xref: /openbmc/linux/drivers/clk/sunxi-ng/ccu_nm.c (revision e724e7aa)
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 
10 #include "ccu_frac.h"
11 #include "ccu_gate.h"
12 #include "ccu_nm.h"
13 
14 struct _ccu_nm {
15 	unsigned long	n, min_n, max_n;
16 	unsigned long	m, min_m, max_m;
17 };
18 
19 static unsigned long ccu_nm_calc_rate(unsigned long parent,
20 				      unsigned long n, unsigned long m)
21 {
22 	u64 rate = parent;
23 
24 	rate *= n;
25 	do_div(rate, m);
26 
27 	return rate;
28 }
29 
30 static unsigned long ccu_nm_find_best(unsigned long parent, unsigned long rate,
31 				      struct _ccu_nm *nm)
32 {
33 	unsigned long best_rate = 0;
34 	unsigned long best_n = 0, best_m = 0;
35 	unsigned long _n, _m;
36 
37 	for (_n = nm->min_n; _n <= nm->max_n; _n++) {
38 		for (_m = nm->min_m; _m <= nm->max_m; _m++) {
39 			unsigned long tmp_rate = ccu_nm_calc_rate(parent,
40 								  _n, _m);
41 
42 			if (tmp_rate > rate)
43 				continue;
44 
45 			if ((rate - tmp_rate) < (rate - best_rate)) {
46 				best_rate = tmp_rate;
47 				best_n = _n;
48 				best_m = _m;
49 			}
50 		}
51 	}
52 
53 	nm->n = best_n;
54 	nm->m = best_m;
55 
56 	return best_rate;
57 }
58 
59 static void ccu_nm_disable(struct clk_hw *hw)
60 {
61 	struct ccu_nm *nm = hw_to_ccu_nm(hw);
62 
63 	return ccu_gate_helper_disable(&nm->common, nm->enable);
64 }
65 
66 static int ccu_nm_enable(struct clk_hw *hw)
67 {
68 	struct ccu_nm *nm = hw_to_ccu_nm(hw);
69 
70 	return ccu_gate_helper_enable(&nm->common, nm->enable);
71 }
72 
73 static int ccu_nm_is_enabled(struct clk_hw *hw)
74 {
75 	struct ccu_nm *nm = hw_to_ccu_nm(hw);
76 
77 	return ccu_gate_helper_is_enabled(&nm->common, nm->enable);
78 }
79 
80 static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
81 					unsigned long parent_rate)
82 {
83 	struct ccu_nm *nm = hw_to_ccu_nm(hw);
84 	unsigned long rate;
85 	unsigned long n, m;
86 	u32 reg;
87 
88 	if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac)) {
89 		rate = ccu_frac_helper_read_rate(&nm->common, &nm->frac);
90 
91 		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
92 			rate /= nm->fixed_post_div;
93 
94 		return rate;
95 	}
96 
97 	reg = readl(nm->common.base + nm->common.reg);
98 
99 	n = reg >> nm->n.shift;
100 	n &= (1 << nm->n.width) - 1;
101 	n += nm->n.offset;
102 	if (!n)
103 		n++;
104 
105 	m = reg >> nm->m.shift;
106 	m &= (1 << nm->m.width) - 1;
107 	m += nm->m.offset;
108 	if (!m)
109 		m++;
110 
111 	if (ccu_sdm_helper_is_enabled(&nm->common, &nm->sdm))
112 		rate = ccu_sdm_helper_read_rate(&nm->common, &nm->sdm, m, n);
113 	else
114 		rate = ccu_nm_calc_rate(parent_rate, n, m);
115 
116 	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
117 		rate /= nm->fixed_post_div;
118 
119 	return rate;
120 }
121 
122 static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
123 			      unsigned long *parent_rate)
124 {
125 	struct ccu_nm *nm = hw_to_ccu_nm(hw);
126 	struct _ccu_nm _nm;
127 
128 	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
129 		rate *= nm->fixed_post_div;
130 
131 	if (rate < nm->min_rate) {
132 		rate = nm->min_rate;
133 		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
134 			rate /= nm->fixed_post_div;
135 		return rate;
136 	}
137 
138 	if (nm->max_rate && rate > nm->max_rate) {
