xref: /openbmc/linux/drivers/clk/qcom/clk-cpu-8996.c (revision 2d99a7ec)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2020, The Linux Foundation. All rights reserved.
4  */
5 
6 /*
7  * Each of the CPU clusters (Power and Perf) on msm8996 are
8  * clocked via 2 PLLs, a primary and alternate. There are also
9  * 2 Mux'es, a primary and secondary all connected together
10  * as shown below
11  *
12  *                              +-------+
13  *               XO             |       |
14  *           +------------------>0      |
15  *               SYS_APCS_AUX   |       |
16  *           +------------------>3      |
17  *                              |       |
18  *                    PLL/2     | SMUX  +----+
19  *                      +------->1      |    |
20  *                      |       |       |    |
21  *                      |       +-------+    |    +-------+
22  *                      |                    +---->0      |
23  *                      |                         |       |
24  * +---------------+    |             +----------->1      | CPU clk
25  * |Primary PLL    +----+ PLL_EARLY   |           |       +------>
26  * |               +------+-----------+    +------>2 PMUX |
27  * +---------------+      |                |      |       |
28  *                        |   +------+     |   +-->3      |
29  *                        +--^+  ACD +-----+   |  +-------+
30  * +---------------+          +------+         |
31  * |Alt PLL        |                           |
32  * |               +---------------------------+
33  * +---------------+         PLL_EARLY
34  *
35  * The primary PLL is what drives the CPU clk, except for times
36  * when we are reprogramming the PLL itself (for rate changes) when
37  * we temporarily switch to an alternate PLL.
38  *
39  * The primary PLL operates on a single VCO range, between 600MHz
40  * and 3GHz. However the CPUs do support OPPs with frequencies
41  * between 300MHz and 600MHz. In order to support running the CPUs
42  * at those frequencies we end up having to lock the PLL at twice
43  * the rate and drive the CPU clk via the PLL/2 output and SMUX.
44  *
45  * So for frequencies above 600MHz we follow the following path
46  *  Primary PLL --> PLL_EARLY --> PMUX(1) --> CPU clk
47  * and for frequencies between 300MHz and 600MHz we follow
48  *  Primary PLL --> PLL/2 --> SMUX(1) --> PMUX(0) --> CPU clk
49  *
50  * ACD stands for Adaptive Clock Distribution and is used to
51  * detect voltage droops.
52  */
53 
54 #include <linux/bitfield.h>
55 #include <linux/clk.h>
56 #include <linux/clk-provider.h>
57 #include <linux/io.h>
58 #include <linux/module.h>
59 #include <linux/platform_device.h>
60 #include <linux/regmap.h>
61 #include <soc/qcom/kryo-l2-accessors.h>
62 
63 #include <asm/cputype.h>
64 
65 #include "clk-alpha-pll.h"
66 #include "clk-regmap.h"
67 #include "clk-regmap-mux.h"
