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charset="us-ascii"; Format="flowed" Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org Hi Krzysztof, On 4/9/2026 2:12 PM, Krzysztof Kozlowski wrote: > [ EXTERNAL EMAIL ] > > On 08/04/2026 16:32, Chuan Liu wrote: >> Hi Krzysztof (& ALL), >> Thanks for review. >> >> On 2/9/2026 9:17 PM, Krzysztof Kozlowski wrote: >>> [ EXTERNAL EMAIL ] >>> >>> On 09/02/2026 06:48, Chuan Liu via B4 Relay wrote: >>>> From: Chuan Liu >>>> >>>> Implement core clock driver for Amlogic SoC platforms, supporting >>> >>> So how did all existing Amlogic SoC platforms work so far without basic >>> clock driver? Really, how? >>> >>> You are suppose to grow existing code, not add your completely new >>> "basic" driver just because you have it that way in downstream. >>> >> >> Firstly, apologies for the delayed response. I had intended to >> consolidate the V1 review feedback and come back with a clearer plan for >> V2 changes. In the meantime, Martin has provided many detailed and >> valuable suggestions - much appreciated. >> >> The original goal of optimizing the HW based on A9 and introducing a new >> clock driver is to reduce unnecessary complexity in the driver. On A9, > > Nah, you just don't care about upstream and it is easier for you to > duplicate new code. Regarding the "duplicate new code": the ops implemented in clk-basic.c are indeed based on the CCF components (clk-mux, clk-divider, clk-gate), with the following enhancements: - Register access via regmap (meson clock driver looks like this) - Additional debug nodes to support Amlogic clock automated test tools (in conjunction with clk-measure to verify hardware functionality of each clock) - Clock context save/restore support for STD/STR Other drivers mainly focus on adapting to A9-specific hardware optimizations, as well as improving and refactoring the existing meson drivers. > >> we optimized the Clock/PLL controller HW to simplify driver performance, >> complexity, memory footprint, and reusability. Improvements on the HW >> side can also help drive corresponding enhancements in the driver: >> - Performance: Encapsulates sub-clock functions, reducing call paths >> - Complexity: Standardized register bits eliminate a large number of >> bit definitions (~1/3 of original code is defined register bit [1]) >> - Memory: Object-oriented design avoids copy/paste for repeated clocks > > Object oriented design? Sorry, what? In the new driver, clocks are modeled as the SoC CCU itself. For example, pwm_a/b/c... and emmc_a/b/c use the same CCU, represented as a "composite-ccu". We instantiate the CCU once, rather than redefining clocks for each module. > >> - Reusability: Same controller works across SoCs without driver >> changes (or with minimal changes) >> >> The old meson driver required compromises to unify legacy controller >> characteristics and driver styles. On A9, we want a fresh start. > > And maintainers don't want that. We expressed this many times already. > Not only in this thread - that's one of the most known feedbacks. Thanks for the clarification. > > Best regards, > Krzysztof -- Best regards, Chuan _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic