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