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_device.h>
13#include <linux/module.h>
14
15#define CH_MAX 4
16#define RATIO_REG_SIZE 4
17
18#define DEVICE_ID 0x1
19#define DEVICE_CTRL 0x2
20#define DEVICE_CFG1 0x3
21#define DEVICE_CFG2 0x4
22#define GLOBAL_CFG 0x5
23#define Ratio_Add(x, nth) (6 + (x * 4) + (nth))
24#define Ratio_Val(x, nth) ((x >> (24 - (8 * nth))) & 0xFF)
25#define Val_Ratio(x, nth) ((x & 0xFF) << (24 - (8 * nth)))
26#define FUNC_CFG1 0x16
27#define FUNC_CFG2 0x17
28
29/* DEVICE_ID */
30#define REVISION_MASK (0x7)
31#define REVISION_B2_B3 (0x4)
32#define REVISION_C1 (0x6)
33
34/* DEVICE_CTRL */
35#define PLL_UNLOCK (1 << 7)
36#define AUXOUTDIS (1 << 1)
37#define CLKOUTDIS (1 << 0)
38
39/* DEVICE_CFG1 */
40#define RSEL(x) (((x) & 0x3) << 3)
41#define RSEL_MASK RSEL(0x3)
42#define ENDEV1 (0x1)
43
44/* DEVICE_CFG2 */
45#define AUTORMOD (1 << 3)
46#define LOCKCLK(x) (((x) & 0x3) << 1)
47#define LOCKCLK_MASK LOCKCLK(0x3)
48#define FRACNSRC_MASK (1 << 0)
49#define FRACNSRC_STATIC (0 << 0)
50#define FRACNSRC_DYNAMIC (1 << 1)
51
52/* GLOBAL_CFG */
53#define ENDEV2 (0x1)
54
55/* FUNC_CFG1 */
56#define CLKSKIPEN (1 << 7)
57#define REFCLKDIV(x) (((x) & 0x3) << 3)
58#define REFCLKDIV_MASK REFCLKDIV(0x3)
59
60/* FUNC_CFG2 */
61#define LFRATIO_MASK (1 << 3)
62#define LFRATIO_20_12 (0 << 3)
63#define LFRATIO_12_20 (1 << 3)
64
65#define CH_SIZE_ERR(ch) ((ch < 0) || (ch >= CH_MAX))
66#define hw_to_priv(_hw) container_of(_hw, struct cs2000_priv, hw)
67#define priv_to_client(priv) (priv->client)
68#define priv_to_dev(priv) (&(priv_to_client(priv)->dev))
69
70#define CLK_IN 0
71#define REF_CLK 1
72#define CLK_MAX 2
73
74struct cs2000_priv {
75 struct clk_hw hw;
76 struct i2c_client *client;
77 struct clk *clk_in;
78 struct clk *ref_clk;
79
80 /* suspend/resume */
81 unsigned long saved_rate;
82 unsigned long saved_parent_rate;
83};
84
85static const struct of_device_id cs2000_of_match[] = {
86 { .compatible = "cirrus,cs2000-cp", },
87 {},
88};
89MODULE_DEVICE_TABLE(of, cs2000_of_match);
90
91static const struct i2c_device_id cs2000_id[] = {
92 { "cs2000-cp", },
93 {}
94};
95MODULE_DEVICE_TABLE(i2c, cs2000_id);
96
97#define cs2000_read(priv, addr) \
98 i2c_smbus_read_byte_data(priv_to_client(priv), addr)
99#define cs2000_write(priv, addr, val) \
100 i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)
101
102static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
103{
104 s32 data;
105
106 data = cs2000_read(priv, addr);
107 if (data < 0)
108 return data;
109
110 data &= ~mask;
111 data |= (val & mask);
112
113 return cs2000_write(priv, addr, data);
114}
115
116static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
117{
118 int ret;
119
120 ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1,
121 enable ? ENDEV1 : 0);
122 if (ret < 0)
123 return ret;
124
125 ret = cs2000_bset(priv, GLOBAL_CFG, ENDEV2,
126 enable ? ENDEV2 : 0);
127 if (ret < 0)
128 return ret;
129
