diff options
Diffstat (limited to 'drivers/clk/bcm')
| -rw-r--r-- | drivers/clk/bcm/clk-kona.c | 54 |
1 files changed, 53 insertions, 1 deletions
diff --git a/drivers/clk/bcm/clk-kona.c b/drivers/clk/bcm/clk-kona.c index d603c4e22fc..95af2e665dd 100644 --- a/drivers/clk/bcm/clk-kona.c +++ b/drivers/clk/bcm/clk-kona.c @@ -1031,6 +1031,58 @@ static long kona_peri_clk_round_rate(struct clk_hw *hw, unsigned long rate, rate ? rate : 1, *parent_rate, NULL); } +static long kona_peri_clk_determine_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate, struct clk **best_parent) +{ + struct kona_clk *bcm_clk = to_kona_clk(hw); + struct clk *clk = hw->clk; + struct clk *current_parent; + unsigned long parent_rate; + unsigned long best_delta; + unsigned long best_rate; + u32 parent_count; + u32 which; + + /* + * If there is no other parent to choose, use the current one. + * Note: We don't honor (or use) CLK_SET_RATE_NO_REPARENT. + */ + WARN_ON_ONCE(bcm_clk->init_data.flags & CLK_SET_RATE_NO_REPARENT); + parent_count = (u32)bcm_clk->init_data.num_parents; + if (parent_count < 2) + return kona_peri_clk_round_rate(hw, rate, best_parent_rate); + + /* Unless we can do better, stick with current parent */ + current_parent = clk_get_parent(clk); + parent_rate = __clk_get_rate(current_parent); + best_rate = kona_peri_clk_round_rate(hw, rate, &parent_rate); + best_delta = abs(best_rate - rate); + + /* Check whether any other parent clock can produce a better result */ + for (which = 0; which < parent_count; which++) { + struct clk *parent = clk_get_parent_by_index(clk, which); + unsigned long delta; + unsigned long other_rate; + + BUG_ON(!parent); + if (parent == current_parent) + continue; + + /* We don't support CLK_SET_RATE_PARENT */ + parent_rate = __clk_get_rate(parent); + other_rate = kona_peri_clk_round_rate(hw, rate, &parent_rate); + delta = abs(other_rate - rate); + if (delta < best_delta) { + best_delta = delta; + best_rate = other_rate; + *best_parent = parent; + *best_parent_rate = parent_rate; + } + } + + return best_rate; +} + static int kona_peri_clk_set_parent(struct clk_hw *hw, u8 index) { struct kona_clk *bcm_clk = to_kona_clk(hw); @@ -1135,7 +1187,7 @@ struct clk_ops kona_peri_clk_ops = { .disable = kona_peri_clk_disable, .is_enabled = kona_peri_clk_is_enabled, .recalc_rate = kona_peri_clk_recalc_rate, - .round_rate = kona_peri_clk_round_rate, + .determine_rate = kona_peri_clk_determine_rate, .set_parent = kona_peri_clk_set_parent, .get_parent = kona_peri_clk_get_parent, .set_rate = kona_peri_clk_set_rate, |