xref: /openbmc/linux/drivers/clk/sunxi-ng/ccu_mux.c (revision 78e7f7da)
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.h>
8 #include <linux/clk-provider.h>
9 #include <linux/delay.h>
10 #include <linux/io.h>
11 
12 #include "ccu_gate.h"
13 #include "ccu_mux.h"
14 
15 #define CCU_MUX_KEY_VALUE		0x16aa0000
16 
ccu_mux_get_prediv(struct ccu_common * common,struct ccu_mux_internal * cm,int parent_index)17 static u16 ccu_mux_get_prediv(struct ccu_common *common,
18 			      struct ccu_mux_internal *cm,
19 			      int parent_index)
20 {
21 	u16 prediv = 1;
22 	u32 reg;
23 
24 	if (!((common->features & CCU_FEATURE_FIXED_PREDIV) ||
25 	      (common->features & CCU_FEATURE_VARIABLE_PREDIV) ||
26 	      (common->features & CCU_FEATURE_ALL_PREDIV)))
27 		return 1;
28 
29 	if (common->features & CCU_FEATURE_ALL_PREDIV)
30 		return common->prediv;
31 
32 	reg = readl(common->base + common->reg);
33 	if (parent_index < 0) {
34 		parent_index = reg >> cm->shift;
35 		parent_index &= (1 << cm->width) - 1;
36 	}
37 
38 	if (common->features & CCU_FEATURE_FIXED_PREDIV) {
39 		int i;
40 
41 		for (i = 0; i < cm->n_predivs; i++)
42 			if (parent_index == cm->fixed_predivs[i].index)
43 				prediv = cm->fixed_predivs[i].div;
44 	}
45 
46 	if (common->features & CCU_FEATURE_VARIABLE_PREDIV) {
47 		int i;
48 
49 		for (i = 0; i < cm->n_var_predivs; i++)
50 			if (parent_index == cm->var_predivs[i].index) {
51 				u8 div;
52 
53 				div = reg >> cm->var_predivs[i].shift;
54 				div &= (1 << cm->var_predivs[i].width) - 1;
55 				prediv = div + 1;
56 			}
57 	}
58 
59 	return prediv;
60 }
61 
ccu_mux_helper_apply_prediv(struct ccu_common * common,struct ccu_mux_internal * cm,int parent_index,unsigned long parent_rate)62 unsigned long ccu_mux_helper_apply_prediv(struct ccu_common *common,
63 					  struct ccu_mux_internal *cm,
64 					  int parent_index,
65 					  unsigned long parent_rate)
66 {
67 	return parent_rate / ccu_mux_get_prediv(common, cm, parent_index);
68 }
69 EXPORT_SYMBOL_NS_GPL(ccu_mux_helper_apply_prediv, SUNXI_CCU);
70 
ccu_mux_helper_unapply_prediv(struct ccu_common * common,struct ccu_mux_internal * cm,int parent_index,unsigned long parent_rate)71 static unsigned long ccu_mux_helper_unapply_prediv(struct ccu_common *common,
72 					    struct ccu_mux_internal *cm,
73 					    int parent_index,
74 					    unsigned long parent_rate)
75 {
76 	return parent_rate * ccu_mux_get_prediv(common, cm, parent_index);
77 }
78 
ccu_mux_helper_determine_rate(struct ccu_common * common,struct ccu_mux_internal * cm,struct clk_rate_request * req,unsigned long (* round)(struct ccu_mux_internal *,struct clk_hw *,unsigned long *,unsigned long,void *),void * data)79 int ccu_mux_helper_determine_rate(struct ccu_common *common,
80 				  struct ccu_mux_internal *cm,
81 				  struct clk_rate_request *req,
82 				  unsigned long (*round)(struct ccu_mux_internal *,
83 							 struct clk_hw *,
84 							 unsigned long *,
85 							 unsigned long,
86 							 void *),
87 				  void *data)
88 {
89 	unsigned long best_parent_rate = 0, best_rate = 0;
90 	struct clk_hw *best_parent, *hw = &common->hw;
91 	unsigned int i;
92 
93 	if (clk_hw_get_flags(hw) & CLK_SET_RATE_NO_REPARENT) {
94 		unsigned long adj_parent_rate;
95 
96 		best_parent = clk_hw_get_parent(hw);
97 		best_parent_rate = clk_hw_get_rate(best_parent);
98 		adj_parent_rate = ccu_mux_helper_apply_prediv(common, cm, -1,
99 							      best_parent_rate);
100 
101 		best_rate = round(cm, best_parent, &adj_parent_rate,
102 				  req->rate, data);
103 
104 		/*
105 		 * adj_parent_rate might have been modified by our clock.
