Backport axi-pwmgen driver #2602
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ukleinek
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nunojsa,
mhennerich,
dbogdan,
btogorean,
chegbeli,
buha,
amiclaus,
rbolboac,
danmois,
CiprianRegus and
machschmitt
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added 3 commits
September 30, 2024 16:58
The driver's probe function had an open-coded variant of devm_clk_get_enabled(). Replace it by the actual function with the same semantics. Signed-off-by: Uwe Kleine-König <[email protected]>
With knowing the input clock of the PWM hardware unit, the optimal period can be calculated such that the sample frequency is configured as the highest possible value not bigger than the requested value. Do that with some commentary that explains the calculation. Note that currently the initial claim about the axi-pwmgen driver's implemented period isn't true. But it's true for the mainline driver and soon for the driver in this tree as well. Signed-off-by: Uwe Kleine-König <[email protected]>
With knowing the input clock of the PWM hardware unit, the optimal period can be calculated such that the sample frequency is configured as the highest possible value not bigger than the requested value. Do that with some commentary that explains the calculation. Note that currently the initial claim about the axi-pwmgen driver's implemented period isn't true. But it's true for the mainline driver and soon for the driver in this tree as well. Signed-off-by: Uwe Kleine-König <[email protected]>
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Fixed a typo in two commit logs noticed by checkpatch. I'd like to see the other checkpatch issues ignored. It wails about |
Backporting involved several changes. These were marked using some cpp magic to simplify updates to newer kernel version and for documentation purposes. The relevant semantical changes are: - The apply callback uses round down now to match the policy upstream. - The compatible string changed. All devicetrees are updated accordingly. - The v1 hardware revision isn't supported any more. The v1 documentation isn't in the public documentations any more, so this is expected to be ok. Signed-off-by: Uwe Kleine-König <[email protected]>
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One more push after test feedback by Trevor Gamblin. Thanks! |
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Trevor Gamblin mainlined the axi-pwmgen driver (Linux commit and a few followup improvements.) This MR updates the ADI vendor tree to use a backport of that driver. It contains several
#ifdefs that intend to make updating to a newer Linux base version easy. Compared to the previous implementation the rounding behavior is different. So the consumer drivers that invest some math to get a deterministic PWM waveform are adapted (and improved) to continue to work with the new driver. I don't expect the other drivers to break. If I'm wrong here, please tell me that I can fix the fallout.Note that comments about the PWM driver introduced in these commits only become true with the update of the axi-pwmgen driver in the last commit, the math however already works with the old driver under the assumption that its input clock is less than 500 MHz.
An unrelated drive-by simplification is also included.
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