68 
69 enum _pmux_input {
70 	SMUX_INDEX = 0,
71 	PLL_INDEX,
72 	ACD_INDEX,
73 	ALT_INDEX,
74 	NUM_OF_PMUX_INPUTS
75 };
76 
77 #define DIV_2_THRESHOLD		600000000
78 #define PWRCL_REG_OFFSET 0x0
79 #define PERFCL_REG_OFFSET 0x80000
80 #define MUX_OFFSET	0x40
81 #define CLK_CTL_OFFSET 0x44
82 #define CLK_CTL_AUTO_CLK_SEL BIT(8)
83 #define ALT_PLL_OFFSET	0x100
84 #define SSSCTL_OFFSET 0x160
85 #define PSCTL_OFFSET 0x164
86 
87 #define PMUX_MASK	0x3
88 #define MUX_AUTO_CLK_SEL_ALWAYS_ON_MASK GENMASK(5, 4)
89 #define MUX_AUTO_CLK_SEL_ALWAYS_ON_GPLL0_SEL \
90 	FIELD_PREP(MUX_AUTO_CLK_SEL_ALWAYS_ON_MASK, 0x03)
91 
92 static const u8 prim_pll_regs[PLL_OFF_MAX_REGS] = {
93 	[PLL_OFF_L_VAL] = 0x04,
94 	[PLL_OFF_ALPHA_VAL] = 0x08,
95 	[PLL_OFF_USER_CTL] = 0x10,
96 	[PLL_OFF_CONFIG_CTL] = 0x18,
97 	[PLL_OFF_CONFIG_CTL_U] = 0x1c,
98 	[PLL_OFF_TEST_CTL] = 0x20,
99 	[PLL_OFF_TEST_CTL_U] = 0x24,
100 	[PLL_OFF_STATUS] = 0x28,
101 };
102 
103 static const u8 alt_pll_regs[PLL_OFF_MAX_REGS] = {
104 	[PLL_OFF_L_VAL] = 0x04,
105 	[PLL_OFF_ALPHA_VAL] = 0x08,
106 	[PLL_OFF_USER_CTL] = 0x10,
107 	[PLL_OFF_CONFIG_CTL] = 0x18,
108 	[PLL_OFF_TEST_CTL] = 0x20,
109 	[PLL_OFF_STATUS] = 0x28,
110 };
111 
112 /* PLLs */
113 
114 static const struct alpha_pll_config hfpll_config = {
115 	.l = 54,
116 	.config_ctl_val = 0x200d4828,
117 	.config_ctl_hi_val = 0x006,
118 	.test_ctl_val = 0x1c000000,
119 	.test_ctl_hi_val = 0x00004000,
120 	.pre_div_mask = BIT(12),
121 	.post_div_mask = 0x3 << 8,
122 	.post_div_val = 0x1 << 8,
123 	.main_output_mask = BIT(0),
124 	.early_output_mask = BIT(3),
125 };
126 
127 static const struct clk_parent_data pll_parent[] = {
128 	{ .fw_name = "xo" },
129 };
130 
131 static struct clk_alpha_pll pwrcl_pll = {
132 	.offset = PWRCL_REG_OFFSET,
133 	.regs = prim_pll_regs,
134 	.flags = SUPPORTS_DYNAMIC_UPDATE | SUPPORTS_FSM_MODE,
135 	.clkr.hw.init = &(struct clk_init_data){
136 		.name = "pwrcl_pll",
137 		.parent_data = pll_parent,
138 		.num_parents = ARRAY_SIZE(pll_parent),
139 		.ops = &clk_alpha_pll_hwfsm_ops,
140 	},
141 };
142 
143 static struct clk_alpha_pll perfcl_pll = {
144 	.offset = PERFCL_REG_OFFSET,
145 	.regs = prim_pll_regs,
146 	.flags = SUPPORTS_DYNAMIC_UPDATE | SUPPORTS_FSM_MODE,
147 	.clkr.hw.init = &(struct clk_init_data){
148 		.name = "perfcl_pll",
149 		.parent_data = pll_parent,
150 		.num_parents = ARRAY_SIZE(pll_parent),
151 		.ops = &clk_alpha_pll_hwfsm_ops,
152 	},
153 };
154 
155 static struct clk_fixed_factor pwrcl_pll_postdiv = {
156 	.mult = 1,
157 	.div = 2,
158 	.hw.init = &(struct clk_init_data){
159 		.name = "pwrcl_pll_postdiv",
160 		.parent_data = &(const struct clk_parent_data){
161 			.hw = &pwrcl_pll.clkr.hw
162 		},
163 		.num_parents = 1,
164 		.ops = &clk_fixed_factor_ops,
165 		.flags = CLK_SET_RATE_PARENT,
166 	},
167 };
168 
169 static struct clk_fixed_factor perfcl_pll_postdiv = {
170 	.mult = 1,
171 	.div = 2,
172 	.hw.init = &(struct clk_init_data){
173 		.name = "perfcl_pll_postdiv",
174 		.parent_data = &(const struct clk_parent_data){
175 			.hw = &perfcl_pll.clkr.hw
176 		},
177 		.num_parents = 1,
178 		.ops = &clk_fixed_factor_ops,
179 		.flags = CLK_SET_RATE_PARENT,
180 	},
181 };
182 
183 static struct clk_fixed_factor perfcl_pll_acd = {
184 	.mult = 1,
185 	.div = 1,
186 	.hw.init = &(struct clk_init_data){
187 		.name = "perfcl_pll_acd",
188 		.parent_data = &(const struct clk_parent_data){
189 			.hw = &perfcl_pll.clkr.hw
190 		},
191 		.num_parents = 1,
192 		.ops = &clk_fixed_factor_ops,
193 		.flags = CLK_SET_RATE_PARENT,
194 	},
195 };
196 
197 static struct clk_fixed_factor pwrcl_pll_acd = {
198 	.mult = 1,
199 	.div = 1,
200 	.hw.init = &(struct clk_init_data){
201 		.name = "pwrcl_pll_acd",
202 		.parent_data = &(const struct clk_parent_data){
203 			.hw = &pwrcl_pll.clkr.hw
204 		},
205 		.num_parents = 1,
206 		.ops = &clk_fixed_factor_ops,
207 		.flags = CLK_SET_RATE_PARENT,
208 	},
209 };
210 
211 static const struct pll_vco alt_pll_vco_modes[] = {
212 	VCO(3,  250000000,  500000000),
213 	VCO(2,  500000000,  750000000),
214 	VCO(1,  750000000, 1000000000),
215 	VCO(0, 1000000000, 2150400000),
216 };
217 
218 static const struct alpha_pll_config altpll_config = {
219 	.l = 16,
220 	.vco_val = 0x3 << 20,
221 	.vco_mask = 0x3 << 20,
222 	.config_ctl_val = 0x4001051b,
223 	.post_div_mask = 0x3 << 8,
224 	.post_div_val = 0x1 << 8,
225 	.main_output_mask = BIT(0),
226 	.early_output_mask = BIT(3),
227 };
228 
229 static struct clk_alpha_pll pwrcl_alt_pll = {
230 	.offset = PWRCL_REG_OFFSET + ALT_PLL_OFFSET,
231 	.regs = alt_pll_regs,
232 	.vco_table = alt_pll_vco_modes,
233 	.num_vco = ARRAY_SIZE(alt_pll_vco_modes),
234 	.flags = SUPPORTS_OFFLINE_REQ | SUPPORTS_FSM_MODE,
235 	.clkr.hw.init = &(struct clk_init_data) {
236 		.name = "pwrcl_alt_pll",
237 		.parent_data = pll_parent,
238 		.num_parents = ARRAY_SIZE(pll_parent),
239 		.ops = &clk_alpha_pll_hwfsm_ops,
240 	},
241 };
242 
243 static struct clk_alpha_pll perfcl_alt_pll = {
244 	.offset = PERFCL_REG_OFFSET + ALT_PLL_OFFSET,
245 	.regs = alt_pll_regs,
246 	.vco_table = alt_pll_vco_modes,
247 	.num_vco = ARRAY_SIZE(alt_pll_vco_modes),
248 	.flags = SUPPORTS_OFFLINE_REQ | SUPPORTS_FSM_MODE,
249 	.clkr.hw.init = &(struct clk_init_data) {
250 		.name = "perfcl_alt_pll",
251 		.parent_data = pll_parent,
252 		.num_parents = ARRAY_SIZE(pll_parent),
253 		.ops = &clk_alpha_pll_hwfsm_ops,
254 	},
255 };
256 
257 struct clk_cpu_8996_pmux {
258 	u32	reg;
259 	struct notifier_block nb;
260 	struct clk_regmap clkr;
261 };
262 
263 static int cpu_clk_notifier_cb(struct notifier_block *nb, unsigned long event,
264 			       void *data);
265 
266 #define to_clk_cpu_8996_pmux_nb(_nb) \
267 	container_of(_nb, struct clk_cpu_8996_pmux, nb)
268 
