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1/*
2 * drivers/clk/at91/sckc.c
3 *
4 * Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 */
12
13#include <linux/clk-provider.h>
14#include <linux/clkdev.h>
15#include <linux/delay.h>
16#include <linux/of.h>
17#include <linux/of_address.h>
18#include <linux/io.h>
19
20#define SLOW_CLOCK_FREQ 32768
21#define SLOWCK_SW_CYCLES 5
22#define SLOWCK_SW_TIME_USEC ((SLOWCK_SW_CYCLES * USEC_PER_SEC) / \
23 SLOW_CLOCK_FREQ)
24
25#define AT91_SCKC_CR 0x00
26#define AT91_SCKC_RCEN (1 << 0)
27#define AT91_SCKC_OSC32EN (1 << 1)
28#define AT91_SCKC_OSC32BYP (1 << 2)
29#define AT91_SCKC_OSCSEL (1 << 3)
30
31struct clk_slow_osc {
32 struct clk_hw hw;
33 void __iomem *sckcr;
34 unsigned long startup_usec;
35};
36
37#define to_clk_slow_osc(hw) container_of(hw, struct clk_slow_osc, hw)
38
39struct clk_sama5d4_slow_osc {
40 struct clk_hw hw;
41 void __iomem *sckcr;
42 unsigned long startup_usec;
43 bool prepared;
44};
45
46#define to_clk_sama5d4_slow_osc(hw) container_of(hw, struct clk_sama5d4_slow_osc, hw)
47
48struct clk_slow_rc_osc {
49 struct clk_hw hw;
50 void __iomem *sckcr;
51 unsigned long frequency;
52 unsigned long accuracy;
53 unsigned long startup_usec;
54};
55
56#define to_clk_slow_rc_osc(hw) container_of(hw, struct clk_slow_rc_osc, hw)
57
58struct clk_sam9x5_slow {
59 struct clk_hw hw;
60 void __iomem *sckcr;
61 u8 parent;
62};
63
64#define to_clk_sam9x5_slow(hw) container_of(hw, struct clk_sam9x5_slow, hw)
65
66static int clk_slow_osc_prepare(struct clk_hw *hw)
67{
68 struct clk_slow_osc *osc = to_clk_slow_osc(hw);
69 void __iomem *sckcr = osc->sckcr;
70 u32 tmp = readl(sckcr);
71
72 if (tmp & (AT91_SCKC_OSC32BYP | AT91_SCKC_OSC32EN))
73 return 0;
74
75 writel(tmp | AT91_SCKC_OSC32EN, sckcr);
76
77 usleep_range(osc->startup_usec, osc->startup_usec + 1);
78
79 return 0;
80}
81
82static void clk_slow_osc_unprepare(struct clk_hw *hw)
83{
84 struct clk_slow_osc *osc = to_clk_slow_osc(hw);
85 void __iomem *sckcr = osc->sckcr;
86 u32 tmp = readl(sckcr);
87
88 if (tmp & AT91_SCKC_OSC32BYP)
89 return;
90
91 writel(tmp & ~AT91_SCKC_OSC32EN, sckcr);
92}
93
94static int clk_slow_osc_is_prepared(struct clk_hw *hw)
95{
96 struct clk_slow_osc *osc = to_clk_slow_osc(hw);
97 void __iomem *sckcr = osc->sckcr;
98 u32 tmp = readl(sckcr);
99
100 if (tmp & AT91_SCKC_OSC32BYP)
101 return 1;
102
103 return !!(tmp & AT91_SCKC_OSC32EN);
104}
105
106static const struct clk_ops slow_osc_ops = {
107 .prepare = clk_slow_osc_prepare,
108 .unprepare = clk_slow_osc_unprepare,
109 .is_prepared = clk_slow_osc_is_prepared,
110};
111
112static struct clk_hw * __init
113at91_clk_register_slow_osc(void __iomem *sckcr,
114 const char *name,
115 const char *parent_name,
116 unsigned long startup,
117 bool bypass)
118{
119 struct clk_slow_osc *osc;
120 struct clk_hw *hw;
121 struct clk_init_data init;
122 int ret;
123
124 if (!sckcr || !name || !parent_name)
125 return ERR_PTR(-EINVAL);
126
127 osc = kzalloc(sizeof(*osc), GFP_KERNEL);
128 if (!osc)
129 return ERR_PTR(-ENOMEM);
130
131 init.name = name;
132 init.ops = &slow_osc_ops;
133 init.parent_names = &parent_name;
134 init.num_parents = 1;
135 init.flags = CLK_IGNORE_UNUSED;
136
137 osc->hw.init = &init;
138 osc->sckcr = sckcr;
