1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
4  */
5 
6 #include <linux/bitops.h>
7 #include <linux/clk-provider.h>
8 #include <linux/clkdev.h>
9 #include <linux/clk/at91_pmc.h>
10 #include <linux/of.h>
11 #include <linux/mfd/syscon.h>
12 #include <linux/regmap.h>
13 
14 #include "pmc.h"
15 
16 DEFINE_SPINLOCK(pmc_pcr_lock);
17 
18 #define PERIPHERAL_ID_MIN	2
19 #define PERIPHERAL_ID_MAX	31
20 #define PERIPHERAL_MASK(id)	(1 << ((id) & PERIPHERAL_ID_MAX))
21 
22 #define PERIPHERAL_MAX_SHIFT	3
23 
24 struct clk_peripheral {
25 	struct clk_hw hw;
26 	struct regmap *regmap;
27 	u32 id;
28 };
29 
30 #define to_clk_peripheral(hw) container_of(hw, struct clk_peripheral, hw)
31 
32 struct clk_sam9x5_peripheral {
33 	struct clk_hw hw;
34 	struct regmap *regmap;
35 	struct clk_range range;
36 	spinlock_t *lock;
37 	u32 id;
38 	u32 div;
39 	const struct clk_pcr_layout *layout;
40 	struct at91_clk_pms pms;
41 	bool auto_div;
42 	int chg_pid;
43 };
44 
45 #define to_clk_sam9x5_peripheral(hw) \
46 	container_of(hw, struct clk_sam9x5_peripheral, hw)
47 
48 static int clk_peripheral_enable(struct clk_hw *hw)
49 {
50 	struct clk_peripheral *periph = to_clk_peripheral(hw);
51 	int offset = AT91_PMC_PCER;
52 	u32 id = periph->id;
53 
54 	if (id < PERIPHERAL_ID_MIN)
55 		return 0;
56 	if (id > PERIPHERAL_ID_MAX)
57 		offset = AT91_PMC_PCER1;
58 	regmap_write(periph->regmap, offset, PERIPHERAL_MASK(id));
59 
60 	return 0;
61 }
62 
63 static void clk_peripheral_disable(struct clk_hw *hw)
64 {
65 	struct clk_peripheral *periph = to_clk_peripheral(hw);
66 	int offset = AT91_PMC_PCDR;
67 	u32 id = periph->id;
68 
69 	if (id < PERIPHERAL_ID_MIN)
70 		return;
71 	if (id > PERIPHERAL_ID_MAX)
72 		offset = AT91_PMC_PCDR1;
73 	regmap_write(periph->regmap, offset, PERIPHERAL_MASK(id));
74 }
75 
76 static int clk_peripheral_is_enabled(struct clk_hw *hw)
77 {
78 	struct clk_peripheral *periph = to_clk_peripheral(hw);
79 	int offset = AT91_PMC_PCSR;
80 	unsigned int status;
81 	u32 id = periph->id;
82 
83 	if (id < PERIPHERAL_ID_MIN)
84 		return 1;
85 	if (id > PERIPHERAL_ID_MAX)
86 		offset = AT91_PMC_PCSR1;
87 	regmap_read(periph->regmap, offset, &status);
88 
89 	return status & PERIPHERAL_MASK(id) ? 1 : 0;
90 }
91 
92 static const struct clk_ops peripheral_ops = {
93 	.enable = clk_peripheral_enable,
94 	.disable = clk_peripheral_disable,
95 	.is_enabled = clk_peripheral_is_enabled,
96 };
97 
98 struct clk_hw * __init
99 at91_clk_register_peripheral(struct regmap *regmap, const char *name,
100 			     const char *parent_name, u32 id)
101 {
102 	struct clk_peripheral *periph;
103 	struct clk_init_data init;
104 	struct clk_hw *hw;
105 	int ret;
106 
107 	if (!name || !parent_name || id > PERIPHERAL_ID_MAX)
108 		return ERR_PTR(-EINVAL);
109 
110 	periph = kzalloc(sizeof(*periph), GFP_KERNEL);
111 	if (!periph)
112 		return ERR_PTR(-ENOMEM);
113 
114 	init.name = name;
115 	init.ops = &peripheral_ops;
116 	init.parent_names = &parent_name;
117 	init.num_parents = 1;
118 	init.flags = 0;
119 
120 	periph->id = id;
121 	periph->hw.init = &init;
122 	periph->regmap = regmap;
123 
124 	hw = &periph->hw;
125 	ret = clk_hw_register(NULL, &periph->hw);
126 	if (ret) {
127 		kfree(periph);
128 		hw = ERR_PTR(ret);
129 	}
130 
131 	return hw;
132 }
133 
134 static void clk_sam9x5_peripheral_autodiv(struct clk_sam9x5_peripheral *periph)
135 {
136 	struct clk_hw *parent;
137 	unsigned long parent_rate;
138 	int shift = 0;
139 
140 	if (!periph->auto_div)
141 		return;
142 
143 	if (periph->range.max) {
