diff options
| -rw-r--r-- | arch/arm/mach-omap2/clock.c | 35 |
1 files changed, 18 insertions, 17 deletions
diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c index 2f0eaaad4819..76e20bcc4e8a 100644 --- a/arch/arm/mach-omap2/clock.c +++ b/arch/arm/mach-omap2/clock.c @@ -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. @@ -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) @@ -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; } /** @@ -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); @@ -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) { |