139 osc->startup_usec = startup;
140
141 if (bypass)
142 writel((readl(sckcr) & ~AT91_SCKC_OSC32EN) | AT91_SCKC_OSC32BYP,
143 sckcr);
144
145 hw = &osc->hw;
146 ret = clk_hw_register(NULL, &osc->hw);
147 if (ret) {
148 kfree(osc);
149 hw = ERR_PTR(ret);
150 }
151
152 return hw;
153}
154
155static void __init
156of_at91sam9x5_clk_slow_osc_setup(struct device_node *np, void __iomem *sckcr)
157{
158 struct clk_hw *hw;
159 const char *parent_name;
160 const char *name = np->name;
161 u32 startup;
162 bool bypass;
163
164 parent_name = of_clk_get_parent_name(np, 0);
165 of_property_read_string(np, "clock-output-names", &name);
166 of_property_read_u32(np, "atmel,startup-time-usec", &startup);
167 bypass = of_property_read_bool(np, "atmel,osc-bypass");
168
169 hw = at91_clk_register_slow_osc(sckcr, name, parent_name, startup,
170 bypass);
171 if (IS_ERR(hw))
172 return;
173
174 of_clk_add_hw_provider(np, of_clk_hw_simple_get, hw);
175}
176
177static unsigned long clk_slow_rc_osc_recalc_rate(struct clk_hw *hw,
178 unsigned long parent_rate)
179{
180 struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
181
182 return osc->frequency;
183}
184
185static unsigned long clk_slow_rc_osc_recalc_accuracy(struct clk_hw *hw,
186 unsigned long parent_acc)
187{
188 struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
189
190 return osc->accuracy;
191}
192
193static int clk_slow_rc_osc_prepare(struct clk_hw *hw)
194{
195 struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
196 void __iomem *sckcr = osc->sckcr;
197
198 writel(readl(sckcr) | AT91_SCKC_RCEN, sckcr);
199
200 usleep_range(osc->startup_usec, osc->startup_usec + 1);
201
202 return 0;
203}
204
205static void clk_slow_rc_osc_unprepare(struct clk_hw *hw)
206{
207 struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
208 void __iomem *sckcr = osc->sckcr;
209
210 writel(readl(sckcr) & ~AT91_SCKC_RCEN, sckcr);
211}
212
213static int clk_slow_rc_osc_is_prepared(struct clk_hw *hw)
214{
215 struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
216
217 return !!(readl(osc->sckcr) & AT91_SCKC_RCEN);
218}
219
220static const struct clk_ops slow_rc_osc_ops = {
221 .prepare = clk_slow_rc_osc_prepare,
222 .unprepare = clk_slow_rc_osc_unprepare,
223 .is_prepared = clk_slow_rc_osc_is_prepared,
224 .recalc_rate = clk_slow_rc_osc_recalc_rate,
225 .recalc_accuracy = clk_slow_rc_osc_recalc_accuracy,
226};
227
228static struct clk_hw * __init
229at91_clk_register_slow_rc_osc(void __iomem *sckcr,
230 const char *name,
231 unsigned long frequency,
232 unsigned long accuracy,
233 unsigned long startup)
234{
235 struct clk_slow_rc_osc *osc;
236 struct clk_hw *hw;
237 struct clk_init_data init;
238 int ret;
239
240 if (!sckcr || !name)
241 return ERR_PTR(-EINVAL);
242
243 osc = kzalloc(sizeof(*osc), GFP_KERNEL);
244 if (!osc)
245 return ERR_PTR(-ENOMEM);
246
247 init.name = name;
248 init.ops = &slow_rc_osc_ops;
249 init.parent_names = NULL;
250 init.num_parents = 0;
251 init.flags = CLK_IGNORE_UNUSED;
252
253 osc->hw.init = &init;
254 osc->sckcr = sckcr;
255 osc->frequency = frequency;
256 osc->accuracy = accuracy;
257 osc->startup_usec = startup;
258
259 hw = &osc->hw;
260 ret = clk_hw_register(NULL, &osc->hw);
261 if (ret) {
262 kfree(osc);
263 hw = ERR_PTR(ret);
