xref: /openbmc/linux/drivers/clk/pistachio/clk-pll.c (revision e7bae9bb)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2014 Google, Inc.
4  */
5 
6 #define pr_fmt(fmt) "%s: " fmt, __func__
7 
8 #include <linux/clk-provider.h>
9 #include <linux/io.h>
10 #include <linux/kernel.h>
11 #include <linux/printk.h>
12 #include <linux/slab.h>
13 
14 #include "clk.h"
15 
16 #define PLL_STATUS			0x0
17 #define PLL_STATUS_LOCK			BIT(0)
18 
19 #define PLL_CTRL1			0x4
20 #define PLL_CTRL1_REFDIV_SHIFT		0
21 #define PLL_CTRL1_REFDIV_MASK		0x3f
22 #define PLL_CTRL1_FBDIV_SHIFT		6
23 #define PLL_CTRL1_FBDIV_MASK		0xfff
24 #define PLL_INT_CTRL1_POSTDIV1_SHIFT	18
25 #define PLL_INT_CTRL1_POSTDIV1_MASK	0x7
26 #define PLL_INT_CTRL1_POSTDIV2_SHIFT	21
27 #define PLL_INT_CTRL1_POSTDIV2_MASK	0x7
28 #define PLL_INT_CTRL1_PD		BIT(24)
29 #define PLL_INT_CTRL1_DSMPD		BIT(25)
30 #define PLL_INT_CTRL1_FOUTPOSTDIVPD	BIT(26)
31 #define PLL_INT_CTRL1_FOUTVCOPD		BIT(27)
32 
33 #define PLL_CTRL2			0x8
34 #define PLL_FRAC_CTRL2_FRAC_SHIFT	0
35 #define PLL_FRAC_CTRL2_FRAC_MASK	0xffffff
36 #define PLL_FRAC_CTRL2_POSTDIV1_SHIFT	24
37 #define PLL_FRAC_CTRL2_POSTDIV1_MASK	0x7
38 #define PLL_FRAC_CTRL2_POSTDIV2_SHIFT	27
39 #define PLL_FRAC_CTRL2_POSTDIV2_MASK	0x7
40 #define PLL_INT_CTRL2_BYPASS		BIT(28)
41 
42 #define PLL_CTRL3			0xc
43 #define PLL_FRAC_CTRL3_PD		BIT(0)
44 #define PLL_FRAC_CTRL3_DACPD		BIT(1)
45 #define PLL_FRAC_CTRL3_DSMPD		BIT(2)
46 #define PLL_FRAC_CTRL3_FOUTPOSTDIVPD	BIT(3)
47 #define PLL_FRAC_CTRL3_FOUT4PHASEPD	BIT(4)
48 #define PLL_FRAC_CTRL3_FOUTVCOPD	BIT(5)
49 
50 #define PLL_CTRL4			0x10
51 #define PLL_FRAC_CTRL4_BYPASS		BIT(28)
52 
53 #define MIN_PFD				9600000UL
54 #define MIN_VCO_LA			400000000UL
55 #define MAX_VCO_LA			1600000000UL
56 #define MIN_VCO_FRAC_INT		600000000UL
57 #define MAX_VCO_FRAC_INT		1600000000UL
58 #define MIN_VCO_FRAC_FRAC		600000000UL
59 #define MAX_VCO_FRAC_FRAC		2400000000UL
60 #define MIN_OUTPUT_LA			8000000UL
61 #define MAX_OUTPUT_LA			1600000000UL
62 #define MIN_OUTPUT_FRAC			12000000UL
63 #define MAX_OUTPUT_FRAC			1600000000UL
64 
65 /* Fractional PLL operating modes */
66 enum pll_mode {
67 	PLL_MODE_FRAC,
68 	PLL_MODE_INT,
69 };
70 
71 struct pistachio_clk_pll {
72 	struct clk_hw hw;
73 	void __iomem *base;
74 	struct pistachio_pll_rate_table *rates;
75 	unsigned int nr_rates;
76 };
77 
78 static inline u32 pll_readl(struct pistachio_clk_pll *pll, u32 reg)
79 {
80 	return readl(pll->base + reg);
81 }
82 
83 static inline void pll_writel(struct pistachio_clk_pll *pll, u32 val, u32 reg)
84 {
85 	writel(val, pll->base + reg);
86 }
87 
88 static inline void pll_lock(struct pistachio_clk_pll *pll)
89 {
90 	while (!(pll_readl(pll, PLL_STATUS) & PLL_STATUS_LOCK))
91 		cpu_relax();
92 }
93 
94 static inline u64 do_div_round_closest(u64 dividend, u64 divisor)
95 {
96 	dividend += divisor / 2;
97 	return div64_u64(dividend, divisor);
98 }
99 
100 static inline struct pistachio_clk_pll *to_pistachio_pll(struct clk_hw *hw)
101 {
102 	return container_of(hw, struct pistachio_clk_pll, hw);
103 }
104 
105 static inline enum pll_mode pll_frac_get_mode(struct clk_hw *hw)
106 {
107 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
108 	u32 val;
109 
110 	val = pll_readl(pll, PLL_CTRL3) & PLL_FRAC_CTRL3_DSMPD;
111 	return val ? PLL_MODE_INT : PLL_MODE_FRAC;
112 }
113 
114 static inline void pll_frac_set_mode(struct clk_hw *hw, enum pll_mode mode)
115 {
116 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
117 	u32 val;
118 
119 	val = pll_readl(pll, PLL_CTRL3);
120 	if (mode == PLL_MODE_INT)
121 		val |= PLL_FRAC_CTRL3_DSMPD | PLL_FRAC_CTRL3_DACPD;
122 	else
123 		val &= ~(PLL_FRAC_CTRL3_DSMPD | PLL_FRAC_CTRL3_DACPD);
124 
125 	pll_writel(pll, val, PLL_CTRL3);
126 }
127 
128 static struct pistachio_pll_rate_table *
129 pll_get_params(struct pistachio_clk_pll *pll, unsigned long fref,
130 	       unsigned long fout)
131 {
132 	unsigned int i;
133 
134 	for (i = 0; i < pll->nr_rates; i++) {
135 		if (pll->rates[i].fref == fref && pll->rates[i].fout == fout)
136 			return &pll->rates[i];
137 	}
138 
139 	return NULL;
140 }
141 
142 static long pll_round_rate(struct clk_hw *hw, unsigned long rate,
143 			   unsigned long *parent_rate)
144 {
145 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
146 	unsigned int i;
147 
148 	for (i = 0; i < pll->nr_rates; i++) {
149 		if (i > 0 && pll->rates[i].fref == *parent_rate &&
150 		    pll->rates[i].fout <= rate)
151 			return pll->rates[i - 1].fout;
152 	}
153 
154 	return pll->rates[0].fout;
155 }
156 
157 static int pll_gf40lp_frac_enable(struct clk_hw *hw)
158 {
159 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
160 	u32 val;
161 
162 	val = pll_readl(pll, PLL_CTRL3);
163 	val &= ~(PLL_FRAC_CTRL3_PD | PLL_FRAC_CTRL3_FOUTPOSTDIVPD |
164 		 PLL_FRAC_CTRL3_FOUT4PHASEPD | PLL_FRAC_CTRL3_FOUTVCOPD);
165 	pll_writel(pll, val, PLL_CTRL3);
166 
167 	val = pll_readl(pll, PLL_CTRL4);
168 	val &= ~PLL_FRAC_CTRL4_BYPASS;
169 	pll_writel(pll, val, PLL_CTRL4);
170 
171 	pll_lock(pll);
172 
173 	return 0;
174 }
175 
176 static void pll_gf40lp_frac_disable(struct clk_hw *hw)
177 {
178 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
179 	u32 val;
180 
181 	val = pll_readl(pll, PLL_CTRL3);
182 	val |= PLL_FRAC_CTRL3_PD;
183 	pll_writel(pll, val, PLL_CTRL3);
184 }
185 
186 static int pll_gf40lp_frac_is_enabled(struct clk_hw *hw)
