S5PV210 Android 矩阵键盘驱动［基于x210开发板］

矩阵键盘驱动源文件：

kernel/drivers/input/touchscreen/keyboard/s3c-keypad.c

kernel/drivers/input/touchscreen/keyboard/s3c-keypad.h

kernel/arch/arm/mach-s5pv210/mach-smdkc110.c

kernel/arch/arm/plat-s5p/devs.c

首先，make menuconfig，

Device Drivers --->

Input device support --->

Keyboards --->

< *> S3C keypad support

注意，手动配置menuconfig后，需要手动将.config覆盖到arch/arm/configs下的

s5pv210_android_defconfig文件，否则脚本自动会将该文件覆盖到内核根目录下。

然后，在mach-smdkc110.c中配置矩阵键盘的IO口:

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void s3c_setup_keypad_cfg_gpio(int rows, int columns)
{
unsigned int gpio;
unsigned int end;

end = S5PV210_GPH3(rows);

/* Set all the necessary GPH2 pins to special-function 0 */
for (gpio = S5PV210_GPH3(0); gpio < end; gpio++)
{
s3c_gpio_cfgpin(gpio, S3C_GPIO_SFN(3));
s3c_gpio_setpull(gpio, S3C_GPIO_PULL_UP);
}

end = S5PV210_GPH2(columns);

/* Set all the necessary GPK pins to special-function 0 */
//for (gpio = S5PV210_GPH2(0); gpio < end; gpio++)

for (gpio = S5PV210_GPH2(3); gpio < (end+3); gpio++)//lqm changed.

{
s3c_gpio_cfgpin(gpio, S3C_GPIO_SFN(3));
s3c_gpio_setpull(gpio, S3C_GPIO_PULL_NONE);
}
}

void s3c_setup_keypad_cfg_gpio(int rows, int columns)
{
unsigned int gpio;
unsigned int end;

end = S5PV210_GPH3(rows);

/* Set all the necessary GPH2 pins to special-function 0 */
for (gpio = S5PV210_GPH3(0); gpio < end; gpio++)
{
s3c_gpio_cfgpin(gpio, S3C_GPIO_SFN(3));
s3c_gpio_setpull(gpio, S3C_GPIO_PULL_UP);
}

end = S5PV210_GPH2(columns);

/* Set all the necessary GPK pins to special-function 0 */
//for (gpio = S5PV210_GPH2(0); gpio < end; gpio++)
for (gpio = S5PV210_GPH2(3); gpio < (end+3); gpio++)//lqm changed.
{
s3c_gpio_cfgpin(gpio, S3C_GPIO_SFN(3));
s3c_gpio_setpull(gpio, S3C_GPIO_PULL_NONE);
}
}

注意，这里需和硬件电路匹配，具体使用了8＊8或是4＊4或是2＊5等，最好程序做相应的调整。

紧接着，在devs.c中，会有平台设备的定义以及一些资源的定义：

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/* Keypad interface */
static struct resource s3c_keypad_resource[] = {
[0] = {
.start = S3C_PA_KEYPAD,
.end = S3C_PA_KEYPAD + S3C_SZ_KEYPAD - 1,
.flags = IORESOURCE_MEM,
},
[1] = {
.start = IRQ_KEYPAD,
.end = IRQ_KEYPAD,
.flags = IORESOURCE_IRQ,
}
};

struct platform_device s3c_device_keypad = {
.name = "s3c-keypad",
.id = -1,
.num_resources = ARRAY_SIZE(s3c_keypad_resource),
.resource = s3c_keypad_resource,
};

/* Keypad interface */
static struct resource s3c_keypad_resource[] = {
[0] = {
.start = S3C_PA_KEYPAD,
.end   = S3C_PA_KEYPAD + S3C_SZ_KEYPAD - 1,
.flags = IORESOURCE_MEM,
},
[1] = {
.start = IRQ_KEYPAD,
.end   = IRQ_KEYPAD,
.flags = IORESOURCE_IRQ,
}
};

struct platform_device s3c_device_keypad = {
.name             = "s3c-keypad",
.id               = -1,
.num_resources    = ARRAY_SIZE(s3c_keypad_resource),
.resource         = s3c_keypad_resource,
};

