4 * Copyright (C) 2013 Texas Instruments, Inc.
6 * Tero Kristo <t-kristo@ti.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
13 * kind, whether express or implied; without even the implied warranty
14 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/clk-provider.h>
19 #include <linux/slab.h>
20 #include <linux/err.h>
22 #include <linux/of_address.h>
23 #include <linux/clk/ti.h>
27 #define pr_fmt(fmt) "%s: " fmt, __func__
29 #define div_mask(d) ((1 << ((d)->width)) - 1)
31 static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
33 unsigned int maxdiv = 0;
34 const struct clk_div_table *clkt;
36 for (clkt = table; clkt->div; clkt++)
37 if (clkt->div > maxdiv)
42 static unsigned int _get_maxdiv(struct clk_omap_divider *divider)
44 if (divider->flags & CLK_DIVIDER_ONE_BASED)
45 return div_mask(divider);
46 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
47 return 1 << div_mask(divider);
49 return _get_table_maxdiv(divider->table);
50 return div_mask(divider) + 1;
53 static unsigned int _get_table_div(const struct clk_div_table *table,
56 const struct clk_div_table *clkt;
58 for (clkt = table; clkt->div; clkt++)
64 static unsigned int _get_div(struct clk_omap_divider *divider, unsigned int val)
66 if (divider->flags & CLK_DIVIDER_ONE_BASED)
68 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
71 return _get_table_div(divider->table, val);
75 static unsigned int _get_table_val(const struct clk_div_table *table,
78 const struct clk_div_table *clkt;
80 for (clkt = table; clkt->div; clkt++)
86 static unsigned int _get_val(struct clk_omap_divider *divider, u8 div)
88 if (divider->flags & CLK_DIVIDER_ONE_BASED)
90 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
93 return _get_table_val(divider->table, div);
97 static unsigned long ti_clk_divider_recalc_rate(struct clk_hw *hw,
98 unsigned long parent_rate)
100 struct clk_omap_divider *divider = to_clk_omap_divider(hw);
101 unsigned int div, val;
103 val = ti_clk_ll_ops->clk_readl(÷r->reg) >> divider->shift;
104 val &= div_mask(divider);
106 div = _get_div(divider, val);
108 WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
109 "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
110 clk_hw_get_name(hw));
114 return DIV_ROUND_UP(parent_rate, div);
118 * The reverse of DIV_ROUND_UP: The maximum number which
121 #define MULT_ROUND_UP(r, m) ((r) * (m) + (m) - 1)
123 static bool _is_valid_table_div(const struct clk_div_table *table,
126 const struct clk_div_table *clkt;
128 for (clkt = table; clkt->div; clkt++)
129 if (clkt->div == div)
134 static bool _is_valid_div(struct clk_omap_divider *divider, unsigned int div)
136 if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
137 return is_power_of_2(div);
139 return _is_valid_table_div(divider->table, div);
143 static int _div_round_up(const struct clk_div_table *table,
144 unsigned long parent_rate, unsigned long rate)
146 const struct clk_div_table *clkt;
148 int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
150 for (clkt = table; clkt->div; clkt++) {
151 if (clkt->div == div)
153 else if (clkt->div < div)
156 if ((clkt->div - div) < (up - div))
163 static int _div_round(const struct clk_div_table *table,
164 unsigned long parent_rate, unsigned long rate)
167 return DIV_ROUND_UP(parent_rate, rate);
169 return _div_round_up(table, parent_rate, rate);
172 static int ti_clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
173 unsigned long *best_parent_rate)
175 struct clk_omap_divider *divider = to_clk_omap_divider(hw);
177 unsigned long parent_rate, best = 0, now, maxdiv;
178 unsigned long parent_rate_saved = *best_parent_rate;
183 maxdiv = _get_maxdiv(divider);
185 if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
186 parent_rate = *best_parent_rate;
187 bestdiv = _div_round(divider->table, parent_rate, rate);
188 bestdiv = bestdiv == 0 ? 1 : bestdiv;
189 bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
194 * The maximum divider we can use without overflowing
195 * unsigned long in rate * i below
197 maxdiv = min(ULONG_MAX / rate, maxdiv);
199 for (i = 1; i <= maxdiv; i++) {
200 if (!_is_valid_div(divider, i))
202 if (rate * i == parent_rate_saved) {
204 * It's the most ideal case if the requested rate can be
205 * divided from parent clock without needing to change
206 * parent rate, so return the divider immediately.
