PWM Kernel Driver

Amey Ghanekar

Hi,

I 'm using linux/pwm.h to access PWM from Kernel space as per my application requirement. While using pwmchip_sysfs_unexport or pwmchip_sysfs_export, I have encountered following error.

Building modules, stage 2.
MODPOST 1 modules
WARNING: "pwmchip_sysfs_unexport" [/home/Timer/timer_module.ko] undefined!
WARNING: "pwmchip_sysfs_export" [/home/Timer/timer_module.ko] undefined!

I have verified that CONFIG_PWM_SYSFS is enabled in config file. Can someone suggest me a way-out to use these functions. Any sample code to use pwm.h in kernel space will also do.

System Details

Board: - Beaglebone black (AM335x)

(uname -r): - 4.1.13-g8dc6617

ti sdk : -ti-processor-sdk-linux-am335x-evm-02.00.01.07

Thanks in advance!

over 9 years ago

0 Cvetolin Shulev-XID over 9 years ago

TI__Guru 65405 points

Hi Amey,

Check in your menuconfig whether the eHRPWM and eCAP PWM support are enabled as it is described in the Linux Core PWM User's Guide at:
processors.wiki.ti.com/.../Linux_Core_PWM_User's_Guide

BR
Tsvetolin Shulev

0 Shankari G over 9 years ago

TI__Mastermind 43955 points

Hi Amey,
Able to see those functions in the following PWM driver file ?
drivers/pwm/sysfs.c

I have verified that CONFIG_PWM_SYSFS is enabled in config file. Can someone suggest me a way-out to use these functions. Any sample code to use pwm.h in kernel space will also do.

After enabled the CONFIG_PWM_SYSFS in config file, have you rebuild the kernel and point out that kernel source for kernel timer module building ?

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PWM Kernel Driver