j5x regulator-l17 voltage set too high

[rbrijder]

In this repo, j5 and j5x share a file where the regulator voltages are set. However, according to downstream, for regulator-l17, j5x requires voltage <2850000>, while j5 requires voltage <3000000>. Indeed, in downstream msm8916-regulator.dtsi sets the voltage to <2850000>, which is overwritten in msm8916-sec-j5nlte-eur-r05.dtsi for j5 but not in the corresponding file for j5x. Too high voltage could damage the device (in this case, it seems the proximity sensor of the device).

[stephan-gh]

The l17 regulator has a voltage range assigned on j5x, as you can see in msm8916-regulator.dtsi (note that this file exists twice, once in the qcom folder and once in the samsung/msm8916 folder):

		regulator-min-microvolt = <2850000>;
		regulator-max-microvolt = <3100000>;

Indeed by default the lowest voltage <2850000> will be used. However, now you need to look at all drivers making use of the regulator, because they might request a higher voltage.

The driver for the proximity sensor happens to contain a line that requests the 3.0V:

	if(!regulator_get_voltage(data->vdd))
		regulator_set_voltage(data->vdd, 3000000, 3300000);

(although I'm not sure if the !regulator_get_voltage(data->vdd) condition is actually triggered).

I think many sensors have a fairly flexible supply voltage, e.g. the similar CM36651 can work with anything between 2.5 V to 3.6 V. So all in all I think this works just fine the way it is. What do you think?

I suppose you could check the exact voltage used at runtime on downstream to be sure but I think there is no strict need to exactly follow downstream in this case.

[rbrijder]

note that this file exists twice, once in the qcom folder and once in the samsung/msm8916 folder):

		regulator-min-microvolt = <2850000>;
		regulator-max-microvolt = <3100000>;

Ah, I was looking at the file in the qcom folder msm8916-regulator.dtsi, which has

		regulator-min-microvolt = <2850000>;
		regulator-max-microvolt = <2850000>;

but the you mention (in the samsung/msm8916 folder) seems the one that is actually included.

So all in all I think this works just fine the way it is. What do you think?

I am not knowledgeable at all, but given the leeway in voltages you mention and the code for the proximity sensor, I am quite reassured the current value is OK. Thanks!