208 *best_parent_rate = parent_rate_saved;
211 parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
212 MULT_ROUND_UP(rate, i));
213 now = DIV_ROUND_UP(parent_rate, i);
214 if (now <= rate && now > best) {
217 *best_parent_rate = parent_rate;
222 bestdiv = _get_maxdiv(divider);
224 clk_hw_round_rate(clk_hw_get_parent(hw), 1);
230 static long ti_clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
231 unsigned long *prate)
234 div = ti_clk_divider_bestdiv(hw, rate, prate);
236 return DIV_ROUND_UP(*prate, div);
239 static int ti_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
240 unsigned long parent_rate)
242 struct clk_omap_divider *divider;
243 unsigned int div, value;
249 divider = to_clk_omap_divider(hw);
251 div = DIV_ROUND_UP(parent_rate, rate);
252 value = _get_val(divider, div);
254 if (value > div_mask(divider))
255 value = div_mask(divider);
257 if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
258 val = div_mask(divider) << (divider->shift + 16);
260 val = ti_clk_ll_ops->clk_readl(÷r->reg);
261 val &= ~(div_mask(divider) << divider->shift);
263 val |= value << divider->shift;
264 ti_clk_ll_ops->clk_writel(val, ÷r->reg);
266 ti_clk_latch(÷r->reg, divider->latch);
272 * clk_divider_save_context - Save the divider value
273 * @hw: pointer struct clk_hw
275 * Save the divider value
277 static int clk_divider_save_context(struct clk_hw *hw)
279 struct clk_omap_divider *divider = to_clk_omap_divider(hw);
282 val = ti_clk_ll_ops->clk_readl(÷r->reg) >> divider->shift;
283 divider->context = val & div_mask(divider);
289 * clk_divider_restore_context - restore the saved the divider value
290 * @hw: pointer struct clk_hw
292 * Restore the saved the divider value
294 static void clk_divider_restore_context(struct clk_hw *hw)
296 struct clk_omap_divider *divider = to_clk_omap_divider(hw);
299 val = ti_clk_ll_ops->clk_readl(÷r->reg);
300 val &= ~(div_mask(divider) << divider->shift);
301 val |= divider->context << divider->shift;
302 ti_clk_ll_ops->clk_writel(val, ÷r->reg);
305 const struct clk_ops ti_clk_divider_ops = {
306 .recalc_rate = ti_clk_divider_recalc_rate,
307 .round_rate = ti_clk_divider_round_rate,
308 .set_rate = ti_clk_divider_set_rate,
309 .save_context = clk_divider_save_context,
310 .restore_context = clk_divider_restore_context,
313 static struct clk *_register_divider(struct device *dev, const char *name,
314 const char *parent_name,
316 struct clk_omap_reg *reg,
317 u8 shift, u8 width, s8 latch,
318 u8 clk_divider_flags,
319 const struct clk_div_table *table)
321 struct clk_omap_divider *div;
323 struct clk_init_data init;
325 if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
326 if (width + shift > 16) {
327 pr_warn("divider value exceeds LOWORD field\n");
328 return ERR_PTR(-EINVAL);
332 /* allocate the divider */
333 div = kzalloc(sizeof(*div), GFP_KERNEL);
335 return ERR_PTR(-ENOMEM);
338 init.ops = &ti_clk_divider_ops;
340 init.parent_names = (parent_name ? &parent_name : NULL);
341 init.num_parents = (parent_name ? 1 : 0);
343 /* struct clk_divider assignments */
344 memcpy(&div->reg, reg, sizeof(*reg));
348 div->flags = clk_divider_flags;
349 div->hw.init = &init;
352 /* register the clock */
353 clk = ti_clk_register(dev, &div->hw, name);
361 int ti_clk_parse_divider_data(int *div_table, int num_dividers, int max_div,
363 const struct clk_div_table **table)
369 struct clk_div_table *tmp;
372 if (flags & CLKF_INDEX_STARTS_AT_ONE)
379 while (div < max_div) {
380 if (flags & CLKF_INDEX_POWER_OF_TWO)
395 while (!num_dividers || i < num_dividers) {
396 if (div_table[i] == -1)
