查看“MY-I.MX6 评估板开发指导（GPIO）”的源代码

<div>

= '''GPIO输出和输入（GPIO output & input）''' =
GPIO输入输出以SD1_CLK管脚为例。<br>
<span style="background:#CCCCCC">GPIO output & input take SD1_CLK leads as an example。</span><br>

== '''修改.h文件(modification “.h” file)''' ==
1）检查头文件中对SD1_CLK的配置<br>
<span style="background:#CCCCCC">check configuration for SD1_CLK in file）</span><br>
示例如下(example)：<br>
$ sed -n "/PAD_SD1_CLK/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
2）注释头文件中对SD1_CLK的配置<br>
<span style="background:#CCCCCC">configuration for SD1_CLK in comment header file</span><br>
示例如下(example)：<br>
$ sed -i "s/MX6Q_PAD_SD1_CLK/\/\/ &/g" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
3）在mx6q_sabresd_pads中添加对SD1_CLK的配置<br>
<span style="background:#CCCCCC">adding configuration for SD1_CLK in mx6q_sabresd_pads</span><br>
配置SD1_CLK功能为MX6Q_PAD_SD1_CLK__GPIO_1_20<br>
<span style="background:#CCCCCC">configure SD1_CLK function as MX6Q_PAD_SD1_CLK__GPIO_1_20</span><br>
示例如下(example)：<br>
$ sed -i "/mx6q_sabresd_pads/a\\\t MX6Q_PAD_SD1_CLK__GPIO_1_20," \<br>
arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
4）查看修改结果<br>
<span style="background:#CCCCCC">check modified result</span><br>

示例如下(example)：<br>
$ sed -n "/PAD_SD1_CLK/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>


== '''配置内核(configure kernel)''' ==
*菜单定位(mamu position)<br>
Device Drivers  --->  -*- GPIO Support  --->  [*]   /sys/class/gpio/... (sysfs interface)<br>
[[文件:my_imx6_gpio_1.2.0.1.jpg]]<br>


== '''编译(compilation)''' ==
make uImage<br>
== '''重新烧写系统并启动(re-program system and boot)''' ==
== '''设备操作(device operation)''' ==

=== 查看gpio目录(check out gpio directory) ===
在/sys/class/gpio/目录下可以看到已经导出的GPIO<br>
<span style="background:#CCCCCC">GPIO led out can bee seen under /sys/class/gpio/ directory</span><br>
$ ls /sys/class/gpio/<br>
<br>
　　[[文件:my_imx6_gpio_1.5.1.1.jpg]]<br>
<br>

=== 向系统注册GPIO(register GPIO to system) ===
　　使用echo注册GPIO_1_20到系统，即可看到gpio目录下多出一个gpio20目录。<br>
　　<span style="background:#CCCCCC">register GPIO_1_20 to system with echo，then an extra gpio20 directory can be found under gpio directory。</span><br>
　　提示：I.MX6 GPIO的值计算方法是（所在的组 - 1） * 32 + 序号，所以GPIO_1_20的管脚值为 （1 – 1） * 32 + 20 = 20。<br>
　　<span style="background:#CCCCCC">tips：I.MX6 GPIO value is calculation this way（where grouped - 1） * 32 + order number，so lead number of GPIO_1_20 is（1 – 1） * 32 + 20 = 20。</span><br>
$ echo 20 > /sys/class/gpio/export<br>
<br>
　　[[文件:my_imx6_gpio_1.5.2.1.jpg]]<br>
<br>

=== GPIO输出控制(GPIO output control) ===
*设置管脚为输出状态
<span style="background:#CCCCCC">set leads as output state</span><br>
$ echo out > /sys/class/gpio/gpio20/direction<br>
*设置管脚为输出为高电平
<span style="background:#CCCCCC">set lead output at high electrical level</span><br>
echo 1 > /sys/class/gpio/gpio20/value<br>
*设置管脚为输出为低电平
<span style="background:#CCCCCC">set lead output at low electrical level</span><br>
echo 0 > /sys/class/gpio/gpio20/value<br>

=== GPIO输入设置(set lead as input state) ===
*设置管脚为输入状态
<span style="background:#CCCCCC">set lead as input state</span><br>
echo in > /sys/class/gpio/gpio20/direction<br>
*获取输入值<br>
<span style="background:#CCCCCC">gain lead value</span><br>
cat /sys/class/gpio/gpio20/value<br>

