how to add a new GPIO based LEDs to sysfs directory .....

Hi Shankar,

What you want to do it there in StarteKit configurations. Please see initializations in am335x-evmsk.dts file. Of course you have to change the gpio pins, but it's a good example for your purpose.

BR
Ivan

Hi Ivan Matrakov,

  Thanks for reply, I want to control my gpio leds through sysfs filesystem  like user defined leds(usr0 to usr3), how can i approach to sysfs directory in which (sys/class/leds/label_name/attributes) how can i create attributes under label

Ex :

root@am335x-evm:/sys/class/leds/beaglebone:green:usr3# ls
brightness      max_brightness  subsystem       uevent
device          power           trigger

Hi Shankar,

If you want to control leds through sysfs you have to remove their definitions from the xxx.dts file and from console to write:
root@am335x-evm:~# echo xx > /sys/class/gpio/export
root@am335x-evm:~# echo out > /sys/class/gpio/gpioxx/direction
root@am335x-evm:~# echo 1 > /sys/class/gpio/gpioxx/value
root@am335x-evm:~# echo 0 > /sys/class/gpio/gpioxx/value
where the xx is number of gpio calculated as 32*bank + gpio. For example if the gpio is gpio1_22
root@am335x-evm:~# echo 54 > /sys/class/gpio/export
root@am335x-evm:~# echo out > /sys/class/gpio/gpio54/direction
root@am335x-evm:~# echo 1 > /sys/class/gpio/gpio54/value
root@am335x-evm:~# echo 0 > /sys/class/gpio/gpio54/value

You can read this in a:
processors.wiki.ti.com/.../Linux_PSP_GPIO_Driver_Guide
Please see what is needed to initialize in xxxdefconfig file. In's setting by default, but see it.

BR
Ivan

Hi Ivan Matrakov,

Thank you.... using above commands user can control manually gpio leds from shell prompt and above commands are working fine but i want to create sysfs attributes at boot time, like brightness, max_brightness and trigger

ex of controlling usr3 led:
root@am335x-evm:~# echo 1 >/sys/class/leds/beaglebone:green:usr3\brightness
root@am335x-evm:~# echo 1 >/sys/class/leds/beaglebone:green:usr3\brightness

Hi Shankar,

This is not so easy. To do this you have to read:
<>ti-sdk-am335x-evm-07.00.00.00/board-support/linux-3.12.10-ti2013.12.0/Documentation/leds/leds-class.txt
<>ti-sdk-am335x-evm-07.00.00.00/board-support/linux-3.12.10-ti2013.12.0/Documentation/leds/leds-blinkm.txt

You can see that in a /sys/devices/backlight.9/backlight/backlight.9 directory there are some files as:
actual_brightness
brightness
max_brightness

Changing the value in a brightness file you will change the brightness of the screen.

BR
Ivan

Hi Ivan Matrakov,
Thank you ...... I am studied leds txt file as well as I am go through led based platform driver pgms like leds-gpio.c ,led-class.c and their i found sysfs related macro attributes, call back functions sys_ops structure( show,store) is it use full for me,
In DTS am335x-bone-common.dtsi file i am changed label name and gpio flags and after compilation i able see sysfs attributes all leds, my question is it correct process for controlling user defined gpio-leds through sysfs ,is it correct then i am going to interface gpio-leds for bbb board.
DTS file:
pin muxing:
0xa0 (PIN_INPUT_PULLDOWN | MUX_MODE7) /* lcd_data0.gpio2_6 D0/Away_LED 0x481A_C000*/

/* shan gpio_led nodes*/
led@6 {
label = "Away_led";
gpios = <&gpio2 6 GPIO_ACTIVE_HIGH>;
linux,default-trigger = "heartbeat";
default-state = "on";
};

root@am335x-evm:/sys/class/leds# ls
Alaram_led RGB_cntr2
Away_led beaglebone:green:heartbeat
Error_led beaglebone:green:mmc0
HF_led beaglebone:green:usr2
RGB_cnt0 beaglebone:green:usr3
RGB_cntr1

root@am335x-evm:/sys/class/leds# cd RGB_cnt0
root@am335x-evm:/sys/class/leds/RGB_cnt0# ls

brightness max_brightness subsystem uevent
device power trigger

root@am335x-evm:/sys/class/leds/RGB_cnt0# cat brightness
0

Hi Shankar,

For me the better way to control lcds is through kernel, but I don't know your case to give you any advice. For some cases control through sysfs is better.

