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Switch parent clock when setting frequency if a new parent is a better

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candidate for the target rate.

Reviewed by:	andrew, manu
This commit is contained in:
Jared McNeill 2016-08-25 10:27:22 +00:00
parent 1ff131af88
commit 30a0ebdb1c
1 changed files with 29 additions and 10 deletions
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39
sys/arm/allwinner/clk/aw_modclk.c
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@ -160,28 +160,47 @@ aw_modclk_set_freq(struct clknode *clk, uint64_t fin, uint64_t *fout,
int flags, int *stop)
{
struct aw_modclk_sc *sc;
uint32_t val, m, n, best_m, best_n;
uint32_t val, m, n, src, best_m, best_n, best_src;
uint64_t cur_freq;
int64_t best_diff, cur_diff;
int error;
sc = clknode_get_softc(clk);
best_n = best_m = 0;
best_diff = (int64_t)*fout;
best_src = 0;
for (n = 0; n <= CLK_RATIO_N_MAX; n++)
for (m = 0; m <= CLK_RATIO_M_MAX; m++) {
cur_freq = fin / (1 << n) / (m + 1);
cur_diff = (int64_t)*fout - cur_freq;
if (cur_diff >= 0 && cur_diff < best_diff) {
best_diff = cur_diff;
best_m = m;
best_n = n;
for (src = 0; src < CLK_SRC_SEL_MAX; src++) {
error = clknode_set_parent_by_idx(clk, src);
if (error != 0)
continue;
error = clknode_get_freq(clknode_get_parent(clk), &fin);
if (error != 0)
continue;
for (n = 0; n <= CLK_RATIO_N_MAX; n++)
for (m = 0; m <= CLK_RATIO_M_MAX; m++) {
cur_freq = fin / (1 << n) / (m + 1);
cur_diff = (int64_t)*fout - cur_freq;
if (cur_diff >= 0 && cur_diff < best_diff) {
best_src = src;
best_diff = cur_diff;
best_m = m;
best_n = n;
}
}
}
}
if (best_diff == (int64_t)*fout)
return (ERANGE);
error = clknode_set_parent_by_idx(clk, best_src);
if (error != 0)
return (error);
error = clknode_get_freq(clknode_get_parent(clk), &fin);
if (error != 0)
return (error);
DEVICE_LOCK(sc);
MODCLK_READ(sc, &val);
val &= ~(CLK_RATIO_N | CLK_RATIO_M);