1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * CS2000 -- CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
4 *
5 * Copyright (C) 2015 Renesas Electronics Corporation
6 * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
7 */
8 #include <linux/clk-provider.h>
9 #include <linux/delay.h>
10 #include <linux/clk.h>
11 #include <linux/i2c.h>
12 #include <linux/of.h>
13 #include <linux/module.h>
14 #include <linux/regmap.h>
15
16 #define CH_MAX 4
17 #define RATIO_REG_SIZE 4
18
19 #define DEVICE_ID 0x1
20 #define DEVICE_CTRL 0x2
21 #define DEVICE_CFG1 0x3
22 #define DEVICE_CFG2 0x4
23 #define GLOBAL_CFG 0x5
24 #define Ratio_Add(x, nth) (6 + (x * 4) + (nth))
25 #define Ratio_Val(x, nth) ((x >> (24 - (8 * nth))) & 0xFF)
26 #define Val_Ratio(x, nth) ((x & 0xFF) << (24 - (8 * nth)))
27 #define FUNC_CFG1 0x16
28 #define FUNC_CFG2 0x17
29
30 /* DEVICE_ID */
31 #define REVISION_MASK (0x7)
32 #define REVISION_B2_B3 (0x4)
33 #define REVISION_C1 (0x6)
34
35 /* DEVICE_CTRL */
36 #define PLL_UNLOCK (1 << 7)
37 #define AUXOUTDIS (1 << 1)
38 #define CLKOUTDIS (1 << 0)
39
40 /* DEVICE_CFG1 */
41 #define RSEL(x) (((x) & 0x3) << 3)
42 #define RSEL_MASK RSEL(0x3)
43 #define AUXOUTSRC(x) (((x) & 0x3) << 1)
44 #define AUXOUTSRC_MASK AUXOUTSRC(0x3)
45 #define ENDEV1 (0x1)
46
47 /* DEVICE_CFG2 */
48 #define AUTORMOD (1 << 3)
49 #define LOCKCLK(x) (((x) & 0x3) << 1)
50 #define LOCKCLK_MASK LOCKCLK(0x3)
51 #define FRACNSRC_MASK (1 << 0)
52 #define FRACNSRC_STATIC (0 << 0)
53 #define FRACNSRC_DYNAMIC (1 << 0)
54
55 /* GLOBAL_CFG */
56 #define FREEZE (1 << 7)
57 #define ENDEV2 (0x1)
58
59 /* FUNC_CFG1 */
60 #define CLKSKIPEN (1 << 7)
61 #define REFCLKDIV(x) (((x) & 0x3) << 3)
62 #define REFCLKDIV_MASK REFCLKDIV(0x3)
63
64 /* FUNC_CFG2 */
65 #define LFRATIO_MASK (1 << 3)
66 #define LFRATIO_20_12 (0 << 3)
67 #define LFRATIO_12_20 (1 << 3)
68
69 #define CH_SIZE_ERR(ch) ((ch < 0) || (ch >= CH_MAX))
70 #define hw_to_priv(_hw) container_of(_hw, struct cs2000_priv, hw)
71 #define priv_to_client(priv) (priv->client)
72 #define priv_to_dev(priv) (&(priv_to_client(priv)->dev))
73
74 #define CLK_IN 0
75 #define REF_CLK 1
76 #define CLK_MAX 2
77
cs2000_readable_reg(struct device * dev,unsigned int reg)78 static bool cs2000_readable_reg(struct device *dev, unsigned int reg)
79 {
80 return reg > 0;
81 }
82
cs2000_writeable_reg(struct device * dev,unsigned int reg)83 static bool cs2000_writeable_reg(struct device *dev, unsigned int reg)
84 {
85 return reg != DEVICE_ID;
86 }
87
cs2000_volatile_reg(struct device * dev,unsigned int reg)88 static bool cs2000_volatile_reg(struct device *dev, unsigned int reg)
89 {
90 return reg == DEVICE_CTRL;
91 }
92
93 static const struct regmap_config cs2000_regmap_config = {
94 .reg_bits = 8,
95 .val_bits = 8,
96 .max_register = FUNC_CFG2,
97 .readable_reg = cs2000_readable_reg,
98 .writeable_reg = cs2000_writeable_reg,
99 .volatile_reg = cs2000_volatile_reg,
100 };
101
102 struct cs2000_priv {
103 struct clk_hw hw;
104 struct i2c_client *client;
105 struct clk *clk_in;
106 struct clk *ref_clk;
107 struct regmap *regmap;
108
109 bool dynamic_mode;
110 bool lf_ratio;
