drivers/clk/spear/clk.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 ST Microelectronics
   4  * Viresh Kumar <vireshk@kernel.org>
   5  *
   6  * SPEAr clk - Common routines
   7  */
   8
   9 #include <linux/clk-provider.h>
  10 #include <linux/types.h>
  11 #include "clk.h"
  12
  13 long clk_round_rate_index(struct clk_hw *hw, unsigned long drate,
  14                 unsigned long parent_rate, clk_calc_rate calc_rate, u8 rtbl_cnt,
  15                 int *index)
  16 {
  17         unsigned long prev_rate, rate = 0;
  18
  19         for (*index = 0; *index < rtbl_cnt; (*index)++) {
  20                 prev_rate = rate;
  21                 rate = calc_rate(hw, parent_rate, *index);
  22                 if (drate < rate) {
  23                         /* previous clock was best */
  24                         if (*index) {
  25                                 rate = prev_rate;
  26                                 (*index)--;
  27                         }
  28                         break;
  29                 }
  30         }
  31
  32         if ((*index) == rtbl_cnt)
  33                 (*index)--;
  34
  35         return rate;
  36 }