topic Re: Using imx8mm-gpt driver combined question in i.MX Processors

Using imx8mm-gpt driver combined question

edcloudcycle — Tue, 12 Jan 2021 16:19:28 GMT

Hi @igorpadykov @Bio_TICFSL @stevelongerbeam,

Could we get a better response on how to use IMX8MM GPT under Linux? Seems like we are all stuck on the same step. Driver looks present and like it should work, is there a guide somewhere for how to locate the userspace interface to the driver code?

Looks like this is a reasonably popular topic, questions from @magicarrow98, @andyli and @nirgeller all on the same subject.

https://community.nxp.com/t5/i-MX-Processors/GPT-input-Capture-in-I-MX8M-Mini/m-p/1044403

https://community.nxp.com/t5/i-MX-Processors/GPT-on-i-MX-8M-Mini/m-p/1206969

https://community.nxp.com/t5/i-MX-Processors/imx8mm-evk-gpt-driver/m-p/1203437

Kernel patch seems to be discussed here:

https://lore.kernel.org/linux-arm-kernel/20191027212121.GA3049@bogus/T/#m8d1f56a36543eaf2f9b8d41c99e3d57817cde024

Re: Using imx8mm-gpt driver combined question

Bio_TICFSL — Wed, 13 Jan 2021 15:14:46 GMT

Hello edcloudcycle,

The driver is on yocto drivers/clocksource/timer-imx-gpt.c

The timer module utilizes four hardware timers, to implement clock source and clock event objects.
This is done with the clocksource_mxc structure of struct clocksource type and clockevent_mxc structure of struct clockevent_device type. Both structures provide routines required for reading current timer values and scheduling the next timer event.

The driver works well if you want to change it you can do it.

Regards

Re: Using imx8mm-gpt driver combined question

edcloudcycle — Wed, 13 Jan 2021 15:49:48 GMT

Thanks, that sounds like just what I want but how do I locate the user space interface for it?

Re: Using imx8mm-gpt driver combined question

edcloudcycle — Thu, 14 Jan 2021 10:00:57 GMT

Thanks, that sounds like just what I want but how do I locate the user space interface for it?

Re: Using imx8mm-gpt driver combined question

edcloudcycle — Thu, 14 Jan 2021 15:55:07 GMT

Hi @igorpadykov, @Bio_TICFSL, is it possible to get an answer to this?

Thanks
Ed

Re: Using imx8mm-gpt driver combined question

nirgeller — Mon, 18 Jan 2021 15:43:30 GMT

Hi,

Please refer to the case I opened with regard to GPT on kernel 5.4.47.

https://community.nxp.com/t5/i-MX-Processors/GPT-on-i-MX-8M-Mini/td-p/1206969

I'm able to get the driver compiled and invoked, but getting the clocks fails in the init function.

Can you please provide support for kernel 5.4.47?

Thanks,

Nir.