tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * CS2000 -- CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
3 *
4 * Copyright (C) 2015 Renesas Electronics Corporation
5 * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11#include <linux/clk-provider.h>
12#include <linux/delay.h>
13#include <linux/clk.h>
14#include <linux/i2c.h>
15#include <linux/of_device.h>
16#include <linux/module.h>
17
18#define CH_MAX 4
19#define RATIO_REG_SIZE 4
20
21#define DEVICE_ID 0x1
22#define DEVICE_CTRL 0x2
23#define DEVICE_CFG1 0x3
24#define DEVICE_CFG2 0x4
25#define GLOBAL_CFG 0x5
26#define Ratio_Add(x, nth) (6 + (x * 4) + (nth))
27#define Ratio_Val(x, nth) ((x >> (24 - (8 * nth))) & 0xFF)
28#define Val_Ratio(x, nth) ((x & 0xFF) << (24 - (8 * nth)))
29#define FUNC_CFG1 0x16
30#define FUNC_CFG2 0x17
31
32/* DEVICE_ID */
33#define REVISION_MASK (0x7)
34#define REVISION_B2_B3 (0x4)
35#define REVISION_C1 (0x6)
36
37/* DEVICE_CTRL */
38#define PLL_UNLOCK (1 << 7)
39#define AUXOUTDIS (1 << 1)
40#define CLKOUTDIS (1 << 0)
41
42/* DEVICE_CFG1 */
43#define RSEL(x) (((x) & 0x3) << 3)
44#define RSEL_MASK RSEL(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 << 1)
54
55/* GLOBAL_CFG */
56#define ENDEV2 (0x1)
57
58/* FUNC_CFG1 */
59#define CLKSKIPEN (1 << 7)
60#define REFCLKDIV(x) (((x) & 0x3) << 3)
61#define REFCLKDIV_MASK REFCLKDIV(0x3)
62
63/* FUNC_CFG2 */
64#define LFRATIO_MASK (1 << 3)
65#define LFRATIO_20_12 (0 << 3)
66#define LFRATIO_12_20 (1 << 3)
67
68#define CH_SIZE_ERR(ch) ((ch < 0) || (ch >= CH_MAX))
69#define hw_to_priv(_hw) container_of(_hw, struct cs2000_priv, hw)
70#define priv_to_client(priv) (priv->client)
71#define priv_to_dev(priv) (&(priv_to_client(priv)->dev))
72
73#define CLK_IN 0
74#define REF_CLK 1
75#define CLK_MAX 2
76
77struct cs2000_priv {
78 struct clk_hw hw;
79 struct i2c_client *client;
80 struct clk *clk_in;
81 struct clk *ref_clk;
82
83 /* suspend/resume */
84 unsigned long saved_rate;
85 unsigned long saved_parent_rate;
86};
87
88static const struct of_device_id cs2000_of_match[] = {
89 { .compatible = "cirrus,cs2000-cp", },
90 {},
91};
92MODULE_DEVICE_TABLE(of, cs2000_of_match);
93
94static const struct i2c_device_id cs2000_id[] = {
95 { "cs2000-cp", },
96 {}
97};
98MODULE_DEVICE_TABLE(i2c, cs2000_id);
99
100#define cs2000_read(priv, addr) \
101 i2c_smbus_read_byte_data(priv_to_client(priv), addr)
102#define cs2000_write(priv, addr, val) \
103 i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)
104
105static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
106{
107 s32 data;
108
109 data = cs2000_read(priv, addr);
110 if (data < 0)
111 return data;
112
113 data &= ~mask;
114 data |= (val & mask);
115
116 return cs2000_write(priv, addr, data);
117}
118
119static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
120{
121 int ret;
122
123 ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1,
124 enable ? ENDEV1 : 0);
125 if (ret < 0)
126 return ret;
127
128 ret = cs2000_bset(priv, GLOBAL_CFG, ENDEV2,
129 enable ? ENDEV2 : 0);