264 }
265
266 return hw;
267}
268
269static void __init
270of_at91sam9x5_clk_slow_rc_osc_setup(struct device_node *np, void __iomem *sckcr)
271{
272 struct clk_hw *hw;
273 u32 frequency = 0;
274 u32 accuracy = 0;
275 u32 startup = 0;
276 const char *name = np->name;
277
278 of_property_read_string(np, "clock-output-names", &name);
279 of_property_read_u32(np, "clock-frequency", &frequency);
280 of_property_read_u32(np, "clock-accuracy", &accuracy);
281 of_property_read_u32(np, "atmel,startup-time-usec", &startup);
282
283 hw = at91_clk_register_slow_rc_osc(sckcr, name, frequency, accuracy,
284 startup);
285 if (IS_ERR(hw))
286 return;
287
288 of_clk_add_hw_provider(np, of_clk_hw_simple_get, hw);
289}
290
291static int clk_sam9x5_slow_set_parent(struct clk_hw *hw, u8 index)
292{
293 struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw);
294 void __iomem *sckcr = slowck->sckcr;
295 u32 tmp;
296
297 if (index > 1)
298 return -EINVAL;
299
300 tmp = readl(sckcr);
301
302 if ((!index && !(tmp & AT91_SCKC_OSCSEL)) ||
303 (index && (tmp & AT91_SCKC_OSCSEL)))
304 return 0;
305
306 if (index)
307 tmp |= AT91_SCKC_OSCSEL;
308 else
309 tmp &= ~AT91_SCKC_OSCSEL;
310
311 writel(tmp, sckcr);
312
313 usleep_range(SLOWCK_SW_TIME_USEC, SLOWCK_SW_TIME_USEC + 1);
314
315 return 0;
316}
317
318static u8 clk_sam9x5_slow_get_parent(struct clk_hw *hw)
319{
320 struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw);
321
322 return !!(readl(slowck->sckcr) & AT91_SCKC_OSCSEL);
323}
324
325static const struct clk_ops sam9x5_slow_ops = {
326 .set_parent = clk_sam9x5_slow_set_parent,
327 .get_parent = clk_sam9x5_slow_get_parent,
328};
329
330static struct clk_hw * __init
331at91_clk_register_sam9x5_slow(void __iomem *sckcr,
332 const char *name,
333 const char **parent_names,
334 int num_parents)
335{
336 struct clk_sam9x5_slow *slowck;
337 struct clk_hw *hw;
338 struct clk_init_data init;
339 int ret;
340
341 if (!sckcr || !name || !parent_names || !num_parents)
342 return ERR_PTR(-EINVAL);
343
344 slowck = kzalloc(sizeof(*slowck), GFP_KERNEL);
345 if (!slowck)
346 return ERR_PTR(-ENOMEM);
347
348 init.name = name;
349 init.ops = &sam9x5_slow_ops;
350 init.parent_names = parent_names;
351 init.num_parents = num_parents;
352 init.flags = 0;
353
354 slowck->hw.init = &init;
355 slowck->sckcr = sckcr;
356 slowck->parent = !!(readl(sckcr) & AT91_SCKC_OSCSEL);
357
358 hw = &slowck->hw;
359 ret = clk_hw_register(NULL, &slowck->hw);
360 if (ret) {
361 kfree(slowck);
362 hw = ERR_PTR(ret);
363 }
364
365 return hw;
366}
367
368static void __init
369of_at91sam9x5_clk_slow_setup(struct device_node *np, void __iomem *sckcr)
370{
371 struct clk_hw *hw;
372 const char *parent_names[2];
373 unsigned int num_parents;
374 const char *name = np->name;
375
376 num_parents = of_clk_get_parent_count(np);
377 if (num_parents == 0 || num_parents > 2)
378 return;
379
380 of_clk_parent_fill(np, parent_names, num_parents);
381
382 of_property_read_string(np, "clock-output-names", &name);
383
384 hw = at91_clk_register_sam9x5_slow(sckcr, name, parent_names,
385 num_parents);
386 if (IS_ERR(hw))
387 return;
388
389 of_clk_add_hw_provider(np, of_clk_hw_simple_get, hw);
390}
391
392static const struct of_device_id sckc_clk_ids[] __initconst = {