106 		 * Unapply the pre-divider if there's one, and give
107 		 * the actual frequency the parent needs to run at.
108 		 */
109 		best_parent_rate = ccu_mux_helper_unapply_prediv(common, cm, -1,
110 								 adj_parent_rate);
111 
112 		goto out;
113 	}
114 
115 	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
116 		unsigned long tmp_rate, parent_rate;
117 		struct clk_hw *parent;
118 
119 		parent = clk_hw_get_parent_by_index(hw, i);
120 		if (!parent)
121 			continue;
122 
123 		parent_rate = ccu_mux_helper_apply_prediv(common, cm, i,
124 							  clk_hw_get_rate(parent));
125 
126 		tmp_rate = round(cm, parent, &parent_rate, req->rate, data);
127 
128 		/*
129 		 * parent_rate might have been modified by our clock.
130 		 * Unapply the pre-divider if there's one, and give
131 		 * the actual frequency the parent needs to run at.
132 		 */
133 		parent_rate = ccu_mux_helper_unapply_prediv(common, cm, i,
134 							    parent_rate);
135 		if (tmp_rate == req->rate) {
136 			best_parent = parent;
137 			best_parent_rate = parent_rate;
138 			best_rate = tmp_rate;
139 			goto out;
140 		}
141 
142 		if (ccu_is_better_rate(common, req->rate, tmp_rate, best_rate)) {
143 			best_rate = tmp_rate;
144 			best_parent_rate = parent_rate;
145 			best_parent = parent;
146 		}
147 	}
148 
149 	if (best_rate == 0)
150 		return -EINVAL;
151 
152 out:
153 	req->best_parent_hw = best_parent;
154 	req->best_parent_rate = best_parent_rate;
155 	req->rate = best_rate;
156 	return 0;
157 }
158 EXPORT_SYMBOL_NS_GPL(ccu_mux_helper_determine_rate, SUNXI_CCU);
159 
ccu_mux_helper_get_parent(struct ccu_common * common,struct ccu_mux_internal * cm)160 u8 ccu_mux_helper_get_parent(struct ccu_common *common,
161 			     struct ccu_mux_internal *cm)
162 {
163 	u32 reg;
164 	u8 parent;
165 
166 	reg = readl(common->base + common->reg);
167 	parent = reg >> cm->shift;
168 	parent &= (1 << cm->width) - 1;
169 
170 	if (cm->table) {
171 		int num_parents = clk_hw_get_num_parents(&common->hw);
172 		int i;
173 
174 		for (i = 0; i < num_parents; i++)
175 			if (cm->table[i] == parent)
176 				return i;
177 	}
178 
179 	return parent;
180 }
181 EXPORT_SYMBOL_NS_GPL(ccu_mux_helper_get_parent, SUNXI_CCU);
182 
ccu_mux_helper_set_parent(struct ccu_common * common,struct ccu_mux_internal * cm,u8 index)183 int ccu_mux_helper_set_parent(struct ccu_common *common,
184 			      struct ccu_mux_internal *cm,
185 			      u8 index)
186 {
187 	unsigned long flags;
188 	u32 reg;
189 
190 	if (cm->table)
191 		index = cm->table[index];
192 
193 	spin_lock_irqsave(common->lock, flags);
194 
195 	reg = readl(common->base + common->reg);
196 
197 	/* The key field always reads as zero. */
198 	if (common->features & CCU_FEATURE_KEY_FIELD)
199 		reg |= CCU_MUX_KEY_VALUE;
200 
201 	reg &= ~GENMASK(cm->width + cm->shift - 1, cm->shift);
202 	writel(reg | (index << cm->shift), common->base + common->reg);
203 
204 	spin_unlock_irqrestore(common->lock, flags);
205 
206 	return 0;
207 }
208 EXPORT_SYMBOL_NS_GPL(ccu_mux_helper_set_parent, SUNXI_CCU);
209 
ccu_mux_disable(struct clk_hw * hw)210 static void ccu_mux_disable(struct clk_hw *hw)
211 {
212 	struct ccu_mux *cm = hw_to_ccu_mux(hw);
213 
214 	return ccu_gate_helper_disable(&cm->common, cm->enable);
215 }
216 
