1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
6 * Serge Semin <Sergey.Semin@baikalelectronics.ru>
7 * Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru>
9 * Baikal-T1 CCU PLL interface driver
12 #define pr_fmt(fmt) "bt1-ccu-pll: " fmt
14 #include <linux/kernel.h>
15 #include <linux/printk.h>
16 #include <linux/limits.h>
17 #include <linux/bits.h>
18 #include <linux/bitfield.h>
19 #include <linux/slab.h>
20 #include <linux/clk-provider.h>
22 #include <linux/spinlock.h>
23 #include <linux/regmap.h>
24 #include <linux/iopoll.h>
25 #include <linux/time64.h>
26 #include <linux/rational.h>
27 #include <linux/debugfs.h>
31 #define CCU_PLL_CTL 0x000
32 #define CCU_PLL_CTL_EN BIT(0)
33 #define CCU_PLL_CTL_RST BIT(1)
34 #define CCU_PLL_CTL_CLKR_FLD 2
35 #define CCU_PLL_CTL_CLKR_MASK GENMASK(7, CCU_PLL_CTL_CLKR_FLD)
36 #define CCU_PLL_CTL_CLKF_FLD 8
37 #define CCU_PLL_CTL_CLKF_MASK GENMASK(20, CCU_PLL_CTL_CLKF_FLD)
38 #define CCU_PLL_CTL_CLKOD_FLD 21
39 #define CCU_PLL_CTL_CLKOD_MASK GENMASK(24, CCU_PLL_CTL_CLKOD_FLD)
40 #define CCU_PLL_CTL_BYPASS BIT(30)
41 #define CCU_PLL_CTL_LOCK BIT(31)
42 #define CCU_PLL_CTL1 0x004
43 #define CCU_PLL_CTL1_BWADJ_FLD 3
44 #define CCU_PLL_CTL1_BWADJ_MASK GENMASK(14, CCU_PLL_CTL1_BWADJ_FLD)
46 #define CCU_PLL_LOCK_CHECK_RETRIES 50
48 #define CCU_PLL_NR_MAX \
49 ((CCU_PLL_CTL_CLKR_MASK >> CCU_PLL_CTL_CLKR_FLD) + 1)
50 #define CCU_PLL_NF_MAX \
51 ((CCU_PLL_CTL_CLKF_MASK >> (CCU_PLL_CTL_CLKF_FLD + 1)) + 1)
52 #define CCU_PLL_OD_MAX \
53 ((CCU_PLL_CTL_CLKOD_MASK >> CCU_PLL_CTL_CLKOD_FLD) + 1)
54 #define CCU_PLL_NB_MAX \
55 ((CCU_PLL_CTL1_BWADJ_MASK >> CCU_PLL_CTL1_BWADJ_FLD) + 1)
56 #define CCU_PLL_FDIV_MIN 427000UL
57 #define CCU_PLL_FDIV_MAX 3500000000UL
58 #define CCU_PLL_FOUT_MIN 200000000UL
59 #define CCU_PLL_FOUT_MAX 2500000000UL
60 #define CCU_PLL_FVCO_MIN 700000000UL
61 #define CCU_PLL_FVCO_MAX 3500000000UL
62 #define CCU_PLL_CLKOD_FACTOR 2
64 static inline unsigned long ccu_pll_lock_delay_us(unsigned long ref_clk,
67 u64 us = 500ULL * nr * USEC_PER_SEC;
74 static inline unsigned long ccu_pll_calc_freq(unsigned long ref_clk,
88 static int ccu_pll_reset(struct ccu_pll *pll, unsigned long ref_clk,
94 ud = ccu_pll_lock_delay_us(ref_clk, nr);
95 ut = ud * CCU_PLL_LOCK_CHECK_RETRIES;
97 regmap_update_bits(pll->sys_regs, pll->reg_ctl,
98 CCU_PLL_CTL_RST, CCU_PLL_CTL_RST);
100 return regmap_read_poll_timeout_atomic(pll->sys_regs, pll->reg_ctl, val,
101 val & CCU_PLL_CTL_LOCK, ud, ut);
104 static int ccu_pll_enable(struct clk_hw *hw)
106 struct clk_hw *parent_hw = clk_hw_get_parent(hw);
107 struct ccu_pll *pll = to_ccu_pll(hw);
113 pr_err("Can't enable '%s' with no parent", clk_hw_get_name(hw));
117 regmap_read(pll->sys_regs, pll->reg_ctl, &val);
