[PATCH v3 1/8] clk: Add __clk_mux_determine_rate_closest
From: Stephen Boyd <hidden>
Date: 2015-01-20 02:05:46
Also in:
linux-arm-msm, lkml
Subsystem:
common clk framework, the rest · Maintainers:
Michael Turquette, Stephen Boyd, Linus Torvalds
Some clock drivers want to find the closest rate on the input of a mux instead of a rate that's less than or equal to the desired rate. Add a generic mux function to support this. Signed-off-by: Stephen Boyd <redacted> --- drivers/clk/clk.c | 47 +++++++++++++++++++++++++++++++++++--------- 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 f4963b7d4e17..bd46e3ba2771 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c@@ -694,14 +694,20 @@ 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;
@@ -729,7 +735,7 @@ 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; }
@@ -742,8 +748,31 @@ 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 d936409520f8..d2523f42f4e4 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h@@ -382,6 +382,8 @@ struct clk *clk_register_divider_table(struct device *dev, const char *name, * 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;
@@ -396,7 +398,8 @@ 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;
@@ -552,6 +555,9 @@ 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
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