• Rajendra Nayak's avatar
    ARM: OMAP: dpll: enable bypass clock only when attempting dpll bypass · 469d633d
    Rajendra Nayak authored
    omap3_noncore_dpll_set_rate() attempts an enable of bypass clk as well
    as ref clk for every .set_rate attempt on a noncore DPLL, regardless of
    whether the .set_rate results in the DPLL being locked or put in bypass.
    Early at boot, while some of these DPLLs are programmed and locked
    (using .set_rate for the DPLL), this causes an ordering issue.
    
    For instance, on OMAP5, the USB DPLL derives its bypass clk from ABE DPLL.
    If a .set_rate of USB DPLL which programmes the M,N and locks it is called
    before the one for ABE, the enable of USB bypass clk (derived from ABE DPLL)
    then attempts to lock the ABE DPLL and fails as the M,N values for ABE
    are yet to be programmed.
    
    To get rid of this ordering needs, enable bypass clk for a DPLL as part
    of its .set_rate only when its being put in bypass, and only enable the
    ref clk when its locked.
    Reported-by: default avatarRoger Quadros <rogerq@ti.com>
    Signed-off-by: default avatarRajendra Nayak <rnayak@ti.com>
    Signed-off-by: default avatarPaul Walmsley <paul@pwsan.com>
    469d633d
dpll3xxx.c 17 KB