187 {
188 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
189 
190 	return !(pll_readl(pll, PLL_CTRL3) & PLL_FRAC_CTRL3_PD);
191 }
192 
193 static int pll_gf40lp_frac_set_rate(struct clk_hw *hw, unsigned long rate,
194 				    unsigned long parent_rate)
195 {
196 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
197 	struct pistachio_pll_rate_table *params;
198 	int enabled = pll_gf40lp_frac_is_enabled(hw);
199 	u64 val, vco, old_postdiv1, old_postdiv2;
200 	const char *name = clk_hw_get_name(hw);
201 
202 	if (rate < MIN_OUTPUT_FRAC || rate > MAX_OUTPUT_FRAC)
203 		return -EINVAL;
204 
205 	params = pll_get_params(pll, parent_rate, rate);
206 	if (!params || !params->refdiv)
207 		return -EINVAL;
208 
209 	/* calculate vco */
210 	vco = params->fref;
211 	vco *= (params->fbdiv << 24) + params->frac;
212 	vco = div64_u64(vco, params->refdiv << 24);
213 
214 	if (vco < MIN_VCO_FRAC_FRAC || vco > MAX_VCO_FRAC_FRAC)
215 		pr_warn("%s: VCO %llu is out of range %lu..%lu\n", name, vco,
216 			MIN_VCO_FRAC_FRAC, MAX_VCO_FRAC_FRAC);
217 
218 	val = div64_u64(params->fref, params->refdiv);
219 	if (val < MIN_PFD)
220 		pr_warn("%s: PFD %llu is too low (min %lu)\n",
221 			name, val, MIN_PFD);
222 	if (val > vco / 16)
223 		pr_warn("%s: PFD %llu is too high (max %llu)\n",
224 			name, val, vco / 16);
225 
226 	val = pll_readl(pll, PLL_CTRL1);
227 	val &= ~((PLL_CTRL1_REFDIV_MASK << PLL_CTRL1_REFDIV_SHIFT) |
228 		 (PLL_CTRL1_FBDIV_MASK << PLL_CTRL1_FBDIV_SHIFT));
229 	val |= (params->refdiv << PLL_CTRL1_REFDIV_SHIFT) |
230 		(params->fbdiv << PLL_CTRL1_FBDIV_SHIFT);
231 	pll_writel(pll, val, PLL_CTRL1);
232 
233 	val = pll_readl(pll, PLL_CTRL2);
234 
235 	old_postdiv1 = (val >> PLL_FRAC_CTRL2_POSTDIV1_SHIFT) &
236 		       PLL_FRAC_CTRL2_POSTDIV1_MASK;
237 	old_postdiv2 = (val >> PLL_FRAC_CTRL2_POSTDIV2_SHIFT) &
238 		       PLL_FRAC_CTRL2_POSTDIV2_MASK;
239 	if (enabled &&
240 	    (params->postdiv1 != old_postdiv1 ||
241 	     params->postdiv2 != old_postdiv2))
242 		pr_warn("%s: changing postdiv while PLL is enabled\n", name);
243 
244 	if (params->postdiv2 > params->postdiv1)
245 		pr_warn("%s: postdiv2 should not exceed postdiv1\n", name);
246 
247 	val &= ~((PLL_FRAC_CTRL2_FRAC_MASK << PLL_FRAC_CTRL2_FRAC_SHIFT) |
248 		 (PLL_FRAC_CTRL2_POSTDIV1_MASK <<
249 		  PLL_FRAC_CTRL2_POSTDIV1_SHIFT) |
250 		 (PLL_FRAC_CTRL2_POSTDIV2_MASK <<
251 		  PLL_FRAC_CTRL2_POSTDIV2_SHIFT));
252 	val |= (params->frac << PLL_FRAC_CTRL2_FRAC_SHIFT) |
253 		(params->postdiv1 << PLL_FRAC_CTRL2_POSTDIV1_SHIFT) |
254 		(params->postdiv2 << PLL_FRAC_CTRL2_POSTDIV2_SHIFT);
255 	pll_writel(pll, val, PLL_CTRL2);
256 
257 	/* set operating mode */