ccu_mux_enable(struct clk_hw * hw)217 static int ccu_mux_enable(struct clk_hw *hw)
218 {
219 	struct ccu_mux *cm = hw_to_ccu_mux(hw);
220 
221 	return ccu_gate_helper_enable(&cm->common, cm->enable);
222 }
223 
ccu_mux_is_enabled(struct clk_hw * hw)224 static int ccu_mux_is_enabled(struct clk_hw *hw)
225 {
226 	struct ccu_mux *cm = hw_to_ccu_mux(hw);
227 
228 	return ccu_gate_helper_is_enabled(&cm->common, cm->enable);
229 }
230 
ccu_mux_get_parent(struct clk_hw * hw)231 static u8 ccu_mux_get_parent(struct clk_hw *hw)
232 {
233 	struct ccu_mux *cm = hw_to_ccu_mux(hw);
234 
235 	return ccu_mux_helper_get_parent(&cm->common, &cm->mux);
236 }
237 
ccu_mux_set_parent(struct clk_hw * hw,u8 index)238 static int ccu_mux_set_parent(struct clk_hw *hw, u8 index)
239 {
240 	struct ccu_mux *cm = hw_to_ccu_mux(hw);
241 
242 	return ccu_mux_helper_set_parent(&cm->common, &cm->mux, index);
243 }
244 
ccu_mux_determine_rate(struct clk_hw * hw,struct clk_rate_request * req)245 static int ccu_mux_determine_rate(struct clk_hw *hw,
246 				  struct clk_rate_request *req)
247 {
248 	struct ccu_mux *cm = hw_to_ccu_mux(hw);
249 
250 	if (cm->common.features & CCU_FEATURE_CLOSEST_RATE)
251 		return clk_mux_determine_rate_flags(hw, req, CLK_MUX_ROUND_CLOSEST);
252 
253 	return clk_mux_determine_rate_flags(hw, req, 0);
254 }
255 
ccu_mux_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)256 static unsigned long ccu_mux_recalc_rate(struct clk_hw *hw,
257 					 unsigned long parent_rate)
258 {
259 	struct ccu_mux *cm = hw_to_ccu_mux(hw);
260 
261 	return ccu_mux_helper_apply_prediv(&cm->common, &cm->mux, -1,
262 					   parent_rate);
263 }
264 
265 const struct clk_ops ccu_mux_ops = {
266 	.disable	= ccu_mux_disable,
267 	.enable		= ccu_mux_enable,
268 	.is_enabled	= ccu_mux_is_enabled,
269 
270 	.get_parent	= ccu_mux_get_parent,
271 	.set_parent	= ccu_mux_set_parent,
272 
273 	.determine_rate	= ccu_mux_determine_rate,
274 	.recalc_rate	= ccu_mux_recalc_rate,
275 };
276 EXPORT_SYMBOL_NS_GPL(ccu_mux_ops, SUNXI_CCU);
277 
278 /*
279  * This clock notifier is called when the frequency of the of the parent
280  * PLL clock is to be changed. The idea is to switch the parent to a
281  * stable clock, such as the main oscillator, while the PLL frequency
282  * stabilizes.
283  */
ccu_mux_notifier_cb(struct notifier_block * nb,unsigned long event,void * data)284 static int ccu_mux_notifier_cb(struct notifier_block *nb,
285 			       unsigned long event, void *data)
286 {
287 	struct ccu_mux_nb *mux = to_ccu_mux_nb(nb);
288 	int ret = 0;
289 
290 	if (event == PRE_RATE_CHANGE) {
291 		mux->original_index = ccu_mux_helper_get_parent(mux->common,
292 								mux->cm);
293 		ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
294 						mux->bypass_index);
295 	} else if (event == POST_RATE_CHANGE) {
296 		ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
297 						mux->original_index);
298 	}
299 
300 	udelay(mux->delay_us);
301 
302 	return notifier_from_errno(ret);
303 }
304 
ccu_mux_notifier_register(struct clk * clk,struct ccu_mux_nb * mux_nb)305 int ccu_mux_notifier_register(struct clk *clk, struct ccu_mux_nb *mux_nb)
306 {
307 	mux_nb->clk_nb.notifier_call = ccu_mux_notifier_cb;
308 
309 	return clk_notifier_register(clk, &mux_nb->clk_nb);
310 }
311 EXPORT_SYMBOL_NS_GPL(ccu_mux_notifier_register, SUNXI_CCU);
312