--- /dev/null
+/*
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * 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.
+ *
+ * Adjustable divider clock implementation
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/log2.h>
+
+/*
+ * DOC: basic adjustable divider clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_prepare only ensures that parents are prepared
+ * enable - clk_enable only ensures that parents are enabled
+ * rate - rate is adjustable. clk->rate = DIV_ROUND_UP(parent->rate / divisor)
+ * parent - fixed parent. No clk_set_parent support
+ */
+
+#define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw)
+
+#define div_mask(width) ((1 << (width)) - 1)
+
+static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
+{
+ unsigned int maxdiv = 0;
+ const struct clk_div_table *clkt;
+
+ for (clkt = table; clkt->div; clkt++)
+ if (clkt->div > maxdiv)
+ maxdiv = clkt->div;
+ return maxdiv;
+}
+
+static unsigned int _get_table_mindiv(const struct clk_div_table *table)
+{
+ unsigned int mindiv = UINT_MAX;
+ const struct clk_div_table *clkt;
+
+ for (clkt = table; clkt->div; clkt++)
+ if (clkt->div < mindiv)
+ mindiv = clkt->div;
+ return mindiv;
+}
+
+static unsigned int _get_maxdiv(const struct clk_div_table *table, u8 width,
+ unsigned long flags)
+{
+ if (flags & CLK_DIVIDER_ONE_BASED)
+ return div_mask(width);
+ if (flags & CLK_DIVIDER_POWER_OF_TWO)
+ return 1 << div_mask(width);
+ if (table)
+ return _get_table_maxdiv(table);
+ return div_mask(width) + 1;
+}
+
+static unsigned int _get_table_div(const struct clk_div_table *table,
+ unsigned int val)
+{
+ const struct clk_div_table *clkt;
+
+ for (clkt = table; clkt->div; clkt++)
+ if (clkt->val == val)
+ return clkt->div;
+ return 0;
+}
+
+static unsigned int _get_div(const struct clk_div_table *table,
+ unsigned int val, unsigned long flags)
+{
+ if (flags & CLK_DIVIDER_ONE_BASED)
+ return val;
+ if (flags & CLK_DIVIDER_POWER_OF_TWO)
+ return 1 << val;
+ if (table)
+ return _get_table_div(table, val);
+ return val + 1;
+}
+
+static unsigned int _get_table_val(const struct clk_div_table *table,
+ unsigned int div)
+{
+ const struct clk_div_table *clkt;
+
+ for (clkt = table; clkt->div; clkt++)
+ if (clkt->div == div)
+ return clkt->val;
+ return 0;
+}
+
+static unsigned int _get_val(const struct clk_div_table *table,
+ unsigned int div, unsigned long flags)
+{
+ if (flags & CLK_DIVIDER_ONE_BASED)
+ return div;
+ if (flags & CLK_DIVIDER_POWER_OF_TWO)
+ return __ffs(div);
+ if (table)
+ return _get_table_val(table, div);
+ return div - 1;
+}
+
+unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
+ unsigned int val,
+ const struct clk_div_table *table,
+ unsigned long flags)
+{
+ unsigned int div;
+
+ div = _get_div(table, val, flags);
+ if (!div) {
+ WARN(!(flags & CLK_DIVIDER_ALLOW_ZERO),
+ "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
+ __clk_get_name(hw->clk));
+ return parent_rate;
+ }
+
+ return DIV_ROUND_UP(parent_rate, div);
+}
+EXPORT_SYMBOL_GPL(divider_recalc_rate);
+
+static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_divider *divider = to_clk_divider(hw);
+ unsigned int val;
+
+ val = clk_readl(divider->reg) >> divider->shift;
+ val &= div_mask(divider->width);
+
+ return divider_recalc_rate(hw, parent_rate, val, divider->table,
+ divider->flags);
+}
+
+static bool _is_valid_table_div(const struct clk_div_table *table,
+ unsigned int div)
+{
+ const struct clk_div_table *clkt;
+
+ for (clkt = table; clkt->div; clkt++)
+ if (clkt->div == div)
+ return true;
+ return false;
+}
+
+static bool _is_valid_div(const struct clk_div_table *table, unsigned int div,
+ unsigned long flags)
+{
+ if (flags & CLK_DIVIDER_POWER_OF_TWO)
