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
17static 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
62unsigned 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}
69EXPORT_SYMBOL_NS_GPL(ccu_mux_helper_apply_prediv, SUNXI_CCU);
70
71static 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
79int 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
152out:
153	req->best_parent_hw = best_parent;
154	req->best_parent_rate = best_parent_rate;
155	req->rate = best_rate;
156	return 0;
157}
158EXPORT_SYMBOL_NS_GPL(ccu_mux_helper_determine_rate, SUNXI_CCU);
159
160u8 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}
181EXPORT_SYMBOL_NS_GPL(ccu_mux_helper_get_parent, SUNXI_CCU);
182
183int 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}
208EXPORT_SYMBOL_NS_GPL(ccu_mux_helper_set_parent, SUNXI_CCU);
209
210static 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
217static 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
224static 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
231static 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
238static 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
245static 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
256static 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
265const 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};
276EXPORT_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 */
284static 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
305int 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}
311EXPORT_SYMBOL_NS_GPL(ccu_mux_notifier_register, SUNXI_CCU);
312