1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
4 * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
5 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
7 * Adjustable divider clock implementation
10 #include <linux/clk-provider.h>
11 #include <linux/device.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
15 #include <linux/err.h>
16 #include <linux/string.h>
17 #include <linux/log2.h>
20 * DOC: basic adjustable divider clock that cannot gate
22 * Traits of this clock:
23 * prepare - clk_prepare only ensures that parents are prepared
24 * enable - clk_enable only ensures that parents are enabled
25 * rate - rate is adjustable. clk->rate = ceiling(parent->rate / divisor)
26 * parent - fixed parent. No clk_set_parent support
29 static inline u32
clk_div_readl(struct clk_divider
*divider
)
31 if (divider
->flags
& CLK_DIVIDER_BIG_ENDIAN
)
32 return ioread32be(divider
->reg
);
34 return readl(divider
->reg
);
37 static inline void clk_div_writel(struct clk_divider
*divider
, u32 val
)
39 if (divider
->flags
& CLK_DIVIDER_BIG_ENDIAN
)
40 iowrite32be(val
, divider
->reg
);
42 writel(val
, divider
->reg
);
45 static unsigned int _get_table_maxdiv(const struct clk_div_table
*table
,
48 unsigned int maxdiv
= 0, mask
= clk_div_mask(width
);
49 const struct clk_div_table
*clkt
;
51 for (clkt
= table
; clkt
->div
; clkt
++)
52 if (clkt
->div
> maxdiv
&& clkt
->val
<= mask
)
57 static unsigned int _get_table_mindiv(const struct clk_div_table
*table
)
59 unsigned int mindiv
= UINT_MAX
;
60 const struct clk_div_table
*clkt
;
62 for (clkt
= table
; clkt
->div
; clkt
++)
63 if (clkt
->div
< mindiv
)
68 static unsigned int _get_maxdiv(const struct clk_div_table
*table
, u8 width
,
71 if (flags
& CLK_DIVIDER_ONE_BASED
)
72 return clk_div_mask(width
);
73 if (flags
& CLK_DIVIDER_POWER_OF_TWO
)
74 return 1 << clk_div_mask(width
);
76 return _get_table_maxdiv(table
, width
);
77 return clk_div_mask(width
) + 1;
80 static unsigned int _get_table_div(const struct clk_div_table
*table
,
83 const struct clk_div_table
*clkt
;
85 for (clkt
= table
; clkt
->div
; clkt
++)
91 static unsigned int _get_div(const struct clk_div_table
*table
,
92 unsigned int val
, unsigned long flags
, u8 width
)
94 if (flags
& CLK_DIVIDER_ONE_BASED
)
96 if (flags
& CLK_DIVIDER_POWER_OF_TWO
)
98 if (flags
& CLK_DIVIDER_MAX_AT_ZERO
)
99 return val
? val
: clk_div_mask(width
) + 1;
101 return _get_table_div(table
, val
);
105 static unsigned int _get_table_val(const struct clk_div_table
*table
,
108 const struct clk_div_table
*clkt
;
110 for (clkt
= table
; clkt
->div
; clkt
++)
111 if (clkt
->div
== div
)
116 static unsigned int _get_val(const struct clk_div_table
*table
,
117 unsigned int div
, unsigned long flags
, u8 width
)
119 if (flags
& CLK_DIVIDER_ONE_BASED
)
121 if (flags
& CLK_DIVIDER_POWER_OF_TWO
)
123 if (flags
& CLK_DIVIDER_MAX_AT_ZERO
)
124 return (div
== clk_div_mask(width
) + 1) ? 0 : div
;
126 return _get_table_val(table
, div
);
130 unsigned long divider_recalc_rate(struct clk_hw
*hw
, unsigned long parent_rate
,
132 const struct clk_div_table
*table
,
133 unsigned long flags
, unsigned long width
)
137 div
= _get_div(table
, val
, flags
, width
);
139 WARN(!(flags
& CLK_DIVIDER_ALLOW_ZERO
),
140 "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
141 clk_hw_get_name(hw
));
145 return DIV_ROUND_UP_ULL((u64
)parent_rate
, div
);
147 EXPORT_SYMBOL_GPL(divider_recalc_rate
);
149 static unsigned long clk_divider_recalc_rate(struct clk_hw
*hw
,
150 unsigned long parent_rate
)
152 struct clk_divider
*divider
= to_clk_divider(hw
);
155 val
= clk_div_readl(divider
) >> divider
->shift
;
156 val
&= clk_div_mask(divider
->width
);
158 return divider_recalc_rate(hw
, parent_rate
, val
, divider
