DMTimer LINUX example

sanjeev majumdar

Intellectual 340 points

Hi I am new to SITARA ARM processors & LINUX.

can any body tell us how to exercise DMtimer on linux. one sample example for am335xevm or beagle bone black.

thanks in advance.

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

I will ask the software team to comment.

0 Yordan Kovachev over 9 years ago

TI__Guru**** 161600 points

Hi,

What exactly do you want to exercise?
There is no ready to use Linux example.

The following two threads, could be used to generate PWM with dmtimer:

e2e.ti.com/.../1504767 -> here you can find the DTS configurations of timer4 in BBB:

pinctrl-single,pins = <
0x270 (PIN_OUTPUT_PULLUP | MUX_MODE2) /* TIMER4 -> timer4 -> D24 */
>;
};
&timer4 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&timer4_pins_default>;
};

After this dmtimer is configured, pinmux is set accordingly & the module is enabled.

This post: e2e.ti.com/.../440723 contains a user space script that generates the pwm.

Best Regards,
Yordan

0 sanjeev majumdar over 9 years ago in reply to Yordan Kovachev

Intellectual 340 points

thanks for your reply, as per ur suggestion we have enabled the TIMER4 using Device tree overlay now we need a sample c userspace example to verify timer4 functionality.

kindly provide any userspace sample app.

0 Yordan Kovachev over 9 years ago in reply to sanjeev majumdar

TI__Guru**** 161600 points

What about the one (named timer.txt) in the link above: e2e.ti.com/.../440723

What exactly do you want to test? Timer applications are very specific, so there is NO ready to use api, you should modify the kernel driver or create a user-space driver yourself.

Best Regards,
Yordan

0 sanjeev majumdar over 9 years ago in reply to Yordan Kovachev

Intellectual 340 points

Hi we need to generate 100 ms timer to run specific threads, for this we need userspace API's or user-space driver which can enable TIMER and after the time interval it should invoke the TimerIsr. For this please suggest how we can exerciise.

0 sanjeev majumdar over 9 years ago in reply to sanjeev majumdar

Intellectual 340 points

Hi we are awaiting response... thanks any input will be appreciable.

0 Yordan Kovachev over 9 years ago in reply to sanjeev majumdar

TI__Guru**** 161600 points

Follow the recommendations in Section 20.1.3.1 Timer Mode Functionality through Section 20.1.3.3 Compare Mode Functionality in device TRM. It describes how to set up the registers, so that you can generate timer interrupts in a specified interval of time.

Best Regards,
Yordan

0 Amey Ghanekar over 9 years ago in reply to sanjeev majumdar

Prodigy 200 points

e2e.ti.com/.../415079
Pl refer link given above. It has code to configure timer in comapare match mode.
You can write LKM and expose neccessary functionality to user space.
Regards,
Amey

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DMTimer LINUX example