Commit 2eedf62e authored by James Calligeros's avatar James Calligeros Committed by Viresh Kumar
Browse files

OPP: decouple dt properties in opp_parse_supplies() 



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: default avatarJames Calligeros <jcalligeros99@gmail.com>
Signed-off-by: default avatarJames Calligeros <jcalligeros99@gmail.com>
Co-developed-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
parent e5acb199

drivers/opp/of.c

+25 −11
Original line number Diff line number Diff line
@@ -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);
@@ -689,7 +692,17 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev, 
		goto free_microamp;

	}



	/*

	 * 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;

	}



	for (i = 0, j = 0; i < opp_table->regulator_count; i++) {

		if (microvolt) {

			opp->supplies[i].u_volt = microvolt[j++];



			if (triplet) {
@@ -699,6 +712,7 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev, 
				opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;

				opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;

			}

		}



		if (microamp)

			opp->supplies[i].u_amp = microamp[i];