269 static inline struct clk_cpu_8996_pmux *to_clk_cpu_8996_pmux_hw(struct clk_hw *hw)
270 {
271 	return container_of(to_clk_regmap(hw), struct clk_cpu_8996_pmux, clkr);
272 }
273 
274 static u8 clk_cpu_8996_pmux_get_parent(struct clk_hw *hw)
275 {
276 	struct clk_regmap *clkr = to_clk_regmap(hw);
277 	struct clk_cpu_8996_pmux *cpuclk = to_clk_cpu_8996_pmux_hw(hw);
278 	u32 val;
279 
280 	regmap_read(clkr->regmap, cpuclk->reg, &val);
281 
282 	return FIELD_GET(PMUX_MASK, val);
283 }
284 
285 static int clk_cpu_8996_pmux_set_parent(struct clk_hw *hw, u8 index)
286 {
287 	struct clk_regmap *clkr = to_clk_regmap(hw);
288 	struct clk_cpu_8996_pmux *cpuclk = to_clk_cpu_8996_pmux_hw(hw);
289 	u32 val;
290 
291 	val = FIELD_PREP(PMUX_MASK, index);
292 
293 	return regmap_update_bits(clkr->regmap, cpuclk->reg, PMUX_MASK, val);
294 }
295 
296 static int clk_cpu_8996_pmux_determine_rate(struct clk_hw *hw,
297 					   struct clk_rate_request *req)
298 {
299 	struct clk_hw *parent;
300 
301 	if (req->rate < (DIV_2_THRESHOLD / 2))
302 		return -EINVAL;
303 
304 	if (req->rate < DIV_2_THRESHOLD)
305 		parent = clk_hw_get_parent_by_index(hw, SMUX_INDEX);
306 	else
307 		parent = clk_hw_get_parent_by_index(hw, ACD_INDEX);
308 	if (!parent)
309 		return -EINVAL;
310 
311 	req->best_parent_rate = clk_hw_round_rate(parent, req->rate);
312 	req->best_parent_hw = parent;
313 
314 	return 0;
315 }
316 
317 static const struct clk_ops clk_cpu_8996_pmux_ops = {
318 	.set_parent = clk_cpu_8996_pmux_set_parent,
319 	.get_parent = clk_cpu_8996_pmux_get_parent,
320 	.determine_rate = clk_cpu_8996_pmux_determine_rate,
321 };
322 
323 static const struct parent_map smux_parent_map[] = {
324 	{ .cfg = 0, }, /* xo */
325 	{ .cfg = 1, }, /* pll */
326 	{ .cfg = 3, }, /* sys_apcs_aux */
327 };
328 
329 static const struct clk_parent_data pwrcl_smux_parents[] = {
330 	{ .fw_name = "xo" },
331 	{ .hw = &pwrcl_pll_postdiv.hw },
332 	{ .fw_name = "sys_apcs_aux" },
333 };
334 
335 static const struct clk_parent_data perfcl_smux_parents[] = {
336 	{ .fw_name = "xo" },
337 	{ .hw = &perfcl_pll_postdiv.hw },
338 	{ .fw_name = "sys_apcs_aux" },
339 };
340 
341 static struct clk_regmap_mux pwrcl_smux = {
342 	.reg = PWRCL_REG_OFFSET + MUX_OFFSET,
343 	.shift = 2,
344 	.width = 2,
345 	.parent_map = smux_parent_map,
346 	.clkr.hw.init = &(struct clk_init_data) {
347 		.name = "pwrcl_smux",
348 		.parent_data = pwrcl_smux_parents,
349 		.num_parents = ARRAY_SIZE(pwrcl_smux_parents),
350 		.ops = &clk_regmap_mux_closest_ops,
351 		.flags = CLK_SET_RATE_PARENT,
352 	},
353 };
354 
355 static struct clk_regmap_mux perfcl_smux = {
356 	.reg = PERFCL_REG_OFFSET + MUX_OFFSET,
357 	.shift = 2,
358 	.width = 2,
359 	.parent_map = smux_parent_map,
360 	.clkr.hw.init = &(struct clk_init_data) {
361 		.name = "perfcl_smux",
362 		.parent_data = perfcl_smux_parents,
363 		.num_parents = ARRAY_SIZE(perfcl_smux_parents),