111 bool clk_skip;
112
113 /* suspend/resume */
114 unsigned long saved_rate;
115 unsigned long saved_parent_rate;
116 };
117
118 static const struct of_device_id cs2000_of_match[] = {
119 { .compatible = "cirrus,cs2000-cp", },
120 {},
121 };
122 MODULE_DEVICE_TABLE(of, cs2000_of_match);
123
124 static const struct i2c_device_id cs2000_id[] = {
125 { "cs2000-cp", },
126 {}
127 };
128 MODULE_DEVICE_TABLE(i2c, cs2000_id);
129
cs2000_enable_dev_config(struct cs2000_priv * priv,bool enable)130 static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
131 {
132 int ret;
133
134 ret = regmap_update_bits(priv->regmap, DEVICE_CFG1, ENDEV1,
135 enable ? ENDEV1 : 0);
136 if (ret < 0)
137 return ret;
138
139 ret = regmap_update_bits(priv->regmap, GLOBAL_CFG, ENDEV2,
140 enable ? ENDEV2 : 0);
141 if (ret < 0)
142 return ret;
143
144 ret = regmap_update_bits(priv->regmap, FUNC_CFG1, CLKSKIPEN,
145 (enable && priv->clk_skip) ? CLKSKIPEN : 0);
146 if (ret < 0)
147 return ret;
148
149 return 0;
150 }
151
cs2000_ref_clk_bound_rate(struct cs2000_priv * priv,u32 rate_in)152 static int cs2000_ref_clk_bound_rate(struct cs2000_priv *priv,
153 u32 rate_in)
154 {
155 u32 val;
156
157 if (rate_in >= 32000000 && rate_in < 56000000)
158 val = 0x0;
159 else if (rate_in >= 16000000 && rate_in < 28000000)
160 val = 0x1;
161 else if (rate_in >= 8000000 && rate_in < 14000000)
162 val = 0x2;
163 else
164 return -EINVAL;
165
166 return regmap_update_bits(priv->regmap, FUNC_CFG1,
167 REFCLKDIV_MASK,
168 REFCLKDIV(val));
169 }
170
cs2000_wait_pll_lock(struct cs2000_priv * priv)171 static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
172 {
173 struct device *dev = priv_to_dev(priv);
174 unsigned int i, val;
175 int ret;
176
177 for (i = 0; i < 256; i++) {
178 ret = regmap_read(priv->regmap, DEVICE_CTRL, &val);
179 if (ret < 0)
180 return ret;
181 if (!(val & PLL_UNLOCK))
182 return 0;
183 udelay(1);
184 }
185
186 dev_err(dev, "pll lock failed\n");
187
188 return -ETIMEDOUT;
189 }
190
cs2000_clk_out_enable(struct cs2000_priv * priv,bool enable)191 static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
192 {
193 /* enable both AUX_OUT, CLK_OUT */
194 return regmap_update_bits(priv->regmap, DEVICE_CTRL,
195 (AUXOUTDIS | CLKOUTDIS),
196 enable ? 0 :
197 (AUXOUTDIS | CLKOUTDIS));
198 }
199
cs2000_rate_to_ratio(u32 rate_in,u32 rate_out,bool lf_ratio)200 static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out, bool lf_ratio)
201 {
202 u64 ratio;
203 u32 multiplier = lf_ratio ? 12 : 20;
204
205 /*
206 * ratio = rate_out / rate_in * 2^multiplier
207 *
208 * To avoid over flow, rate_out is u64.
209 * The result should be u32.
210 */
211 ratio = (u64)rate_out << multiplier;
212 do_div(ratio, rate_in);
213
214 return ratio;
215 }
216
cs2000_ratio_to_rate(u32 ratio,u32 rate_in,bool lf_ratio)217 static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in, bool lf_ratio)
218 {
219 u64 rate_out;
220 u32 multiplier = lf_ratio ? 12 : 20;
221
222 /*
223 * ratio = rate_out / rate_in * 2^multiplier
224 *
225 * To avoid over flow, rate_out is u64.
226 * The result should be u32 or unsigned long.