->table
,
159 divider
->flags
, divider
->width
);
162 static bool _is_valid_table_div(const struct clk_div_table
*table
,
165 const struct clk_div_table
*clkt
;
167 for (clkt
= table
; clkt
->div
; clkt
++)
168 if (clkt
->div
== div
)
173 static bool _is_valid_div(const struct clk_div_table
*table
, unsigned int div
,
176 if (flags
& CLK_DIVIDER_POWER_OF_TWO
)
177 return is_power_of_2(div
);
179 return _is_valid_table_div(table
, div
);
183 static int _round_up_table(const struct clk_div_table
*table
, int div
)
185 const struct clk_div_table
*clkt
;
188 for (clkt
= table
; clkt
->div
; clkt
++) {
189 if (clkt
->div
== div
)
191 else if (clkt
->div
< div
)
194 if ((clkt
->div
- div
) < (up
- div
))
201 static int _round_down_table(const struct clk_div_table
*table
, int div
)
203 const struct clk_div_table
*clkt
;
204 int down
= _get_table_mindiv(table
);
206 for (clkt
= table
; clkt
->div
; clkt
++) {
207 if (clkt
->div
== div
)
209 else if (clkt
->div
> div
)
212 if ((div
- clkt
->div
) < (div
- down
))
219 static int _div_round_up(const struct clk_div_table
*table
,
220 unsigned long parent_rate
, unsigned long rate
,
223 int div
= DIV_ROUND_UP_ULL((u64
)parent_rate
, rate
);
225 if (flags
& CLK_DIVIDER_POWER_OF_TWO
)
226 div
= __roundup_pow_of_two(div
);
228 div
= _round_up_table(table
, div
);
233 static int _div_round_closest(const struct clk_div_table
*table
,
234 unsigned long parent_rate
, unsigned long rate
,
238 unsigned long up_rate
, down_rate
;
240 up
= DIV_ROUND_UP_ULL((u64
)parent_rate
, rate
);
241 down
= parent_rate
/ rate
;
243 if (flags
& CLK_DIVIDER_POWER_OF_TWO
) {
244 up
= __roundup_pow_of_two(up
);
245 down
= __rounddown_pow_of_two(down
);
247 up
= _round_up_table(table
, up
);
248 down
= _round_down_table(table
, down
);
251 up_rate
= DIV_ROUND_UP_ULL((u64
)parent_rate
, up
);
252 down_rate
= DIV_ROUND_UP_ULL((u64
)parent_rate
, down
);
254 return (rate
- up_rate
) <= (down_rate
- rate
) ? up
: down
;
257 static int _div_round(const struct clk_div_table
*table
,
258 unsigned long parent_rate
, unsigned long rate
,
261 if (flags
& CLK_DIVIDER_ROUND_CLOSEST
)
262 return _div_round_closest(table
, parent_rate
, rate
, flags
);
264 return _div_round_up(table
, parent_rate
, rate
, flags
);
267 static bool _is_best_div(unsigned long rate
, unsigned long now
,
268 unsigned long best
, unsigned long flags
)
270 if (flags
& CLK_DIVIDER_ROUND_CLOSEST
)
271 return abs(rate
- now
) < abs(rate
- best
);
273 return now
<= rate
&& now
> best
;
276 static int _next_div(const struct clk_div_table
*table
, int div
,
281 if (flags
& CLK_DIVIDER_POWER_OF_TWO
)
282 return __roundup_pow_of_two(div
);
284 return _round_up_table(table
, div
);
289 static int clk_divider_bestdiv(struct clk_hw
*hw
, struct clk_hw
*parent
,
291 unsigned long *best_parent_rate
,
292 const struct clk_div_table
*table
, u8 width
,
296 unsigned long parent_rate
, best
= 0, now
, maxdiv
;
297 unsigned long parent_rate_saved
= *best_parent_rate
;
302 maxdiv
= _get_maxdiv(table
, width
, flags
);
304 if (!(clk_hw_get_flags(hw
) & CLK_SET_RATE_PARENT
)) {
305 parent_rate
= *best_parent_rate
;
306 bestdiv
= _div_round(table
, parent_rate
, rate
, flags
);
307 bestdiv
= bestdiv
== 0 ? 1 : bestdiv
;
308 bestdiv
= bestdiv
> maxdiv
? maxdiv
: bestdiv
;
313 * The maximum divider we can use without overflowing
314 * unsigned long in rate * i below
316 maxdiv
= min(ULONG_MAX
/ rate
, maxdiv
);
318 for (i
= _next_div(table
, 0, flags
); i
<= maxdiv
;
319 i
= _next_div(table
, i
, flags
)) {
320 if (rate
* i
== parent_rate_saved
) {
322 * It's the most ideal case if the requested rate can be
323 * divided from parent clock without needing to change
324 * parent rate, so return the divider immediately.