118 if (val & CCU_PLL_CTL_EN)
121 spin_lock_irqsave(&pll->lock, flags);
122 regmap_write(pll->sys_regs, pll->reg_ctl, val | CCU_PLL_CTL_EN);
123 ret = ccu_pll_reset(pll, clk_hw_get_rate(parent_hw),
124 FIELD_GET(CCU_PLL_CTL_CLKR_MASK, val) + 1);
125 spin_unlock_irqrestore(&pll->lock, flags);
127 pr_err("PLL '%s' reset timed out\n", clk_hw_get_name(hw));
132 static void ccu_pll_disable(struct clk_hw *hw)
134 struct ccu_pll *pll = to_ccu_pll(hw);
137 spin_lock_irqsave(&pll->lock, flags);
138 regmap_update_bits(pll->sys_regs, pll->reg_ctl, CCU_PLL_CTL_EN, 0);
139 spin_unlock_irqrestore(&pll->lock, flags);
142 static int ccu_pll_is_enabled(struct clk_hw *hw)
144 struct ccu_pll *pll = to_ccu_pll(hw);
147 regmap_read(pll->sys_regs, pll->reg_ctl, &val);
149 return !!(val & CCU_PLL_CTL_EN);
152 static unsigned long ccu_pll_recalc_rate(struct clk_hw *hw,
153 unsigned long parent_rate)
155 struct ccu_pll *pll = to_ccu_pll(hw);
156 unsigned long nr, nf, od;
159 regmap_read(pll->sys_regs, pll->reg_ctl, &val);
160 nr = FIELD_GET(CCU_PLL_CTL_CLKR_MASK, val) + 1;
161 nf = FIELD_GET(CCU_PLL_CTL_CLKF_MASK, val) + 1;
162 od = FIELD_GET(CCU_PLL_CTL_CLKOD_MASK, val) + 1;
164 return ccu_pll_calc_freq(parent_rate, nr, nf, od);
167 static void ccu_pll_calc_factors(unsigned long rate, unsigned long parent_rate,
168 unsigned long *nr, unsigned long *nf,
171 unsigned long err, freq, min_err = ULONG_MAX;
172 unsigned long num, denom, n1, d1, nri;
173 unsigned long nr_max, nf_max, od_max;
176 * Make sure PLL is working with valid input signal (Fdiv). If
177 * you want to speed the function up just reduce CCU_PLL_NR_MAX.
178 * This will cause a worse approximation though.
180 nri = (parent_rate / CCU_PLL_FDIV_MAX) + 1;
181 nr_max = min(parent_rate / CCU_PLL_FDIV_MIN, CCU_PLL_NR_MAX);
184 * Find a closest [nr;nf;od] vector taking into account the
185 * limitations like: 1) 700MHz <= Fvco <= 3.5GHz, 2) PLL Od is
186 * either 1 or even number within the acceptable range (alas 1s
187 * is also excluded by the next loop).
189 for (; nri <= nr_max; ++nri) {
190 /* Use Od factor to fulfill the limitation 2). */
191 num = CCU_PLL_CLKOD_FACTOR * rate;
192 denom = parent_rate / nri;
195 * Make sure Fvco is within the acceptable range to fulfill
196 * the condition 1). Note due to the CCU_PLL_CLKOD_FACTOR value
197 * the actual upper limit is also divided by that factor.
198 * It's not big problem for us since practically there is no
199 * need in clocks with that high frequency.
201 nf_max = min(CCU_PLL_FVCO_MAX / denom, CCU_PLL_NF_MAX);
202 od_max = CCU_PLL_OD_MAX / CCU_PLL_CLKOD_FACTOR;
205 * Bypass the out-of-bound values, which can't be properly
206 * handled by the rational fraction approximation algorithm.
