xref: /openbmc/linux/drivers/clk/meson/clk-mpll.c (revision 4da722ca)
1 /*
2  * This file is provided under a dual BSD/GPLv2 license.  When using or
3  * redistributing this file, you may do so under either license.
4  *
5  * GPL LICENSE SUMMARY
6  *
7  * Copyright (c) 2016 AmLogic, Inc.
8  * Author: Michael Turquette <mturquette@baylibre.com>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of version 2 of the GNU General Public License as
12  * published by the Free Software Foundation.
13  *
14  * This program is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  * General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
22  * The full GNU General Public License is included in this distribution
23  * in the file called COPYING
24  *
25  * BSD LICENSE
26  *
27  * Copyright (c) 2016 AmLogic, Inc.
28  * Author: Michael Turquette <mturquette@baylibre.com>
29  *
30  * Redistribution and use in source and binary forms, with or without
31  * modification, are permitted provided that the following conditions
32  * are met:
33  *
34  *   * Redistributions of source code must retain the above copyright
35  *     notice, this list of conditions and the following disclaimer.
36  *   * Redistributions in binary form must reproduce the above copyright
37  *     notice, this list of conditions and the following disclaimer in
38  *     the documentation and/or other materials provided with the
39  *     distribution.
40  *   * Neither the name of Intel Corporation nor the names of its
41  *     contributors may be used to endorse or promote products derived
42  *     from this software without specific prior written permission.
43  *
44  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
45  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
46  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
47  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
48  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
49  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
50  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
51  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
52  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
53  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
54  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
55  */
56 
57 /*
58  * MultiPhase Locked Loops are outputs from a PLL with additional frequency
59  * scaling capabilities. MPLL rates are calculated as:
60  *
61  * f(N2_integer, SDM_IN ) = 2.0G/(N2_integer + SDM_IN/16384)
62  */
63 
64 #include <linux/clk-provider.h>
65 #include "clkc.h"
66 
67 #define SDM_DEN 16384
68 #define N2_MIN	4
69 #define N2_MAX	511
70 
71 #define to_meson_clk_mpll(_hw) container_of(_hw, struct meson_clk_mpll, hw)
72 
73 static long rate_from_params(unsigned long parent_rate,
74 				      unsigned long sdm,
75 				      unsigned long n2)
76 {
77 	unsigned long divisor = (SDM_DEN * n2) + sdm;
78 
79 	if (n2 < N2_MIN)
80 		return -EINVAL;
81 
82 	return DIV_ROUND_UP_ULL((u64)parent_rate * SDM_DEN, divisor);
83 }
84 
85 static void params_from_rate(unsigned long requested_rate,
86 			     unsigned long parent_rate,
87 			     unsigned long *sdm,
88 			     unsigned long *n2)
89 {
90 	uint64_t div = parent_rate;
91 	unsigned long rem = do_div(div, requested_rate);
92 
93 	if (div < N2_MIN) {
94 		*n2 = N2_MIN;
95 		*sdm = 0;
96 	} else if (div > N2_MAX) {
97 		*n2 = N2_MAX;
98 		*sdm = SDM_DEN - 1;
99 	} else {
100 		*n2 = div;
101 		*sdm = DIV_ROUND_UP(rem * SDM_DEN, requested_rate);
