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OPP: decouple dt properties in opp_parse_supplies()

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The opp-microwatt property was added with the intention of providing
platforms a way to specify a precise value for the power consumption
of a device at a given OPP to enable better energy-aware scheduling
decisions by informing the kernel of the total static and dynamic
power of a device at a given OPP, removing the reliance on the EM
subsystem's often flawed estimations. This property is parsed by
opp_parse_supplies(), which creates a hard dependency on the
opp-microvolt property.

Some platforms, such as Apple Silicon, do not describe their device's
voltage regulators in the DT as they cannot be controlled by the kernel
and/or rely on opaque firmware algorithms to control their voltage and
current characteristics at runtime. We can, however, experimentally
determine the power consumption of a given device at a given OPP, taking
advantage of opp-microwatt to provide EAS on such devices as was
initially intended.

Allow platforms to specify and consume any subset of opp-microvolt,
opp-microamp, or opp-microwatt without a hard dependency on
opp-microvolt to enable this functionality on such platforms.

Tested-by: James Calligeros <jcalligeros99@gmail.com>
Signed-off-by: James Calligeros <jcalligeros99@gmail.com>
Co-developed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
This commit is contained in:
James Calligeros 2022-11-03 14:40:44 +05:30 committed by Viresh Kumar
parent e5acb1991b
commit 2eedf62e66
1 changed files with 25 additions and 11 deletions
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36
drivers/opp/of.c
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@ -654,9 +654,12 @@ static u32 *opp_parse_microvolt(struct dev_pm_opp *opp, struct device *dev,
/*
* Missing property isn't a problem, but an invalid
* entry is. This property isn't optional if regulator
* information is provided.
* information is provided. Check only for the first OPP, as
* regulator_count may get initialized after that to a valid
* value.
*/
if (opp_table->regulator_count > 0) {
if (list_empty(&opp_table->opp_list) &&
opp_table->regulator_count > 0) {
dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
__func__);
return ERR_PTR(-EINVAL);
@ -674,7 +677,7 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
bool triplet;
microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);
if (IS_ERR_OR_NULL(microvolt))
if (IS_ERR(microvolt))
return PTR_ERR(microvolt);
microamp = _parse_named_prop(opp, dev, opp_table, "microamp", NULL);
@ -689,15 +692,26 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
goto free_microamp;
}
for (i = 0, j = 0; i < opp_table->regulator_count; i++) {
opp->supplies[i].u_volt = microvolt[j++];
/*
* Initialize regulator_count if it is uninitialized and no properties
* are found.
*/
if (unlikely(opp_table->regulator_count == -1)) {
opp_table->regulator_count = 0;
return 0;
}
if (triplet) {
opp->supplies[i].u_volt_min = microvolt[j++];
opp->supplies[i].u_volt_max = microvolt[j++];
} else {
opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
for (i = 0, j = 0; i < opp_table->regulator_count; i++) {
if (microvolt) {
opp->supplies[i].u_volt = microvolt[j++];
if (triplet) {
opp->supplies[i].u_volt_min = microvolt[j++];
opp->supplies[i].u_volt_max = microvolt[j++];
} else {
opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
}
}
if (microamp)