodes[transfer_code], 0);input_sync(sunxikbd_dev);}dprintk(DEBUG_INT, "key up \n");key_cnt = 0;judge_flag = 0;transfer_code = INITIAL_VALUE;}sunxi_keyboard_clr_ints(reg_val);return IRQ_HANDLED;
}#ifdef CONFIG_ARCH_SUN8IW8P1
static int use_adc_check_bat = 0;
static int bat_max_vol = 0;
static int bat_min_vol = 0;static void battery_adc_init(void)
{script_item_u script_val;script_item_value_type_e type;type = script_get_item("bat_adc_para", "used", &script_val);if (SCIRPT_ITEM_VALUE_TYPE_INT != type) {return ;}use_adc_check_bat = script_val.val;type = script_get_item("bat_adc_para", "bat_max_vol", &script_val);if (SCIRPT_ITEM_VALUE_TYPE_INT == type) {bat_max_vol = script_val.val;}type = script_get_item("bat_adc_para", "bat_min_vol", &script_val);if (SCIRPT_ITEM_VALUE_TYPE_INT == type) {bat_min_vol = script_val.val;}
}static ssize_t adc_get_data(struct device *dev, struct device_attribute *attr, char *buf)
{int key_val = 100;int modify_vol = 0;if (use_adc_check_bat && bat_max_vol && bat_min_vol){key_val = sunxi_keyboard_read_data(KEY_BASSADDRESS+LRADC_DATA0);printk("adc_val=%d\n", key_val);modify_vol = 1000 * key_val / 64 * 2;  // mvif (modify_vol > bat_max_vol)key_val = 100;else if (modify_vol < bat_min_vol)key_val = 0;elsekey_val = 100 * (modify_vol - bat_min_vol) /  (bat_max_vol - bat_min_vol);}printk("modify_vol=%d\n", modify_vol);return sprintf(buf, "%d\n", key_val);
}static struct device_attribute keyboard_attributes[] = {__ATTR(data, 0444, adc_get_data, NULL),
};
#endifstatic void sunxikbd_map_init(void)
{int i = 0;unsigned char j = 0;for(i = 0; i < 64; i++){ if(i * ADC_RESOL > key_vol[j])j++;keypad_mapindex[i] = j;}
}static int sunxikbd_script_init(void)
{int i;char key_name[16];script_item_u   val;script_item_value_type_e  type;type = script_get_item("key_para", "key_used", &val);if (SCIRPT_ITEM_VALUE_TYPE_INT != type) {pr_err("%s: key para not found, used default para. \n", __func__);return 0;}if(1 == val.val){type = script_get_item("key_para", "key_cnt", &val);if(SCIRPT_ITEM_VALUE_TYPE_INT != type){pr_err("%s: get key cnt err! \n", __func__);return -1;}key_num = val.val;dprintk(DEBUG_INT,"%s key number = %d.\n", __func__, key_num);if(key_num < 1 || key_num > VOL_NUM){pr_err("incorrect key number.\n");return -1;}for(i = 0; i<VOL_NUM; i++)key_vol[i] = ADC_MEASURE;for(i = 1; i <= key_num; i++){sprintf(key_name, "key%d_vol", i);type = script_get_item("key_para", key_name, &val);if(SCIRPT_ITEM_VALUE_TYPE_INT != type){pr_err("%s: get %s err! \n", __func__, key_name);return -1;}key_vol[i-1] = val.val;dprintk(DEBUG_INT,"%s: key%d vol = %d.\n", __func__, i, val.val);}sunxikbd_map_init();}else{dprintk(DEBUG_INT,"sunxi key board no used.\n");return -1;}return 0;
}static int __init sunxikbd_init(void)
{int i;int err =0;unsigned long mode, para;dprintk(DEBUG_INIT, "sunxikbd_init \n");if(sunxikbd_script_init()){err = -EFAULT;goto fail1;}#ifdef CONFIG_ARCH_SUN8IW8P1battery_adc_init();
