Okay, the title may be a little "aggressive"? However, the qcom-labibb driver wasn't really .. doing much. The current form of this driver is only taking care of enabling or disabling the regulators, which is pretty useless if they were not pre-set from the bootloader, which sets them only if continuous splash is enabled. Moreover, some bootloaders are setting a higher voltage and/or a higher current limit compared to what's actually required by the attached hardware (which is, in 99.9% of the cases, a display) and this produces a higher power consumption, higher heat output and a risk of actually burning the display if kept up for a very long time: for example, this is true on at least some Sony Xperia MSM8998 (Yoshino platform) and especially on some Sony Xperia SDM845 (Tama platform) smartphones.
In any case, the main reason why this change was necessary for us is that, during the bringup of Sony Xperia MSM8998 phones, we had an issue with the bootloader not turning on the display and not setting the lab and ibb regulators before booting the kernel, making it impossible to powerup the display. With this said, this patchset enables setting voltage, current limiting, overcurrent and short-circuit protection.. and others, on the LAB/IBB regulators. Each commit in this patch series provides as many informations as possible about what's going on and testing methodology. AngeloGioacchino Del Regno (7): regulator: qcom-labibb: Implement voltage selector ops regulator: qcom-labibb: Implement current limiting regulator: qcom-labibb: Implement pull-down, softstart, active discharge dt-bindings: regulator: qcom-labibb: Document soft start properties regulator: qcom-labibb: Implement short-circuit and over-current IRQs dt-bindings: regulator: qcom-labibb: Document SCP/OCP interrupts arm64: dts: pmi8998: Add the right interrupts for LAB/IBB SCP and OCP .../regulator/qcom-labibb-regulator.yaml | 28 +- arch/arm64/boot/dts/qcom/pmi8998.dtsi | 8 +- drivers/regulator/qcom-labibb-regulator.c | 636 +++++++++++++++++- 3 files changed, 660 insertions(+), 12 deletions(-) -- 2.29.2