diff options
| -rw-r--r-- | drivers/clk/bcm/clk-iproc-pll.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/clk/bcm/clk-iproc-pll.c b/drivers/clk/bcm/clk-iproc-pll.c index 7df010b2edcd..ab10819e2c09 100644 --- a/drivers/clk/bcm/clk-iproc-pll.c +++ b/drivers/clk/bcm/clk-iproc-pll.c @@ -285,6 +285,40 @@ static void __pll_bring_out_reset(struct iproc_pll *pll, unsigned int kp, iproc_pll_write(pll, pll->control_base, reset->offset, val); } +/* + * Determines if the change to be applied to the PLL is minor (just an update + * or the fractional divider). If so, then we can avoid going through a + * disruptive reset and lock sequence. + */ +static bool pll_fractional_change_only(struct iproc_pll *pll, + struct iproc_pll_vco_param *vco) +{ + const struct iproc_pll_ctrl *ctrl = pll->ctrl; + u32 val; + u32 ndiv_int; + unsigned int pdiv; + + /* PLL needs to be locked */ + val = readl(pll->status_base + ctrl->status.offset); + if ((val & (1 << ctrl->status.shift)) == 0) + return false; + + val = readl(pll->control_base + ctrl->ndiv_int.offset); + ndiv_int = (val >> ctrl->ndiv_int.shift) & + bit_mask(ctrl->ndiv_int.width); + + if (ndiv_int != vco->ndiv_int) + return false; + + val = readl(pll->control_base + ctrl->pdiv.offset); + pdiv = (val >> ctrl->pdiv.shift) & bit_mask(ctrl->pdiv.width); + + if (pdiv != vco->pdiv) + return false; + + return true; +} + static int pll_set_rate(struct iproc_clk *clk, struct iproc_pll_vco_param *vco, unsigned long parent_rate) { @@ -333,6 +367,19 @@ static int pll_set_rate(struct iproc_clk *clk, struct iproc_pll_vco_param *vco, return ret; } + if (pll_fractional_change_only(clk->pll, vco)) { + /* program fractional part of NDIV */ + if (ctrl->flags & IPROC_CLK_PLL_HAS_NDIV_FRAC) { + val = readl(pll->control_base + ctrl->ndiv_frac.offset); + val &= ~(bit_mask(ctrl->ndiv_frac.width) << + ctrl->ndiv_frac.shift); + val |= vco->ndiv_frac << ctrl->ndiv_frac.shift; + iproc_pll_write(pll, pll->control_base, + ctrl->ndiv_frac.offset, val); + return 0; + } + } + /* put PLL in reset */ __pll_put_in_reset(pll); |