diff options
| -rw-r--r-- | drivers/clk/clk_kendryte.c | 107 |
1 files changed, 53 insertions, 54 deletions
diff --git a/drivers/clk/clk_kendryte.c b/drivers/clk/clk_kendryte.c index 2caa21aec9e..69691c4a04c 100644 --- a/drivers/clk/clk_kendryte.c +++ b/drivers/clk/clk_kendryte.c @@ -709,6 +709,10 @@ TEST_STATIC int k210_pll_calc_config(u32 rate, u32 rate_in, * Whether we swapped r and od while enforcing frequency limits */ bool swapped = false; + /* + * Whether the intermediate frequencies are out-of-spec + */ + bool out_of_spec; u64 last_od = od; u64 last_r = r; @@ -767,76 +771,71 @@ TEST_STATIC int k210_pll_calc_config(u32 rate, u32 rate_in, * aren't in spec, try swapping r and od. If everything is * in-spec, calculate the relative error. */ - while (true) { +again: + out_of_spec = false; + if (r > max_r) { + out_of_spec = true; + } else { /* - * Whether the intermediate frequencies are out-of-spec + * There is no way to only divide once; we need + * to examine the frequency with and without the + * effect of od. */ - bool out_of_spec = false; + u64 vco = DIV_ROUND_CLOSEST_ULL(rate_in * f, r); - if (r > max_r) { + if (vco > 1750000000 || vco < 340000000) out_of_spec = true; - } else { - /* - * There is no way to only divide once; we need - * to examine the frequency with and without the - * effect of od. - */ - u64 vco = DIV_ROUND_CLOSEST_ULL(rate_in * f, r); - - if (vco > 1750000000 || vco < 340000000) - out_of_spec = true; + } + + if (out_of_spec) { + u64 new_r, new_od; + + if (!swapped) { + u64 tmp = r; + + r = od; + od = tmp; + swapped = true; + goto again; } - if (out_of_spec) { - if (!swapped) { - u64 tmp = r; - - r = od; - od = tmp; - swapped = true; - continue; - } else { - /* - * Try looking ahead to see if there are - * additional factors for the same - * product. - */ - if (i + 1 < ARRAY_SIZE(factors)) { - u64 new_r, new_od; - - i++; - new_r = UNPACK_R(factors[i]); - new_od = UNPACK_OD(factors[i]); - if (r * od == new_r * new_od) { - r = new_r; - od = new_od; - swapped = false; - continue; - } - i--; - } - break; + /* + * Try looking ahead to see if there are additional + * factors for the same product. + */ + if (i + 1 < ARRAY_SIZE(factors)) { + i++; + new_r = UNPACK_R(factors[i]); + new_od = UNPACK_OD(factors[i]); + if (r * od == new_r * new_od) { + r = new_r; + od = new_od; + swapped = false; + goto again; } + i--; } - error = DIV_ROUND_CLOSEST_ULL(f * inv_ratio, r * od); - /* The lower 16 bits are spurious */ - error = abs((error - BIT(32))) >> 16; + /* We ran out of things to try */ + continue; + } - if (error < best_error) { - best->r = r; - best->f = f; - best->od = od; - best_error = error; - } - break; + error = DIV_ROUND_CLOSEST_ULL(f * inv_ratio, r * od); + /* The lower 16 bits are spurious */ + error = abs((error - BIT(32))) >> 16; + + if (error < best_error) { + best->r = r; + best->f = f; + best->od = od; + best_error = error; } } while (f < 64 && i + 1 < ARRAY_SIZE(factors) && error != 0); + log_debug("best error %lld\n", best_error); if (best_error == S64_MAX) return -EINVAL; - log_debug("best error %lld\n", best_error); return 0; } |