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| author | John Ogness <john.ogness@linutronix.de> | 2011-02-23 04:00:47 +0100 |
|---|---|---|
| committer | Paul Walmsley <paul@pwsan.com> | 2011-02-23 04:00:47 +0100 |
| commit | ea68c00e2623bb5b001c2117a4dcca4754781b4e (patch) | |
| tree | 02c25b983a7735cd444a525a0b0946dc0be9004a | |
| parent | Linux 2.6.38-rc6 (diff) | |
| download | linux-ea68c00e2623bb5b001c2117a4dcca4754781b4e.tar.xz linux-ea68c00e2623bb5b001c2117a4dcca4754781b4e.zip | |
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 <john.ogness@linutronix.de>
[paul@pwsan.com: added second paragraph to commit message]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
| -rw-r--r-- | arch/arm/mach-omap2/clkt_dpll.c | 2 |
1 files changed, 1 insertions, 1 deletions
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, " |