BR
Ivan

Hi Ivan Matrakov,

Thank you ..... I am unable to understand gpio and gpio-leds driver.

1. from gpio based testing woking fine i am able togole all leds....... ex: echo 70 > /sys/class/gpio/export ; echo out > /sys/class/gpio/gpio70/direction ; echo 1 > /sys/class/gpio/gpio70/value
2. In gpio-leds driver i am able toggle board defined(usr0 -usr3) leds only not user defined leds like gpio2_6 7 8
3. Because my custom board we using am3358 processor and ti sdk 7.
4. my requirement is i am able to control all leds through sysfs(sys/class/leds/device_name/attributes) in this case i able see all leds attributes but no use , if i do any kernel config or any changes driver level , is it possible or please give me suggestion for controlling leds
5. Is TI sdk 7(3.12 kernel) gpio-leds driver support for board define leds only not others .............

Hi Shankar,

If make what is written on the: processors.wiki.ti.com/.../Linux_PSP_GPIO_Driver_Guide
you will see that you can control all used gpio's. The gpio2_6 7 8 you have to initialize in dts and kernel. But you have to add gpio_export(xx, true); command (did you see this). Now with this command you can see all exported gpio's with sysfs and can control with kernel and sysfs.

BR
Ivan

Hi Ivan Matrakov,
once see gpio debug file...
root@am335x-evm:/sys/class/leds/RGB_cnt0# cat /sys/kernel/debug/gpio
GPIOs 0-31, gpio:
gpio-6 (mmc_cd ) in lo
gpio-8 (am335x_uda134x ) out hi
gpio-10 (am335x_uda134x ) out hi

GPIOs 32-63, gpio:
gpio-46 (gpio_ouputexport ) out hi
gpio-53 (beaglebone:green:hea) out lo
gpio-54 (beaglebone:green:mmc) out lo
gpio-55 (beaglebone:green:usr) out hi
gpio-56 (beaglebone:green:usr) out lo

GPIOs 64-95, gpio:
gpio-70 (Away_led ) out lo
gpio-71 (Error_led ) out lo
gpio-72 (HF_led ) out lo
gpio-73 (Alaram_led ) out lo
gpio-74 (RGB_cnt0 ) out lo
gpio-75 (RGB_cntr1 ) out lo
gpio-76 (RGB_cntr2 ) out hi
gpio-81 (am335x_uda134x ) out lo

GPIOs 96-127, gpio:

Hi Ivan,

      Please once check attached file export gpio dr7888.gpio_export.txtiver code.....

Hi Shankar,

I think that the code in attached file is correct and you can use it.

BR
Ivan

Hi Ivan,

when i load attached driver it shows the error i.e Device or resource busy here i am using custom board based on AM335x and sdk-7 not beagle bone black board, we are not using HDMI controller and we direct interface leds lcd_data0* to lcd_data7* pins.
1. In am33xx_pinmux: pinmux@44e10800
0xa0 (PIN_OUTPUT_PULLUP | MUX_MODE7) /* lcd_data0.gpio2_6 D0/Away_LED shan */
2. in leds node
led@6 {
label = "Away_led";
gpios = <&gpio2 6 GPIO_ACTIVE_HIGH>;
linux,default-trigger = "heartbeat";
default-state = "on";
};

3. shell prompt
root@am335x-evm:/# cd sys/class/leds/
Away_led/ beaglebone:green:usr2/
beaglebone:green:heartbeat/ beaglebone:green:usr3/
beaglebone:green:mmc0/
root@am335x-evm:/# cd sys/class/leds/Away_led
root@am335x-evm:/sys/class/leds/Away_led# ls
brightness max_brightness subsystem uevent
device power trigger
root@am335x-evm:/sys/class/leds/Away_led# echo 1 > brightness
root@am335x-evm:/sys/class/leds/Away_led# echo 0 > brightness

4. All commands are executed fine but am unable turn on leds please give me any suggestion......

Thanks and Regards.........

Hi Ivan,

Thank you for your valuable response finally i got it, problem was in hardware........ then i am looking for "gpio-keys" driver in my custom board we are using 4 input buttons can you give me details about gpio-keys driver how to enable kernel configuration and DTS file..........

Hi Shankar,

This thread is closed. Please open the new one with proper title.

BR
Ivan