查看“MY-IMX6 Linux-3.0.35 GPIO Development”的源代码

<div>

= '''GPIO output & input''' =
GPIO output & input take SD1_CLK leads as an example.<br>

== '''Modification “.h” file''' ==
1）Check configuration for SD1_CLK in file.<br>
Example：<br>
$ sed -n "/PAD_SD1_CLK/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
2）Configuration for SD1_CLK in comment header file.<br>
Example：<br>
$ sed -i "s/MX6Q_PAD_SD1_CLK/\/\/ &/g" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
3）Adding configuration for SD1_CLK in mx6q_sabresd_pads <br>
Configure SD1_CLK function as MX6Q_PAD_SD1_CLK__GPIO_1_20 <br>
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）Check modified result<br>
Example：<br>
$ sed -n "/PAD_SD1_CLK/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>


== '''Configure kernel''' ==
*Mamu position<br>
Device Drivers  --->  -*- GPIO Support  --->  [*]   /sys/class/gpio/... (sysfs interface)<br>
[[File:my_imx6_gpio_1.2.0.1.jpg]]<br>


== '''Compilation''' ==
:make uImage<br>
== '''Re-program system and boot''' ==
== '''Device operation''' ==

=== Check out gpio directory ===
GPIO led out can bee seen under /sys/class/gpio/ directory <br>
$ ls /sys/class/gpio/<br>
<br>
　　[[File:my_imx6_gpio_1.5.1.1.jpg]]<br>
<br>

=== Register GPIO to system ===
Register GPIO_1_20 to system with echo，then an extra gpio20 directory can be found under gpio directory.<br>
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.<br>
$ echo 20 > /sys/class/gpio/export<br>
<br>
　　[[File:my_imx6_gpio_1.5.2.1.jpg]]<br>
<br>

===GPIO output control ===
*Set leads as output state <br>
$ echo out > /sys/class/gpio/gpio20/direction<br>
*Set lead output at high electrical level<br>
echo 1 > /sys/class/gpio/gpio20/value<br>
*Set lead output at low electrical level <br>
echo 0 > /sys/class/gpio/gpio20/value<br>

=== Set lead as input state ===
*Set lead as input state.<br>
echo in > /sys/class/gpio/gpio20/direction<br>
*Gain lead value<br>
cat /sys/class/gpio/gpio20/value<br>

=== Logout GPIO interface ===
*Logout GPIO_1_20<br>
echo 20 > /sys/class/gpio/unexport<br>
= '''GPIO LED''' =
----
Instruction：take GPIO LED以PAD NANDF_CS0 as example.<br>

== '''Enter kernel directory''' ==
$ cd ~/MY-I.MX6/linux-3.0.35/<br>
[[File:my_imx6_gpio_2.1.0.1.jpg]]<br>

== '''Add code''' ==
=== Modification.h file ===
1）Check out configuration for NANDF_CS0 in header file.<br>
Example：<br>
$ sed -n "/PAD_NANDF_CS0/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
2）Comment configuration for NANDF_CS0 in header file.<br>
Example：<br>
$ sed -i "s/MX6Q_PAD_NANDF_CS0/\/\/ &/g" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
<br>
3）Add configuration for NANDF_CS0 in mx6q_sabresd_pads.<br>
Configure NANDF_CS0 function as MX6Q_PAD_NANDF_CS0__GPIO_6_11.<br>
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）Check out modified result.<br>
Example：<br>
$ sed -n "/PAD_NANDF_CS0/p" arch/arm/mach-mx6/board-mx6q_sabresd.h<br>


=== Modification.c file ===
1）Check out whether GPIO is used repeatedly in .c file<br>
Example：<br>
$ sed -n '/IMX_GPIO_NR(6,.11)/p' arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
<br>
2）Add macro definition of GPIOin .c file<br>
Add #define SABRESD_USER_LED        IMX_GPIO_NR(6, 11) <br>
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）Check out data definition with gpio_led<br>
Example：<br>
$ sed -n '/struct gpio_led /,/\}/p' arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
<br>
3）Add data definition of user_led<br>
static struct gpio_led imx6q_gpio_leds[] = {<br>
　　　　GPIO_LED(SABRESD_USER_LED, "user_led", 0, 1,<br>
　　　　　　　　"charger"),<br>
}；<br>