130 ret = cs2000_bset(priv, FUNC_CFG1, CLKSKIPEN,
131 enable ? CLKSKIPEN : 0);
132 if (ret < 0)
133 return ret;
134
135 /* FIXME: for Static ratio mode */
136 ret = cs2000_bset(priv, FUNC_CFG2, LFRATIO_MASK,
137 LFRATIO_12_20);
138 if (ret < 0)
139 return ret;
140
141 return 0;
142}
143
144static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
145 u32 rate_in)
146{
147 u32 val;
148
149 if (rate_in >= 32000000 && rate_in < 56000000)
150 val = 0x0;
151 else if (rate_in >= 16000000 && rate_in < 28000000)
152 val = 0x1;
153 else if (rate_in >= 8000000 && rate_in < 14000000)
154 val = 0x2;
155 else
156 return -EINVAL;
157
158 return cs2000_bset(priv, FUNC_CFG1,
159 REFCLKDIV_MASK,
160 REFCLKDIV(val));
161}
162
163static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
164{
165 struct device *dev = priv_to_dev(priv);
166 s32 val;
167 unsigned int i;
168
169 for (i = 0; i < 256; i++) {
170 val = cs2000_read(priv, DEVICE_CTRL);
171 if (val < 0)
172 return val;
173 if (!(val & PLL_UNLOCK))
174 return 0;
175 udelay(1);
176 }
177
178 dev_err(dev, "pll lock failed\n");
179
180 return -ETIMEDOUT;
181}
182
183static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
184{
185 /* enable both AUX_OUT, CLK_OUT */
186 return cs2000_bset(priv, DEVICE_CTRL,
187 (AUXOUTDIS | CLKOUTDIS),
188 enable ? 0 :
189 (AUXOUTDIS | CLKOUTDIS));
190}
191
192static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
193{
194 u64 ratio;
195
196 /*
197 * ratio = rate_out / rate_in * 2^20
198 *
199 * To avoid over flow, rate_out is u64.
200 * The result should be u32.
201 */
202 ratio = (u64)rate_out << 20;
203 do_div(ratio, rate_in);
204
205 return ratio;
206}
207
208static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
209{
210 u64 rate_out;
211
212 /*
213 * ratio = rate_out / rate_in * 2^20
214 *
215 * To avoid over flow, rate_out is u64.
216 * The result should be u32 or unsigned long.
217 */
218
219 rate_out = (u64)ratio * rate_in;
220 return rate_out >> 20;
221}
222
223static int cs2000_ratio_set(struct cs2000_priv *priv,
224 int ch, u32 rate_in, u32 rate_out)
225{
226 u32 val;
227 unsigned int i;
228 int ret;
229
230 if (CH_SIZE_ERR(ch))
231 return -EINVAL;
232
233 val = cs2000_rate_to_ratio(rate_in, rate_out);
234 for (i = 0; i < RATIO_REG_SIZE; i++) {
235 ret = cs2000_write(priv,
236 Ratio_Add(ch, i),
237 Ratio_Val(val, i));
238 if (ret < 0)
239 return ret;
240 }
241
242 return 0;
243}
244
245static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
246{
247 s32 tmp;
248 u32 val;
249 unsigned int i;
250
251 val = 0;
252 for (i = 0; i < RATIO_REG_SIZE; i++) {
253 tmp = cs2000_read(priv, Ratio_Add(ch, i));
254 if (tmp < 0)
255 return 0;
256
257 val |= Val_Ratio(tmp, i);
258 }
259
260 return val;
261}
262
263static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
264{
265 int ret;
266
267 if (CH_SIZE_ERR(ch))
268 return -EINVAL;
269
270 /*
271 * FIXME
272 *
273 * this driver supports static ratio mode only at this point.
