The following patchset adds interconnect[1][2] framework support to the exynos-bus devfreq driver. Extending the devfreq driver with interconnect capabilities started as a response to the issue referenced in [3]. The patches can be subdivided into four logical groups:
(a) Refactoring the existing devfreq driver in order to improve readability and accommodate for adding new code (patches 01--04/11).
(b) Tweaking the interconnect framework to support the exynos-bus use case (patches 05--07/11). Exporting of_icc_get_from_provider() allows us to avoid hardcoding every single graph edge in the DT or driver source, and relaxing the requirement contained in that function removes the need to provide dummy node IDs in the DT. Adjusting the logic in apply_constraints() (drivers/interconnect/core.c) accounts for the fact that every bus is a separate entity and therefore a separate interconnect provider, albeit constituting a part of a larger hierarchy.
(c) Implementing interconnect providers in the exynos-bus devfreq driver and adding required DT properties for one selected platform, namely Exynos4412 (patches 08--09/11). Due to the fact that this aims to be a generic driver for various Exynos SoCs, node IDs are generated dynamically rather than hardcoded. This has been determined to be a simpler approach, but depends on changes described in (b).
(d) Implementing a sample interconnect consumer for exynos-mixer targeted at the issue referenced in [3], again with DT info only for Exynos4412 (patches 10--11/11).
Integration of devfreq and interconnect functionalities comes down to one extra line in the devfreq target() callback, which selects either the frequency calculated by the devfreq governor, or the one requested with the interconnect API, whichever is higher. All new code works equally well when CONFIG_INTERCONNECT is 'n' (as in exynos_defconfig) in which case all interconnect API functions are no-ops.
--- Artur Świgoń Samsung R&D Institute Poland Samsung Electronics
--- References: [1] Documentation/interconnect/interconnect.rst [2] Documentation/devicetree/bindings/interconnect/interconnect.txt [3] https://patchwork.kernel.org/patch/10861757
Artur Świgoń (10): devfreq: exynos-bus: Extract exynos_bus_profile_init() devfreq: exynos-bus: Extract exynos_bus_profile_init_passive() devfreq: exynos-bus: Change goto-based logic to if-else logic devfreq: exynos-bus: Clean up code icc: Export of_icc_get_from_provider() icc: Relax requirement in of_icc_get_from_provider() icc: Relax condition in apply_constraints() arm: dts: exynos: Add parents and #interconnect-cells to Exynos4412 devfreq: exynos-bus: Add interconnect functionality to exynos-bus arm: dts: exynos: Add interconnects to Exynos4412 mixer
Marek Szyprowski (1): drm: exynos: mixer: Add interconnect support
.../boot/dts/exynos4412-odroid-common.dtsi | 1 + arch/arm/boot/dts/exynos4412.dtsi | 10 + drivers/devfreq/exynos-bus.c | 296 ++++++++++++++---- drivers/gpu/drm/exynos/exynos_mixer.c | 68 +++- drivers/interconnect/core.c | 12 +- include/linux/interconnect-provider.h | 6 + 6 files changed, 314 insertions(+), 79 deletions(-)