xref: /openbmc/linux/drivers/clk/sunxi-ng/ccu_frac.c (revision b593bce5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 Maxime Ripard
4  * Maxime Ripard <maxime.ripard@free-electrons.com>
5  */
6 
7 #include <linux/clk-provider.h>
8 #include <linux/io.h>
9 #include <linux/spinlock.h>
10 
11 #include "ccu_frac.h"
12 
13 bool ccu_frac_helper_is_enabled(struct ccu_common *common,
14 				struct ccu_frac_internal *cf)
15 {
16 	if (!(common->features & CCU_FEATURE_FRACTIONAL))
17 		return false;
18 
19 	return !(readl(common->base + common->reg) & cf->enable);
20 }
21 
22 void ccu_frac_helper_enable(struct ccu_common *common,
23 			    struct ccu_frac_internal *cf)
24 {
25 	unsigned long flags;
26 	u32 reg;
27 
28 	if (!(common->features & CCU_FEATURE_FRACTIONAL))
29 		return;
30 
31 	spin_lock_irqsave(common->lock, flags);
32 	reg = readl(common->base + common->reg);
33 	writel(reg & ~cf->enable, common->base + common->reg);
34 	spin_unlock_irqrestore(common->lock, flags);
35 }
36 
37 void ccu_frac_helper_disable(struct ccu_common *common,
38 			     struct ccu_frac_internal *cf)
39 {
40 	unsigned long flags;
41 	u32 reg;
42 
43 	if (!(common->features & CCU_FEATURE_FRACTIONAL))
44 		return;
45 
46 	spin_lock_irqsave(common->lock, flags);
47 	reg = readl(common->base + common->reg);
48 	writel(reg | cf->enable, common->base + common->reg);
49 	spin_unlock_irqrestore(common->lock, flags);
50 }
51 
52 bool ccu_frac_helper_has_rate(struct ccu_common *common,
53 			      struct ccu_frac_internal *cf,
54 			      unsigned long rate)
55 {
56 	if (!(common->features & CCU_FEATURE_FRACTIONAL))
57 		return false;
58 
59 	return (cf->rates[0] == rate) || (cf->rates[1] == rate);
60 }
61 
62 unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,
63 					struct ccu_frac_internal *cf)
64 {
65 	u32 reg;
66 
67 	pr_debug("%s: Read fractional\n", clk_hw_get_name(&common->hw));
68 
69 	if (!(common->features & CCU_FEATURE_FRACTIONAL))
70 		return 0;
71 
72 	pr_debug("%s: clock is fractional (rates %lu and %lu)\n",
73 		 clk_hw_get_name(&common->hw), cf->rates[0], cf->rates[1]);
74 
75 	reg = readl(common->base + common->reg);
76 
77 	pr_debug("%s: clock reg is 0x%x (select is 0x%x)\n",
78 		 clk_hw_get_name(&common->hw), reg, cf->select);
79 
80 	return (reg & cf->select) ? cf->rates[1] : cf->rates[0];
81 }
82 
83 int ccu_frac_helper_set_rate(struct ccu_common *common,
84 			     struct ccu_frac_internal *cf,
85 			     unsigned long rate, u32 lock)
86 {
87 	unsigned long flags;
88 	u32 reg, sel;
89 
90 	if (!(common->features & CCU_FEATURE_FRACTIONAL))
91 		return -EINVAL;
92 
93 	if (cf->rates[0] == rate)
94 		sel = 0;
95 	else if (cf->rates[1] == rate)
96 		sel = cf->select;
97 	else
98 		return -EINVAL;
99 
100 	spin_lock_irqsave(common->lock, flags);
101 	reg = readl(common->base + common->reg);
102 	reg &= ~cf->select;
103 	writel(reg | sel, common->base + common->reg);
104 	spin_unlock_irqrestore(common->lock, flags);
105 
106 	ccu_helper_wait_for_lock(common, lock);
107 
108 	return 0;
109 }
110