+ return is_power_of_2(div);
+ if (table)
+ return _is_valid_table_div(table, div);
+ return true;
+}
+
+static int _round_up_table(const struct clk_div_table *table, int div)
+{
+ const struct clk_div_table *clkt;
+ int up = INT_MAX;
+
+ for (clkt = table; clkt->div; clkt++) {
+ if (clkt->div == div)
+ return clkt->div;
+ else if (clkt->div < div)
+ continue;
+
+ if ((clkt->div - div) < (up - div))
+ up = clkt->div;
+ }
+
+ return up;
+}
+
+static int _round_down_table(const struct clk_div_table *table, int div)
+{
+ const struct clk_div_table *clkt;
+ int down = _get_table_mindiv(table);
+
+ for (clkt = table; clkt->div; clkt++) {
+ if (clkt->div == div)
+ return clkt->div;
+ else if (clkt->div > div)
+ continue;
+
+ if ((div - clkt->div) < (div - down))
+ down = clkt->div;
+ }
+
+ return down;
+}
+
+static int _div_round_up(const struct clk_div_table *table,
+ unsigned long parent_rate, unsigned long rate,
+ unsigned long flags)
+{
+ int div = DIV_ROUND_UP(parent_rate, rate);
+
+ if (flags & CLK_DIVIDER_POWER_OF_TWO)
+ div = __roundup_pow_of_two(div);
+ if (table)
+ div = _round_up_table(table, div);
+
+ return div;
+}
+
+static int _div_round_closest(const struct clk_div_table *table,
+ unsigned long parent_rate, unsigned long rate,
+ unsigned long flags)
+{
+ int up, down;
+ unsigned long up_rate, down_rate;
+
+ up = DIV_ROUND_UP(parent_rate, rate);
+ down = parent_rate / rate;
+
+ if (flags & CLK_DIVIDER_POWER_OF_TWO) {
+ up = __roundup_pow_of_two(up);
+ down = __rounddown_pow_of_two(down);
+ } else if (table) {
+ up = _round_up_table(table, up);
+ down = _round_down_table(table, down);
+ }
+
+ up_rate = DIV_ROUND_UP(parent_rate, up);
+ down_rate = DIV_ROUND_UP(parent_rate, down);
+
+ return (rate - up_rate) <= (down_rate - rate) ? up : down;
+}
+
+static int _div_round(const struct clk_div_table *table,
+ unsigned long parent_rate, unsigned long rate,
+ unsigned long flags)
+{
+ if (flags & CLK_DIVIDER_ROUND_CLOSEST)
+ return _div_round_closest(table, parent_rate, rate, flags);
+
+ return _div_round_up(table, parent_rate, rate, flags);
+}
+
+static bool _is_best_div(unsigned long rate, unsigned long now,
+ unsigned long best, unsigned long flags)
+{
+ if (flags & CLK_DIVIDER_ROUND_CLOSEST)
+ return abs(rate - now) < abs(rate - best);
+
+ return now <= rate && now > best;
+}
+
+static int _next_div(const struct clk_div_table *table, int div,
+ unsigned long flags)
+{
+ div++;
+
+ if (flags & CLK_DIVIDER_POWER_OF_TWO)
+ return __roundup_pow_of_two(div);
+ if (table)
+ return _round_up_table(table, div);
+
+ return div;
+}
+
+static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
+ unsigned long *best_parent_rate,
+ const struct clk_div_table *table, u8 width,
+ unsigned long flags)
+{
+ int i, bestdiv = 0;
+ unsigned long parent_rate, best = 0, now, maxdiv;
+ unsigned long parent_rate_saved = *best_parent_rate;
+
+ if (!rate)
+ rate = 1;
+
+ maxdiv = _get_maxdiv(table, width, flags);
+
+ if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
+ parent_rate = *best_parent_rate;
+ bestdiv = _div_round(table, parent_rate, rate, flags);
+ bestdiv = bestdiv == 0 ? 1 : bestdiv;
+ bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
+ return bestdiv;
+ }
+
+ /*
+ * The maximum divider we can use without overflowing
+ * unsigned long in rate * i below
+ */
+ maxdiv = min(ULONG_MAX / rate, maxdiv);
+
+ for (i = 1; i <= maxdiv; i = _next_div(table, i, flags)) {
+ if (!_is_valid_div(table, i, flags))
+ continue;
+ if (rate * i == parent_rate_saved) {
+ /*
+ * It's the most ideal case if the requested rate can be
+ * divided from parent clock without needing to change
+ * parent rate, so return the divider immediately.