326 *best_parent_rate
= parent_rate_saved
;
329 parent_rate
= clk_hw_round_rate(parent
, rate
* i
);
330 now
= DIV_ROUND_UP_ULL((u64
)parent_rate
, i
);
331 if (_is_best_div(rate
, now
, best
, flags
)) {
334 *best_parent_rate
= parent_rate
;
339 bestdiv
= _get_maxdiv(table
, width
, flags
);
340 *best_parent_rate
= clk_hw_round_rate(parent
, 1);
346 int divider_determine_rate(struct clk_hw
*hw
, struct clk_rate_request
*req
,
347 const struct clk_div_table
*table
, u8 width
,
352 div
= clk_divider_bestdiv(hw
, req
->best_parent_hw
, req
->rate
,
353 &req
->best_parent_rate
, table
, width
, flags
);
355 req
->rate
= DIV_ROUND_UP_ULL((u64
)req
->best_parent_rate
, div
);
359 EXPORT_SYMBOL_GPL(divider_determine_rate
);
361 int divider_ro_determine_rate(struct clk_hw
*hw
, struct clk_rate_request
*req
,
362 const struct clk_div_table
*table
, u8 width
,
363 unsigned long flags
, unsigned int val
)
367 div
= _get_div(table
, val
, flags
, width
);
369 /* Even a read-only clock can propagate a rate change */
370 if (clk_hw_get_flags(hw
) & CLK_SET_RATE_PARENT
) {
371 if (!req
->best_parent_hw
)
374 req
->best_parent_rate
= clk_hw_round_rate(req
->best_parent_hw
,
378 req
->rate
= DIV_ROUND_UP_ULL((u64
)req
->best_parent_rate
, div
);
382 EXPORT_SYMBOL_GPL(divider_ro_determine_rate
);
384 long divider_round_rate_parent(struct clk_hw
*hw
, struct clk_hw
*parent
,
385 unsigned long rate
, unsigned long *prate
,
386 const struct clk_div_table
*table
,
387 u8 width
, unsigned long flags
)
389 struct clk_rate_request req
;
392 clk_hw_init_rate_request(hw
, &req
, rate
);
393 req
.best_parent_rate
= *prate
;
394 req
.best_parent_hw
= parent
;
396 ret
= divider_determine_rate(hw
, &req
, table
, width
, flags
);
400 *prate
= req
.best_parent_rate
;
404 EXPORT_SYMBOL_GPL(divider_round_rate_parent
);
406 long divider_ro_round_rate_parent(struct clk_hw
*hw
, struct clk_hw
*parent
,
407 unsigned long rate
, unsigned long *prate
,
408 const struct clk_div_table
*table
, u8 width
,
409 unsigned long flags
, unsigned int val
)
411 struct clk_rate_request req
;
414 clk_hw_init_rate_request(hw
, &req
, rate
);
415 req
.best_parent_rate
= *prate
;
416 req
.best_parent_hw
= parent
;
418 ret
= divider_ro_determine_rate(hw
, &req
, table
, width
, flags
, val
);
422 *prate
= req
.best_parent_rate
;
426 EXPORT_SYMBOL_GPL(divider_ro_round_rate_parent
);
428 static long clk_divider_round_rate(struct clk_hw
*hw
, unsigned long rate
,
429 unsigned long *prate
)
431 struct clk_divider
*divider
= to_clk_divider(hw
);
433 /* if read only, just return current value */
434 if (divider
->flags
& CLK_DIVIDER_READ_ONLY
) {
437 val
= clk_div_readl(divider
) >> divider
->shift
;
438 val
&= clk_div_mask(divider
->width
);
440 return divider_ro_round_rate(hw
, rate
, prate
, divider
->table
,
441 divider
->width
, divider
->flags
,
445 return divider_round_rate(hw
, rate
, prate
, divider
->table
,
446 divider
->width
, divider
->flags
);