130 if (ret < 0)
131 return ret;
132
133 ret = cs2000_bset(priv, FUNC_CFG1, CLKSKIPEN,
134 enable ? CLKSKIPEN : 0);
135 if (ret < 0)
136 return ret;
137
138 /* FIXME: for Static ratio mode */
139 ret = cs2000_bset(priv, FUNC_CFG2, LFRATIO_MASK,
140 LFRATIO_12_20);
141 if (ret < 0)
142 return ret;
143
144 return 0;
145}
146
147static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
148 u32 rate_in)
149{
150 u32 val;
151
152 if (rate_in >= 32000000 && rate_in < 56000000)
153 val = 0x0;
154 else if (rate_in >= 16000000 && rate_in < 28000000)
155 val = 0x1;
156 else if (rate_in >= 8000000 && rate_in < 14000000)
157 val = 0x2;
158 else
159 return -EINVAL;
160
161 return cs2000_bset(priv, FUNC_CFG1,
162 REFCLKDIV_MASK,
163 REFCLKDIV(val));
164}
165
166static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
167{
168 struct device *dev = priv_to_dev(priv);
169 s32 val;
170 unsigned int i;
171
172 for (i = 0; i < 256; i++) {
173 val = cs2000_read(priv, DEVICE_CTRL);
174 if (val < 0)
175 return val;
176 if (!(val & PLL_UNLOCK))
177 return 0;
178 udelay(1);
179 }
180
181 dev_err(dev, "pll lock failed\n");
182
183 return -ETIMEDOUT;
184}
185
186static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
187{
188 /* enable both AUX_OUT, CLK_OUT */
189 return cs2000_bset(priv, DEVICE_CTRL,
190 (AUXOUTDIS | CLKOUTDIS),
191 enable ? 0 :
192 (AUXOUTDIS | CLKOUTDIS));
193}
194
195static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
196{
197 u64 ratio;
198
199 /*
200 * ratio = rate_out / rate_in * 2^20
201 *
202 * To avoid over flow, rate_out is u64.
203 * The result should be u32.
204 */
205 ratio = (u64)rate_out << 20;
206 do_div(ratio, rate_in);
207
208 return ratio;
209}
210
211static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
212{
213 u64 rate_out;
214
215 /*
216 * ratio = rate_out / rate_in * 2^20
217 *
218 * To avoid over flow, rate_out is u64.
219 * The result should be u32 or unsigned long.
220 */
221
222 rate_out = (u64)ratio * rate_in;
223 return rate_out >> 20;
224}
225
226static int cs2000_ratio_set(struct cs2000_priv *priv,
227 int ch, u32 rate_in, u32 rate_out)
228{
229 u32 val;
230 unsigned int i;
231 int ret;
232
233 if (CH_SIZE_ERR(ch))
234 return -EINVAL;
235
236 val = cs2000_rate_to_ratio(rate_in, rate_out);
237 for (i = 0; i < RATIO_REG_SIZE; i++) {
238 ret = cs2000_write(priv,
239 Ratio_Add(ch, i),
240 Ratio_Val(val, i));
241 if (ret < 0)
242 return ret;
243 }
244
245 return 0;
246}
247
248static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
249{
250 s32 tmp;
251 u32 val;
252 unsigned int i;
253
254 val = 0;
255 for (i = 0; i < RATIO_REG_SIZE; i++) {
256 tmp = cs2000_read(priv, Ratio_Add(ch, i));
257 if (tmp < 0)
258 return 0;
259
260 val |= Val_Ratio(tmp, i);
261 }
262
263 return val;
264}
265
266static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
267{
268 int ret;
269
270 if (CH_SIZE_ERR(ch))
271 return -EINVAL;
272
273 /*
274 * FIXME
275 *
276 * this driver supports static ratio mode only at this point.
277 */
278 ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
279 if (ret < 0)
280 return ret;
281
282 ret = cs2000_bset(priv, DEVICE_CFG2,
283 (AUTORMOD | LOCKCLK_MASK | FRACNSRC_MASK),
284 (LOCKCLK(ch) | FRACNSRC_STATIC));
285 if (ret < 0)
286 return ret;
287
288 return 0;
289}
290
291static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
292 unsigned long parent_rate)
293{
294 struct cs2000_priv *priv = hw_to_priv(hw);
295 int ch = 0; /* it uses ch0 only at this point */
296 u32 ratio;
297
298 ratio = cs2000_ratio_get(priv, ch);
299
300 return cs2000_ratio_to_rate(ratio, parent_rate);
301}
302
303static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
304 unsigned long *parent_rate)
305{
306 u32 ratio;
307
308 ratio = cs2000_rate_to_ratio(*parent_rate, rate);
309
310 return cs2000_ratio_to_rate(ratio, *parent_rate);
311}
312
313static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
314 unsigned long rate, unsigned long parent_rate)
315
316{
317 int ret;
318
319 ret = cs2000_clk_in_bound_rate(priv, parent_rate);
320 if (ret < 0)
321 return ret;
322
323 ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
324 if (ret < 0)
325 return ret;
326
327 ret = cs2000_ratio_select(priv, ch);
328 if (ret < 0)
329 return ret;
330
331 priv->saved_rate = rate;
332 priv->saved_parent_rate = parent_rate;
333
334 return 0;
335}
336
337static int cs2000_set_rate(struct clk_hw *hw,
338 unsigned long rate, unsigned long parent_rate)
339{
340 struct cs2000_priv *priv = hw_to_priv(hw);
341 int ch = 0; /* it uses ch0 only at this point */
342
343 return __cs2000_set_rate(priv, ch, rate, parent_rate);
344}
345
346static int cs2000_enable(struct clk_hw *hw)
347{
348 struct cs2000_priv *priv = hw_to_priv(hw);
349 int ret;
350
351 ret = cs2000_enable_dev_config(priv, true);
352 if (ret < 0)
353 return ret;
354
355 ret = cs2000_clk_out_enable(priv, true);
356 if (ret < 0)
357 return ret;
358
359 ret = cs2000_wait_pll_lock(priv);
360 if (ret < 0)
361 return ret;
362
363 return ret;
364}
365
366static void cs2000_disable(struct clk_hw *hw)
367{
368 struct cs2000_priv *priv = hw_to_priv(hw);
369
370 cs2000_enable_dev_config(priv, false);
371
372 cs2000_clk_out_enable(priv, false);
373}
374
375static u8 cs2000_get_parent(struct clk_hw *hw)
376{
377 /* always return REF_CLK */
378 return REF_CLK;
379}
380
381static const struct clk_ops cs2000_ops = {
382 .get_parent = cs2000_get_parent,
383 .recalc_rate = cs2000_recalc_rate,
384 .round_rate = cs2000_round_rate,
385 .set_rate = cs2000_set_rate,
386 .prepare = cs2000_enable,
387 .unprepare = cs2000_disable,
388};
389
390static int cs2000_clk_get(struct cs2000_priv *priv)
391{
392 struct device *dev = priv_to_dev(priv);
393 struct clk *clk_in, *ref_clk;
394
395 clk_in = devm_clk_get(dev, "clk_in");
396 /* not yet provided */
397 if (IS_ERR(clk_in))
398 return -EPROBE_DEFER;
399
400 ref_clk = devm_clk_get(dev, "ref_clk");
401 /* not yet provided */
402 if (IS_ERR(ref_clk))
403 return -EPROBE_DEFER;
404
405 priv->clk_in = clk_in;
406 priv->ref_clk = ref_clk;
407
408 return 0;
409}
410
411static int cs2000_clk_register(struct cs2000_priv *priv)
412{
413 struct device *dev = priv_to_dev(priv);
414 struct device_node *np = dev->of_node;
415 struct clk_init_data init;
416 const char *name = np->name;
417 static const char *parent_names[CLK_MAX];
418 int ch = 0; /* it uses ch0 only at this point */
419 int rate;
420 int ret;
421
422 of_property_read_string(np, "clock-output-names", &name);
423
424 /*
425 * set default rate as 1/1.
