diff options
| -rw-r--r-- | drivers/clk/clk.c | 47 | ||||
| -rw-r--r-- | include/linux/clk-provider.h | 8 |
2 files changed, 45 insertions, 10 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 30fff56e1f15..9fc209abcb48 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -690,14 +690,20 @@ struct clk *__clk_lookup(const char *name) return NULL; } -/* - * Helper for finding best parent to provide a given frequency. This can be used - * directly as a determine_rate callback (e.g. for a mux), or from a more - * complex clock that may combine a mux with other operations. - */ -long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate, - unsigned long *best_parent_rate, - struct clk_hw **best_parent_p) +static bool mux_is_better_rate(unsigned long rate, unsigned long now, + unsigned long best, unsigned long flags) +{ + if (flags & CLK_MUX_ROUND_CLOSEST) + return abs(now - rate) < abs(best - rate); + + return now <= rate && now > best; +} + +static long +clk_mux_determine_rate_flags(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate, + struct clk_hw **best_parent_p, + unsigned long flags) { struct clk *clk = hw->clk, *parent, *best_parent = NULL; int i, num_parents; @@ -725,7 +731,7 @@ long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate, parent_rate = __clk_round_rate(parent, rate); else parent_rate = __clk_get_rate(parent); - if (parent_rate <= rate && parent_rate > best) { + if (mux_is_better_rate(rate, parent_rate, best, flags)) { best_parent = parent; best = parent_rate; } @@ -738,8 +744,31 @@ out: return best; } + +/* + * Helper for finding best parent to provide a given frequency. This can be used + * directly as a determine_rate callback (e.g. for a mux), or from a more + * complex clock that may combine a mux with other operations. + */ +long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate, + struct clk_hw **best_parent_p) +{ + return clk_mux_determine_rate_flags(hw, rate, best_parent_rate, + best_parent_p, 0); +} EXPORT_SYMBOL_GPL(__clk_mux_determine_rate); +long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate, + struct clk_hw **best_parent_p) +{ + return clk_mux_determine_rate_flags(hw, rate, best_parent_rate, + best_parent_p, + CLK_MUX_ROUND_CLOSEST); +} +EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest); + /*** clk api ***/ void __clk_unprepare(struct clk *clk) diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index ebb7055a6d84..ba858e90d5de 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -384,6 +384,8 @@ void clk_unregister_divider(struct clk *clk); * register, and mask of mux bits are in higher 16-bit of this register. * While setting the mux bits, higher 16-bit should also be updated to * indicate changing mux bits. + * CLK_MUX_ROUND_CLOSEST - Use the parent rate that is closest to the desired + * frequency. */ struct clk_mux { struct clk_hw hw; @@ -398,7 +400,8 @@ struct clk_mux { #define CLK_MUX_INDEX_ONE BIT(0) #define CLK_MUX_INDEX_BIT BIT(1) #define CLK_MUX_HIWORD_MASK BIT(2) -#define CLK_MUX_READ_ONLY BIT(3) /* mux setting cannot be changed */ +#define CLK_MUX_READ_ONLY BIT(3) /* mux can't be changed */ +#define CLK_MUX_ROUND_CLOSEST BIT(4) extern const struct clk_ops clk_mux_ops; extern const struct clk_ops clk_mux_ro_ops; @@ -556,6 +559,9 @@ struct clk *__clk_lookup(const char *name); long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate, unsigned long *best_parent_rate, struct clk_hw **best_parent_p); +long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate, + struct clk_hw **best_parent_p); /* * FIXME clock api without lock protection |