227 */
228
229 rate_out = (u64)ratio * rate_in;
230 return rate_out >> multiplier;
231 }
232
cs2000_ratio_set(struct cs2000_priv * priv,int ch,u32 rate_in,u32 rate_out)233 static int cs2000_ratio_set(struct cs2000_priv *priv,
234 int ch, u32 rate_in, u32 rate_out)
235 {
236 u32 val;
237 unsigned int i;
238 int ret;
239
240 if (CH_SIZE_ERR(ch))
241 return -EINVAL;
242
243 val = cs2000_rate_to_ratio(rate_in, rate_out, priv->lf_ratio);
244 for (i = 0; i < RATIO_REG_SIZE; i++) {
245 ret = regmap_write(priv->regmap,
246 Ratio_Add(ch, i),
247 Ratio_Val(val, i));
248 if (ret < 0)
249 return ret;
250 }
251
252 return 0;
253 }
254
cs2000_ratio_get(struct cs2000_priv * priv,int ch)255 static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
256 {
257 unsigned int tmp, i;
258 u32 val;
259 int ret;
260
261 val = 0;
262 for (i = 0; i < RATIO_REG_SIZE; i++) {
263 ret = regmap_read(priv->regmap, Ratio_Add(ch, i), &tmp);
264 if (ret < 0)
265 return 0;
266
267 val |= Val_Ratio(tmp, i);
268 }
269
270 return val;
271 }
272
cs2000_ratio_select(struct cs2000_priv * priv,int ch)273 static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
274 {
275 int ret;
276 u8 fracnsrc;
277
278 if (CH_SIZE_ERR(ch))
279 return -EINVAL;
280
281 ret = regmap_update_bits(priv->regmap, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
282 if (ret < 0)
283 return ret;
284
285 fracnsrc = priv->dynamic_mode ? FRACNSRC_DYNAMIC : FRACNSRC_STATIC;
286
287 ret = regmap_update_bits(priv->regmap, DEVICE_CFG2,
288 AUTORMOD | LOCKCLK_MASK | FRACNSRC_MASK,
289 LOCKCLK(ch) | fracnsrc);
290 if (ret < 0)
291 return ret;
292
293 return 0;
294 }
295
cs2000_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)296 static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
297 unsigned long parent_rate)
298 {
299 struct cs2000_priv *priv = hw_to_priv(hw);
300 int ch = 0; /* it uses ch0 only at this point */
301 u32 ratio;
302
303 ratio = cs2000_ratio_get(priv, ch);
304
305 return cs2000_ratio_to_rate(ratio, parent_rate, priv->lf_ratio);
306 }
307
cs2000_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent_rate)308 static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
309 unsigned long *parent_rate)
310 {
311 struct cs2000_priv *priv = hw_to_priv(hw);
312 u32 ratio;
313
314 ratio = cs2000_rate_to_ratio(*parent_rate, rate, priv->lf_ratio);
315
316 return cs2000_ratio_to_rate(ratio, *parent_rate, priv->lf_ratio);
317 }
318
cs2000_select_ratio_mode(struct cs2000_priv * priv,unsigned long rate,unsigned long parent_rate)319 static int cs2000_select_ratio_mode(struct cs2000_priv *priv,
320 unsigned long rate,
321 unsigned long parent_rate)
322 {
323 /*
324 * From the datasheet:
325 *
326 * | It is recommended that the 12.20 High-Resolution format be
327 * | utilized whenever the desired ratio is less than 4096 since
328 * | the output frequency accuracy of the PLL is directly proportional
329 * | to the accuracy of the timing reference clock and the resolution
330 * | of the R_UD.
331 *
332 * This mode is only available in dynamic mode.
