AM6412: LED Access Query

Uthaya kumar

Part Number: AM6412

Hi Experts

i am using custom board with am6412 soc, In that i need access my leds connected to OSPI Pins,how can we put the device tree entry for those leds access,can you suggest some points for this query

Thanks in advance

2 months ago

0 Randolph Sapp 2 months ago

TI__Intellectual 1410 points

Hey Uthaya,

I'm working on some graphics patches right now. Please give me another day to respond to this.

Regards,

Randolph

0 Uthaya kumar 2 months ago in reply to Randolph Sapp

Prodigy 220 points

Hi Randolph,

Thanks for the response,i will wait for your inputs,

0 Bin Liu 2 months ago in reply to Uthaya kumar

TI__Guru** 110291 points

Hi Uthaya,

The schematics snipet seems showing all the OSPI pins will be used in GPIO mode, is it correct?

0 Uthaya kumar 2 months ago in reply to Bin Liu

Prodigy 220 points

Hi Bin

Yes you are correct,all pins are in gpio mode

0 Bin Liu 2 months ago in reply to Uthaya kumar

TI__Guru** 110291 points

Hi Uthaya,

Generally, here are the steps:

1. define the pinmux settings in device tree to configure these pins in GPIO mode.

2. add the "pinctrl-names" and "pinctrl-0" DT properties witch point to the pinmux settings to the DT node which controls the GPIO pins.

3. add "xxx-gpios" DT property to the DT node which controls the GPIO pins;

4. in the kernel driver which controls the GPIO pins, use kernel gpiod framework API to query and use the GPIO pins.

Please search the GPIO pin usage in kernel k3-am642-sk.dts for examples.

0 Uthaya kumar 2 months ago in reply to Bin Liu

Prodigy 220 points

Hi Bin

&main_gpio0 {                                                                                                           
     pinctrl-names = "default";                                                                                          
     pinctrl-0 = <&ospi0_pins_default>;                                                                         
                                                                                                                         
     gpio0-3 {                                                                                                          
         gpio-hog;                                                                                                       
         gpios = <3 GPIO_ACTIVE_HIGH>;                                                                                  
         output-high;                                                                                                    
         line-name = "ospi_pins";                                                                                   
     };                                                                                                                  
};

     leds {                                                                                                              
         compatible = "gpio-leds";                                                                                       
         pinctrl-names = "default";                                                                                      
         pinctrl-0 = <&ospi0_pins_default>;                                                                            
                                                                                                                         
         led-0 {                                                                                                         
             label = "am64-gp:red:heartbeat";                                                                          
             gpios = <&main_gpio0 3 GPIO_ACTIVE_HIGH>;                                                                  
             linux,default-trigger = "heartbeat";                                                                        
             function = LED_FUNCTION_HEARTBEAT;                                                                          
             default-state = "off";                                                                                      
         };                                                                                                              
     };

Can you check this is fine ?

0 Bin Liu 2 months ago in reply to Uthaya kumar

TI__Guru** 110291 points

Hi Uthaya,

Mostly looks good to me, but I don't think you should use <&ospi0_pins_default> pinmux more than once. I never did this, and I don't know if it is correct or not.

0 Uthaya kumar 2 months ago in reply to Bin Liu

Prodigy 220 points

Hi Bin

You are correct we can't use <&ospi0_pins_default> twice,so i have used different name for the pins,and it works for me,Now i am able to access the leds.

Thanks for the help.

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AM6412: LED Access Query