364 		.ops = &clk_regmap_mux_closest_ops,
365 		.flags = CLK_SET_RATE_PARENT,
366 	},
367 };
368 
369 static const struct clk_hw *pwrcl_pmux_parents[] = {
370 	[SMUX_INDEX] = &pwrcl_smux.clkr.hw,
371 	[PLL_INDEX] = &pwrcl_pll.clkr.hw,
372 	[ACD_INDEX] = &pwrcl_pll_acd.hw,
373 	[ALT_INDEX] = &pwrcl_alt_pll.clkr.hw,
374 };
375 
376 static const struct clk_hw *perfcl_pmux_parents[] = {
377 	[SMUX_INDEX] = &perfcl_smux.clkr.hw,
378 	[PLL_INDEX] = &perfcl_pll.clkr.hw,
379 	[ACD_INDEX] = &perfcl_pll_acd.hw,
380 	[ALT_INDEX] = &perfcl_alt_pll.clkr.hw,
381 };
382 
383 static struct clk_cpu_8996_pmux pwrcl_pmux = {
384 	.reg = PWRCL_REG_OFFSET + MUX_OFFSET,
385 	.nb.notifier_call = cpu_clk_notifier_cb,
386 	.clkr.hw.init = &(struct clk_init_data) {
387 		.name = "pwrcl_pmux",
388 		.parent_hws = pwrcl_pmux_parents,
389 		.num_parents = ARRAY_SIZE(pwrcl_pmux_parents),
390 		.ops = &clk_cpu_8996_pmux_ops,
391 		/* CPU clock is critical and should never be gated */
392 		.flags = CLK_SET_RATE_PARENT | CLK_IS_CRITICAL,
393 	},
394 };
395 
396 static struct clk_cpu_8996_pmux perfcl_pmux = {
397 	.reg = PERFCL_REG_OFFSET + MUX_OFFSET,
398 	.nb.notifier_call = cpu_clk_notifier_cb,
399 	.clkr.hw.init = &(struct clk_init_data) {
400 		.name = "perfcl_pmux",
401 		.parent_hws = perfcl_pmux_parents,
402 		.num_parents = ARRAY_SIZE(perfcl_pmux_parents),
403 		.ops = &clk_cpu_8996_pmux_ops,
404 		/* CPU clock is critical and should never be gated */
405 		.flags = CLK_SET_RATE_PARENT | CLK_IS_CRITICAL,
406 	},
407 };
408 
409 static const struct regmap_config cpu_msm8996_regmap_config = {
410 	.reg_bits		= 32,
411 	.reg_stride		= 4,
412 	.val_bits		= 32,
413 	.max_register		= 0x80210,
414 	.fast_io		= true,
415 	.val_format_endian	= REGMAP_ENDIAN_LITTLE,
416 };
417 
418 static struct clk_hw *cpu_msm8996_hw_clks[] = {
419 	&pwrcl_pll_postdiv.hw,
420 	&perfcl_pll_postdiv.hw,
421 	&pwrcl_pll_acd.hw,
422 	&perfcl_pll_acd.hw,
423 };
424 
425 static struct clk_regmap *cpu_msm8996_clks[] = {
426 	&pwrcl_pll.clkr,
427 	&perfcl_pll.clkr,
428 	&pwrcl_alt_pll.clkr,
429 	&perfcl_alt_pll.clkr,
430 	&pwrcl_smux.clkr,
431 	&perfcl_smux.clkr,
432 	&pwrcl_pmux.clkr,
433 	&perfcl_pmux.clkr,
434 };
435 
436 static void qcom_cpu_clk_msm8996_acd_init(struct regmap *regmap);
437 
438 static int qcom_cpu_clk_msm8996_register_clks(struct device *dev,
439 					      struct regmap *regmap)
440 {
441 	int i, ret;
442 
443 	/* Select GPLL0 for 300MHz for both clusters */
444 	regmap_write(regmap, PERFCL_REG_OFFSET + MUX_OFFSET, 0xc);
445 	regmap_write(regmap, PWRCL_REG_OFFSET + MUX_OFFSET, 0xc);
446 
447 	/* Ensure write goes through before PLLs are reconfigured */
448 	udelay(5);
449 
450 	/* Set the auto clock sel always-on source to GPLL0/2 (300MHz) */
451 	regmap_update_bits(regmap, PWRCL_REG_OFFSET + MUX_OFFSET,
452 			   MUX_AUTO_CLK_SEL_ALWAYS_ON_MASK,
453 			   MUX_AUTO_CLK_SEL_ALWAYS_ON_GPLL0_SEL);