405 tmp = kcalloc(valid_div + 1, sizeof(*tmp), GFP_KERNEL);
407 *table = ERR_PTR(-ENOMEM);
414 for (i = 0; i < num_dividers; i++)
415 if (div_table[i] > 0) {
416 tmp[valid_div].div = div_table[i];
417 tmp[valid_div].val = i;
422 *width = fls(*width);
428 static struct clk_div_table *
429 __init ti_clk_get_div_table(struct device_node *node)
431 struct clk_div_table *table;
432 const __be32 *divspec;
438 divspec = of_get_property(node, "ti,dividers", &num_div);
447 /* Determine required size for divider table */
448 for (i = 0; i < num_div; i++) {
449 of_property_read_u32_index(node, "ti,dividers", i, &val);
455 pr_err("no valid dividers for %pOFn table\n", node);
456 return ERR_PTR(-EINVAL);
459 table = kcalloc(valid_div + 1, sizeof(*table), GFP_KERNEL);
462 return ERR_PTR(-ENOMEM);
466 for (i = 0; i < num_div; i++) {
467 of_property_read_u32_index(node, "ti,dividers", i, &val);
469 table[valid_div].div = val;
470 table[valid_div].val = i;
478 static int _get_divider_width(struct device_node *node,
479 const struct clk_div_table *table,
488 /* Clk divider table not provided, determine min/max divs */
489 if (of_property_read_u32(node, "ti,min-div", &min_div))
492 if (of_property_read_u32(node, "ti,max-div", &max_div)) {
493 pr_err("no max-div for %pOFn!\n", node);
497 /* Determine bit width for the field */
498 if (flags & CLK_DIVIDER_ONE_BASED)
503 while (div < max_div) {
504 if (flags & CLK_DIVIDER_POWER_OF_TWO)
513 while (table[div].div) {
514 val = table[div].val;
522 static int __init ti_clk_divider_populate(struct device_node *node,
523 struct clk_omap_reg *reg, const struct clk_div_table **table,
524 u32 *flags, u8 *div_flags, u8 *width, u8 *shift, s8 *latch)
529 ret = ti_clk_get_reg_addr(node, 0, reg);
533 if (!of_property_read_u32(node, "ti,bit-shift", &val))
539 if (!of_property_read_u32(node, "ti,latch-bit", &val))
548 if (of_property_read_bool(node, "ti,index-starts-at-one"))
549 *div_flags |= CLK_DIVIDER_ONE_BASED;
551 if (of_property_read_bool(node, "ti,index-power-of-two"))
552 *div_flags |= CLK_DIVIDER_POWER_OF_TWO;
554 if (of_property_read_bool(node, "ti,set-rate-parent"))
555 *flags |= CLK_SET_RATE_PARENT;
557 *table = ti_clk_get_div_table(node);
560 return PTR_ERR(*table);
562 *width = _get_divider_width(node, *table, *div_flags);
568 * of_ti_divider_clk_setup - Setup function for simple div rate clock
569 * @node: device node for this clock
571 * Sets up a basic divider clock.
573 static void __init of_ti_divider_clk_setup(struct device_node *node)
576 const char *parent_name;
577 struct clk_omap_reg reg;
578 u8 clk_divider_flags = 0;
582 const struct clk_div_table *table = NULL;
585 parent_name = of_clk_get_parent_name(node, 0);
587 if (ti_clk_divider_populate(node, ®, &table, &flags,
588 &clk_divider_flags, &width, &shift, &latch))
591 clk = _register_divider(NULL, node->name, parent_name, flags, ®,
592 shift, width, latch, clk_divider_flags, table);
595 of_clk_add_provider(node, of_clk_src_simple_get, clk);
596 of_ti_clk_autoidle_setup(node);
603 CLK_OF_DECLARE(divider_clk, "ti,divider-clock", of_ti_divider_clk_setup);
605 static void __init of_ti_composite_divider_clk_setup(struct device_node *node)
607 struct clk_omap_divider *div;
610 div = kzalloc(sizeof(*div), GFP_KERNEL);
614 if (ti_clk_divider_populate(node, &div->reg, &div->table, &val,
615 &div->flags, &div->width, &div->shift,
619 if (!ti_clk_add_component(node, &div->hw, CLK_COMPONENT_TYPE_DIVIDER))
626 CLK_OF_DECLARE(ti_composite_divider_clk, "ti,composite-divider-clock",
627 of_ti_composite_divider_clk_setup);