449 static int clk_divider_determine_rate(struct clk_hw
*hw
,
450 struct clk_rate_request
*req
)
452 struct clk_divider
*divider
= to_clk_divider(hw
);
454 /* if read only, just return current value */
455 if (divider
->flags
& CLK_DIVIDER_READ_ONLY
) {
458 val
= clk_div_readl(divider
) >> divider
->shift
;
459 val
&= clk_div_mask(divider
->width
);
461 return divider_ro_determine_rate(hw
, req
, divider
->table
,
463 divider
->flags
, val
);
466 return divider_determine_rate(hw
, req
, divider
->table
, divider
->width
,
470 int divider_get_val(unsigned long rate
, unsigned long parent_rate
,
471 const struct clk_div_table
*table
, u8 width
,
474 unsigned int div
, value
;
476 div
= DIV_ROUND_UP_ULL((u64
)parent_rate
, rate
);
478 if (!_is_valid_div(table
, div
, flags
))
481 value
= _get_val(table
, div
, flags
, width
);
483 return min_t(unsigned int, value
, clk_div_mask(width
));
485 EXPORT_SYMBOL_GPL(divider_get_val
);
487 static int clk_divider_set_rate(struct clk_hw
*hw
, unsigned long rate
,
488 unsigned long parent_rate
)
490 struct clk_divider
*divider
= to_clk_divider(hw
);
492 unsigned long flags
= 0;
495 value
= divider_get_val(rate
, parent_rate
, divider
->table
,
496 divider
->width
, divider
->flags
);
501 spin_lock_irqsave(divider
->lock
, flags
);
503 __acquire(divider
->lock
);
505 if (divider
->flags
& CLK_DIVIDER_HIWORD_MASK
) {
506 val
= clk_div_mask(divider
->width
) << (divider
->shift
+ 16);
508 val
= clk_div_readl(divider
);
509 val
&= ~(clk_div_mask(divider
->width
) << divider
->shift
);
511 val
|= (u32
)value
<< divider
->shift
;
512 clk_div_writel(divider
, val
);
515 spin_unlock_irqrestore(divider
->lock
, flags
);
517 __release(divider
->lock
);
522 const struct clk_ops clk_divider_ops
= {
523 .recalc_rate
= clk_divider_recalc_rate
,
524 .round_rate
= clk_divider_round_rate
,
525 .determine_rate
= clk_divider_determine_rate
,
526 .set_rate
= clk_divider_set_rate
,
528 EXPORT_SYMBOL_GPL(clk_divider_ops
);
530 const struct clk_ops clk_divider_ro_ops
= {
531 .recalc_rate
= clk_divider_recalc_rate
,
532 .round_rate
= clk_divider_round_rate
,
533 .determine_rate
= clk_divider_determine_rate
,
535 EXPORT_SYMBOL_GPL(clk_divider_ro_ops
);
537 struct clk_hw
*__clk_hw_register_divider(struct device
*dev
,
538 struct device_node
*np
, const char *name
,
539 const char *parent_name
, const struct clk_hw
*parent_hw
,
540 const struct clk_parent_data
*parent_data
, unsigned long flags
,
541 void __iomem
*reg
, u8 shift
, u8 width
, u8 clk_divider_flags
,
542 const struct clk_div_table
*table
, spinlock_t
*lock
)
544 struct clk_divider
*div
;
546 struct clk_init_data init
= {};
549 if (clk_divider_flags
& CLK_DIVIDER_HIWORD_MASK
) {
550 if (width
+ shift
> 16) {
551 pr_warn("divider value exceeds LOWORD field\n");
552 return ERR_PTR(-EINVAL
);
556 /* allocate the divider */
557 div
= kzalloc(sizeof(*div
), GFP_KERNEL
);
559 return ERR_PTR(-ENOMEM
);
562 if (clk_divider_flags
& CLK_DIVIDER_READ_ONLY
)
563 init