208 if (num / denom >= nf_max) {
211 } else if (denom / num >= od_max) {
215 rational_best_approximation(num, denom, nf_max, od_max,
219 /* Select the best approximation of the target rate. */
220 freq = ccu_pll_calc_freq(parent_rate, nri, n1, d1);
221 err = abs((int64_t)freq - num);
226 *od = CCU_PLL_CLKOD_FACTOR * d1;
231 static long ccu_pll_round_rate(struct clk_hw *hw, unsigned long rate,
232 unsigned long *parent_rate)
234 unsigned long nr = 1, nf = 1, od = 1;
236 ccu_pll_calc_factors(rate, *parent_rate, &nr, &nf, &od);
238 return ccu_pll_calc_freq(*parent_rate, nr, nf, od);
242 * This method is used for PLLs, which support the on-the-fly dividers
243 * adjustment. So there is no need in gating such clocks.
245 static int ccu_pll_set_rate_reset(struct clk_hw *hw, unsigned long rate,
246 unsigned long parent_rate)
248 struct ccu_pll *pll = to_ccu_pll(hw);
249 unsigned long nr, nf, od;
254 ccu_pll_calc_factors(rate, parent_rate, &nr, &nf, &od);
256 mask = CCU_PLL_CTL_CLKR_MASK | CCU_PLL_CTL_CLKF_MASK |
257 CCU_PLL_CTL_CLKOD_MASK;
258 val = FIELD_PREP(CCU_PLL_CTL_CLKR_MASK, nr - 1) |
259 FIELD_PREP(CCU_PLL_CTL_CLKF_MASK, nf - 1) |
260 FIELD_PREP(CCU_PLL_CTL_CLKOD_MASK, od - 1);
262 spin_lock_irqsave(&pll->lock, flags);
263 regmap_update_bits(pll->sys_regs, pll->reg_ctl, mask, val);
264 ret = ccu_pll_reset(pll, parent_rate, nr);
265 spin_unlock_irqrestore(&pll->lock, flags);
267 pr_err("PLL '%s' reset timed out\n", clk_hw_get_name(hw));
273 * This method is used for PLLs, which don't support the on-the-fly dividers
274 * adjustment. So the corresponding clocks are supposed to be gated first.
276 static int ccu_pll_set_rate_norst(struct clk_hw *hw, unsigned long rate,
277 unsigned long parent_rate)
279 struct ccu_pll *pll = to_ccu_pll(hw);
280 unsigned long nr, nf, od;
284 ccu_pll_calc_factors(rate, parent_rate, &nr, &nf, &od);
287 * Disable PLL if it was enabled by default or left enabled by the
290 mask = CCU_PLL_CTL_CLKR_MASK | CCU_PLL_CTL_CLKF_MASK |
291 CCU_PLL_CTL_CLKOD_MASK | CCU_PLL_CTL_EN;
292 val = FIELD_PREP(CCU_PLL_CTL_CLKR_MASK, nr - 1) |
293 FIELD_PREP(CCU_PLL_CTL_CLKF_MASK, nf - 1) |
294 FIELD_PREP(CCU_PLL_CTL_CLKOD_MASK, od - 1);
296 spin_lock_irqsave(&pll->lock, flags);
297 regmap_update_bits(pll->sys_regs, pll->reg_ctl, mask, val);
298 spin_unlock_irqrestore(&pll->lock, flags);
303 #ifdef CONFIG_DEBUG_FS
305 struct ccu_pll_dbgfs_bit {
312 struct ccu_pll_dbgfs_fld {
322 #define CCU_PLL_DBGFS_BIT_ATTR(_name, _reg, _mask) \
329 #define CCU_PLL_DBGFS_FLD_ATTR(_name, _reg, _lsb, _mask, _min, _max) \
339 static const struct ccu_pll_dbgfs_bit ccu_pll_bits[] = {
340 CCU_PLL_DBGFS_BIT_ATTR("pll_en", CCU_PLL_CTL, CCU_PLL_CTL_EN),