144 		parent = clk_hw_get_parent_by_index(&periph->hw, 0);
145 		parent_rate = clk_hw_get_rate(parent);
146 		if (!parent_rate)
147 			return;
148 
149 		for (; shift < PERIPHERAL_MAX_SHIFT; shift++) {
150 			if (parent_rate >> shift <= periph->range.max)
151 				break;
152 		}
153 	}
154 
155 	periph->auto_div = false;
156 	periph->div = shift;
157 }
158 
159 static int clk_sam9x5_peripheral_set(struct clk_sam9x5_peripheral *periph,
160 				     unsigned int status)
161 {
162 	unsigned long flags;
163 	unsigned int enable = status ? AT91_PMC_PCR_EN : 0;
164 
165 	if (periph->id < PERIPHERAL_ID_MIN)
166 		return 0;
167 
168 	spin_lock_irqsave(periph->lock, flags);
169 	regmap_write(periph->regmap, periph->layout->offset,
170 		     (periph->id & periph->layout->pid_mask));
171 	regmap_update_bits(periph->regmap, periph->layout->offset,
172 			   periph->layout->div_mask | periph->layout->cmd |
173 			   enable,
174 			   field_prep(periph->layout->div_mask, periph->div) |
175 			   periph->layout->cmd | enable);
176 	spin_unlock_irqrestore(periph->lock, flags);
177 
178 	return 0;
179 }
180 
181 static int clk_sam9x5_peripheral_enable(struct clk_hw *hw)
182 {
183 	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
184 
185 	return clk_sam9x5_peripheral_set(periph, 1);
186 }
187 
188 static void clk_sam9x5_peripheral_disable(struct clk_hw *hw)
189 {
190 	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
191 	unsigned long flags;
192 
193 	if (periph->id < PERIPHERAL_ID_MIN)
194 		return;
195 
196 	spin_lock_irqsave(periph->lock, flags);
197 	regmap_write(periph->regmap, periph->layout->offset,
198 		     (periph->id & periph->layout->pid_mask));
199 	regmap_update_bits(periph->regmap, periph->layout->offset,
200 			   AT91_PMC_PCR_EN | periph->layout->cmd,
201 			   periph->layout->cmd);
202 	spin_unlock_irqrestore(periph->lock, flags);
203 }
204 
205 static int clk_sam9x5_peripheral_is_enabled(struct clk_hw *hw)
206 {
207 	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
208 	unsigned long flags;
209 	unsigned int status;
210 
211 	if (periph->id < PERIPHERAL_ID_MIN)
212 		return 1;
213 
214 	spin_lock_irqsave(periph->lock, flags);
215 	regmap_write(periph->regmap, periph->layout->offset,
216 		     (periph->id & periph->layout->pid_mask));
217 	regmap_read(periph->regmap, periph->layout->offset, &status);
218 	spin_unlock_irqrestore(periph->lock, flags);
219 
220 	return !!(status & AT91_PMC_PCR_EN);
221 }
222 
223 static unsigned long
224 clk_sam9x5_peripheral_recalc_rate(struct clk_hw *hw,
225 				  unsigned long parent_rate)
226 {
227 	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
228 	unsigned long flags;
229 	unsigned int status;
230 
231 	if (periph->id < PERIPHERAL_ID_MIN)
232 		return parent_rate;
233 
234 	spin_lock_irqsave(periph->lock, flags);
235 	regmap_write(periph->regmap, periph->layout->offset,
236 		     (periph->id & periph->layout->pid_mask));
237 	regmap_read(periph->regmap, periph->layout->offset, &status);
238 	spin_unlock_irqrestore(periph->lock, flags);
239 
240 	if (status & AT91_PMC_PCR_EN) {
241 		periph->div = field_get(periph->layout->div_mask, status);
242 		periph->auto_div = false;
243 	} else {
244 		clk_sam9x5_peripheral_autodiv(periph);
245 	}
246 
247 	return parent_rate >> periph->div;
248 }
249 
250 static void clk_sam9x5_peripheral_best_diff(struct clk_rate_request *req,
251 					    struct clk_hw *parent,
252 					    unsigned long parent_rate,
253 					    u32 shift, long *best_diff,
254 					    long *best_rate)