== '''Kernel configuration''' ==
*manu position<br>
Device Drivers  --->  [*] LED Support  --->  <*>   LED Support for GPIO connected LEDs<br>
[[File:my_imx6_gpio_2.3.0.1.jpg]]<br>

== '''Compilation''' ==
make uImage<br>
== '''Re-program system and boot''' ==
== '''GPIO_LED operation''' ==
=== Device file directory ===
To be saved under /sys/class/leds/user_led directory after booting system，which can be seen with ls.<br>
$ ls /sys/class/leds/user_led<br>
<br>
　　[[File:my_imx6_gpio_2.6.1.1.jpg]]<br>
<br>

=== Operating example ===
1）Set NANDF_CS0 as 1<br>
$ echo 1 > /sys/class/leds/user_led/brightness<br>
2）Set NANDF_CS0 as 0<br>
$ echo 0 > /sys/class/leds/user_led/brightness<br>

= '''GPIO key''' =
----
GPIO key by taking GPIO_4、EIM_BCLK、CSI0_DATA_EN as example，are separetely SW2，SW3和SW4 in schematic.<br>

== '''Modification.h file''' ==
1）Check out configuration for PAD in header file.<br>
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）Comment configuration for PAD in header file.<br>
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）Add configuration for PAD in mx6q_sabresd_pads.<br>
Configure GPIO_4 function as MX6Q_PAD_GPIO_4__GPIO_1_4.<br>
Example：<br>
$ sed -i "/mx6q_sabresd_pads/a\\\tMX6Q_PAD_GPIO_4__GPIO_1_4," arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
Configure EIM_BCLK function as MX6Q_PAD_EIM_BCLK__GPIO_6_31.<br>
Example：<br>
$ sed -i "/mx6q_sabresd_pads/a\\\tMX6Q_PAD_EIM_BCLK__GPIO_6_31," arch/arm/mach-mx6/board-mx6q_sabresd.h<br>
Configrue PAD function of CSI0_DATA_EN as MX6Q_PAD_CSI0_DATA_EN__GPIO_5_20.<br>
Example：<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）Check out modified result<br>
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>

== '''Modification.c file''' ==
1）Check out whether GPIO is used repeatedly in .c file.<br>
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）Add macro definition of GPIO in .c file.<br>
*MX6Q_PAD_GPIO_4__GPIO_1_4<br>
In .c file add #define SABRESD_POWER_OFF    IMX_GPIO_NR(1, 4))<br>
Example：<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>
In .c file add #define SABRESD_VOLUME_UP   IMX_GPIO_NR(6, 31).<br>
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>
In .c file add #define SABRESD_VOLUME_DN   IMX_GPIO_NR(5, 20)) <br>
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）Chech out data definition with gpio_keys_button.<br>
Example：<br>
$ sed -n '/gpio_keys_button/,/\}/p' arch/arm/mach-mx6/board-mx6q_sabresd.c<br>
<br>
4）Add data definition for volume-up、volume-down、power.<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>

== '''Kernel configuration''' ==
*manu position：<br>
Device Drivers  --->  Input device support  --->  [*]   Keyboards  --->  <*>   GPIO Buttons<br>
[[File:my_imx6_gpio_3.2.0.1.jpg]]<br>

== '''Compilation''' ==
make uImage<br>
== '''Re-program system and boot''' ==
== '''GPIO key operation''' ==
===GPIO_KEYS device ===
To be saved under /sys/devices/platform/gpio-keys directory after booting system，which can be seen with ls.<br>
<br>
　　[[File:my_imx6_gpio_3.5.1.1.jpg]]<br>
<br>
$ ls /sys/devices/platform/gpio-keys<br>

=== Check out device information ===
Relatie information can be found in proc file system.<br>
$ cat /proc/bus/input/devices<br>
<br>
　　[[File:my_imx6_gpio_3.5.2.1.jpg]]<br>
<br>

=== Device file ===
Event0 is matched up with device file corresponding to gpio key，check out with ls.<br>
<br>
　　[[File:my_imx6_gpio_3.5.3.1.jpg]]<br>
<br>
$ ls /dev/input/event0 –la<br>

=== Operating example ===
Refer to Linux test manual.<br>

</div>