clk: clk-divider: sync with kernel code
This updates the clk-divider to Kernel code, but without power-of-two divider support which we do not need yet. This also adds table based divider support to the divider. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
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503cc1518e
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d4aaca3647
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@ -20,61 +20,192 @@
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#include <linux/clk.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/err.h>
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static unsigned int clk_divider_maxdiv(struct clk_divider *div)
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#define div_mask(d) ((1 << ((d)->width)) - 1)
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static unsigned int _get_maxdiv(struct clk_divider *divider)
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{
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{
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if (div->flags & CLK_DIVIDER_ONE_BASED)
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if (divider->flags & CLK_DIVIDER_ONE_BASED)
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return (1 << div->width) - 1;
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return div_mask(divider);
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return 1 << div->width;
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return div_mask(divider) + 1;
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}
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}
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static int clk_divider_set_rate(struct clk *clk, unsigned long rate,
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static unsigned int _get_table_div(const struct clk_div_table *table,
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unsigned long parent_rate)
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unsigned int val)
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{
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{
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struct clk_divider *div = container_of(clk, struct clk_divider, clk);
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const struct clk_div_table *clkt;
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unsigned int val, divval;
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if (rate > parent_rate)
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rate = parent_rate;
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if (!rate)
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rate = 1;
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divval = DIV_ROUND_UP(parent_rate, rate);
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if (divval > clk_divider_maxdiv(div))
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divval = clk_divider_maxdiv(div);
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if (!(div->flags & CLK_DIVIDER_ONE_BASED))
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divval--;
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val = readl(div->reg);
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val &= ~(((1 << div->width) - 1) << div->shift);
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val |= divval << div->shift;
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writel(val, div->reg);
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for (clkt = table; clkt->div; clkt++)
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if (clkt->val == val)
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return clkt->div;
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return 0;
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return 0;
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}
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}
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static unsigned int _get_div(struct clk_divider *divider, unsigned int val)
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{
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if (divider->flags & CLK_DIVIDER_ONE_BASED)
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return val;
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if (divider->table)
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return _get_table_div(divider->table, val);
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return val + 1;
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}
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static unsigned int _get_table_val(const struct clk_div_table *table,
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unsigned int div)
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{
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const struct clk_div_table *clkt;
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for (clkt = table; clkt->div; clkt++)
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if (clkt->div == div)
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return clkt->val;
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return 0;
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}
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static unsigned int _get_val(struct clk_divider *divider, unsigned int div)
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{
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if (divider->flags & CLK_DIVIDER_ONE_BASED)
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return div;
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if (divider->table)
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return _get_table_val(divider->table, div);
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return div - 1;
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}
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static unsigned long clk_divider_recalc_rate(struct clk *clk,
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static unsigned long clk_divider_recalc_rate(struct clk *clk,
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unsigned long parent_rate)
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unsigned long parent_rate)
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{
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{
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struct clk_divider *div = container_of(clk, struct clk_divider, clk);
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struct clk_divider *divider = container_of(clk, struct clk_divider, clk);
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unsigned int val;
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unsigned int div, val;
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val = readl(div->reg) >> div->shift;
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val = readl(divider->reg) >> divider->shift;
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val &= (1 << div->width) - 1;
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val &= div_mask(divider);
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if (div->flags & CLK_DIVIDER_ONE_BASED) {
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div = _get_div(divider, val);
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if (!val)
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val++;
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return parent_rate / div;
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} else {
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}
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val++;
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/*
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* The reverse of DIV_ROUND_UP: The maximum number which
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* divided by m is r
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*/
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#define MULT_ROUND_UP(r, m) ((r) * (m) + (m) - 1)
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static bool _is_valid_table_div(const struct clk_div_table *table,
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unsigned int div)
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{
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const struct clk_div_table *clkt;
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for (clkt = table; clkt->div; clkt++)
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if (clkt->div == div)
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return true;
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return false;
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}
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static bool _is_valid_div(struct clk_divider *divider, unsigned int div)
