clk: divider: Add round to closest divider (774b5143) · Commits · 戴 / test

drivers/clk/clk-divider.c

+67 −2

Original line number	Diff line number	Diff line
		@@ -43,6 +43,17 @@ static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
		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(struct clk_divider *divider)
		{
		if (divider->flags & CLK_DIVIDER_ONE_BASED)
		@@ -162,6 +173,24 @@ static int _round_up_table(const struct clk_div_table *table, int 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(struct clk_divider *divider,
		unsigned long parent_rate, unsigned long rate)
		{
		@@ -175,6 +204,42 @@ static int _div_round_up(struct clk_divider *divider,
		return div;
		}

		static int _div_round_closest(struct clk_divider *divider,
		unsigned long parent_rate, unsigned long rate)
		{
		int up, down, div;

		up = down = div = DIV_ROUND_CLOSEST(parent_rate, rate);

		if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) {
		up = __roundup_pow_of_two(div);
		down = __rounddown_pow_of_two(div);
		} else if (divider->table) {
		up = _round_up_table(divider->table, div);
		down = _round_down_table(divider->table, div);
		}

		return (up - div) <= (div - down) ? up : down;
		}

		static int _div_round(struct clk_divider *divider, unsigned long parent_rate,
		unsigned long rate)
		{
		if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
		return _div_round_closest(divider, parent_rate, rate);

		return _div_round_up(divider, parent_rate, rate);
		}

		static bool _is_best_div(struct clk_divider *divider,
		int rate, int now, int best)
		{
		if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
		return abs(rate - now) < abs(rate - best);

		return now <= rate && now > best;
		}

		static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
		unsigned long *best_parent_rate)
		{
		@@ -190,7 +255,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,

		if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
		parent_rate = *best_parent_rate;
		bestdiv = _div_round_up(divider, parent_rate, rate);
		bestdiv = _div_round(divider, parent_rate, rate);
		bestdiv = bestdiv == 0 ? 1 : bestdiv;
		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
		return bestdiv;
		@@ -217,7 +282,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
		parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
		MULT_ROUND_UP(rate, i));
		now = DIV_ROUND_UP(parent_rate, i);
		if (now <= rate && now > best) {
		if (_is_best_div(divider, rate, now, best)) {
		bestdiv = i;
		best = now;
		*best_parent_rate = parent_rate;

include/linux/clk-provider.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -312,6 +312,8 @@ struct clk_div_table {
		* of this register, and mask of divider bits are in higher 16-bit of this
		* register. While setting the divider bits, higher 16-bit should also be
		* updated to indicate changing divider bits.
		* CLK_DIVIDER_ROUND_CLOSEST - Makes the best calculated divider to be rounded
		* to the closest integer instead of the up one.
		*/
		struct clk_divider {
		struct clk_hw hw;
		@@ -327,6 +329,7 @@ struct clk_divider {
		#define CLK_DIVIDER_POWER_OF_TWO BIT(1)
		#define CLK_DIVIDER_ALLOW_ZERO BIT(2)
		#define CLK_DIVIDER_HIWORD_MASK BIT(3)
		#define CLK_DIVIDER_ROUND_CLOSEST BIT(4)

		extern const struct clk_ops clk_divider_ops;
		struct clk clk_register_divider(struct device dev, const char *name,

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