xref: /openbmc/linux/drivers/clk/spear/clk.c (revision c4c3c32d)
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 }
37