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e66d1cb3c2
Changing voltage and enabling regulator might require delays so the regulator stabilizes at expected level. Add support for "regulator-ramp-delay" binding which can introduce required time to both enabling the regulator and to changing the voltage. Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Tested-by: Anand Moon <linux.amoon@gmail.com> Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
65 lines
2.8 KiB
Text
65 lines
2.8 KiB
Text
Voltage/Current regulator
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Binding:
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The regulator devices don't use the "compatible" property. The binding is done
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by the prefix of regulator node's name, or, if this fails, by the prefix of the
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regulator's "regulator-name" property. Usually the pmic I/O driver will provide
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the array of 'struct pmic_child_info' with the prefixes and compatible drivers.
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The bind is done by calling function: pmic_bind_childs().
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Example drivers:
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pmic: drivers/power/pmic/max77686.c
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regulator: drivers/power/regulator/max77686.c
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For the node name e.g.: "prefix[:alpha:]num { ... }":
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- the driver prefix should be: "prefix" - case sensitive
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- the node name's "num" is set as "dev->driver_data" on bind
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Example the prefix "ldo" will pass for: "ldo1", "ldo@1", "ldoreg@1, ...
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Binding by means of the node's name is preferred. However if the node names
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would produce ambiguous prefixes (like "regulator@1" and "regualtor@11") and you
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can't or do not want to change them then binding against the "regulator-name"
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property is possible. The syntax for the prefix of the "regulator-name" property
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is the same as the one for the regulator's node name.
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Use case: a regulator named "regulator@1" to be bound to a driver named
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"LDO_DRV" and a regulator named "regualator@11" to be bound to an other driver
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named "BOOST_DRV". Using prefix "regualtor@1" for driver matching would load
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the same driver for both regulators, hence the prefix is ambiguous.
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Optional properties:
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- regulator-name: a string, required by the regulator uclass, used for driver
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binding if binding by node's name prefix fails
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- regulator-min-microvolt: a minimum allowed Voltage value
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- regulator-max-microvolt: a maximum allowed Voltage value
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- regulator-min-microamp: a minimum allowed Current value
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- regulator-max-microamp: a maximum allowed Current value
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- regulator-always-on: regulator should never be disabled
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- regulator-boot-on: enabled by bootloader/firmware
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- regulator-ramp-delay: ramp delay for regulator (in uV/us)
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Note
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The "regulator-name" constraint is used for setting the device's uclass
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platform data '.name' field. And the regulator device name is set from
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it's node name. If "regulator-name" is not provided in dts, node name
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is chosen for setting the device's uclass platform data '.name' field.
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Other kernel-style properties, are currently not used.
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Note:
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For the regulator autoset from constraints, the framework expects that:
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- regulator-min-microvolt is equal to regulator-max-microvolt
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- regulator-min-microamp is equal to regulator-max-microamp
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- regulator-always-on or regulator-boot-on is set
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Example:
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ldo0 {
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/* Optional */
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regulator-name = "VDDQ_EMMC_1.8V";
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regulator-min-microvolt = <1800000>;
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regulator-max-microvolt = <1800000>;
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regulator-min-microamp = <100000>;
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regulator-max-microamp = <100000>;
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regulator-always-on;
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regulator-boot-on;
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regulator-ramp-delay = <12000>;
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};
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