393 /* Slow clock */
394 {
395 .compatible = "atmel,at91sam9x5-clk-slow-osc",
396 .data = of_at91sam9x5_clk_slow_osc_setup,
397 },
398 {
399 .compatible = "atmel,at91sam9x5-clk-slow-rc-osc",
400 .data = of_at91sam9x5_clk_slow_rc_osc_setup,
401 },
402 {
403 .compatible = "atmel,at91sam9x5-clk-slow",
404 .data = of_at91sam9x5_clk_slow_setup,
405 },
406 { /*sentinel*/ }
407};
408
409static void __init of_at91sam9x5_sckc_setup(struct device_node *np)
410{
411 struct device_node *childnp;
412 void (*clk_setup)(struct device_node *, void __iomem *);
413 const struct of_device_id *clk_id;
414 void __iomem *regbase = of_iomap(np, 0);
415
416 if (!regbase)
417 return;
418
419 for_each_child_of_node(np, childnp) {
420 clk_id = of_match_node(sckc_clk_ids, childnp);
421 if (!clk_id)
422 continue;
423 clk_setup = clk_id->data;
424 clk_setup(childnp, regbase);
425 }
426}
427CLK_OF_DECLARE(at91sam9x5_clk_sckc, "atmel,at91sam9x5-sckc",
428 of_at91sam9x5_sckc_setup);
429
430static int clk_sama5d4_slow_osc_prepare(struct clk_hw *hw)
431{
432 struct clk_sama5d4_slow_osc *osc = to_clk_sama5d4_slow_osc(hw);
433
434 if (osc->prepared)
435 return 0;
436
437 /*
438 * Assume that if it has already been selected (for example by the
439 * bootloader), enough time has aready passed.
440 */
441 if ((readl(osc->sckcr) & AT91_SCKC_OSCSEL)) {
442 osc->prepared = true;
443 return 0;
444 }
445
446 usleep_range(osc->startup_usec, osc->startup_usec + 1);
447 osc->prepared = true;
448
449 return 0;
450}
451
452static int clk_sama5d4_slow_osc_is_prepared(struct clk_hw *hw)
453{
454 struct clk_sama5d4_slow_osc *osc = to_clk_sama5d4_slow_osc(hw);
455
456 return osc->prepared;
457}
458
459static const struct clk_ops sama5d4_slow_osc_ops = {
460 .prepare = clk_sama5d4_slow_osc_prepare,
461 .is_prepared = clk_sama5d4_slow_osc_is_prepared,
462};
463
464static void __init of_sama5d4_sckc_setup(struct device_node *np)
465{
466 void __iomem *regbase = of_iomap(np, 0);
467 struct clk_hw *hw;
468 struct clk_sama5d4_slow_osc *osc;
469 struct clk_init_data init;
470 const char *xtal_name;
471 const char *parent_names[2] = { "slow_rc_osc", "slow_osc" };
472 bool bypass;
473 int ret;
474
475 if (!regbase)
476 return;
477
478 hw = clk_hw_register_fixed_rate_with_accuracy(NULL, parent_names[0],
479 NULL, 0, 32768,
480 250000000);
481 if (IS_ERR(hw))
482 return;
483
484 xtal_name = of_clk_get_parent_name(np, 0);
485
486 bypass = of_property_read_bool(np, "atmel,osc-bypass");
487
488 osc = kzalloc(sizeof(*osc), GFP_KERNEL);
489 if (!osc)
490 return;
491
492 init.name = parent_names[1];
493 init.ops = &sama5d4_slow_osc_ops;
494 init.parent_names = &xtal_name;
495 init.num_parents = 1;
496 init.flags = CLK_IGNORE_UNUSED;
497
498 osc->hw.init = &init;
499 osc->sckcr = regbase;
500 osc->startup_usec = 1200000;
501
502 if (bypass)
503 writel((readl(regbase) | AT91_SCKC_OSC32BYP), regbase);
504
505 hw = &osc->hw;
506 ret = clk_hw_register(NULL, &osc->hw);
507 if (ret) {
508 kfree(osc);
509 return;
510 }
511
512 hw = at91_clk_register_sam9x5_slow(regbase, "slowck", parent_names, 2);
513 if (IS_ERR(hw))
514 return;
515
516 of_clk_add_hw_provider(np, of_clk_hw_simple_get, hw);
517}
518CLK_OF_DECLARE(sama5d4_clk_sckc, "atmel,sama5d4-sckc",
519 of_sama5d4_sckc_setup);