255 {
256 	unsigned long tmp_rate = parent_rate >> shift;
257 	unsigned long tmp_diff = abs(req->rate - tmp_rate);
258 
259 	if (*best_diff < 0 || *best_diff >= tmp_diff) {
260 		*best_rate = tmp_rate;
261 		*best_diff = tmp_diff;
262 		req->best_parent_rate = parent_rate;
263 		req->best_parent_hw = parent;
264 	}
265 }
266 
267 static int clk_sam9x5_peripheral_determine_rate(struct clk_hw *hw,
268 						struct clk_rate_request *req)
269 {
270 	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
271 	struct clk_hw *parent = clk_hw_get_parent(hw);
272 	struct clk_rate_request req_parent = *req;
273 	unsigned long parent_rate = clk_hw_get_rate(parent);
274 	unsigned long tmp_rate;
275 	long best_rate = LONG_MIN;
276 	long best_diff = LONG_MIN;
277 	u32 shift;
278 
279 	if (periph->id < PERIPHERAL_ID_MIN || !periph->range.max)
280 		return parent_rate;
281 
282 	/* Fist step: check the available dividers. */
283 	for (shift = 0; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
284 		tmp_rate = parent_rate >> shift;
285 
286 		if (periph->range.max && tmp_rate > periph->range.max)
287 			continue;
288 
289 		clk_sam9x5_peripheral_best_diff(req, parent, parent_rate,
290 						shift, &best_diff, &best_rate);
291 
292 		if (!best_diff || best_rate <= req->rate)
293 			break;
294 	}
295 
296 	if (periph->chg_pid < 0)
297 		goto end;
298 
299 	/* Step two: try to request rate from parent. */
300 	parent = clk_hw_get_parent_by_index(hw, periph->chg_pid);
301 	if (!parent)
302 		goto end;
303 
304 	for (shift = 0; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
305 		req_parent.rate = req->rate << shift;
306 
307 		if (__clk_determine_rate(parent, &req_parent))
308 			continue;
309 
310 		clk_sam9x5_peripheral_best_diff(req, parent, req_parent.rate,
311 						shift, &best_diff, &best_rate);
312 
313 		if (!best_diff)
314 			break;
315 	}
316 end:
317 	if (best_rate < 0 ||
318 	    (periph->range.max && best_rate > periph->range.max))
319 		return -EINVAL;
320 
321 	pr_debug("PCK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
322 		 __func__, best_rate,
323 		 __clk_get_name((req->best_parent_hw)->clk),
324 		 req->best_parent_rate);
325 
326 	req->rate = best_rate;
327 
328 	return 0;
329 }
330 
331 static long clk_sam9x5_peripheral_round_rate(struct clk_hw *hw,
332 					     unsigned long rate,
333 					     unsigned long *parent_rate)
334 {
335 	int shift = 0;
336 	unsigned long best_rate;
337 	unsigned long best_diff;
338 	unsigned long cur_rate = *parent_rate;
339 	unsigned long cur_diff;
340 	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
341 
342 	if (periph->id < PERIPHERAL_ID_MIN || !periph->range.max)
343 		return *parent_rate;
344 
345 	if (periph->range.max) {
346 		for (; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
347 			cur_rate = *parent_rate >> shift;
348 			if (cur_rate <= periph->range.max)
349 				break;
350 		}
351 	}
352 
353 	if (rate >= cur_rate)
354 		return cur_rate;
355 
356 	best_diff = cur_rate - rate;
357 	best_rate = cur_rate;
358 	for (; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
359 		cur_rate = *parent_rate >> shift;
360 		if (cur_rate < rate)
361 			cur_diff = rate - cur_rate;
362 		else
363 			cur_diff = cur_rate - rate;
364 
365 		if (cur_diff < best_diff) {
366 			best_diff = cur_diff;
367 			best_rate = cur_rate;
368 		}
369 
370 		if (!best_diff || cur_rate < rate)
371 			break;
372 	}
373 
374 	return best_rate;
375 }
376 
377 static int clk_sam9x5_peripheral_set_rate(struct clk_hw *hw,
378 					  unsigned long rate,
