Linux-libre 4.4-gnupck-4.4-gnu

1 files changed, 130 insertions, 0 deletions

diff --git a/drivers/clk/clk-multiplier.c b/drivers/clk/clk-multiplier.c
new file mode 100644
index 000000000..fe7806506
--- /dev/null
+++ b/drivers/clk/clk-multiplier.c
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2015 Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#define to_clk_multiplier(_hw) container_of(_hw, struct clk_multiplier, hw)
+
+static unsigned long __get_mult(struct clk_multiplier *mult,
+				unsigned long rate,
+				unsigned long parent_rate)
+{
+	if (mult->flags & CLK_MULTIPLIER_ROUND_CLOSEST)
+		return DIV_ROUND_CLOSEST(rate, parent_rate);
+
+	return rate / parent_rate;
+}
+
+static unsigned long clk_multiplier_recalc_rate(struct clk_hw *hw,
+						unsigned long parent_rate)
+{
+	struct clk_multiplier *mult = to_clk_multiplier(hw);
+	unsigned long val;
+
+	val = clk_readl(mult->reg) >> mult->shift;
+	val &= GENMASK(mult->width - 1, 0);
+
+	if (!val && mult->flags & CLK_MULTIPLIER_ZERO_BYPASS)
+		val = 1;
+
+	return parent_rate * val;
+}
+
+static bool __is_best_rate(unsigned long rate, unsigned long new,
+			   unsigned long best, unsigned long flags)
+{
+	if (flags & CLK_MULTIPLIER_ROUND_CLOSEST)
+		return abs(rate - new) < abs(rate - best);
+
+	return new >= rate && new < best;
+}
+
+static unsigned long __bestmult(struct clk_hw *hw, unsigned long rate,
+				unsigned long *best_parent_rate,
+				u8 width, unsigned long flags)
+{
+	unsigned long orig_parent_rate = *best_parent_rate;
+	unsigned long parent_rate, current_rate, best_rate = ~0;
+	unsigned int i, bestmult = 0;
+
+	if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT))
+		return rate / *best_parent_rate;
+
+	for (i = 1; i < ((1 << width) - 1); i++) {
+		if (rate == orig_parent_rate * i) {
+			/*
+			 * This is the best case for us if we have a
+			 * perfect match without changing the parent
+			 * rate.
+			 */
+			*best_parent_rate = orig_parent_rate;
+			return i;
+		}
+
+		parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
+						rate / i);
+		current_rate = parent_rate * i;
+
+		if (__is_best_rate(rate, current_rate, best_rate, flags)) {
+			bestmult = i;
+			best_rate = current_rate;
+			*best_parent_rate = parent_rate;
+		}
+	}
+
+	return bestmult;
+}
+
+static long clk_multiplier_round_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long *parent_rate)
+{
+	struct clk_multiplier *mult = to_clk_multiplier(hw);
+	unsigned long factor = __bestmult(hw, rate, parent_rate,
+					  mult->width, mult->flags);
+
+	return *parent_rate * factor;
+}
+
+static int clk_multiplier_set_rate(struct clk_hw *hw, unsigned long rate,
+			       unsigned long parent_rate)
+{
+	struct clk_multiplier *mult = to_clk_multiplier(hw);
+	unsigned long factor = __get_mult(mult, rate, parent_rate);
+	unsigned long flags = 0;
+	unsigned long val;
+
+	if (mult->lock)
+		spin_lock_irqsave(mult->lock, flags);
+	else
+		__acquire(mult->lock);
+
+	val = clk_readl(mult->reg);
+	val &= ~GENMASK(mult->width + mult->shift - 1, mult->shift);
+	val |= factor << mult->shift;
+	clk_writel(val, mult->reg);
+
+	if (mult->lock)
+		spin_unlock_irqrestore(mult->lock, flags);
+	else
+		__release(mult->lock);
+
+	return 0;
+}
+
+const struct clk_ops clk_multiplier_ops = {
+	.recalc_rate	= clk_multiplier_recalc_rate,
+	.round_rate	= clk_multiplier_round_rate,
+	.set_rate	= clk_multiplier_set_rate,
+};
+EXPORT_SYMBOL_GPL(clk_multiplier_ops);