PM / devfreq: event: Change prototype of devfreq_event_get_edev_by_phandle function

Previously, devfreq core support 'devfreq-events' property in order to get
the devfreq-event device by phandle. But, 'devfreq-events' property name is
not proper on devicetree binding because this name doesn't mean
the any h/w attribute.

The devfreq-event core hand over the rights to decide the property name
for getting the devfreq-event device on devicetree. Each devfreq-event driver
will decide the property name on devicetree binding and then pass
the their own property name to devfreq_event_get_edev_by_phandle function.

And change the prototype of devfreq_event_get_edev_count function
because of used deprecated 'devfreq-events' property.

Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

PM / devfreq: events: extend events by type of counted data

This patch adds posibility to choose what type of data should be counted
by the PPMU counter. Now the type comes from DT where the event has been
defined. When there is no 'event-data-type' the default value is used,
which is 'read+write data in bytes'.
It is needed when you want to know not only read+write data bytes but
i.e. only write data in byte, or number of read requests, etc.

Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
[Updated property by MyungJoo. data_type --> event_type]
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM / devfreq: event: remove duplicate devfreq_event_get_drvdata()

there define two devfreq_event_get_drvdata() function in devfreq-event.h
when disable CONFIG_PM_DEVFREQ_EVENT, it will lead to build fail. So
remove devfreq_event_get_drvdata() function.

Fixes: f262f28c1470 ("PM / devfreq: event: Add devfreq_event class")
Cc: stable@vger.kernel.org
Signed-off-by: Lin Huang <hl@rock-chips.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

PM / devfreq: event: Add const keyword for devfreq_event_ops structure

This patch adds the const keyword for devfreq_event_ops structure
because the ops of devfreq_event_desc structure should not be changed
after initialization.

Cc: Myungjoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

PM / devfreq: event: Add devfreq_event class

This patch adds a new class in devfreq, devfreq_event, which provides
raw data (e.g., memory bus utilization, GPU utilization) for devfreq
governors.

- devfreq_event device : Provides raw data for a governor of a devfreq device
- devfreq device : Monitors device state and changes frequency/voltage
of the device using the raw data from its
devfreq_event device.

A devfreq device dertermines performance states (normally the frequency
and the voltage vlues) based on the results its designtated devfreq governor:
e.g., ondemand, performance, powersave.

In order to give such results required by a devfreq device, the devfreq
governor requires data that indicates the performance requirement given
to the devfreq device. The conventional (previous) implementatino of
devfreq subsystem requires a devfreq device driver to implement its own
mechanism to acquire performance requirement for its governor. However,
there had been issues with such requirements:

1. Although performance requirement of such devices is usually acquired
from common devices (PMU/PPMU), we do not have any abstract structure to
represent them properly.
2. Such performance requirement devices (PMU/PPMU) are actual hardware
pieces that may be represented by Device Tree directly while devfreq device
itself is a virtual entity that are not considered to be represented by
Device Tree according to Device Tree folks.

In order to address such issues, a devferq_event device (represented by
this patch) provides a template for device drivers representing
performance monitoring unit, which gives the basic or raw data for
preformance requirement, which in turn, is required by devfreq governors.

The following description explains the feature of two kind of devfreq class:
- devfreq class (existing)
: devfreq consumer device use raw data from devfreq_event device for
determining proper current system state and change voltage/frequency
dynamically using various governors.

- devfreq_event class (new)
: Provide measured raw data to devfreq device for governor

Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
[Commit message rewritten & conflict resolved by MyungJoo]
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>