.ops
= &clk_divider_ro_ops
;
565 init
.ops
= &clk_divider_ops
;
567 init
.parent_names
= parent_name
? &parent_name
: NULL
;
568 init
.parent_hws
= parent_hw
? &parent_hw
: NULL
;
569 init
.parent_data
= parent_data
;
570 if (parent_name
|| parent_hw
|| parent_data
)
571 init
.num_parents
= 1;
573 init
.num_parents
= 0;
575 /* struct clk_divider assignments */
579 div
->flags
= clk_divider_flags
;
581 div
->hw
.init
= &init
;
584 /* register the clock */
586 ret
= clk_hw_register(dev
, hw
);
594 EXPORT_SYMBOL_GPL(__clk_hw_register_divider
);
597 * clk_register_divider_table - register a table based divider clock with
598 * the clock framework
599 * @dev: device registering this clock
600 * @name: name of this clock
601 * @parent_name: name of clock's parent
602 * @flags: framework-specific flags
603 * @reg: register address to adjust divider
604 * @shift: number of bits to shift the bitfield
605 * @width: width of the bitfield
606 * @clk_divider_flags: divider-specific flags for this clock
607 * @table: array of divider/value pairs ending with a div set to 0
608 * @lock: shared register lock for this clock
610 struct clk
*clk_register_divider_table(struct device
*dev
, const char *name
,
611 const char *parent_name
, unsigned long flags
,
612 void __iomem
*reg
, u8 shift
, u8 width
,
613 u8 clk_divider_flags
, const struct clk_div_table
*table
,
618 hw
= __clk_hw_register_divider(dev
, NULL
, name
, parent_name
, NULL
,
619 NULL
, flags
, reg
, shift
, width
, clk_divider_flags
,
625 EXPORT_SYMBOL_GPL(clk_register_divider_table
);
627 void clk_unregister_divider(struct clk
*clk
)
629 struct clk_divider
*div
;
632 hw
= __clk_get_hw(clk
);
636 div
= to_clk_divider(hw
);
641 EXPORT_SYMBOL_GPL(clk_unregister_divider
);
644 * clk_hw_unregister_divider - unregister a clk divider
645 * @hw: hardware-specific clock data to unregister
647 void clk_hw_unregister_divider(struct clk_hw
*hw
)
649 struct clk_divider
*div
;
651 div
= to_clk_divider(hw
);
653 clk_hw_unregister(hw
);
656 EXPORT_SYMBOL_GPL(clk_hw_unregister_divider
);
658 static void devm_clk_hw_release_divider(struct device
*dev
, void *res
)
660 clk_hw_unregister_divider(*(struct clk_hw
**)res
);
663 struct clk_hw
*__devm_clk_hw_register_divider(struct device
*dev
,
664 struct device_node
*np
, const char *name
,
665 const char *parent_name
, const struct clk_hw
*parent_hw
,
666 const struct clk_parent_data
*parent_data
, unsigned long flags
,
667 void __iomem
*reg
, u8 shift
, u8 width
, u8 clk_divider_flags
,
668 const struct clk_div_table
*table
, spinlock_t
*lock
)
670 struct clk_hw
**ptr
, *hw
;
672 ptr
= devres_alloc(devm_clk_hw_release_divider
, sizeof(*ptr
), GFP_KERNEL
);
674 return ERR_PTR(-ENOMEM
);
676 hw
= __clk_hw_register_divider(dev
, np
, name
, parent_name
, parent_hw
,
677 parent_data
, flags
, reg
, shift
, width
,
678 clk_divider_flags
, table
, lock
);
682 devres_add(dev
, ptr
);
689 EXPORT_SYMBOL_GPL(__devm_clk_hw_register_divider
);