Re: [PATCH v6 3/3] clk: basic clock hardware types

Hi Mike,

+static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,

• unsigned long *best_parent_rate)
  

+{

• struct clk_divider *divider = to_clk_divider(hw);
• int i, bestdiv = 0;
• unsigned long parent_rate, best = 0, now, maxdiv;
• maxdiv = (1 << divider->width);
• if (divider->flags & CLK_DIVIDER_ONE_BASED)

• maxdiv--;
  

• if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {

• parent_rate = __clk_get_rate(__clk_get_parent(hw->clk));
  

• bestdiv = parent_rate / rate;
  

• bestdiv = bestdiv == 0 ? 1 : bestdiv;
  

• bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
  

• goto out;
  

• }
• /*

• * 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++) {

• int div;
  

• parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
  

• 		rate * i);
  

• div = parent_rate / rate;
  

• div = div > maxdiv ? maxdiv : div;
  

• div = div < 1 ? 1 : div;
  

• now = parent_rate / div;
  

• if (now <= rate && now >= best) {
  

• 	bestdiv = div;
  

• 	best = now;
  

• 	*best_parent_rate = parent_rate;
  

if (now == rate) break; we don't need it to loop to end, and smaller parent_rate is better.

• }
  

• }
• if (!bestdiv) {

• bestdiv = (1 << divider->width);
  

• parent_rate = __clk_round_rate(__clk_get_parent(hw->clk), 1);
  

• } else {

• parent_rate = best * bestdiv;
  

• }

+out:

• if (best_parent_rate)

• *best_parent_rate = parent_rate;
  

• return bestdiv;

+}