333 */
334 priv->lf_ratio = priv->dynamic_mode && ((rate / parent_rate) > 4096);
335
336 return regmap_update_bits(priv->regmap, FUNC_CFG2, LFRATIO_MASK,
337 priv->lf_ratio ? LFRATIO_20_12 : LFRATIO_12_20);
338 }
339
__cs2000_set_rate(struct cs2000_priv * priv,int ch,unsigned long rate,unsigned long parent_rate)340 static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
341 unsigned long rate, unsigned long parent_rate)
342
343 {
344 int ret;
345
346 ret = regmap_update_bits(priv->regmap, GLOBAL_CFG, FREEZE, FREEZE);
347 if (ret < 0)
348 return ret;
349
350 ret = cs2000_select_ratio_mode(priv, rate, parent_rate);
351 if (ret < 0)
352 return ret;
353
354 ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
355 if (ret < 0)
356 return ret;
357
358 ret = cs2000_ratio_select(priv, ch);
359 if (ret < 0)
360 return ret;
361
362 ret = regmap_update_bits(priv->regmap, GLOBAL_CFG, FREEZE, 0);
363 if (ret < 0)
364 return ret;
365
366 priv->saved_rate = rate;
367 priv->saved_parent_rate = parent_rate;
368
369 return 0;
370 }
371
cs2000_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)372 static int cs2000_set_rate(struct clk_hw *hw,
373 unsigned long rate, unsigned long parent_rate)
374 {
375 struct cs2000_priv *priv = hw_to_priv(hw);
376 int ch = 0; /* it uses ch0 only at this point */
377
378 return __cs2000_set_rate(priv, ch, rate, parent_rate);
379 }
380
cs2000_set_saved_rate(struct cs2000_priv * priv)381 static int cs2000_set_saved_rate(struct cs2000_priv *priv)
382 {
383 int ch = 0; /* it uses ch0 only at this point */
384
385 return __cs2000_set_rate(priv, ch,
386 priv->saved_rate,
387 priv->saved_parent_rate);
388 }
389
cs2000_enable(struct clk_hw * hw)390 static int cs2000_enable(struct clk_hw *hw)
391 {
392 struct cs2000_priv *priv = hw_to_priv(hw);
393 int ret;
394
395 ret = cs2000_enable_dev_config(priv, true);
396 if (ret < 0)
397 return ret;
398
399 ret = cs2000_clk_out_enable(priv, true);
400 if (ret < 0)
401 return ret;
402
403 ret = cs2000_wait_pll_lock(priv);
404 if (ret < 0)
405 return ret;
406
407 return ret;
408 }
409
cs2000_disable(struct clk_hw * hw)410 static void cs2000_disable(struct clk_hw *hw)
411 {
412 struct cs2000_priv *priv = hw_to_priv(hw);
413
414 cs2000_enable_dev_config(priv, false);
415
416 cs2000_clk_out_enable(priv, false);
417 }
418
cs2000_get_parent(struct clk_hw * hw)419 static u8 cs2000_get_parent(struct clk_hw *hw)
420 {
421 struct cs2000_priv *priv = hw_to_priv(hw);
422
423 /*
424 * In dynamic mode, output rates are derived from CLK_IN.
425 * In static mode, CLK_IN is ignored, so we return REF_CLK instead.
426 */
427 return priv->dynamic_mode ? CLK_IN : REF_CLK;
428 }
429
430 static const struct clk_ops cs2000_ops = {
431 .get_parent = cs2000_get_parent,
432 .recalc_rate = cs2000_recalc_rate,
433 .round_rate = cs2000_round_rate,
434 .set_rate = cs2000_set_rate,
435 .prepare = cs2000_enable,
436 .unprepare = cs2000_disable,
437 };
438
cs2000_clk_get(struct cs2000_priv * priv)439 static int cs2000_clk_get(struct cs2000_priv *priv)
440 {
441 struct device *dev = priv_to_dev(priv);
442 struct clk *clk_in, *ref_clk;
443
444 clk_in = devm_clk_get(dev, "clk_in");
445 /* not yet provided */
446 if (IS_ERR(clk_in))
447 return -EPROBE_DEFER;
448
449 ref_clk = devm_clk_get(dev, "ref_clk");
450 /* not yet provided */
451 if (IS_ERR(ref_clk))
452 return -EPROBE_DEFER;
453
454 priv->clk_in = clk_in;
455 priv->ref_clk = ref_clk;
456
457 return 0;
458 }
459
cs2000_clk_register(struct cs2000_priv * priv)460 static int cs2000_clk_register(struct cs2000_priv *priv)
461 {
462 struct device *dev = priv_to_dev(priv);
463 struct device_node *np = dev->of_node;
464 struct clk_init_data init;
465 const char *name = np->name;
466 static const char *parent_names[CLK_MAX];
467 u32 aux_out = 0;
468 int ref_clk_rate;
469 int ch = 0; /* it uses ch0 only at this point */
470 int ret;
471
472 of_property_read_string(np, "clock-output-names", &name);
473
474 priv->dynamic_mode = of_property_read_bool(np, "cirrus,dynamic-mode");
475 dev_info(dev, "operating in %s mode\n",
476 priv->dynamic_mode ? "dynamic" : "static");
477
478 of_property_read_u32(np, "cirrus,aux-output-source", &aux_out);
479 ret = regmap_update_bits(priv->regmap, DEVICE_CFG1,
480 AUXOUTSRC_MASK, AUXOUTSRC(aux_out));
481 if (ret < 0)
482 return ret;
483
484 priv->clk_skip = of_property_read_bool(np, "cirrus,clock-skip");
485
486 ref_clk_rate = clk_get_rate(priv->ref_clk);
487 ret = cs2000_ref_clk_bound_rate(priv, ref_clk_rate);
488 if (ret < 0)
489 return ret;
490
491 if (priv->dynamic_mode) {
492 /* Default to low-frequency mode to allow for large ratios */
493 priv->lf_ratio = true;
494 } else {
495 /*
496 * set default rate as 1/1.
