ARM: dts: tegra30-microsoft-surface-rt: Fix WM8962 SPKVDD supply#140
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ARM: dts: tegra30-microsoft-surface-rt: Fix WM8962 SPKVDD supply#140blakegordon wants to merge 1 commit into
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The WM8962 Class-D speaker outputs require SPKVDD in the 2.5V-5.5V range. The device tree currently wires SPKVDD1/2 to vdd_1v8_sys (1.8V), below the minimum. On postmarketOS/grate the codec probes and playback succeeds in software, but no sound is produced and dmesg reports ASoC error (-16) at register 0x30 and DC servo timeouts. Use vdd_5v0_sys for SPKVDD1/2; digital/analog core supplies stay at 1.8V. Signed-off-by: Blake Gordon <blakegordon@berkeley.edu>
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Summary
Fix silent audio on Microsoft Surface RT by wiring the WM8962 Class-D speaker
amplifier supplies (SPKVDD1/2) to the board 5 V rail instead of 1.8 V.
Problem
On postmarketOS with
linux-postmarketos-grate, the WM8962 codec probessuccessfully and ALSA playback appears to work, but no sound is produced from
the internal speakers or headphones. During playback, mixer routes and Class-D
enable bits look correct in software.
dmesgreports on every playback attempt:Root cause
Per the WM8962 datasheet, SPKVDD must be in the 2.5 V–5.5 V range for the
Class-D speaker outputs (SPKOUTL/R). The device tree currently assigns both
SPKVDD1-supplyandSPKVDD2-supplytovdd_1v8_sys(1.8 V), which is belowthe minimum operating voltage for the speaker amplifier.
Digital and analog core supplies correctly remain on 1.8 V; only the speaker
amplifier rails need the higher voltage.
Fix
Point
SPKVDD1-supplyandSPKVDD2-supplyatvdd_5v0_sys, which is alreadymodeled in the device tree and used by other board peripherals (backlight, USB
VBUS, etc.).
The EFI variant (
tegra30-microsoft-surface-rt-efi.dts) includes this file, sono separate change is required there.
Testing
speaker-test -Dhw:1,0dmesgno longer reports WM8962 register0x30errors / DC servo timeouts during playbackTested-by: Blake Gordon blakegordon@berkeley.edu (pending kernel rebuild)
References
linux-postmarketos-grate-7.0.1-r0