• Stephan Gerhold's avatar
    arm64: dts: qcom: msm8916: Fix regulator constraints · 35575082
    Stephan Gerhold authored
    The regulator constraints for most MSM8916 devices (except DB410c) were
    originally taken from Qualcomm's msm-3.10 vendor device tree (for lack
    of better documentation). Unfortunately it turns out that Qualcomm's
    voltages are slightly off as well and do not match the voltage
    constraints applied by the RPM firmware.
    
    This means that we sometimes request a specific voltage but the RPM
    firmware actually applies a much lower or higher voltage. This is
    particularly critical for pm8916_l11 which is used as SD card VMMC
    regulator: The SD card can choose a voltage from the current range of
    1.8 - 2.95V. If it chooses to run at 1.8V we pretend that this is fine
    but the RPM firmware will still silently end up configuring 2.95V.
    This can be easily reproduced with a multimeter or by checking the
    SPMI hardware registers of the regulator.
    
    Fix this by making the voltages match the actual "specified range" in
    the PM8916 Device Specification which is enforced by the RPM firmware.
    Signed-off-by: default avatarStephan Gerhold <stephan@gerhold.net>
    Signed-off-by: default avatarBjorn Andersson <andersson@kernel.org>
    Link: https://lore.kernel.org/r/20230510-msm8916-regulators-v1-3-54d4960a05fc@gerhold.net
    35575082
msm8916-longcheer-l8910.dts 5.21 KB