#endifsunxikbd_dev = input_allocate_device();if (!sunxikbd_dev) {pr_err("sunxikbd: not enough memory for input device\n");err = -ENOMEM;goto fail1;}sunxikbd_dev->name = INPUT_DEV_NAME;sunxikbd_dev->phys = "sunxikbd/input0";sunxikbd_dev->id.bustype = BUS_HOST;sunxikbd_dev->id.vendor = 0x0001;sunxikbd_dev->id.product = 0x0001;sunxikbd_dev->id.version = 0x0100;#ifdef REPORT_REPEAT_KEY_BY_INPUT_COREsunxikbd_dev->evbit[0] = BIT_MASK(EV_KEY)|BIT_MASK(EV_REP);pr_info("REPORT_REPEAT_KEY_BY_INPUT_CORE is defined, support report repeat key value. \n");
#elsesunxikbd_dev->evbit[0] = BIT_MASK(EV_KEY);
#endiffor (i = 0; i < KEY_MAX_CNT; i++)set_bit(sunxi_scankeycodes[i], sunxikbd_dev->keybit);#ifdef CONFIG_ARCH_SUN9IW1P1sunxikbd_clk_cfg();
#endif#ifdef ONE_CHANNEL
#ifdef CONFIG_ARCH_SUN8IW8P1if (!use_adc_check_bat)
#endif{mode = ADC0_DOWN_INT_SET | ADC0_UP_INT_SET | ADC0_DATA_INT_SET;para = LRADC_ADC0_DOWN_EN | LRADC_ADC0_UP_EN | LRADC_ADC0_DATA_EN;sunxi_keyboard_int_set(mode, para);}mode = CONCERT_DLY_SET | ADC_CHAN_SET | KEY_MODE_SET | LRADC_HOLD_SET | LEVELB_VOL_SET \| LRADC_SAMPLE_SET | LRADC_EN_SET;para = FIRST_CONCERT_DLY|LEVELB_VOL|KEY_MODE_SELECT|LRADC_HOLD_EN|ADC_CHAN_SELECT \|LRADC_SAMPLE_250HZ|LRADC_EN;sunxi_keyboard_ctrl_set(mode, para);
#else
#endifif (request_irq(SW_INT_IRQNO_LRADC, sunxi_isr_key, 0, "sunxikbd", NULL)) {err = -EBUSY;pr_err("request irq failure. \n");goto fail2;}#ifdef CONFIG_HAS_EARLYSUSPEND
#else
#ifdef CONFIG_PMkeyboard_pm_domain.ops.suspend = sunxi_keyboard_suspend;keyboard_pm_domain.ops.resume = sunxi_keyboard_resume;sunxikbd_dev->dev.pm_domain = &keyboard_pm_domain;
#endif
#endiferr = input_register_device(sunxikbd_dev);if (err)goto fail3;#ifdef CONFIG_HAS_EARLYSUSPEND dprintk(DEBUG_INIT, "==register_early_suspend =\n");keyboard_data = kzalloc(sizeof(*keyboard_data), GFP_KERNEL);if (keyboard_data == NULL) {err = -ENOMEM;goto err_alloc_data_failed;}keyboard_data->early_suspend.level = EARLY_SUSPEND_LEVEL_BLANK_SCREEN + 3;keyboard_data->early_suspend.suspend = sunxi_keyboard_early_suspend;keyboard_data->early_suspend.resume     = sunxi_keyboard_late_resume;register_early_suspend(&keyboard_data->early_suspend);
#endif#ifdef CONFIG_ARCH_SUN8IW8P1if (use_adc_check_bat)device_create_file(&sunxikbd_dev->dev, &keyboard_attributes[0]);
#endifdprintk(DEBUG_INIT, "sunxikbd_init end\n");return 0;
#ifdef CONFIG_HAS_EARLYSUSPEND
err_alloc_data_failed:
#endif
fail3:free_irq(SW_INT_IRQNO_LRADC, NULL);
fail2:input_free_device(sunxikbd_dev);
fail1:pr_err("sunxikbd_init failed. \n");return err;
}static void __exit sunxikbd_exit(void)
{#ifdef CONFIG_HAS_EARLYSUSPEND  unregister_early_suspend(&keyboard_data->early_suspend);
#endiffree_irq(SW_INT_IRQNO_LRADC, NULL);
#ifdef CONFIG_ARCH_SUN9IW1P1sunxikbd_clk_uncfg();
#endif
#ifdef CONFIG_ARCH_SUN8IW8P1if (use_adc_check_bat)device_remove_file(&sunxikbd_dev->dev, &keyboard_attributes[0]);
#endifinput_unregister_device(sunxikbd_dev);
}module_init(sunxikbd_init);
module_exit(sunxikbd_exit);MODULE_AUTHOR(" <@>");
MODULE_DESCRIPTION("sunxi-keyboard driver");
MODULE_LICENSE("GPL");

