From 2eedf62e66c28f6991425b580af68b3d89fa8021 Mon Sep 17 00:00:00 2001 From: James Calligeros Date: Thu, 3 Nov 2022 14:40:44 +0530 Subject: 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: James Calligeros Signed-off-by: James Calligeros Co-developed-by: Viresh Kumar Signed-off-by: Viresh Kumar --- drivers/opp/of.c | 36 +++++++++++++++++++++++++----------- 1 file changed, 25 insertions(+), 11 deletions(-) (limited to 'drivers/opp') diff --git a/drivers/opp/of.c b/drivers/opp/of.c index 08d97b97c326..e55c6095adf0 100644 --- a/drivers/opp/of.c +++ b/drivers/opp/of.c @@ -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) -- cgit v1.2.3-58-ga151