426 * otherwise .set_rate which setup ratio
427 * is never called if user requests 1/1 rate
428 */
429 rate = clk_get_rate(priv->ref_clk);
430 ret = __cs2000_set_rate(priv, ch, rate, rate);
431 if (ret < 0)
432 return ret;
433
434 parent_names[CLK_IN] = __clk_get_name(priv->clk_in);
435 parent_names[REF_CLK] = __clk_get_name(priv->ref_clk);
436
437 init.name = name;
438 init.ops = &cs2000_ops;
439 init.flags = CLK_SET_RATE_GATE;
440 init.parent_names = parent_names;
441 init.num_parents = ARRAY_SIZE(parent_names);
442
443 priv->hw.init = &init;
444
445 ret = clk_hw_register(dev, &priv->hw);
446 if (ret)
447 return ret;
448
449 ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
450 if (ret < 0) {
451 clk_hw_unregister(&priv->hw);
452 return ret;
453 }
454
455 return 0;
456}
457
458static int cs2000_version_print(struct cs2000_priv *priv)
459{
460 struct device *dev = priv_to_dev(priv);
461 s32 val;
462 const char *revision;
463
464 val = cs2000_read(priv, DEVICE_ID);
465 if (val < 0)
466 return val;
467
468 /* CS2000 should be 0x0 */
469 if (val >> 3)
470 return -EIO;
471
472 switch (val & REVISION_MASK) {
473 case REVISION_B2_B3:
474 revision = "B2 / B3";
475 break;
476 case REVISION_C1:
477 revision = "C1";
478 break;
479 default:
480 return -EIO;
481 }
482
483 dev_info(dev, "revision - %s\n", revision);
484
485 return 0;
486}
487
488static int cs2000_remove(struct i2c_client *client)
489{
490 struct cs2000_priv *priv = i2c_get_clientdata(client);
491 struct device *dev = priv_to_dev(priv);
492 struct device_node *np = dev->of_node;
493
494 of_clk_del_provider(np);
495
496 clk_hw_unregister(&priv->hw);
497
498 return 0;
499}
500
501static int cs2000_probe(struct i2c_client *client,
502 const struct i2c_device_id *id)
503{
504 struct cs2000_priv *priv;
505 struct device *dev = &client->dev;
506 int ret;
507
508 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
509 if (!priv)
510 return -ENOMEM;
511
512 priv->client = client;
513 i2c_set_clientdata(client, priv);
514
515 ret = cs2000_clk_get(priv);
516 if (ret < 0)
517 return ret;
518
519 ret = cs2000_clk_register(priv);
520 if (ret < 0)
521 return ret;
522
523 ret = cs2000_version_print(priv);
524 if (ret < 0)
525 goto probe_err;
526
527 return 0;
528
529probe_err:
530 cs2000_remove(client);
531
532 return ret;
533}
534
535static int cs2000_resume(struct device *dev)
536{
537 struct cs2000_priv *priv = dev_get_drvdata(dev);
538 int ch = 0; /* it uses ch0 only at this point */
539
540 return __cs2000_set_rate(priv, ch,
541 priv->saved_rate,
542 priv->saved_parent_rate);
543}
544
545static const struct dev_pm_ops cs2000_pm_ops = {
546 .resume_early = cs2000_resume,
547};
548
549static struct i2c_driver cs2000_driver = {
550 .driver = {
551 .name = "cs2000-cp",
552 .pm = &cs2000_pm_ops,
553 .of_match_table = cs2000_of_match,
554 },
555 .probe = cs2000_probe,
556 .remove = cs2000_remove,
557 .id_table = cs2000_id,
558};
559
560module_i2c_driver(cs2000_driver);
561
562MODULE_DESCRIPTION("CS2000-CP driver");
563MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
564MODULE_LICENSE("GPL v2");