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Diffstat (limited to 'Documentation/power/regulator/consumer.txt')
| -rw-r--r-- | Documentation/power/regulator/consumer.txt | 42 |
1 files changed, 39 insertions, 3 deletions
diff --git a/Documentation/power/regulator/consumer.txt b/Documentation/power/regulator/consumer.txt index 55c4175..8afb236c 100644 --- a/Documentation/power/regulator/consumer.txt +++ b/Documentation/power/regulator/consumer.txt @@ -143,8 +143,9 @@ This will cause the core to recalculate the total load on the regulator (based on all its consumers) and change operating mode (if necessary and permitted) to best match the current operating load. -The load_uA value can be determined from the consumers datasheet. e.g.most -datasheets have tables showing the max current consumed in certain situations. +The load_uA value can be determined from the consumer's datasheet. e.g. most +datasheets have tables showing the maximum current consumed in certain +situations. Most consumers will use indirect operating mode control since they have no knowledge of the regulator or whether the regulator is shared with other @@ -173,10 +174,45 @@ Consumers can register interest in regulator events by calling :- int regulator_register_notifier(struct regulator *regulator, struct notifier_block *nb); -Consumers can uregister interest by calling :- +Consumers can unregister interest by calling :- int regulator_unregister_notifier(struct regulator *regulator, struct notifier_block *nb); Regulators use the kernel notifier framework to send event to their interested consumers. + +7. Regulator Direct Register Access +=================================== +Some kinds of power management hardware or firmware are designed such that +they need to do low-level hardware access to regulators, with no involvement +from the kernel. Examples of such devices are: + +- clocksource with a voltage-controlled oscillator and control logic to change + the supply voltage over I2C to achieve a desired output clock rate +- thermal management firmware that can issue an arbitrary I2C transaction to + perform system poweroff during overtemperature conditions + +To set up such a device/firmware, various parameters like I2C address of the +regulator, addresses of various regulator registers etc. need to be configured +to it. The regulator framework provides the following helpers for querying +these details. + +Bus-specific details, like I2C addresses or transfer rates are handled by the +regmap framework. To get the regulator's regmap (if supported), use :- + +struct regmap *regulator_get_regmap(struct regulator *regulator); + +To obtain the hardware register offset and bitmask for the regulator's voltage +selector register, use :- + +int regulator_get_hardware_vsel_register(struct regulator *regulator, + unsigned *vsel_reg, + unsigned *vsel_mask); + +To convert a regulator framework voltage selector code (used by +regulator_list_voltage) to a hardware-specific voltage selector that can be +directly written to the voltage selector register, use :- + +int regulator_list_hardware_vsel(struct regulator *regulator, + unsigned selector); |