Merge "power: battery_current_limit: Support btm based current measurement"

* Battery Current Limit

This Battery Current Limit device, provides an interface to detect and notify

This Battery Current Limit(BCL) device, provides an interface to detect and notify

interested applications when the SOC is drawing current in excess of the limits

specified.

The BCL driver has another operation mode, where it monitors the battery

current sensor via ADC TM hardware called BTM. The newer devices support

a BTM hardware configuration, which can measure the battery current and voltage.

This ADC hardware is capable of sampling the sensor every 1 msec and interrupts

the BCL driver, which in turn mitigates the CPU frequency based on the

current load thresholds. The BCL drivers operation mode is decided based

on the parameters given in the device tree. In this BTM operation mode, BCL

driver provides sysfs entries to configure the thresholds, ADC polling

timer interval and other operational parameters.

The device tree parameters for bcl are:

Required parameters:

- compatible: Must be "qcom,bcl"

Optional parameters:

- qcom,bcl-enable : If this property is defined, BCL functionality will

		be enabled from boot. The mode of operation, will be based

		on the properties defined in the device tree.

- qcom,ibat-vadc = <&vadc_phandle>: A phandle to the VADC device. The BTM mode

		of operation requires this property to be defined if and only

		if qcom,ibat-threshold-adc_tm and qcom,ibat-monitor are defined.

		Error in any of these properties will disable BTM mode of operation

		and will fall back to the available current monitor mode.

- qcom,ibat-threshold-adc_tm = <&vadc_tm_phandle>: A phandle to the ADC TM

		device. BCL registers with the hardware monitor for this TM

		device to be able to set thresholds and get threshold

		notifications. The BTM mode of operation requires this property

		to be defined if and only if qcom,ibat-vadc and qcom,ibat-monitor

		are defined. Error in any of these properties will disable BTM

		mode of operation and will fall back to the available current

		monitor mode.

Optional nodes:

- qcom,ibat-monitor: This optional node defines all the parameters for the

		battery current monitoring. The BTM mode of operation requires

		all the below properties to be defined with valid values. Also,

		this node should be defined if and only if qcom,ibat-vadc and

		qcom,ibat-threshold-adc_tm are defined. Error in any of these

		properties will disable BTM mode of operation and will fall

		back to the available current monitor mode.

	* high-threshold-uamp: The battery current, in microampere, after which

		the BCL driver should cap the maximum frequency.

	* low-threshold-uamp: The battery current, in microampere, below which

		the BCL driver should clear the CPU frequency mitigation.

	* mitigation-freq-khz: The maximum frequency value the BCL driver

		should mitigate the CPUS's with. This frequency shouldn't be

		less than the minimum frequency request that the kernel thermal

		monitor driver places during vdd restriction.

	* ibat-channel: The ADC hardware's channel number.

	* uv-to-ua-numerator: The conversion parameter required for converting

		the voltage measure from ADC hardware to current value.

	* uv-to-ua-denominator: The conversion parameter required for

		converting the voltage measure from ADC hardware to current.

		The microvolt to microampere (or vice-versa) conversion uses

		the below conversion formulae.

		ua = (uv * uv-to-ua-numerator) / uv-to-ua-denominator

	* adc-interval-usec: The polling interval, in microseconds, for the ADC

		hardware.

Example:

	qcom,bcl {

		compatible = "qcom,bcl";

		qcom,ibat-vadc = <&pma8084_vadc>;

		qcom,ibat-threshold-adc_tm = <&pma8084_adc_tm>;

		qcom,ibat-monitor {

			high-threshold-uamp = <1500>;

			low-threshold-uamp = <500>;

			mitigation-freq-khz = <1958400>;

			ibat-channel = <0x15>;

			adc-interval-usec = <3900>;

			uv-to-ua-numerator = <2>;

			uv-to-ua-denominator = <1>;

		};

	};