=== 注销GPIO接口(logout GPIO interface) ===
*注销GPIO_1_20
<span style="background:#CCCCCC">logout GPIO_1_20</span><br>
echo 20 > /sys/class/gpio/unexport<br>
= '''GPIO LED''' =
----
说明：GPIO LED以PAD NANDF_CS0为例。<br>
<span style="background:#CCCCCC">instruction：take GPIO LED以PAD NANDF_CS0 as example。</span><br>

== '''进入内核目录(enter kernel directory)''' ==
$ cd ~/MY-I.MX6/linux-3.0.35/<br>
[[文件:my_imx6_gpio_2.1.0.1.jpg]]<br>

== '''添加代码(add code)''' ==
=== 修改.h文件(modification.h file) ===
1）查找头文件中对NANDF_CS0的配置<br>
<span style="background:#CCCCCC">check out configuration for NANDF_CS0 in header file.</span><br>
示例如下(example)：<br>
$ sed -n "/PAD_NANDF_CS0/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
2）注释头文件中对NANDF_CS0的配置<br>
<span style="background:#CCCCCC">comment configuration for NANDF_CS0 in header file.</span><br>
示例如下(example)：<br>
$ sed -i "s/MX6Q_PAD_NANDF_CS0/\/\/ &/g" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
3）在mx6q_sabresd_pads中添加对NANDF_CS0的配置<br>
<span style="background:#CCCCCC">add configuration for NANDF_CS0 in mx6q_sabresd_pads.</span><br>
配置NANDF_CS0功能为MX6Q_PAD_NANDF_CS0__GPIO_6_11<br>
<span style="background:#CCCCCC">configure NANDF_CS0 function as MX6Q_PAD_NANDF_CS0__GPIO_6_11.</span><br>
示例如下(example)：<br>
$ sed -i "/mx6q_sabresd_pads/a\\\tMX6Q_PAD_NANDF_CS0__GPIO_6_11," arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>

4）查看修改结果<br>
<span style="background:#CCCCCC">check out modified result.</span><br>
示例如下(example)：<br>
$ sed -n "/PAD_NANDF_CS0/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>


=== 修改.c文件(modification.c file) ===
1）检查.c文件中GPIO是否被重复使用<br>
<span style="background:#CCCCCC">check out whether GPIO is used repeatedly in .c file</span><br>
示例如下(example)：<br>
$ sed -n '/IMX_GPIO_NR(6,.11)/p' arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
<br>
2）在.c文件中增加GPIO的宏定义<br>
<span style="background:#CCCCCC">add macro definition of GPIOin .c file</span><br>
增加#define SABRESD_USER_LED        IMX_GPIO_NR(6, 11)<br>
<span style="background:#CCCCCC">add #define SABRESD_USER_LED        IMX_GPIO_NR(6, 11)</span><br>
示例如下(example)：<br>
$ GPIO_DEFINE="#define SABRESD_USER_LED\tIMX_GPIO_NR(6, 11)"<br>
$ sed -i "1,/#define/{/#define/s/#define/${GPIO_DEFINE}\n&/}" arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
<br>
2）检查gpio_led类型的数据定义<br>
<span style="background:#CCCCCC">check out data definition with gpio_led</span><br>
示例如下(example)：<br>
$ sed -n '/struct gpio_led /,/\}/p' arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
<br>
3）增加user_led的数据定义<br>
<span style="background:#CCCCCC">add data definition of user_led</span><br>
static struct gpio_led imx6q_gpio_leds[] = {<br>
　　　　GPIO_LED(SABRESD_USER_LED, "user_led", 0, 1,<br>
　　　　　　　　"charger"),<br>
}；<br>

== '''内核配置(kernel configuration)''' ==
*菜单定位(manu position) <br>
Device Drivers  --->  [*] LED Support  --->  <*>   LED Support for GPIO connected LEDs<br>
[[文件:my_imx6_gpio_2.3.0.1.jpg]]<br>

== '''编译(compilation)''' ==
make uImage<br>
== '''重新烧写系统并启动(re-program system and boot)''' ==
== '''GPIO_LED操作(GPIO_LED operation)''' ==
=== 设备文件目录(device file directory) ===
启动系统后即存在/sys/class/leds/user_led目录，使用ls即可看到<br>
<span style="background:#CCCCCC">to be saved under /sys/class/leds/user_led directory after booting system，which can be seen with ls.</span><br>
$ ls /sys/class/leds/user_led<br>
<br>
　　[[文件:my_imx6_gpio_2.6.1.1.jpg]]<br>
<br>