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{
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if (divider->table)
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return _is_valid_table_div(divider->table, div);
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return true;
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}
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static int clk_divider_bestdiv(struct clk *clk, unsigned long rate,
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unsigned long *best_parent_rate)
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{
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struct clk_divider *divider = container_of(clk, struct clk_divider, clk);
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int i, bestdiv = 0;
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unsigned long parent_rate, best = 0, now, maxdiv;
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unsigned long parent_rate_saved = *best_parent_rate;
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if (!rate)
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rate = 1;
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maxdiv = _get_maxdiv(divider);
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if (!(clk->flags & CLK_SET_RATE_PARENT)) {
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parent_rate = *best_parent_rate;
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bestdiv = DIV_ROUND_UP(parent_rate, rate);
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bestdiv = bestdiv == 0 ? 1 : bestdiv;
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bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
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return bestdiv;
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}
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}
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return parent_rate / val;
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/*
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* The maximum divider we can use without overflowing
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* unsigned long in rate * i below
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*/
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maxdiv = min(ULONG_MAX / rate, maxdiv);
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for (i = 1; i <= maxdiv; i++) {
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if (!_is_valid_div(divider, i))
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continue;
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if (rate * i == parent_rate_saved) {
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/*
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* It's the most ideal case if the requested rate can be
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* divided from parent clock without needing to change
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* parent rate, so return the divider immediately.
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*/
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*best_parent_rate = parent_rate_saved;
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return i;
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}
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parent_rate = clk_round_rate(clk_get_parent(clk),
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MULT_ROUND_UP(rate, i));
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now = parent_rate / i;
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if (now <= rate && now > best) {
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bestdiv = i;
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best = now;
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*best_parent_rate = parent_rate;
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}
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}
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if (!bestdiv) {
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bestdiv = _get_maxdiv(divider);
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*best_parent_rate = clk_round_rate(clk_get_parent(clk), 1);
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}
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return bestdiv;
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}
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static long clk_divider_round_rate(struct clk *clk, unsigned long rate,
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unsigned long *parent_rate)
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{
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int div;
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div = clk_divider_bestdiv(clk, rate, parent_rate);
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return *parent_rate / div;
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}
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static int clk_divider_set_rate(struct clk *clk, unsigned long rate,
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unsigned long parent_rate)
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{
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struct clk_divider *divider = container_of(clk, struct clk_divider, clk);
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unsigned int div, value;
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u32 val;
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if (clk->flags & CLK_SET_RATE_PARENT) {
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unsigned long best_parent_rate = parent_rate;
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div = clk_divider_bestdiv(clk, rate, &best_parent_rate);
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clk_set_rate(clk_get_parent(clk), best_parent_rate);
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} else {
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div = parent_rate / rate;
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}
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value = _get_val(divider, div);
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if (value > div_mask(divider))
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value = div_mask(divider);
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val = readl(divider->reg);
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val &= ~(div_mask(divider) << divider->shift);
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val |= value << divider->shift;
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writel(val, divider->reg);
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return 0;
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}
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}
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struct clk_ops clk_divider_ops = {
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struct clk_ops clk_divider_ops = {
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.set_rate = clk_divider_set_rate,
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.set_rate = clk_divider_set_rate,
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.recalc_rate = clk_divider_recalc_rate,
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.recalc_rate = clk_divider_recalc_rate,
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.round_rate = clk_divider_round_rate,
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};
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};
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struct clk *clk_divider(const char *name, const char *parent,
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struct clk *clk_divider(const char *name, const char *parent,
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@ -240,6 +240,9 @@ struct clk_divider {
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const char *parent;
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const char *parent;
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#define CLK_DIVIDER_ONE_BASED (1 << 0)
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#define CLK_DIVIDER_ONE_BASED (1 << 0)
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unsigned flags;
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unsigned flags;
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const struct clk_div_table *table;
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int max_div_index;
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int table_size;
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};
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};
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extern struct clk_ops clk_divider_ops;
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extern struct clk_ops clk_divider_ops;
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