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Commit ced30683 authored by Keerthy's avatar Keerthy Committed by Stephen Boyd
Browse files

clk: ti: divider: Add the table parsing to get the best divider value 



Currently the divider selection logic blindly divides the parent_rate
by the clk rate and gives the divider value for the divider clocks
which do not have the CLK_SET_RATE_PARENT flag set. Add the clk divider
table parsing to get the closest divider available in the table
provided via Device tree.

The code is pretty much taken from: drivers/clk/clk-divider.c.
and used here to fix up the best divider selection logic.

Signed-off-by: default avatarKeerthy <j-keerthy@ti.com>
Reported-by: default avatarRichard Woodruff <r-woodruff2@ti.com>
Acked-by: default avatarTero Kristo <t-kristo@ti.com>
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
parent 843be1e7

drivers/clk/ti/divider.c

+30 −1
Original line number Diff line number Diff line
@@ -140,6 +140,35 @@ static bool _is_valid_div(struct clk_divider *divider, unsigned int div) 
	return true;

}



static int _div_round_up(const struct clk_div_table *table,

			 unsigned long parent_rate, unsigned long rate)

{

	const struct clk_div_table *clkt;

	int up = INT_MAX;

	int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);



	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 _div_round(const struct clk_div_table *table,

		      unsigned long parent_rate, unsigned long rate)

{

	if (!table)

		return DIV_ROUND_UP(parent_rate, rate);



	return _div_round_up(table, parent_rate, rate);

}



static int ti_clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,

				  unsigned long *best_parent_rate)

{
@@ -155,7 +184,7 @@ static int ti_clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, 


	if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {

		parent_rate = *best_parent_rate;

		bestdiv = DIV_ROUND_UP(parent_rate, rate);

		bestdiv = _div_round(divider->table, parent_rate, rate);

		bestdiv = bestdiv == 0 ? 1 : bestdiv;

		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;

		return bestdiv;