341 CCU_PLL_DBGFS_BIT_ATTR("pll_rst", CCU_PLL_CTL, CCU_PLL_CTL_RST),
342 CCU_PLL_DBGFS_BIT_ATTR("pll_bypass", CCU_PLL_CTL, CCU_PLL_CTL_BYPASS),
343 CCU_PLL_DBGFS_BIT_ATTR("pll_lock", CCU_PLL_CTL, CCU_PLL_CTL_LOCK)
346 #define CCU_PLL_DBGFS_BIT_NUM ARRAY_SIZE(ccu_pll_bits)
348 static const struct ccu_pll_dbgfs_fld ccu_pll_flds[] = {
349 CCU_PLL_DBGFS_FLD_ATTR("pll_nr", CCU_PLL_CTL, CCU_PLL_CTL_CLKR_FLD,
350 CCU_PLL_CTL_CLKR_MASK, 1, CCU_PLL_NR_MAX),
351 CCU_PLL_DBGFS_FLD_ATTR("pll_nf", CCU_PLL_CTL, CCU_PLL_CTL_CLKF_FLD,
352 CCU_PLL_CTL_CLKF_MASK, 1, CCU_PLL_NF_MAX),
353 CCU_PLL_DBGFS_FLD_ATTR("pll_od", CCU_PLL_CTL, CCU_PLL_CTL_CLKOD_FLD,
354 CCU_PLL_CTL_CLKOD_MASK, 1, CCU_PLL_OD_MAX),
355 CCU_PLL_DBGFS_FLD_ATTR("pll_nb", CCU_PLL_CTL1, CCU_PLL_CTL1_BWADJ_FLD,
356 CCU_PLL_CTL1_BWADJ_MASK, 1, CCU_PLL_NB_MAX)
359 #define CCU_PLL_DBGFS_FLD_NUM ARRAY_SIZE(ccu_pll_flds)
362 * It can be dangerous to change the PLL settings behind clock framework back,
363 * therefore we don't provide any kernel config based compile time option for
364 * this feature to enable.
366 #undef CCU_PLL_ALLOW_WRITE_DEBUGFS
367 #ifdef CCU_PLL_ALLOW_WRITE_DEBUGFS
369 static int ccu_pll_dbgfs_bit_set(void *priv, u64 val)
371 const struct ccu_pll_dbgfs_bit *bit = priv;
372 struct ccu_pll *pll = bit->pll;
375 spin_lock_irqsave(&pll->lock, flags);
376 regmap_update_bits(pll->sys_regs, pll->reg_ctl + bit->reg,
377 bit->mask, val ? bit->mask : 0);
378 spin_unlock_irqrestore(&pll->lock, flags);
383 static int ccu_pll_dbgfs_fld_set(void *priv, u64 val)
385 struct ccu_pll_dbgfs_fld *fld = priv;
386 struct ccu_pll *pll = fld->pll;
390 val = clamp_t(u64, val, fld->min, fld->max);
391 data = ((val - 1) << fld->lsb) & fld->mask;
393 spin_lock_irqsave(&pll->lock, flags);
394 regmap_update_bits(pll->sys_regs, pll->reg_ctl + fld->reg, fld->mask,
396 spin_unlock_irqrestore(&pll->lock, flags);
401 #define ccu_pll_dbgfs_mode 0644
403 #else /* !CCU_PLL_ALLOW_WRITE_DEBUGFS */
405 #define ccu_pll_dbgfs_bit_set NULL
406 #define ccu_pll_dbgfs_fld_set NULL
407 #define ccu_pll_dbgfs_mode 0444
409 #endif /* !CCU_PLL_ALLOW_WRITE_DEBUGFS */
411 static int ccu_pll_dbgfs_bit_get(void *priv, u64 *val)
413 struct ccu_pll_dbgfs_bit *bit = priv;
414 struct ccu_pll *pll = bit->pll;
417 regmap_read(pll->sys_regs, pll->reg_ctl + bit->reg, &data);
418 *val = !!(data & bit->mask);
422 DEFINE_DEBUGFS_ATTRIBUTE(ccu_pll_dbgfs_bit_fops,
423 ccu_pll_dbgfs_bit_get, ccu_pll_dbgfs_bit_set, "%llu\n");
425 static int ccu_pll_dbgfs_fld_get(void *priv, u64 *val)
427 struct ccu_pll_dbgfs_fld *fld = priv;
428 struct ccu_pll *pll = fld->pll;
431 regmap_read(pll->sys_regs, pll->reg_ctl + fld->reg, &data);
432 *val = ((data & fld->mask) >> fld->lsb) + 1;
