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121 lines
4.3 KiB
Diff
121 lines
4.3 KiB
Diff
From 15a02c1f6dd7c2bb150c61d00ffb33f584ff2288 Mon Sep 17 00:00:00 2001
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From: Stephen Boyd <sboyd@codeaurora.org>
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Date: Mon, 19 Jan 2015 18:05:28 -0800
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Subject: [PATCH] clk: Add __clk_mux_determine_rate_closest
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Some clock drivers want to find the closest rate on the input of
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a mux instead of a rate that's less than or equal to the desired
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rate. Add a generic mux function to support this.
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Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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Tested-by: Kenneth Westfield <kwestfie@codeaurora.org>
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Signed-off-by: Michael Turquette <mturquette@linaro.org>
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---
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drivers/clk/clk.c | 47 +++++++++++++++++++++++++++++++++++---------
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include/linux/clk-provider.h | 8 +++++++-
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2 files changed, 45 insertions(+), 10 deletions(-)
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--- a/drivers/clk/clk.c
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+++ b/drivers/clk/clk.c
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@@ -695,14 +695,20 @@ struct clk *__clk_lookup(const char *nam
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return NULL;
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}
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-/*
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- * Helper for finding best parent to provide a given frequency. This can be used
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- * directly as a determine_rate callback (e.g. for a mux), or from a more
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- * complex clock that may combine a mux with other operations.
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- */
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-long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
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- unsigned long *best_parent_rate,
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- struct clk **best_parent_p)
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+static bool mux_is_better_rate(unsigned long rate, unsigned long now,
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+ unsigned long best, unsigned long flags)
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+{
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+ if (flags & CLK_MUX_ROUND_CLOSEST)
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+ return abs(now - rate) < abs(best - rate);
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+
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+ return now <= rate && now > best;
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+}
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+
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+static long
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+clk_mux_determine_rate_flags(struct clk_hw *hw, unsigned long rate,
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+ unsigned long *best_parent_rate,
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+ struct clk **best_parent_p,
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+ unsigned long flags)
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{
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struct clk *clk = hw->clk, *parent, *best_parent = NULL;
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int i, num_parents;
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@@ -730,7 +736,7 @@ long __clk_mux_determine_rate(struct clk
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parent_rate = __clk_round_rate(parent, rate);
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else
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parent_rate = __clk_get_rate(parent);
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- if (parent_rate <= rate && parent_rate > best) {
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+ if (mux_is_better_rate(rate, parent_rate, best, flags)) {
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best_parent = parent;
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best = parent_rate;
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}
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@@ -743,8 +749,31 @@ out:
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return best;
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}
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+
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+/*
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+ * Helper for finding best parent to provide a given frequency. This can be used
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+ * directly as a determine_rate callback (e.g. for a mux), or from a more
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+ * complex clock that may combine a mux with other operations.
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+ */
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+long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
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+ unsigned long *best_parent_rate,
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+ struct clk **best_parent_p)
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+{
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+ return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
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+ best_parent_p, 0);
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+}
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EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
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+long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
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+ unsigned long *best_parent_rate,
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+ struct clk **best_parent_p)
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+{
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+ return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
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+ best_parent_p,
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+ CLK_MUX_ROUND_CLOSEST);
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+}
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+EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest);
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+
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/*** clk api ***/
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void __clk_unprepare(struct clk *clk)
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--- a/include/linux/clk-provider.h
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+++ b/include/linux/clk-provider.h
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@@ -382,6 +382,8 @@ struct clk *clk_register_divider_table(s
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* register, and mask of mux bits are in higher 16-bit of this register.
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* While setting the mux bits, higher 16-bit should also be updated to
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* indicate changing mux bits.
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+ * CLK_MUX_ROUND_CLOSEST - Use the parent rate that is closest to the desired
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+ * frequency.
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*/
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struct clk_mux {
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struct clk_hw hw;
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@@ -396,7 +398,8 @@ struct clk_mux {
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#define CLK_MUX_INDEX_ONE BIT(0)
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#define CLK_MUX_INDEX_BIT BIT(1)
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#define CLK_MUX_HIWORD_MASK BIT(2)
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-#define CLK_MUX_READ_ONLY BIT(3) /* mux setting cannot be changed */
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+#define CLK_MUX_READ_ONLY BIT(3) /* mux can't be changed */
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+#define CLK_MUX_ROUND_CLOSEST BIT(4)
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extern const struct clk_ops clk_mux_ops;
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extern const struct clk_ops clk_mux_ro_ops;
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@@ -554,6 +557,9 @@ struct clk *__clk_lookup(const char *nam
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long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long *best_parent_rate,
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struct clk **best_parent_p);
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+long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
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+ unsigned long *best_parent_rate,
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+ struct clk **best_parent_p);
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/*
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* FIXME clock api without lock protection
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