102 	}
103 }
104 
105 static unsigned long mpll_recalc_rate(struct clk_hw *hw,
106 		unsigned long parent_rate)
107 {
108 	struct meson_clk_mpll *mpll = to_meson_clk_mpll(hw);
109 	struct parm *p;
110 	unsigned long reg, sdm, n2;
111 	long rate;
112 
113 	p = &mpll->sdm;
114 	reg = readl(mpll->base + p->reg_off);
115 	sdm = PARM_GET(p->width, p->shift, reg);
116 
117 	p = &mpll->n2;
118 	reg = readl(mpll->base + p->reg_off);
119 	n2 = PARM_GET(p->width, p->shift, reg);
120 
121 	rate = rate_from_params(parent_rate, sdm, n2);
122 	if (rate < 0)
123 		return 0;
124 
125 	return rate;
126 }
127 
128 static long mpll_round_rate(struct clk_hw *hw,
129 			    unsigned long rate,
130 			    unsigned long *parent_rate)
131 {
132 	unsigned long sdm, n2;
133 
134 	params_from_rate(rate, *parent_rate, &sdm, &n2);
135 	return rate_from_params(*parent_rate, sdm, n2);
136 }
137 
138 static int mpll_set_rate(struct clk_hw *hw,
139 			 unsigned long rate,
140 			 unsigned long parent_rate)
141 {
142 	struct meson_clk_mpll *mpll = to_meson_clk_mpll(hw);
143 	struct parm *p;
144 	unsigned long reg, sdm, n2;
145 	unsigned long flags = 0;
146 
147 	params_from_rate(rate, parent_rate, &sdm, &n2);
148 
149 	if (mpll->lock)
150 		spin_lock_irqsave(mpll->lock, flags);
151 	else
152 		__acquire(mpll->lock);
153 
154 	p = &mpll->sdm;
155 	reg = readl(mpll->base + p->reg_off);
156 	reg = PARM_SET(p->width, p->shift, reg, sdm);
157 	writel(reg, mpll->base + p->reg_off);
158 
159 	p = &mpll->sdm_en;
160 	reg = readl(mpll->base + p->reg_off);
161 	reg = PARM_SET(p->width, p->shift, reg, 1);
162 	writel(reg, mpll->base + p->reg_off);
163 
164 	p = &mpll->n2;
165 	reg = readl(mpll->base + p->reg_off);
166 	reg = PARM_SET(p->width, p->shift, reg, n2);
167 	writel(reg, mpll->base + p->reg_off);
168 
169 	if (mpll->lock)
170 		spin_unlock_irqrestore(mpll->lock, flags);
171 	else
172 		__release(mpll->lock);
173 
174 	return 0;
175 }
176 
177 static void mpll_enable_core(struct clk_hw *hw, int enable)
178 {
179 	struct meson_clk_mpll *mpll = to_meson_clk_mpll(hw);
180 	struct parm *p;
181 	unsigned long reg;
182 	unsigned long flags = 0;
183 
184 	if (mpll->lock)
185 		spin_lock_irqsave(mpll->lock, flags);
186 	else
187 		__acquire(mpll->lock);
188 
189 	p = &mpll->en;
190 	reg = readl(mpll->base + p->reg_off);
191 	reg = PARM_SET(p->width, p->shift, reg, enable ? 1 : 0);
192 	writel(reg, mpll->base + p->reg_off);
193 
194 	if (mpll->lock)
195 		spin_unlock_irqrestore(mpll->lock, flags);
196 	else
197 		__release(mpll->lock);
198 }
199 
200 
201 static int mpll_enable(struct clk_hw *hw)
202 {
203 	mpll_enable_core(hw, 1);
204 
205 	return 0;
206 }
207 
208 static void mpll_disable(struct clk_hw *hw)
209 {
210 	mpll_enable_core(hw, 0);
211 }
212 
213 static int mpll_is_enabled(struct clk_hw *hw)
214 {
215 	struct meson_clk_mpll *mpll = to_meson_clk_mpll(hw);
216 	struct parm *p;
217 	unsigned long reg;
218 	int en;
219 
220 	p = &mpll->en;
221 	reg = readl(mpll->base + p->reg_off);
222 	en = PARM_GET(p->width, p->shift, reg);
223 
224 	return en;
225 }
226 
227 const struct clk_ops meson_clk_mpll_ro_ops = {
228 	.recalc_rate	= mpll_recalc_rate,
229 	.round_rate	= mpll_round_rate,
230 	.is_enabled	= mpll_is_enabled,
231 };
232 
233 const struct clk_ops meson_clk_mpll_ops = {
234 	.recalc_rate	= mpll_recalc_rate,
235 	.round_rate	= mpll_round_rate,
236 	.set_rate	= mpll_set_rate,
237 	.enable		= mpll_enable,
238 	.disable	= mpll_disable,
239 	.is_enabled	= mpll_is_enabled,
240 };
241