497 * otherwise .set_rate which setup ratio
498 * is never called if user requests 1/1 rate
499 */
500 ret = __cs2000_set_rate(priv, ch, ref_clk_rate, ref_clk_rate);
501 if (ret < 0)
502 return ret;
503 }
504
505 parent_names[CLK_IN] = __clk_get_name(priv->clk_in);
506 parent_names[REF_CLK] = __clk_get_name(priv->ref_clk);
507
508 init.name = name;
509 init.ops = &cs2000_ops;
510 init.flags = CLK_SET_RATE_GATE;
511 init.parent_names = parent_names;
512 init.num_parents = ARRAY_SIZE(parent_names);
513
514 priv->hw.init = &init;
515
516 ret = clk_hw_register(dev, &priv->hw);
517 if (ret)
518 return ret;
519
520 ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
521 if (ret < 0) {
522 clk_hw_unregister(&priv->hw);
523 return ret;
524 }
525
526 return 0;
527 }
528
cs2000_version_print(struct cs2000_priv * priv)529 static int cs2000_version_print(struct cs2000_priv *priv)
530 {
531 struct device *dev = priv_to_dev(priv);
532 const char *revision;
533 unsigned int val;
534 int ret;
535
536 ret = regmap_read(priv->regmap, DEVICE_ID, &val);
537 if (ret < 0)
538 return ret;
539
540 /* CS2000 should be 0x0 */
541 if (val >> 3)
542 return -EIO;
543
544 switch (val & REVISION_MASK) {
545 case REVISION_B2_B3:
546 revision = "B2 / B3";
547 break;
548 case REVISION_C1:
549 revision = "C1";
550 break;
551 default:
552 return -EIO;
553 }
554
555 dev_info(dev, "revision - %s\n", revision);
556
557 return 0;
558 }
559
cs2000_remove(struct i2c_client * client)560 static void cs2000_remove(struct i2c_client *client)
561 {
562 struct cs2000_priv *priv = i2c_get_clientdata(client);
563 struct device *dev = priv_to_dev(priv);
564 struct device_node *np = dev->of_node;
565
566 of_clk_del_provider(np);
567
568 clk_hw_unregister(&priv->hw);
569 }
570
cs2000_probe(struct i2c_client * client)571 static int cs2000_probe(struct i2c_client *client)
572 {
573 struct cs2000_priv *priv;
574 struct device *dev = &client->dev;
575 int ret;
576
577 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
578 if (!priv)
579 return -ENOMEM;
580
581 priv->client = client;
582 i2c_set_clientdata(client, priv);
583
584 priv->regmap = devm_regmap_init_i2c(client, &cs2000_regmap_config);
585 if (IS_ERR(priv->regmap))
586 return PTR_ERR(priv->regmap);
587
588 ret = cs2000_clk_get(priv);
589 if (ret < 0)
590 return ret;
591
592 ret = cs2000_clk_register(priv);
593 if (ret < 0)
594 return ret;
595
596 ret = cs2000_version_print(priv);
597 if (ret < 0)
598 goto probe_err;
599
600 return 0;
601
602 probe_err:
603 cs2000_remove(client);
604
605 return ret;
606 }
607
cs2000_resume(struct device * dev)608 static int __maybe_unused cs2000_resume(struct device *dev)
609 {
610 struct cs2000_priv *priv = dev_get_drvdata(dev);
611
612 return cs2000_set_saved_rate(priv);
613 }
614
615 static const struct dev_pm_ops cs2000_pm_ops = {
616 SET_LATE_SYSTEM_SLEEP_PM_OPS(NULL, cs2000_resume)
617 };
618
619 static struct i2c_driver cs2000_driver = {
620 .driver = {
621 .name = "cs2000-cp",
622 .pm = &cs2000_pm_ops,
623 .of_match_table = cs2000_of_match,
624 },
625 .probe = cs2000_probe,
626 .remove = cs2000_remove,
627 .id_table = cs2000_id,
628 };
629
630 module_i2c_driver(cs2000_driver);
631
632 MODULE_DESCRIPTION("CS2000-CP driver");
633 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
634 MODULE_LICENSE("GPL v2");
635