四、重新开始一个

新编一个驱动.ko

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <asm/io.h>          //含有ioremap函数iounmap函数
#include <asm/uaccess.h>     //含有copy_from_user函数和含有copy_to_user函数
#include <linux/device.h>    //含有类相关的设备函数
#include <linux/cdev.h>
#include <linux/platform_device.h> //包含platform函数
#include <linux/of.h>        //包含设备树相关函数
#include <linux/irq.h>       //含有IRQ_HANDLED和IRQ_TYPE_EDGE_RISING
#include <linux/interrupt.h> //含有request_irq、free_irq函数
#include <linux/input.h>
#include <linux/irq.h>struct input_dev *mykeypad_dev;           //定义一个input_dev结构体  ssize_t  volatile *keyadc_ctrl;
ssize_t  volatile *keyadc_intc;
ssize_t  volatile *keyadc_ints;
ssize_t  volatile *keyadc_data;static unsigned int key_value = 0; //定义一个变量保存按键值static irqreturn_t  mykeypad_irq (int irq, void *dev_id)       //中断服务函数
{/*上报事件*/if(((*keyadc_ints)&(1<<1)) != 0)  //按键按下{ key_value = ((*keyadc_data)&(0x3f));   //获取按键值if(key_value == 24){input_event(mykeypad_dev, EV_KEY, KEY_A , 1); //上报EV_KEY类型,1(按下)    }else if(key_value == 17){input_event(mykeypad_dev, EV_KEY, KEY_B, 1);  //上报EV_KEY类型, 1(按下)    }else if(key_value == 11){input_event(mykeypad_dev, EV_KEY, KEY_C, 1);  //上报EV_KEY类型, 1(按下)    }else{input_event(mykeypad_dev, EV_KEY, KEY_D, 1);  //上报EV_KEY类型, 1(按下)    }}else if(((*keyadc_ints)&(1<<4)) != 0) //按键释放{if(key_value == 24){input_event(mykeypad_dev, EV_KEY, KEY_A , 0);  //上报EV_KEY类型, 0(释放)    }else if(key_value == 17){input_event(mykeypad_dev, EV_KEY, KEY_B, 0);  //上报EV_KEY类型, 0(释放)   }else if(key_value == 11){input_event(mykeypad_dev, EV_KEY, KEY_C, 0);  //上报EV_KEY类型, 0(释放)    }else{input_event(mykeypad_dev, EV_KEY, KEY_D, 0);  //上报EV_KEY类型, 0(释放)    }}input_sync(mykeypad_dev);       // 上传同步事件,告诉系统有事件出现*keyadc_ints |= ((1<<0) | (1<<1) | (1<<2) | (1<<3) | (1<<4));return IRQ_HANDLED;
}static int mykeypad_probe(struct platform_device *pdev)
{int ret;      struct resource *res;mykeypad_dev=input_allocate_device();      //向内核申请input_dev结构体set_bit(EV_KEY,mykeypad_dev->evbit);       //支持键盘事件set_bit(EV_REP,mykeypad_dev->evbit);       //支持键盘重复按事件set_bit(KEY_A,mykeypad_dev->keybit);       //支持按键 Aset_bit(KEY_B,mykeypad_dev->keybit);       //支持按键 Bset_bit(KEY_C,mykeypad_dev->keybit);       //支持按键 Cset_bit(KEY_D,mykeypad_dev->keybit);       //支持按键 Dmykeypad_dev->name = pdev->name;           //设备名称mykeypad_dev->phys = "mykeypad/input0";    //设备文件路径mykeypad_dev->open = NULL;                 //设备打开操作函数mykeypad_dev->close = NULL;                //设备关闭操作函数mykeypad_dev->id.bustype = BUS_HOST;       //设备总线类型mykeypad_dev->id.vendor = 0x0001;          //设备厂家编号mykeypad_dev->id.product = 0x0001;         //设备产品编号mykeypad_dev->id.version = 0x0100;         //设备版本ret = input_register_device(mykeypad_dev);       //注册input_devif(ret){input_free_device(mykeypad_dev);printk(KERN_ERR "regoster input device failed!\n");return ret;}mykeypad_dev->name="mykeypad";res = platform_get_resource(pdev, IORESOURCE_MEM, 0);//获取device中的LRADC_CTRLkeyadc_ctrl = ioremap(res->start,(res->end - res->start)+1);res = platform_get_resource(pdev, IORESOURCE_MEM, 1);//获取device中的LRADC_INTCkeyadc_intc = ioremap(res->start,(res->end - res->start)+1);res = platform_get_resource(pdev, IORESOURCE_MEM, 2);//获取device中的LRADC_INTSkeyadc_ints = ioremap(res->start,(res->end - res->start)+1);res = platform_get_resource(pdev, IORESOURCE_MEM, 3);//获取device中的LRADC_DATAkeyadc_data = ioremap(res->start,(res->end - res->start)+1);ret = devm_request_irq(&pdev->dev, platform_get_irq(pdev, 0), mykeypad_irq, 0, "mykey", (void*)&key_value);*keyadc_ctrl&=0;*keyadc_ctrl |= (1<<12);  //单次模式，其他默认*keyadc_intc |= (1<<4) | (1<<1);*keyadc_ctrl |= (1<<0);if(ret){return ret;}return 0;
}static int mykeypad_remove(struct platform_device *pdev)
{iounmap(keyadc_ctrl);   //取消LRADC_CTRL映射iounmap(keyadc_intc);   //取消LRADC_INTC映射iounmap(keyadc_ints);   //取消LRADC_INTS映射iounmap(keyadc_data);   //取消LRADC_DATA映射input_unregister_device(mykeypad_dev);     //卸载类下的驱动设备input_free_device(mykeypad_dev);           //释放驱动结构体return 0;
}static struct of_device_id mykeypad_match_table[] = {  {.compatible = "mykeypad",},
}; static struct platform_device_id mykeypad_device_ids[] = {{.name = "mykeypad",},
};static struct platform_driver mykeypad_driver=
{  .probe  = mykeypad_probe,  .remove = mykeypad_remove,  .driver={  .name = "mykeypad",  .of_match_table = mykeypad_match_table,  },  .id_table = mykeypad_device_ids,
};module_platform_driver(mykeypad_driver);MODULE_LICENSE("GPL");          //不加的话加载会有错误提醒
MODULE_AUTHOR("liefyuan@qq.com");     //作者
MODULE_VERSION("0.1");          //版本
MODULE_DESCRIPTION("mykeypad_driver");  //简单的描述