274 */
275 ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
276 if (ret < 0)
277 return ret;
278
279 ret = cs2000_bset(priv, DEVICE_CFG2,
280 (AUTORMOD | LOCKCLK_MASK | FRACNSRC_MASK),
281 (LOCKCLK(ch) | FRACNSRC_STATIC));
282 if (ret < 0)
283 return ret;
284
285 return 0;
286}
287
288static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
289 unsigned long parent_rate)
290{
291 struct cs2000_priv *priv = hw_to_priv(hw);
292 int ch = 0; /* it uses ch0 only at this point */
293 u32 ratio;
294
295 ratio = cs2000_ratio_get(priv, ch);
296
297 return cs2000_ratio_to_rate(ratio, parent_rate);
298}
299
300static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
301 unsigned long *parent_rate)
302{
303 u32 ratio;
304
305 ratio = cs2000_rate_to_ratio(*parent_rate, rate);
306
307 return cs2000_ratio_to_rate(ratio, *parent_rate);
308}
309
310static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
311 unsigned long rate, unsigned long parent_rate)
312
313{
314 int ret;
315
316 ret = cs2000_clk_in_bound_rate(priv, parent_rate);
317 if (ret < 0)
318 return ret;
319
320 ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
321 if (ret < 0)
322 return ret;
323
324 ret = cs2000_ratio_select(priv, ch);
325 if (ret < 0)
326 return ret;
327
328 priv->saved_rate = rate;
329 priv->saved_parent_rate = parent_rate;
330
331 return 0;
332}
333
334static int cs2000_set_rate(struct clk_hw *hw,
335 unsigned long rate, unsigned long parent_rate)
336{
337 struct cs2000_priv *priv = hw_to_priv(hw);
338 int ch = 0; /* it uses ch0 only at this point */
339
340 return __cs2000_set_rate(priv, ch, rate, parent_rate);
341}
342
343static int cs2000_set_saved_rate(struct cs2000_priv *priv)
344{
345 int ch = 0; /* it uses ch0 only at this point */
346
347 return __cs2000_set_rate(priv, ch,
348 priv->saved_rate,
349 priv->saved_parent_rate);
350}
351
352static int cs2000_enable(struct clk_hw *hw)
353{
354 struct cs2000_priv *priv = hw_to_priv(hw);
355 int ret;
356
357 ret = cs2000_enable_dev_config(priv, true);
358 if (ret < 0)
359 return ret;
360
361 ret = cs2000_clk_out_enable(priv, true);
362 if (ret < 0)
363 return ret;
364
365 ret = cs2000_wait_pll_lock(priv);
366 if (ret < 0)
367 return ret;
368
369 return ret;
370}
371
372static void cs2000_disable(struct clk_hw *hw)
373{
374 struct cs2000_priv *priv = hw_to_priv(hw);
375
376 cs2000_enable_dev_config(priv, false);
377
378 cs2000_clk_out_enable(priv, false);
379}
380
381static u8 cs2000_get_parent(struct clk_hw *hw)
382{
383 /* always return REF_CLK */
384 return REF_CLK;
385}
386
387static const struct clk_ops cs2000_ops = {
388 .get_parent = cs2000_get_parent,
389 .recalc_rate = cs2000_recalc_rate,
390 .round_rate = cs2000_round_rate,
391 .set_rate = cs2000_set_rate,
392 .prepare = cs2000_enable,
393 .unprepare = cs2000_disable,
394};
395
396static int cs2000_clk_get(struct cs2000_priv *priv)
397{
398 struct device *dev = priv_to_dev(priv);
399 struct clk *clk_in, *ref_clk;
400
401 clk_in = devm_clk_get(dev, "clk_in");
402 /* not yet provided */
403 if (IS_ERR(clk_in))
404 return -EPROBE_DEFER;
405
406 ref_clk = devm_clk_get(dev, "ref_clk");
407 /* not yet provided */
408 if (IS_ERR(ref_clk))
409 return -EPROBE_DEFER;
410
411 priv->clk_in = clk_in;
412 priv->ref_clk = ref_clk;
413
414 return 0;
415}
416
417static int cs2000_clk_register(struct cs2000_priv *priv)
418{
419 struct device *dev = priv_to_dev(priv);
420 struct device_node *np = dev->of_node;
421 struct clk_init_data init;
422 const char *name = np->name;
423 static const char *parent_names[CLK_MAX];
424 int ch = 0; /* it uses ch0 only at this point */
425 int rate;
426 int ret;
427
428 of_property_read_string(np, "clock-output-names", &name);
429
430 /*
431 * set default rate as 1/1.