+ */
+ *best_parent_rate = parent_rate_saved;
+ return i;
+ }
+ parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
+ rate * i);
+ now = DIV_ROUND_UP(parent_rate, i);
+ if (_is_best_div(rate, now, best, flags)) {
+ bestdiv = i;
+ best = now;
+ *best_parent_rate = parent_rate;
+ }
+ }
+
+ if (!bestdiv) {
+ bestdiv = _get_maxdiv(table, width, flags);
+ *best_parent_rate = __clk_round_rate(__clk_get_parent(hw->clk), 1);
+ }
+
+ return bestdiv;
+}
+
+long divider_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate, const struct clk_div_table *table,
+ u8 width, unsigned long flags)
+{
+ int div;
+
+ div = clk_divider_bestdiv(hw, rate, prate, table, width, flags);
+
+ return DIV_ROUND_UP(*prate, div);
+}
+EXPORT_SYMBOL_GPL(divider_round_rate);
+
+static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ struct clk_divider *divider = to_clk_divider(hw);
+ int bestdiv;
+
+ /* if read only, just return current value */
+ if (divider->flags & CLK_DIVIDER_READ_ONLY) {
+ bestdiv = readl(divider->reg) >> divider->shift;
+ bestdiv &= div_mask(divider->width);
+ bestdiv = _get_div(divider->table, bestdiv, divider->flags);
+ return DIV_ROUND_UP(*prate, bestdiv);
+ }
+
+ return divider_round_rate(hw, rate, prate, divider->table,
+ divider->width, divider->flags);
+}
+
+int divider_get_val(unsigned long rate, unsigned long parent_rate,
+ const struct clk_div_table *table, u8 width,
+ unsigned long flags)
+{
+ unsigned int div, value;
+
+ div = DIV_ROUND_UP(parent_rate, rate);
+
+ if (!_is_valid_div(table, div, flags))
+ return -EINVAL;
+
+ value = _get_val(table, div, flags);
+
+ return min_t(unsigned int, value, div_mask(width));
+}
+EXPORT_SYMBOL_GPL(divider_get_val);
+
+static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_divider *divider = to_clk_divider(hw);
+ unsigned int value;
+ unsigned long flags = 0;
+ u32 val;
+
+ value = divider_get_val(rate, parent_rate, divider->table,
+ divider->width, divider->flags);
+
+ if (divider->lock)
+ spin_lock_irqsave(divider->lock, flags);
+
+ if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
+ val = div_mask(divider->width) << (divider->shift + 16);
+ } else {
+ val = clk_readl(divider->reg);
+ val &= ~(div_mask(divider->width) << divider->shift);
+ }
+ val |= value << divider->shift;
+ clk_writel(val, divider->reg);
+
+ if (divider->lock)
+ spin_unlock_irqrestore(divider->lock, flags);
+
+ return 0;
+}
+
+const struct clk_ops clk_divider_ops = {
+ .recalc_rate = clk_divider_recalc_rate,
+ .round_rate = clk_divider_round_rate,
+ .set_rate = clk_divider_set_rate,
+};
+EXPORT_SYMBOL_GPL(clk_divider_ops);
+
+static struct clk *_register_divider(struct device *dev, const char *name,
+ const char *parent_name, unsigned long flags,
+ void __iomem *reg, u8 shift, u8 width,
+ u8 clk_divider_flags, const struct clk_div_table *table,
+ spinlock_t *lock)
+{
+ struct clk_divider *div;
+ struct clk *clk;
+ struct clk_init_data init;
+
+ if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