mykeypad: mykeypad@1c22800 {compatible = "mykeypad";reg = <0x01c22800 0x4>, <0x01c22804 0x4>, <0x01c22808 0x4>, <0x01c2280c 0x4>;interrupts = <GIC_SPI 30 IRQ_TYPE_LEVEL_HIGH>;status = "okay";
};

编译.ko文件：
makefile
方式一：

KERNEL_DIR := /home/liefyuan/Liefyuan/cherry-pi/linux-zero-4.10.y
CURRENT_PATH := $(shell pwd)
obj-m := mykeypad.obuild: kernel_moduleskernel_modules:$(MAKE) -C $(KERNEL_DIR) M=$(CURRENT_PATH) modulesclean:$(MAKE) -C $(KERNEL_DIR) M=$(CURRENT_PATH) clean

方式二：

KERN_DIR = /home/liefyuan/Liefyuan/cherry-pi/linux-zero-4.10.y
all:make -C $(KERN_DIR) M=$(shell pwd) modules clean:rm -rf *.order *o *.symvers *.mod.c *.mod *.koobj-m += mykeypad.o

编译：

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j16

测试程序

lradc_key.c

#include <string.h>
#include <fcntl.h>
#include <linux/input.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>#define  CHECK_POINT
int main(int argc, char** argv)
{int fd = open(argv[1],O_RDONLY);#ifdef CHECK_POINTprintf("fd = %d\n",fd);#endifstruct input_event t;printf("size of t = %d\n",sizeof(t));while(1){printf("while -\n");int len = read(fd, &t, sizeof(t));if(len == sizeof(t)){printf("read over\n");if(t.type==EV_KEY){printf("key %d %s\n", t.code, (t.value) ? "Pressed" : "Released");if(t.code == KEY_ESC)break;}}#ifdef CHECK_POINTprintf("len = %d\n",len);#endif}return 0;
}

编译测试程序：

arm-linux-gnueabihf-gcc lradc_key.c -o lradc_key

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