=== 操作示例(operating example) ===
1）置NANDF_CS0为1(set NANDF_CS0 as 1)<br>
$ echo 1 > /sys/class/leds/user_led/brightness<br>
2）置NANDF_CS0为0(set NANDF_CS0 as 0)<br>
$ echo 0 > /sys/class/leds/user_led/brightness<br>

= '''GPIO按键(GPIO key)''' =
----
GPIO按键以GPIO_4、EIM_BCLK、CSI0_DATA_EN为例，分别是原理图的按键SW2，SW3和SW4。<br>
<span style="background:#CCCCCC">GPIO key by taking GPIO_4、EIM_BCLK、CSI0_DATA_EN as example，are separetely SW2，SW3和SW4 in schematic。</span><br>

== '''修改.h文件(modification.h file)''' ==
1）查找头文件中对PAD的配置<br>
<span style="background:#CCCCCC">check out configuration for PAD in header file.</span><br>
示例如下(example)：<br>
$ sed -n "/PAD_GPIO_4/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
$ sed -n "/PAD_EIM_BCLK/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
$ sed -n "/PAD_CSI0_DATA_EN/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
2）注释头文件中对PAD的配置<br>
<span style="background:#CCCCCC">comment configuration for PAD in header file.</span><br>
示例如下(example)：<br>
$ sed -i "s/MX6Q_PAD_GPIO_4/\/\/ &/g" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
$ sed -i "s/MX6Q_PAD_EIM_BCLK/\/\/ &/g" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
$ sed -i "s/MX6Q_PAD_CSI0_DATA_EN/\/\/ &/g" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
3）在mx6q_sabresd_pads中添加对PAD的配置<br>
<span style="background:#CCCCCC">add configuration for PAD in mx6q_sabresd_pads.</span><br>
配置GPIO_4功能为MX6Q_PAD_GPIO_4__GPIO_1_4<br>
<span style="background:#CCCCCC">configure GPIO_4 function as MX6Q_PAD_GPIO_4__GPIO_1_4.</span><br>
示例如下(example)：<br>
$ sed -i "/mx6q_sabresd_pads/a\\\tMX6Q_PAD_GPIO_4__GPIO_1_4," arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
配置EIM_BCLK功能为MX6Q_PAD_EIM_BCLK__GPIO_6_31<br>
<span style="background:#CCCCCC">configure EIM_BCLK function as MX6Q_PAD_EIM_BCLK__GPIO_6_31.</span><br>
示例如下(example)：<br>
$ sed -i "/mx6q_sabresd_pads/a\\\tMX6Q_PAD_EIM_BCLK__GPIO_6_31," arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
配置CSI0_DATA_EN的PAD功能为MX6Q_PAD_CSI0_DATA_EN__GPIO_5_20<br>
<span style="background:#CCCCCC">configrue PAD function of CSI0_DATA_EN as MX6Q_PAD_CSI0_DATA_EN__GPIO_5_20.</span><br>
示例如下：<br>
$ sed -i "/mx6q_sabresd_pads/a\\\tMX6Q_PAD_CSI0_DATA_EN__GPIO_5_20," arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
4）查看修改结果<br>
<span style="background:#CCCCCC">check out modified result</span><br>
示例如下(example)：<br>
$ sed -n "/PAD_GPIO_4/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
$ sed -n "/PAD_EIM_BCLK/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
$ sed -n "/PAD_CSI0_DATA_EN/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>

