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yaml
---
r: 137338
b: refs/heads/master
c: 85a5f78
h: refs/heads/master
v: v3
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Paul Walmsley authored and Russell King committed Feb 8, 2009
1 parent 38536c0 commit 5524b6d
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Showing 2 changed files with 19 additions and 18 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: b32450409847dddf060a468707212d3493df4f63
refs/heads/master: 85a5f78d2b15a2e73b6486a24b77bb3ab67d5bbc
35 changes: 18 additions & 17 deletions trunk/arch/arm/mach-omap2/clock.c
Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,7 @@
#define DPLL_MIN_DIVIDER 1

/* Possible error results from _dpll_test_mult */
#define DPLL_MULT_UNDERFLOW (1 << 0)
#define DPLL_MULT_UNDERFLOW -1

/*
* Scale factor to mitigate roundoff errors in DPLL rate rounding.
Expand Down Expand Up @@ -826,7 +826,7 @@ static int _dpll_test_mult(int *m, int n, unsigned long *new_rate,
unsigned long target_rate,
unsigned long parent_rate)
{
int flags = 0, carry = 0;
int r = 0, carry = 0;

/* Unscale m and round if necessary */
if (*m % DPLL_SCALE_FACTOR >= DPLL_ROUNDING_VAL)
Expand All @@ -847,13 +847,13 @@ static int _dpll_test_mult(int *m, int n, unsigned long *new_rate,
if (*m < DPLL_MIN_MULTIPLIER) {
*m = DPLL_MIN_MULTIPLIER;
*new_rate = 0;
flags = DPLL_MULT_UNDERFLOW;
r = DPLL_MULT_UNDERFLOW;
}

if (*new_rate == 0)
*new_rate = _dpll_compute_new_rate(parent_rate, *m, n);

return flags;
return r;
}

/**
Expand Down Expand Up @@ -892,21 +892,27 @@ long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate)

dd->last_rounded_rate = 0;

for (n = dd->max_divider; n >= DPLL_MIN_DIVIDER; n--) {
for (n = DPLL_MIN_DIVIDER; n <= dd->max_divider; n++) {

/* Compute the scaled DPLL multiplier, based on the divider */
m = scaled_rt_rp * n;

/*
* Since we're counting n down, a m overflow means we can
* can immediately skip to the next n
* Since we're counting n up, a m overflow means we
* can bail out completely (since as n increases in
* the next iteration, there's no way that m can
* increase beyond the current m)
*/
if (m > scaled_max_m)
continue;
break;

r = _dpll_test_mult(&m, n, &new_rate, target_rate,
clk->parent->rate);

/* m can't be set low enough for this n - try with a larger n */
if (r == DPLL_MULT_UNDERFLOW)
continue;

e = target_rate - new_rate;
pr_debug("clock: n = %d: m = %d: rate error is %d "
"(new_rate = %ld)\n", n, m, e, new_rate);
Expand All @@ -918,16 +924,11 @@ long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate)
min_e_n = n;

pr_debug("clock: found new least error %d\n", min_e);
}

/*
* Since we're counting n down, a m underflow means we
* can bail out completely (since as n decreases in
* the next iteration, there's no way that m can
* increase beyond the current m)
*/
if (r & DPLL_MULT_UNDERFLOW)
break;
/* We found good settings -- bail out now */
if (min_e <= clk->dpll_data->rate_tolerance)
break;
}
}

if (min_e < 0) {
Expand Down

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