About the Jetson Tx1 module PWM

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX1
1

there is a pin named LCD0_BKLT_PWM ,But how can I setup the pwm frequency and duty? I can’t find it in TRM datasheet.could you tell me which regisiter can I set?

2

Hi BillBai, you can refer to below registers’ description in TRM.

DC_DISP_SD_BL_PARAMETERS_0
DC_DISP_SD_BL_TF_0
DC_DISP_SD_BL_CONTROL_0
SOR_NV_PDISP_SOR_PWM_DIV_0
SOR_NV_PDISP_SOR_PWM_CTL_0

3

Hi BillBai
You can control it by the sysfs. This pin is for the PWM0 for tegra_pwm.

sudo su
export PWM=0
echo $PWM > /sys/class/pwm/pwmchip0/export
than you can control this it by the enable/ duty_cycle, period .... at below dir.
/sys/class/pwm/pwmchip0/pwm0
4

Hi ShaneCCC，

How to enable the PWM0 by default, not by the sysfs.

For DTSI, I add the following code, but it’s not work.

backlight {
	compatible = "pwm-backlight";
	status = "okay";
	panel-a-wuxga-8-0-bl {
		pwms = <&tegra_pwm 0 40161>;
	};
     }

BRs
Thanks
Pan Andy

5

@PanAndy
I think you can try to add the script to /init/nv.conf