258 	if (params->frac)
259 		pll_frac_set_mode(hw, PLL_MODE_FRAC);
260 	else
261 		pll_frac_set_mode(hw, PLL_MODE_INT);
262 
263 	if (enabled)
264 		pll_lock(pll);
265 
266 	return 0;
267 }
268 
269 static unsigned long pll_gf40lp_frac_recalc_rate(struct clk_hw *hw,
270 						 unsigned long parent_rate)
271 {
272 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
273 	u64 val, prediv, fbdiv, frac, postdiv1, postdiv2, rate;
274 
275 	val = pll_readl(pll, PLL_CTRL1);
276 	prediv = (val >> PLL_CTRL1_REFDIV_SHIFT) & PLL_CTRL1_REFDIV_MASK;
277 	fbdiv = (val >> PLL_CTRL1_FBDIV_SHIFT) & PLL_CTRL1_FBDIV_MASK;
278 
279 	val = pll_readl(pll, PLL_CTRL2);
280 	postdiv1 = (val >> PLL_FRAC_CTRL2_POSTDIV1_SHIFT) &
281 		PLL_FRAC_CTRL2_POSTDIV1_MASK;
282 	postdiv2 = (val >> PLL_FRAC_CTRL2_POSTDIV2_SHIFT) &
283 		PLL_FRAC_CTRL2_POSTDIV2_MASK;
284 	frac = (val >> PLL_FRAC_CTRL2_FRAC_SHIFT) & PLL_FRAC_CTRL2_FRAC_MASK;
285 
286 	/* get operating mode (int/frac) and calculate rate accordingly */
287 	rate = parent_rate;
288 	if (pll_frac_get_mode(hw) == PLL_MODE_FRAC)
289 		rate *= (fbdiv << 24) + frac;
290 	else
291 		rate *= (fbdiv << 24);
292 
293 	rate = do_div_round_closest(rate, (prediv * postdiv1 * postdiv2) << 24);
294 
295 	return rate;
296 }
297 
298 static const struct clk_ops pll_gf40lp_frac_ops = {
299 	.enable = pll_gf40lp_frac_enable,
300 	.disable = pll_gf40lp_frac_disable,
301 	.is_enabled = pll_gf40lp_frac_is_enabled,
302 	.recalc_rate = pll_gf40lp_frac_recalc_rate,
303 	.round_rate = pll_round_rate,
304 	.set_rate = pll_gf40lp_frac_set_rate,
305 };
306 
307 static const struct clk_ops pll_gf40lp_frac_fixed_ops = {
308 	.enable = pll_gf40lp_frac_enable,
309 	.disable = pll_gf40lp_frac_disable,
310 	.is_enabled = pll_gf40lp_frac_is_enabled,
311 	.recalc_rate = pll_gf40lp_frac_recalc_rate,
312 };
313 
314 static int pll_gf40lp_laint_enable(struct clk_hw *hw)
315 {
316 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
317 	u32 val;
318 
319 	val = pll_readl(pll, PLL_CTRL1);
320 	val &= ~(PLL_INT_CTRL1_PD |
321 		 PLL_INT_CTRL1_FOUTPOSTDIVPD | PLL_INT_CTRL1_FOUTVCOPD);
322 	pll_writel(pll, val, PLL_CTRL1);
323 
324 	val = pll_readl(pll, PLL_CTRL2);
325 	val &= ~PLL_INT_CTRL2_BYPASS;
326 	pll_writel(pll, val, PLL_CTRL2);
327 
328 	pll_lock(pll);
329 
330 	return 0;
331 }
332 
333 static void pll_gf40lp_laint_disable(struct clk_hw *hw)
334 {
335 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
336 	u32 val;
337 
338 	val = pll_readl(pll, PLL_CTRL1);
339 	val |= PLL_INT_CTRL1_PD;
340 	pll_writel(pll, val, PLL_CTRL1);
341 }
342 
343 static int pll_gf40lp_laint_is_enabled(struct clk_hw *hw)
344 {