454 	regmap_update_bits(regmap, PERFCL_REG_OFFSET + MUX_OFFSET,
455 			   MUX_AUTO_CLK_SEL_ALWAYS_ON_MASK,
456 			   MUX_AUTO_CLK_SEL_ALWAYS_ON_GPLL0_SEL);
457 
458 	clk_alpha_pll_configure(&pwrcl_pll, regmap, &hfpll_config);
459 	clk_alpha_pll_configure(&perfcl_pll, regmap, &hfpll_config);
460 	clk_alpha_pll_configure(&pwrcl_alt_pll, regmap, &altpll_config);
461 	clk_alpha_pll_configure(&perfcl_alt_pll, regmap, &altpll_config);
462 
463 	/* Wait for PLL(s) to lock */
464 	udelay(50);
465 
466 	/* Enable auto clock selection for both clusters */
467 	regmap_update_bits(regmap, PWRCL_REG_OFFSET + CLK_CTL_OFFSET,
468 			   CLK_CTL_AUTO_CLK_SEL, CLK_CTL_AUTO_CLK_SEL);
469 	regmap_update_bits(regmap, PERFCL_REG_OFFSET + CLK_CTL_OFFSET,
470 			   CLK_CTL_AUTO_CLK_SEL, CLK_CTL_AUTO_CLK_SEL);
471 
472 	/* Ensure write goes through before muxes are switched */
473 	udelay(5);
474 
475 	qcom_cpu_clk_msm8996_acd_init(regmap);
476 
477 	/* Pulse swallower and soft-start settings */
478 	regmap_write(regmap, PWRCL_REG_OFFSET + PSCTL_OFFSET, 0x00030005);
479 	regmap_write(regmap, PERFCL_REG_OFFSET + PSCTL_OFFSET, 0x00030005);
480 
481 	/* Switch clusters to use the ACD leg */
482 	regmap_write(regmap, PWRCL_REG_OFFSET + MUX_OFFSET, 0x32);
483 	regmap_write(regmap, PERFCL_REG_OFFSET + MUX_OFFSET, 0x32);
484 
485 	for (i = 0; i < ARRAY_SIZE(cpu_msm8996_hw_clks); i++) {
486 		ret = devm_clk_hw_register(dev, cpu_msm8996_hw_clks[i]);
487 		if (ret)
488 			return ret;
489 	}
490 
491 	for (i = 0; i < ARRAY_SIZE(cpu_msm8996_clks); i++) {
492 		ret = devm_clk_register_regmap(dev, cpu_msm8996_clks[i]);
493 		if (ret)
494 			return ret;
495 	}
496 
497 	/* Enable alt PLLs */
498 	clk_prepare_enable(pwrcl_alt_pll.clkr.hw.clk);
499 	clk_prepare_enable(perfcl_alt_pll.clkr.hw.clk);
500 
501 	devm_clk_notifier_register(dev, pwrcl_pmux.clkr.hw.clk, &pwrcl_pmux.nb);
502 	devm_clk_notifier_register(dev, perfcl_pmux.clkr.hw.clk, &perfcl_pmux.nb);
503 
504 	return ret;
505 }
506 
507 #define CPU_CLUSTER_AFFINITY_MASK 0xf00
508 #define PWRCL_AFFINITY_MASK 0x000
509 #define PERFCL_AFFINITY_MASK 0x100
510 
511 #define L2ACDCR_REG 0x580ULL
512 #define L2ACDTD_REG 0x581ULL
513 #define L2ACDDVMRC_REG 0x584ULL
514 #define L2ACDSSCR_REG 0x589ULL
515 
516 static DEFINE_SPINLOCK(qcom_clk_acd_lock);
517 
518 static void qcom_cpu_clk_msm8996_acd_init(struct regmap *regmap)
519 {
520 	u64 hwid;
521 	u32 val;
522 	unsigned long flags;
523 
524 	spin_lock_irqsave(&qcom_clk_acd_lock, flags);
525 
526 	val = kryo_l2_get_indirect_reg(L2ACDTD_REG);
527 	if (val == 0x00006a11)
528 		goto out;
529 
530 	kryo_l2_set_indirect_reg(L2ACDTD_REG, 0x00006a11);
531 	kryo_l2_set_indirect_reg(L2ACDDVMRC_REG, 0x000e0f0f);
532 	kryo_l2_set_indirect_reg(L2ACDSSCR_REG, 0x00000601);
533 
534 	kryo_l2_set_indirect_reg(L2ACDCR_REG, 0x002c5ffd);
535 
536 	hwid = read_cpuid_mpidr();
