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Unable to enable PWM driver in uboot

DKapu.2
Associate

We have custom SOM which has been designed with STM32MP157C and we want to enable the backlight of a display panel using a PWM driver in uboot. 

For this, we tried enabling the pwm_backlight.c driver available in /drivers/video/ in uboot.

Following configuration was done to enable the driver:

Changes in the dts file

0693W00000UnvTrQAJ.pngUpdated the Kconfig in /driver/video/

0693W00000UnvJJQAZ.png 

Updated to Makefile in /driver/video/

obj-$(CONFIG_BACKLIGHT_PWM) += pwm_backlight.o

Added the config in defconfig

CONFIG_BACKLIGHT_PWM=y

CONFIG_DM_PWM=y

The image builds successfully, however looking at the log of lists.c during boot, it is unable to find the driver and hence fails to bind.

Another observation is that there is no stm32 core driver file for PWM in uboot. Is this the reason why any of the pwm-based drivers fails to be enabled or is something missing in the configuration mentioned above?

TIA.

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