432 * otherwise .set_rate which setup ratio
433 * is never called if user requests 1/1 rate
434 */
435 rate = clk_get_rate(priv->ref_clk);
436 ret = __cs2000_set_rate(priv, ch, rate, rate);
437 if (ret < 0)
438 return ret;
439
440 parent_names[CLK_IN] = __clk_get_name(priv->clk_in);
441 parent_names[REF_CLK] = __clk_get_name(priv->ref_clk);
442
443 init.name = name;
444 init.ops = &cs2000_ops;
445 init.flags = CLK_SET_RATE_GATE;
446 init.parent_names = parent_names;
447 init.num_parents = ARRAY_SIZE(parent_names);
448
449 priv->hw.init = &init;
450
451 ret = clk_hw_register(dev, &priv->hw);
452 if (ret)
453 return ret;
454
455 ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
456 if (ret < 0) {
457 clk_hw_unregister(&priv->hw);
458 return ret;
459 }
460
461 return 0;
462}
463
464static int cs2000_version_print(struct cs2000_priv *priv)
465{
466 struct device *dev = priv_to_dev(priv);
467 s32 val;
468 const char *revision;
469
470 val = cs2000_read(priv, DEVICE_ID);
471 if (val < 0)
472 return val;
473
474 /* CS2000 should be 0x0 */
475 if (val >> 3)
476 return -EIO;
477
478 switch (val & REVISION_MASK) {
479 case REVISION_B2_B3:
480 revision = "B2 / B3";
481 break;
482 case REVISION_C1:
483 revision = "C1";
484 break;
485 default:
486 return -EIO;
487 }
488
489 dev_info(dev, "revision - %s\n", revision);
490
491 return 0;
492}
493
494static int cs2000_remove(struct i2c_client *client)
495{
496 struct cs2000_priv *priv = i2c_get_clientdata(client);
497 struct device *dev = priv_to_dev(priv);
498 struct device_node *np = dev->of_node;
499
500 of_clk_del_provider(np);
501
502 clk_hw_unregister(&priv->hw);
503
504 return 0;
505}
506
507static int cs2000_probe(struct i2c_client *client,
508 const struct i2c_device_id *id)
509{
510 struct cs2000_priv *priv;
511 struct device *dev = &client->dev;
512 int ret;
513
514 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
515 if (!priv)
516 return -ENOMEM;
517
518 priv->client = client;
519 i2c_set_clientdata(client, priv);
520
521 ret = cs2000_clk_get(priv);
522 if (ret < 0)
523 return ret;
524
525 ret = cs2000_clk_register(priv);
526 if (ret < 0)
527 return ret;
528
529 ret = cs2000_version_print(priv);
530 if (ret < 0)
531 goto probe_err;
532
533 return 0;
534
535probe_err:
536 cs2000_remove(client);
537
538 return ret;
539}
540
541static int __maybe_unused cs2000_resume(struct device *dev)
542{
543 struct cs2000_priv *priv = dev_get_drvdata(dev);
544
545 return cs2000_set_saved_rate(priv);
546}
547
548static const struct dev_pm_ops cs2000_pm_ops = {
549 SET_LATE_SYSTEM_SLEEP_PM_OPS(NULL, cs2000_resume)
550};
551
552static struct i2c_driver cs2000_driver = {
553 .driver = {
554 .name = "cs2000-cp",
555 .pm = &cs2000_pm_ops,
556 .of_match_table = cs2000_of_match,
557 },
558 .probe = cs2000_probe,
559 .remove = cs2000_remove,
560 .id_table = cs2000_id,
561};
562
563module_i2c_driver(cs2000_driver);
564
565MODULE_DESCRIPTION("CS2000-CP driver");
566MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
567MODULE_LICENSE("GPL v2");
568