345 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
346 
347 	return !(pll_readl(pll, PLL_CTRL1) & PLL_INT_CTRL1_PD);
348 }
349 
350 static int pll_gf40lp_laint_set_rate(struct clk_hw *hw, unsigned long rate,
351 				     unsigned long parent_rate)
352 {
353 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
354 	struct pistachio_pll_rate_table *params;
355 	int enabled = pll_gf40lp_laint_is_enabled(hw);
356 	u32 val, vco, old_postdiv1, old_postdiv2;
357 	const char *name = clk_hw_get_name(hw);
358 
359 	if (rate < MIN_OUTPUT_LA || rate > MAX_OUTPUT_LA)
360 		return -EINVAL;
361 
362 	params = pll_get_params(pll, parent_rate, rate);
363 	if (!params || !params->refdiv)
364 		return -EINVAL;
365 
366 	vco = div_u64(params->fref * params->fbdiv, params->refdiv);
367 	if (vco < MIN_VCO_LA || vco > MAX_VCO_LA)
368 		pr_warn("%s: VCO %u is out of range %lu..%lu\n", name, vco,
369 			MIN_VCO_LA, MAX_VCO_LA);
370 
371 	val = div_u64(params->fref, params->refdiv);
372 	if (val < MIN_PFD)
373 		pr_warn("%s: PFD %u is too low (min %lu)\n",
374 			name, val, MIN_PFD);
375 	if (val > vco / 16)
376 		pr_warn("%s: PFD %u is too high (max %u)\n",
377 			name, val, vco / 16);
378 
379 	val = pll_readl(pll, PLL_CTRL1);
380 
381 	old_postdiv1 = (val >> PLL_INT_CTRL1_POSTDIV1_SHIFT) &
382 		       PLL_INT_CTRL1_POSTDIV1_MASK;
383 	old_postdiv2 = (val >> PLL_INT_CTRL1_POSTDIV2_SHIFT) &
384 		       PLL_INT_CTRL1_POSTDIV2_MASK;
385 	if (enabled &&
386 	    (params->postdiv1 != old_postdiv1 ||
387 	     params->postdiv2 != old_postdiv2))
388 		pr_warn("%s: changing postdiv while PLL is enabled\n", name);
389 
390 	if (params->postdiv2 > params->postdiv1)
391 		pr_warn("%s: postdiv2 should not exceed postdiv1\n", name);
392 
393 	val &= ~((PLL_CTRL1_REFDIV_MASK << PLL_CTRL1_REFDIV_SHIFT) |
394 		 (PLL_CTRL1_FBDIV_MASK << PLL_CTRL1_FBDIV_SHIFT) |
395 		 (PLL_INT_CTRL1_POSTDIV1_MASK << PLL_INT_CTRL1_POSTDIV1_SHIFT) |
396 		 (PLL_INT_CTRL1_POSTDIV2_MASK << PLL_INT_CTRL1_POSTDIV2_SHIFT));
397 	val |= (params->refdiv << PLL_CTRL1_REFDIV_SHIFT) |
398 		(params->fbdiv << PLL_CTRL1_FBDIV_SHIFT) |
399 		(params->postdiv1 << PLL_INT_CTRL1_POSTDIV1_SHIFT) |
400 		(params->postdiv2 << PLL_INT_CTRL1_POSTDIV2_SHIFT);
401 	pll_writel(pll, val, PLL_CTRL1);
402 
403 	if (enabled)
404 		pll_lock(pll);
405 
406 	return 0;
407 }
408 
409 static unsigned long pll_gf40lp_laint_recalc_rate(struct clk_hw *hw,
410 						  unsigned long parent_rate)
411 {
412 	struct pistachio_clk_pll *pll = to_pistachio_pll(hw);
413 	u32 val, prediv, fbdiv, postdiv1, postdiv2;
414 	u64 rate = parent_rate;
415 
416 	val = pll_readl(pll, PLL_CTRL1);
417 	prediv = (val >> PLL_CTRL1_REFDIV_SHIFT) & PLL_CTRL1_REFDIV_MASK;
