Imx9 flexio pwm #12048
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Imx9 flexio pwm #12048
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This is a high resolution PWM driver, utilizing one 16-bit Flex-IO timer for generating PWM period and the rest of the timers to generate PWM duty cycles. This means that the period has to be the same for every PWM generated from one FLEXIO block, but this way we can get 16-bit resolution for the PWM signals. For a typical IMX9 HW there are 8 timers for each Flex-IO block, which means that by using this driver one can get 7 PWM outputs from one block. This driver can be later extended to have configuration options to use all 8 channels per flex-io by either using 8+8 -bit timer (less resolution) or by using an external trigger from an LPIT. Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
xiaoxiang781216
approved these changes
Apr 4, 2024
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Summary
This driver implements 16-bit PWMs by using flex-io module. The driver uses one flex-io timer as a trigger for the rest of the timers (generating frequency of the pwm), and the other drivers generate the duty pulse. This method provides 7 PWM outputs per flex-io module. Using both flex-io modules, one can obtain 14 PWM outputs.
There are a few other alternatives for using flex-io to generate PWM
This driver is easily extendable later for both of the above.
An alternative way to generate PWM is to use LPTPM timer modules on IMX9. But LPTPM modules are muxed to the same pins with I2C and SPI blocks, so if one needs to use all of those, LPTPM won't have enough pins available. I will however also provide a driver for LPTPM PWM generation later.
Impact
Enables PWM generation from FLEX-IO outputs for IMX9 platform
Testing
Tested on NXPs i.MX93 EVK board w. a logic analyzer