• Leonard Crestez's avatar
    cpufreq: imx6q: Fix imx6sx low frequency support · fded5fc8
    Leonard Crestez authored
    This patch contains the minimal changes required to support imx6sx OPP
    of 198 Mhz. Without this patch cpufreq still reports success but the
    frequency is not changed, the "arm" clock will still be at 396000000 in
    clk_summary.
    
    In order to do this PLL1 needs to be still kept enabled while changing
    the ARM clock. This is a hardware requirement: when ARM_PODF is changed
    in CCM we need to check the busy bit of CCM_CDHIPR bit 16 arm_podf_busy,
    and this bit is sync with PLL1 clock, so if PLL1 NOT enabled, this
    bit will never get clear.
    
    Keep pll1_sys explicitly enabled until after the rate is change to deal
    with this. Otherwise from the clk framework perspective pll1_sys is
    unused and gets turned off.
    Signed-off-by: default avatarLeonard Crestez <leonard.crestez@nxp.com>
    Reviewed-by: default avatarLucas Stach <l.stach@pengutronix.de>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    fded5fc8
imx6q-cpufreq.c 11.9 KB