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  • MyungJoo Ham's avatar
    PM/Devfreq: Add Exynos4-bus device DVFS driver for Exynos4210/4212/4412. · 7b405038
    MyungJoo Ham authored
    
    
    Exynos4-bus device devfreq driver add DVFS capability for
    Exynos4210/4212/4412-Bus (memory). The driver monitors PPMU counters of memory
    controllers and adjusts operating frequencies and voltages with OPP.
    For Exynos4210, vdd_int is controlled. For exynos4412/4212, vdd_mif and
    vdd_int are controlled.
    
    Dependency (CONFIG_EXYNOS_ASV):
    Exynos4 ASV driver has been posted in the mailing list; however, it
    si not yet upstreamed. Although the current revision of Exynos4 ASV
    patch does not contain "CONFIG_EXYNOS_ASV", we have added the symbol
    to hide the dependent from compilers for now. As soon as Exynos4 ASV
    drivers are merged, the #ifdef statement will be removed or the
    name will be changed.
    
    However, enabling ASV is essential in most Exynos4 chips to reduce
    the power consumption of Exynos4210 because without ASV, this Devfreq
    driver assumes the worst case scenario, which consumes more power.
    
    Signed-off-by: default avatarMyungJoo Ham <myungjoo.ham@samsung.com>
    Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
    
    ---
    Changes from v1
    - Support 4212 and 4412 as well as 4210.
    7b405038