379 					  unsigned long parent_rate)
380 {
381 	int shift;
382 	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
383 	if (periph->id < PERIPHERAL_ID_MIN || !periph->range.max) {
384 		if (parent_rate == rate)
385 			return 0;
386 		else
387 			return -EINVAL;
388 	}
389 
390 	if (periph->range.max && rate > periph->range.max)
391 		return -EINVAL;
392 
393 	for (shift = 0; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
394 		if (parent_rate >> shift == rate) {
395 			periph->auto_div = false;
396 			periph->div = shift;
397 			return 0;
398 		}
399 	}
400 
401 	return -EINVAL;
402 }
403 
404 static int clk_sam9x5_peripheral_save_context(struct clk_hw *hw)
405 {
406 	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
407 
408 	periph->pms.status = clk_sam9x5_peripheral_is_enabled(hw);
409 
410 	return 0;
411 }
412 
413 static void clk_sam9x5_peripheral_restore_context(struct clk_hw *hw)
414 {
415 	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
416 
417 	if (periph->pms.status)
418 		clk_sam9x5_peripheral_set(periph, periph->pms.status);
419 }
420 
421 static const struct clk_ops sam9x5_peripheral_ops = {
422 	.enable = clk_sam9x5_peripheral_enable,
423 	.disable = clk_sam9x5_peripheral_disable,
424 	.is_enabled = clk_sam9x5_peripheral_is_enabled,
425 	.recalc_rate = clk_sam9x5_peripheral_recalc_rate,
426 	.round_rate = clk_sam9x5_peripheral_round_rate,
427 	.set_rate = clk_sam9x5_peripheral_set_rate,
428 	.save_context = clk_sam9x5_peripheral_save_context,
429 	.restore_context = clk_sam9x5_peripheral_restore_context,
430 };
431 
432 static const struct clk_ops sam9x5_peripheral_chg_ops = {
433 	.enable = clk_sam9x5_peripheral_enable,
434 	.disable = clk_sam9x5_peripheral_disable,
435 	.is_enabled = clk_sam9x5_peripheral_is_enabled,
436 	.recalc_rate = clk_sam9x5_peripheral_recalc_rate,
437 	.determine_rate = clk_sam9x5_peripheral_determine_rate,
438 	.set_rate = clk_sam9x5_peripheral_set_rate,
439 	.save_context = clk_sam9x5_peripheral_save_context,
440 	.restore_context = clk_sam9x5_peripheral_restore_context,
441 };
442 
443 struct clk_hw * __init
444 at91_clk_register_sam9x5_peripheral(struct regmap *regmap, spinlock_t *lock,
445 				    const struct clk_pcr_layout *layout,
446 				    const char *name, const char *parent_name,
447 				    u32 id, const struct clk_range *range,
448 				    int chg_pid)
449 {
450 	struct clk_sam9x5_peripheral *periph;
451 	struct clk_init_data init;
452 	struct clk_hw *hw;
453 	int ret;
454 
455 	if (!name || !parent_name)
456 		return ERR_PTR(-EINVAL);
457 
458 	periph = kzalloc(sizeof(*periph), GFP_KERNEL);
459 	if (!periph)
460 		return ERR_PTR(-ENOMEM);
461 
462 	init.name = name;
463 	init.parent_names = &parent_name;
464 	init.num_parents = 1;
465 	if (chg_pid < 0) {
466 		init.flags = 0;
467 		init.ops = &sam9x5_peripheral_ops;
468 	} else {
469 		init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
470 			     CLK_SET_RATE_PARENT;
471 		init.ops = &sam9x5_peripheral_chg_ops;
472 	}
473 
474 	periph->id = id;
475 	periph->hw.init = &init;
476 	periph->div = 0;
477 	periph->regmap = regmap;
478 	periph->lock = lock;
479 	if (layout->div_mask)
480 		periph->auto_div = true;
481 	periph->layout = layout;
482 	periph->range = *range;
483 	periph->chg_pid = chg_pid;
484 
485 	hw = &periph->hw;
486 	ret = clk_hw_register(NULL, &periph->hw);
487 	if (ret) {
488 		kfree(periph);
489 		hw = ERR_PTR(ret);
490 	} else {
491 		clk_sam9x5_peripheral_autodiv(periph);
492 	}
493 
494 	return hw;
495 }
496