最后，就是键盘驱动了，具体在s3c-keypad.c和s3c-keypad.h中，s3c_keypad_probe

函数通过platform_get_resource获取按键的IO，中断资源，调用mach-smdkc110.c中

的s3c_setup_keypad_cfg_gpio函数配置IO口，通过s3c-keypad.h中的相关定义填充

结构体s3c_keypad，再利用了内核定时器不断扫描按键。

按键扫描函数在keypad_timer_handler中，它反复调用keypad_scan函数，然后通过算

法判断是否有键按下，关键语句如下：

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press_mask = ((keymask[col] ^ prevmask[col]) & keymask[col]); release_mask = ((keymask[col] ^ prevmask[col]) & prevmask[col]); ...... prevmask[col] = keymask[col]; ......

press_mask = ((keymask[col] ^ prevmask[col]) & keymask[col]);
release_mask = ((keymask[col] ^ prevmask[col]) & prevmask[col]);
......
prevmask[col] = keymask[col];
......

然后通过两个while循环检测按下的键值，并上报给系统。

以上三条语句非常的巧妙，能够很好的识别按下和抬起的事件，在keypad_scan函数中，利用

逐行扫描法，以4＊4为例，如首先将行设置为0xe，这时最末一列被赋为低，再检测列上的电平，

如也出现低电平，则根据具体的位置判断是哪颗键按下。然后依次将行设置为0xd,0xb,0x7。

将检测到的键保存到rval后再取反，再保存到keymask数组中，然后利用上面的算法得到

press_mask和release_mask，根据得到的值判断是否有键按下或抬起。

键值码表在s3c-keypad.h中，定义如下：

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int keypad_keycode[] = { 1, 2, 3, 4, 5, 6, 7, 8,34, 10 };

int keypad_keycode[] = {
1, 2, 3, 4, 5,
6, 7, 8,34, 10
};

这里是2＊5的码表，如是4＊4或是其他组合，修改该码表即可，上面对应了相应按键发送给系统的

键值，android键值码表在device/samsung/smdkv210/s3c-keypad.kl中，内容如下：

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key 42 VOLUME_UP WAKE
key 58 VOLUME_DOWN WAKE
key 51 HOME WAKE_DROPPED
key 50 MENU WAKE_DROPPED
key 26 ENDCALL WAKE_DROPPED
key 34 BACK WAKE_DROPPED
key 57 DPAD_LEFT WAKE_DROPPED
key 49 DPAD_RIGHT WAKE_DROPPED
key 25 DPAD_UP WAKE_DROPPED
key 41 DPAD_DOWN WAKE_DROPPED
key 33 DPAD_CENTER WAKE_DROPPED
key 10 POWER WAKE

key 42    VOLUME_UP         WAKE
key 58    VOLUME_DOWN       WAKE
key 51    HOME              WAKE_DROPPED
key 50    MENU              WAKE_DROPPED
key 26    ENDCALL           WAKE_DROPPED
key 34    BACK              WAKE_DROPPED
key 57    DPAD_LEFT         WAKE_DROPPED
key 49    DPAD_RIGHT        WAKE_DROPPED
key 25    DPAD_UP           WAKE_DROPPED
key 41    DPAD_DOWN         WAKE_DROPPED
key 33    DPAD_CENTER       WAKE_DROPPED
key 10    POWER     	    WAKE

我们按下第9个键时，驱动中发送的是34，对应android码表中key34为BACK键，那么第9个

键将扮演返回的角色，其他同理。

附：相关源码下载：

http://xboot.org/forum.php?mod=viewthread&tid=348&extra=

转载自:/article/7602394.html