537 	if ((hwid & CPU_CLUSTER_AFFINITY_MASK) == PWRCL_AFFINITY_MASK)
538 		regmap_write(regmap, PWRCL_REG_OFFSET + SSSCTL_OFFSET, 0xf);
539 	else
540 		regmap_write(regmap, PERFCL_REG_OFFSET + SSSCTL_OFFSET, 0xf);
541 
542 out:
543 	spin_unlock_irqrestore(&qcom_clk_acd_lock, flags);
544 }
545 
546 static int cpu_clk_notifier_cb(struct notifier_block *nb, unsigned long event,
547 			       void *data)
548 {
549 	struct clk_cpu_8996_pmux *cpuclk = to_clk_cpu_8996_pmux_nb(nb);
550 	struct clk_notifier_data *cnd = data;
551 
552 	switch (event) {
553 	case PRE_RATE_CHANGE:
554 		qcom_cpu_clk_msm8996_acd_init(cpuclk->clkr.regmap);
555 
556 		/*
557 		 * Avoid overvolting. clk_core_set_rate_nolock() walks from top
558 		 * to bottom, so it will change the rate of the PLL before
559 		 * chaging the parent of PMUX. This can result in pmux getting
560 		 * clocked twice the expected rate.
561 		 *
562 		 * Manually switch to PLL/2 here.
563 		 */
564 		if (cnd->new_rate < DIV_2_THRESHOLD &&
565 		    cnd->old_rate > DIV_2_THRESHOLD)
566 			clk_cpu_8996_pmux_set_parent(&cpuclk->clkr.hw, SMUX_INDEX);
567 
568 		break;
569 	case ABORT_RATE_CHANGE:
570 		/* Revert manual change */
571 		if (cnd->new_rate < DIV_2_THRESHOLD &&
572 		    cnd->old_rate > DIV_2_THRESHOLD)
573 			clk_cpu_8996_pmux_set_parent(&cpuclk->clkr.hw, ACD_INDEX);
574 		break;
575 	default:
576 		break;
577 	}
578 
579 	return NOTIFY_OK;
580 };
581 
582 static int qcom_cpu_clk_msm8996_driver_probe(struct platform_device *pdev)
583 {
584 	static void __iomem *base;
585 	struct regmap *regmap;
586 	struct clk_hw_onecell_data *data;
587 	struct device *dev = &pdev->dev;
588 	int ret;
589 
590 	data = devm_kzalloc(dev, struct_size(data, hws, 2), GFP_KERNEL);
591 	if (!data)
592 		return -ENOMEM;
593 
594 	base = devm_platform_ioremap_resource(pdev, 0);
595 	if (IS_ERR(base))
596 		return PTR_ERR(base);
597 
598 	regmap = devm_regmap_init_mmio(dev, base, &cpu_msm8996_regmap_config);
599 	if (IS_ERR(regmap))
600 		return PTR_ERR(regmap);
601 
602 	ret = qcom_cpu_clk_msm8996_register_clks(dev, regmap);
603 	if (ret)
604 		return ret;
605 
606 	data->hws[0] = &pwrcl_pmux.clkr.hw;
607 	data->hws[1] = &perfcl_pmux.clkr.hw;
608 	data->num = 2;
609 
610 	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, data);
611 }
612 
613 static const struct of_device_id qcom_cpu_clk_msm8996_match_table[] = {
614 	{ .compatible = "qcom,msm8996-apcc" },
615 	{}
616 };
617 MODULE_DEVICE_TABLE(of, qcom_cpu_clk_msm8996_match_table);
618 
619 static struct platform_driver qcom_cpu_clk_msm8996_driver = {
620 	.probe = qcom_cpu_clk_msm8996_driver_probe,
621 	.driver = {
622 		.name = "qcom-msm8996-apcc",
623 		.of_match_table = qcom_cpu_clk_msm8996_match_table,
624 	},
625 };
626 module_platform_driver(qcom_cpu_clk_msm8996_driver);
627 
628 MODULE_DESCRIPTION("QCOM MSM8996 CPU Clock Driver");
629 MODULE_LICENSE("GPL v2");
630