436 DEFINE_DEBUGFS_ATTRIBUTE(ccu_pll_dbgfs_fld_fops,
437 ccu_pll_dbgfs_fld_get, ccu_pll_dbgfs_fld_set, "%llu\n");
439 static void ccu_pll_debug_init(struct clk_hw *hw, struct dentry *dentry)
441 struct ccu_pll *pll = to_ccu_pll(hw);
442 struct ccu_pll_dbgfs_bit *bits;
443 struct ccu_pll_dbgfs_fld *flds;
446 bits = kcalloc(CCU_PLL_DBGFS_BIT_NUM, sizeof(*bits), GFP_KERNEL);
450 for (idx = 0; idx < CCU_PLL_DBGFS_BIT_NUM; ++idx) {
451 bits[idx] = ccu_pll_bits[idx];
454 debugfs_create_file_unsafe(bits[idx].name, ccu_pll_dbgfs_mode,
456 &ccu_pll_dbgfs_bit_fops);
459 flds = kcalloc(CCU_PLL_DBGFS_FLD_NUM, sizeof(*flds), GFP_KERNEL);
463 for (idx = 0; idx < CCU_PLL_DBGFS_FLD_NUM; ++idx) {
464 flds[idx] = ccu_pll_flds[idx];
467 debugfs_create_file_unsafe(flds[idx].name, ccu_pll_dbgfs_mode,
469 &ccu_pll_dbgfs_fld_fops);
473 #else /* !CONFIG_DEBUG_FS */
475 #define ccu_pll_debug_init NULL
477 #endif /* !CONFIG_DEBUG_FS */
479 static const struct clk_ops ccu_pll_gate_to_set_ops = {
480 .enable = ccu_pll_enable,
481 .disable = ccu_pll_disable,
482 .is_enabled = ccu_pll_is_enabled,
483 .recalc_rate = ccu_pll_recalc_rate,
484 .round_rate = ccu_pll_round_rate,
485 .set_rate = ccu_pll_set_rate_norst,
486 .debug_init = ccu_pll_debug_init
489 static const struct clk_ops ccu_pll_straight_set_ops = {
490 .enable = ccu_pll_enable,
491 .disable = ccu_pll_disable,
492 .is_enabled = ccu_pll_is_enabled,
493 .recalc_rate = ccu_pll_recalc_rate,
494 .round_rate = ccu_pll_round_rate,
495 .set_rate = ccu_pll_set_rate_reset,
496 .debug_init = ccu_pll_debug_init
499 struct ccu_pll *ccu_pll_hw_register(const struct ccu_pll_init_data *pll_init)
501 struct clk_parent_data parent_data = { };
502 struct clk_init_data hw_init = { };
507 return ERR_PTR(-EINVAL);
509 pll = kzalloc(sizeof(*pll), GFP_KERNEL);
511 return ERR_PTR(-ENOMEM);
514 * Note since Baikal-T1 System Controller registers are MMIO-backed
515 * we won't check the regmap IO operations return status, because it
516 * must be zero anyway.
518 pll->hw.init = &hw_init;
519 pll->reg_ctl = pll_init->base + CCU_PLL_CTL;
520 pll->reg_ctl1 = pll_init->base + CCU_PLL_CTL1;
521 pll->sys_regs = pll_init->sys_regs;
522 pll->id = pll_init->id;
523 spin_lock_init(&pll->lock);
525 hw_init.name = pll_init->name;
526 hw_init.flags = pll_init->flags;
528 if (hw_init.flags & CLK_SET_RATE_GATE)
529 hw_init.ops = &ccu_pll_gate_to_set_ops;
531 hw_init.ops = &ccu_pll_straight_set_ops;
533 if (!pll_init->parent_name) {
537 parent_data.fw_name = pll_init->parent_name;
538 hw_init.parent_data = &parent_data;
539 hw_init.num_parents = 1;
541 ret = of_clk_hw_register(pll_init->np, &pll->hw);
553 void ccu_pll_hw_unregister(struct ccu_pll *pll)
555 clk_hw_unregister(&pll->hw);