overlay: Rework/fix the Pi 5 MIDI UART overlays#6743
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pelwell merged 1 commit intoraspberrypi:rpi-6.12.yfrom Mar 27, 2025
Merged
overlay: Rework/fix the Pi 5 MIDI UART overlays#6743pelwell merged 1 commit intoraspberrypi:rpi-6.12.yfrom
pelwell merged 1 commit intoraspberrypi:rpi-6.12.yfrom
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The old Pi 5 MIDI UART overlays replaced the reference to the UART's source clock with a fixed clock (essentially an integer dressed up like a clock). This is fragile, in that the fixed clock must be updated if the source clock's (fixed) frequency is ever changed, but it also relies on the source clock having been enabled, which is likely not to be the case unless another RP1 UART is being actively used. Switching to a fixed-factor-clock solves both of those problems. See: https://forums.raspberrypi.com/viewtopic.php?t=385906 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
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kernel: overlay: Rework/fix the Pi 5 MIDI UART overlays See: raspberrypi/linux#6743 kernel: Add debug knobs to pcie_brcmstb See: raspberrypi/linux#6745 kernel: ARM64: dts: Add sd and sd_poll_once params to CM5 See: raspberrypi/linux#6744 firmware: Vl805 reset improvements
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kernel: overlay: Rework/fix the Pi 5 MIDI UART overlays See: raspberrypi/linux#6743 kernel: Add debug knobs to pcie_brcmstb See: raspberrypi/linux#6745 kernel: ARM64: dts: Add sd and sd_poll_once params to CM5 See: raspberrypi/linux#6744 firmware: Vl805 reset improvements
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The old Pi 5 MIDI UART overlays replaced the reference to the UART's source clock with a fixed clock (essentially an integer dressed up like a clock). This is fragile, in that the fixed clock must be updated if the source clock's (fixed) frequency is ever changed, but it also relies on the source clock having been enabled, which is likely not to be the case unless another RP1 UART is being actively used.
Switching to a fixed-factor-clock solves both of those problems.
See: https://forums.raspberrypi.com/viewtopic.php?t=385906