+ if (width + shift > 16) {
+ pr_warn("divider value exceeds LOWORD field\n");
+ return ERR_PTR(-EINVAL);
+ }
+ }
+
+ /* allocate the divider */
+ div = kzalloc(sizeof(struct clk_divider), GFP_KERNEL);
+ if (!div) {
+ pr_err("%s: could not allocate divider clk\n", __func__);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ init.name = name;
+ init.ops = &clk_divider_ops;
+ init.flags = flags | CLK_IS_BASIC;
+ init.parent_names = (parent_name ? &parent_name: NULL);
+ init.num_parents = (parent_name ? 1 : 0);
+
+ /* struct clk_divider assignments */
+ div->reg = reg;
+ div->shift = shift;
+ div->width = width;
+ div->flags = clk_divider_flags;
+ div->lock = lock;
+ div->hw.init = &init;
+ div->table = table;
+
+ /* register the clock */
+ clk = clk_register(dev, &div->hw);
+
+ if (IS_ERR(clk))
+ kfree(div);
+
+ return clk;
+}
+
+/**
+ * clk_register_divider - register a divider clock with the clock framework
+ * @dev: device registering this clock
+ * @name: name of this clock
+ * @parent_name: name of clock's parent
+ * @flags: framework-specific flags
+ * @reg: register address to adjust divider
+ * @shift: number of bits to shift the bitfield
+ * @width: width of the bitfield
+ * @clk_divider_flags: divider-specific flags for this clock
+ * @lock: shared register lock for this clock
+ */
+struct clk *clk_register_divider(struct device *dev, const char *name,
+ const char *parent_name, unsigned long flags,
+ void __iomem *reg, u8 shift, u8 width,
+ u8 clk_divider_flags, spinlock_t *lock)
+{
+ return _register_divider(dev, name, parent_name, flags, reg, shift,
+ width, clk_divider_flags, NULL, lock);
+}
+EXPORT_SYMBOL_GPL(clk_register_divider);
+
+/**
+ * clk_register_divider_table - register a table based divider clock with
+ * the clock framework
+ * @dev: device registering this clock
+ * @name: name of this clock
+ * @parent_name: name of clock's parent
+ * @flags: framework-specific flags
+ * @reg: register address to adjust divider
+ * @shift: number of bits to shift the bitfield
+ * @width: width of the bitfield
+ * @clk_divider_flags: divider-specific flags for this clock
+ * @table: array of divider/value pairs ending with a div set to 0
+ * @lock: shared register lock for this clock
+ */
+struct clk *clk_register_divider_table(struct device *dev, const char *name,
+ const char *parent_name, unsigned long flags,
+ void __iomem *reg, u8 shift, u8 width,
+ u8 clk_divider_flags, const struct clk_div_table *table,
+ spinlock_t *lock)
+{
+ return _register_divider(dev, name, parent_name, flags, reg, shift,
+ width, clk_divider_flags, table, lock);
+}
+EXPORT_SYMBOL_GPL(clk_register_divider_table);
+
+void clk_unregister_divider(struct clk *clk)
+{
+ struct clk_divider *div;
+ struct clk_hw *hw;
+
+ hw = __clk_get_hw(clk);
+ if (!hw)
+ return;
+
+ div = to_clk_divider(hw);
+
+ clk_unregister(clk);
+ kfree(div);
+}
+EXPORT_SYMBOL_GPL(clk_unregister_divider);
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