139 		rate = nm->max_rate;
140 		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
141 			rate /= nm->fixed_post_div;
142 		return rate;
143 	}
144 
145 	if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
146 		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
147 			rate /= nm->fixed_post_div;
148 		return rate;
149 	}
150 
151 	if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
152 		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
153 			rate /= nm->fixed_post_div;
154 		return rate;
155 	}
156 
157 	_nm.min_n = nm->n.min ?: 1;
158 	_nm.max_n = nm->n.max ?: 1 << nm->n.width;
159 	_nm.min_m = 1;
160 	_nm.max_m = nm->m.max ?: 1 << nm->m.width;
161 
162 	rate = ccu_nm_find_best(*parent_rate, rate, &_nm);
163 
164 	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
165 		rate /= nm->fixed_post_div;
166 
167 	return rate;
168 }
169 
170 static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
171 			   unsigned long parent_rate)
172 {
173 	struct ccu_nm *nm = hw_to_ccu_nm(hw);
174 	struct _ccu_nm _nm;
175 	unsigned long flags;
176 	u32 reg;
177 
178 	/* Adjust target rate according to post-dividers */
179 	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
180 		rate = rate * nm->fixed_post_div;
181 
182 	if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
183 		spin_lock_irqsave(nm->common.lock, flags);
184 
185 		/* most SoCs require M to be 0 if fractional mode is used */
186 		reg = readl(nm->common.base + nm->common.reg);
187 		reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
188 		writel(reg, nm->common.base + nm->common.reg);
189 
190 		spin_unlock_irqrestore(nm->common.lock, flags);
191 
192 		ccu_frac_helper_enable(&nm->common, &nm->frac);
193 
194 		return ccu_frac_helper_set_rate(&nm->common, &nm->frac,
195 						rate, nm->lock);
196 	} else {
197 		ccu_frac_helper_disable(&nm->common, &nm->frac);
198 	}
199 
200 	_nm.min_n = nm->n.min ?: 1;
201 	_nm.max_n = nm->n.max ?: 1 << nm->n.width;
202 	_nm.min_m = 1;
203 	_nm.max_m = nm->m.max ?: 1 << nm->m.width;
204 
205 	if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
206 		ccu_sdm_helper_enable(&nm->common, &nm->sdm, rate);
207 
208 		/* Sigma delta modulation requires specific N and M factors */
209 		ccu_sdm_helper_get_factors(&nm->common, &nm->sdm, rate,
210 					   &_nm.m, &_nm.n);
211 	} else {
212 		ccu_sdm_helper_disable(&nm->common, &nm->sdm);
213 		ccu_nm_find_best(parent_rate, rate, &_nm);
214 	}
215 
216 	spin_lock_irqsave(nm->common.lock, flags);
217 
218 	reg = readl(nm->common.base + nm->common.reg);
219 	reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
220 	reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
221 
222 	reg |= (_nm.n - nm->n.offset) << nm->n.shift;
223 	reg |= (_nm.m - nm->m.offset) << nm->m.shift;
224 	writel(reg, nm->common.base + nm->common.reg);
225 
226 	spin_unlock_irqrestore(nm->common.lock, flags);
227 
228 	ccu_helper_wait_for_lock(&nm->common, nm->lock);
229 
230 	return 0;
231 }
232 
233 const struct clk_ops ccu_nm_ops = {
234 	.disable	= ccu_nm_disable,
235 	.enable		= ccu_nm_enable,
236 	.is_enabled	= ccu_nm_is_enabled,
237 
238 	.recalc_rate	= ccu_nm_recalc_rate,
239 	.round_rate	= ccu_nm_round_rate,
240 	.set_rate	= ccu_nm_set_rate,
241 };
242 EXPORT_SYMBOL_NS_GPL(ccu_nm_ops, SUNXI_CCU);
243