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iommu/arm-smmu: Add support for regulator deferred disable

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In case of unmap call, regulator is enabled/disabled. This may introduce
additional delay. For clients who do not detach, it's not possible to keep
regulator vote while smmu is attached.
Add support for regulator deferred disable. The time delay for deferred
disable can be set using dt property qcom,deferred-regulator-disable-delay
in ms.

Change-Id: I462e1999bd81f6332169b24749632d7b247c75c5
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>
This commit is contained in:
Prakash Gupta 2017-05-16 12:13:02 +05:30
parent a62f42964d
commit 65f095ea8f
2 changed files with 15 additions and 1 deletions
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6
Documentation/devicetree/bindings/iommu/arm,smmu.txt
View file

@ -121,6 +121,12 @@ conditions.
supported as we are directly comparing client SID with ID bits
of SMR registers.
- qcom,deferred-regulator-disable-delay : The time delay for deferred regulator
disable in ms. In case of unmap call, regulator is
enabled/disabled. This may introduce additional delay. For
clients who do not detach, it's not possible to keep regulator
vote while smmu is attached. Type is <u32>.
- clocks : List of clocks to be used during SMMU register access. See
Documentation/devicetree/bindings/clock/clock-bindings.txt
for information about the format. For each clock specified

10
drivers/iommu/arm-smmu.c
View file

@ -404,6 +404,7 @@ struct arm_smmu_device {
struct msm_bus_scale_pdata *bus_pdata;
enum tz_smmu_device_id sec_id;
int regulator_defer;
};
struct arm_smmu_cfg {
@ -950,7 +951,8 @@ static int arm_smmu_disable_regulators(struct arm_smmu_device *smmu)
arm_smmu_unprepare_clocks(smmu);
arm_smmu_unrequest_bus(smmu);
if (smmu->gdsc) {
ret = regulator_disable(smmu->gdsc);
ret = regulator_disable_deferred(smmu->gdsc,
smmu->regulator_defer);
WARN(ret, "%s: Regulator disable failed\n",
dev_name(smmu->dev));
}
@ -3610,6 +3612,12 @@ static int arm_smmu_init_regulators(struct arm_smmu_device *smmu)
if (!of_get_property(dev->of_node, "vdd-supply", NULL))
return 0;
if (!of_property_read_u32(dev->of_node,
"qcom,deferred-regulator-disable-delay",
&(smmu->regulator_defer)))
dev_info(dev, "regulator defer delay %d\n",
smmu->regulator_defer);
smmu->gdsc = devm_regulator_get(dev, "vdd");
if (IS_ERR(smmu->gdsc))
return PTR_ERR(smmu->gdsc);