Imx7d and led pwm animation

[maash]

Hi.

I've got pwm led connected to pwm capable gpio (pwmchip0). I can use the pwm output by writing the sysfs pwm0 period and output in userspace.

However I would like to run pulsating animations (25hz) in the led. Is this doable in (is there DMA capability) in kernel or user space side? What I've understood is that this isn't really suitable with embedded linux applications nor I did find any dma to pwm examples. Is the led driver only option?

Any comments regarding this would be appreciated as I'm pretty new to IMX7 and yocto.

[Carlos_Musich]

Hi Matti,

I don't have any example but you may find very useful this book Linux Driver Development for Embedded Processors. Specifically you can look at LAB 8.3: "DMA from user space" Module

You may also take a look to the following thread How to use SDMA in i.MX7D ? 

Regards,
Carlos

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