== '''修改.c文件(modification.c file)''' ==
1）检查.c文件中GPIO是否被重复使用<br>
<span style="background:#CCCCCC">check out whether GPIO is used repeatedly in .c file.</span><br>
示例如下(example)：<br>
$ sed -n '/IMX_GPIO_NR(1,.4)/p' arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
$ sed -n '/IMX_GPIO_NR(6,.31)/p' arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
$ sed -n '/IMX_GPIO_NR(5,.20)/p' arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
<br>
2）在.c文件中增加GPIO的宏定义<br>
<span style="background:#CCCCCC">add macro definition of GPIO in .c file.</span><br>
*MX6Q_PAD_GPIO_4__GPIO_1_4<br>
在.c文件中添加#define SABRESD_POWER_OFF    IMX_GPIO_NR(1, 4)<br>
<span style="background:#CCCCCC">in .c file add #define SABRESD_POWER_OFF    IMX_GPIO_NR(1, 4))</span><br>
示例如下：<br>
$ GPIO_DEFINE="#define SABRESD_POWER_OFF\tIMX_GPIO_NR(1, 4)"<br>
$ sed -i "1,/#define/{/#define/s/#define/${GPIO_DEFINE}\n&/}" arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
*MX6Q_PAD_CSI0_DATA_EN__GPIO_5_20<br>
在.c文件中添加#define SABRESD_VOLUME_UP   IMX_GPIO_NR(6, 31)<br>
<span style="background:#CCCCCC">in .c file add #define SABRESD_VOLUME_UP   IMX_GPIO_NR(6, 31))</span><br>
示例如下(example)：<br>
$ GPIO_DEFINE="#define SABRESD_VOLUME_UP\tIMX_GPIO_NR(6, 31)"<br>
$ sed -i "1,/#define/{/#define/s/#define/${GPIO_DEFINE}\n&/}" arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
*MX6Q_PAD_CSI0_DATA_EN__GPIO_5_20<br>
在.c文件中添加#define SABRESD_VOLUME_DN   IMX_GPIO_NR(5, 20)<br>
<span style="background:#CCCCCC">in .c file add #define SABRESD_VOLUME_DN   IMX_GPIO_NR(5, 20))</span><br>
示例如下(example)：<br>
$ GPIO_DEFINE="#define SABRESD_VOLUME_DN\tIMX_GPIO_NR(5, 20)"<br>
$ sed -i "1,/#define/{/#define/s/#define/${GPIO_DEFINE}\n&/}" arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
<br>
3）检查gpio_keys_button类型的数据定义<br>
<span style="background:#CCCCCC">chech out data definition with gpio_keys_button.</span><br>
示例如下(example)：<br>
$ sed -n '/gpio_keys_button/,/\}/p' arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
<br>
4）增加volume-up、volume-down、power的数据定义<br>
<span style="background:#CCCCCC">add data definition for volume-up、volume-down、power.</span><br>
static struct gpio_keys_button imx6q_buttons[] = {<br>
GPIO_BUTTON(SABRESD_VOLUME_UP, KEY_VOLUMEUP, 1, "volume-up", 0, 1),<br>
GPIO_BUTTON(SABRESD_VOLUME_DN, KEY_VOLUMEDOWN, 1, "volume-down", 0, 1),<br>
GPIO_BUTTON(SABRESD_POWER_OFF, KEY_POWER, 1, "power", 1, 1),<br>
};<br>

== '''内核配置(kernel configuration)''' ==
*菜单定位(manu position)：<br>
Device Drivers  --->  Input device support  --->  [*]   Keyboards  --->  <*>   GPIO Buttons<br>
[[文件:my_imx6_gpio_3.2.0.1.jpg]]<br>

== '''编译(compilation)''' ==
make uImage<br>
== '''重新烧写系统并启动(re-program system and boot)''' ==
== '''GPIO按键操作(GPIO key operation)''' ==
=== GPIO_KEYS设备(GPIO_KEYS device) ===
启动系统后即存在/sys/devices/platform/gpio-keys目录，使用ls即可看到<br>
<span style="background:#CCCCCC">to be saved under /sys/devices/platform/gpio-keys directory after booting system，which can be seen with ls.</span><br>
<br>
　　[[文件:my_imx6_gpio_3.5.1.1.jpg]]<br>
<br>
$ ls /sys/devices/platform/gpio-keys<br>

=== 查看设备信息(check out device information) ===
在proc文件系统下可以看到相关信息<br>
<span style="background:#CCCCCC">relatie information can be found in proc file system.</span><br>
$ cat /proc/bus/input/devices<br>
<br>
　　[[文件:my_imx6_gpio_3.5.2.1.jpg]]<br>
<br>

=== 设备文件(device file) ===
event0即对应gpio按键对应的设备文件，使用ls可以查看：<br>
<span style="background:#CCCCCC">event0 is matched up with device file corresponding to gpio key，check out with ls.</span><br>
<br>
　　[[文件:my_imx6_gpio_3.5.3.1.jpg]]<br>
<br>
$ ls /dev/input/event0 –la<br>

=== 操作示例<span style="background:#CCCCCC">operating example) ===
见Linux测试手册<br>
<span style="background:#CCCCCC">refer to Linux test manual.</span><br>
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