ccu_mux.c

  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	if (common->features & CCU_FEATURE_UPDATE_BIT)
201		reg |= CCU_SUNXI_UPDATE_BIT;
202
203	reg &= ~GENMASK(cm->width + cm->shift - 1, cm->shift);
204	writel(reg | (index << cm->shift), common->base + common->reg);
205
206	spin_unlock_irqrestore(common->lock, flags);
207
208	return 0;
209}
210EXPORT_SYMBOL_NS_GPL(ccu_mux_helper_set_parent, "SUNXI_CCU");
211
212static void ccu_mux_disable(struct clk_hw *hw)
213{
214	struct ccu_mux *cm = hw_to_ccu_mux(hw);
215
216	return ccu_gate_helper_disable(&cm->common, cm->enable);
217}
218
219static int ccu_mux_enable(struct clk_hw *hw)
220{
221	struct ccu_mux *cm = hw_to_ccu_mux(hw);
222
223	return ccu_gate_helper_enable(&cm->common, cm->enable);
224}
225
226static int ccu_mux_is_enabled(struct clk_hw *hw)
227{
228	struct ccu_mux *cm = hw_to_ccu_mux(hw);
229
230	return ccu_gate_helper_is_enabled(&cm->common, cm->enable);
231}
232
233static u8 ccu_mux_get_parent(struct clk_hw *hw)
234{
235	struct ccu_mux *cm = hw_to_ccu_mux(hw);
236
237	return ccu_mux_helper_get_parent(&cm->common, &cm->mux);
238}
239
240static int ccu_mux_set_parent(struct clk_hw *hw, u8 index)
241{
242	struct ccu_mux *cm = hw_to_ccu_mux(hw);
243
244	return ccu_mux_helper_set_parent(&cm->common, &cm->mux, index);
245}
246
247static int ccu_mux_determine_rate(struct clk_hw *hw,
248				  struct clk_rate_request *req)
249{
250	struct ccu_mux *cm = hw_to_ccu_mux(hw);
251
252	if (cm->common.features & CCU_FEATURE_CLOSEST_RATE)
253		return clk_mux_determine_rate_flags(hw, req, CLK_MUX_ROUND_CLOSEST);
254
255	return clk_mux_determine_rate_flags(hw, req, 0);
256}
257
258static unsigned long ccu_mux_recalc_rate(struct clk_hw *hw,
259					 unsigned long parent_rate)
260{
261	struct ccu_mux *cm = hw_to_ccu_mux(hw);
262
263	return ccu_mux_helper_apply_prediv(&cm->common, &cm->mux, -1,
264					   parent_rate);
265}
266
267const struct clk_ops ccu_mux_ops = {
268	.disable	= ccu_mux_disable,
269	.enable		= ccu_mux_enable,
270	.is_enabled	= ccu_mux_is_enabled,
271
272	.get_parent	= ccu_mux_get_parent,
273	.set_parent	= ccu_mux_set_parent,
274
275	.determine_rate	= ccu_mux_determine_rate,
276	.recalc_rate	= ccu_mux_recalc_rate,
277};
278EXPORT_SYMBOL_NS_GPL(ccu_mux_ops, "SUNXI_CCU");
279
280/*
281 * This clock notifier is called when the frequency of the of the parent
282 * PLL clock is to be changed. The idea is to switch the parent to a
283 * stable clock, such as the main oscillator, while the PLL frequency
284 * stabilizes.
285 */
286static int ccu_mux_notifier_cb(struct notifier_block *nb,
287			       unsigned long event, void *data)
288{
289	struct ccu_mux_nb *mux = to_ccu_mux_nb(nb);
290	int ret = 0;
291
292	if (event == PRE_RATE_CHANGE) {
293		mux->original_index = ccu_mux_helper_get_parent(mux->common,
294								mux->cm);
295		ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
296						mux->bypass_index);
297	} else if (event == POST_RATE_CHANGE) {
298		ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
299						mux->original_index);
300	}
301
302	udelay(mux->delay_us);
303
304	return notifier_from_errno(ret);
305}
306
307int ccu_mux_notifier_register(struct clk *clk, struct ccu_mux_nb *mux_nb)
308{
309	mux_nb->clk_nb.notifier_call = ccu_mux_notifier_cb;
310
311	return clk_notifier_register(clk, &mux_nb->clk_nb);
312}
313EXPORT_SYMBOL_NS_GPL(ccu_mux_notifier_register, "SUNXI_CCU");