From 469d633d20c774ecd34ac615c838193e1e150c62 Mon Sep 17 00:00:00 2001 From: Rajendra Nayak Date: Sun, 31 Mar 2013 20:22:23 -0600 Subject: [PATCH] ARM: OMAP: dpll: enable bypass clock only when attempting dpll bypass 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: Roger Quadros Signed-off-by: Rajendra Nayak Signed-off-by: Paul Walmsley --- arch/arm/mach-omap2/dpll3xxx.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/arch/arm/mach-omap2/dpll3xxx.c b/arch/arm/mach-omap2/dpll3xxx.c index 3aed4b0b9563..6e9873ff1844 100644 --- a/arch/arm/mach-omap2/dpll3xxx.c +++ b/arch/arm/mach-omap2/dpll3xxx.c @@ -480,20 +480,22 @@ int omap3_noncore_dpll_set_rate(struct clk_hw *hw, unsigned long rate, if (!dd) return -EINVAL; - __clk_prepare(dd->clk_bypass); - clk_enable(dd->clk_bypass); - __clk_prepare(dd->clk_ref); - clk_enable(dd->clk_ref); - if (__clk_get_rate(dd->clk_bypass) == rate && (dd->modes & (1 << DPLL_LOW_POWER_BYPASS))) { pr_debug("%s: %s: set rate: entering bypass.\n", __func__, __clk_get_name(hw->clk)); + __clk_prepare(dd->clk_bypass); + clk_enable(dd->clk_bypass); ret = _omap3_noncore_dpll_bypass(clk); if (!ret) new_parent = dd->clk_bypass; + clk_disable(dd->clk_bypass); + __clk_unprepare(dd->clk_bypass); } else { + __clk_prepare(dd->clk_ref); + clk_enable(dd->clk_ref); + if (dd->last_rounded_rate != rate) rate = __clk_round_rate(hw->clk, rate); @@ -514,6 +516,8 @@ int omap3_noncore_dpll_set_rate(struct clk_hw *hw, unsigned long rate, ret = omap3_noncore_dpll_program(clk, freqsel); if (!ret) new_parent = dd->clk_ref; + clk_disable(dd->clk_ref); + __clk_unprepare(dd->clk_ref); } /* * FIXME - this is all wrong. common code handles reparenting and @@ -525,11 +529,6 @@ int omap3_noncore_dpll_set_rate(struct clk_hw *hw, unsigned long rate, if (!ret) __clk_reparent(hw->clk, new_parent); - clk_disable(dd->clk_ref); - __clk_unprepare(dd->clk_ref); - clk_disable(dd->clk_bypass); - __clk_unprepare(dd->clk_bypass); - return 0; } -- 2.20.1