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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: Keerthy <j-keerthy@ti.com>
Reported-by: Richard Woodruff <r-woodruff2@ti.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
This commit is contained in:
Keerthy 2016-12-02 14:35:43 +05:30 committed by Stephen Boyd
parent 843be1e7fb
commit ced3068344
1 changed files with 30 additions and 1 deletions
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31
drivers/clk/ti/divider.c
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@ -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;