418 	fbdiv = (val >> PLL_CTRL1_FBDIV_SHIFT) & PLL_CTRL1_FBDIV_MASK;
419 	postdiv1 = (val >> PLL_INT_CTRL1_POSTDIV1_SHIFT) &
420 		PLL_INT_CTRL1_POSTDIV1_MASK;
421 	postdiv2 = (val >> PLL_INT_CTRL1_POSTDIV2_SHIFT) &
422 		PLL_INT_CTRL1_POSTDIV2_MASK;
423 
424 	rate *= fbdiv;
425 	rate = do_div_round_closest(rate, prediv * postdiv1 * postdiv2);
426 
427 	return rate;
428 }
429 
430 static const struct clk_ops pll_gf40lp_laint_ops = {
431 	.enable = pll_gf40lp_laint_enable,
432 	.disable = pll_gf40lp_laint_disable,
433 	.is_enabled = pll_gf40lp_laint_is_enabled,
434 	.recalc_rate = pll_gf40lp_laint_recalc_rate,
435 	.round_rate = pll_round_rate,
436 	.set_rate = pll_gf40lp_laint_set_rate,
437 };
438 
439 static const struct clk_ops pll_gf40lp_laint_fixed_ops = {
440 	.enable = pll_gf40lp_laint_enable,
441 	.disable = pll_gf40lp_laint_disable,
442 	.is_enabled = pll_gf40lp_laint_is_enabled,
443 	.recalc_rate = pll_gf40lp_laint_recalc_rate,
444 };
445 
446 static struct clk *pll_register(const char *name, const char *parent_name,
447 				unsigned long flags, void __iomem *base,
448 				enum pistachio_pll_type type,
449 				struct pistachio_pll_rate_table *rates,
450 				unsigned int nr_rates)
451 {
452 	struct pistachio_clk_pll *pll;
453 	struct clk_init_data init;
454 	struct clk *clk;
455 
456 	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
457 	if (!pll)
458 		return ERR_PTR(-ENOMEM);
459 
460 	init.name = name;
461 	init.flags = flags | CLK_GET_RATE_NOCACHE;
462 	init.parent_names = &parent_name;
463 	init.num_parents = 1;
464 
465 	switch (type) {
466 	case PLL_GF40LP_FRAC:
467 		if (rates)
468 			init.ops = &pll_gf40lp_frac_ops;
469 		else
470 			init.ops = &pll_gf40lp_frac_fixed_ops;
471 		break;
472 	case PLL_GF40LP_LAINT:
473 		if (rates)
474 			init.ops = &pll_gf40lp_laint_ops;
475 		else
476 			init.ops = &pll_gf40lp_laint_fixed_ops;
477 		break;
478 	default:
479 		pr_err("Unrecognized PLL type %u\n", type);
480 		kfree(pll);
481 		return ERR_PTR(-EINVAL);
482 	}
483 
484 	pll->hw.init = &init;
485 	pll->base = base;
486 	pll->rates = rates;
487 	pll->nr_rates = nr_rates;
488 
489 	clk = clk_register(NULL, &pll->hw);
490 	if (IS_ERR(clk))
491 		kfree(pll);
492 
493 	return clk;
494 }
495 
496 void pistachio_clk_register_pll(struct pistachio_clk_provider *p,
497 				struct pistachio_pll *pll,
498 				unsigned int num)
499 {
500 	struct clk *clk;
501 	unsigned int i;
502 
503 	for (i = 0; i < num; i++) {
504 		clk = pll_register(pll[i].name, pll[i].parent,
505 				   0, p->base + pll[i].reg_base,
506 				   pll[i].type, pll[i].rates,
507 				   pll[i].nr_rates);
508 		p->clk_data.clks[pll[i].id] = clk;
509 	}
510 }
511