From: John Ogness Date: Wed, 23 Feb 2011 03:00:47 +0000 (-0700) Subject: OMAP2/3: clock: fix fint calculation for DPLL_FREQSEL X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ea68c00e2623bb5b001c2117a4dcca4754781b4e;p=linux-beck.git OMAP2/3: clock: fix fint calculation for DPLL_FREQSEL In OMAP35X TRM Rev 2010-05 Figure 7-18 "DPLL With EMI Reduction Feature", it is shown that the internal frequency is calculated by CLK_IN/(N+1). However, the value passed to _dpll_test_fint() is already "N+1" since Linux is using the values to divide by. In the technical reference manual, "N" is referring to the divider's register value (0-127). During power management testing, it was observed that programming the wrong jitter correction value can cause the system to become unstable and eventually crash. Signed-off-by: John Ogness [paul@pwsan.com: added second paragraph to commit message] Signed-off-by: Paul Walmsley --- diff --git a/arch/arm/mach-omap2/clkt_dpll.c b/arch/arm/mach-omap2/clkt_dpll.c index 337392c3f549..acb7ae5b0a25 100644 --- a/arch/arm/mach-omap2/clkt_dpll.c +++ b/arch/arm/mach-omap2/clkt_dpll.c @@ -77,7 +77,7 @@ static int _dpll_test_fint(struct clk *clk, u8 n) dd = clk->dpll_data; /* DPLL divider must result in a valid jitter correction val */ - fint = clk->parent->rate / (n + 1); + fint = clk->parent->rate / n; if (fint < DPLL_FINT_BAND1_MIN) { pr_debug("rejecting n=%d due to Fint failure, "