1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2010 Samsung Electronics Co., Ltd.
4 *		http://www.samsung.com
5 *
6 * CPU frequency scaling for S5PC110/S5PV210
7*/
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/types.h>
12#include <linux/kernel.h>
13#include <linux/init.h>
14#include <linux/err.h>
15#include <linux/clk.h>
16#include <linux/io.h>
17#include <linux/cpufreq.h>
18#include <linux/of.h>
19#include <linux/of_address.h>
20#include <linux/platform_device.h>
21#include <linux/reboot.h>
22#include <linux/regulator/consumer.h>
23
24static void __iomem *clk_base;
25static void __iomem *dmc_base[2];
26
27#define S5P_CLKREG(x)		(clk_base + (x))
28
29#define S5P_APLL_LOCK		S5P_CLKREG(0x00)
30#define S5P_APLL_CON		S5P_CLKREG(0x100)
31#define S5P_CLK_SRC0		S5P_CLKREG(0x200)
32#define S5P_CLK_SRC2		S5P_CLKREG(0x208)
33#define S5P_CLK_DIV0		S5P_CLKREG(0x300)
34#define S5P_CLK_DIV2		S5P_CLKREG(0x308)
35#define S5P_CLK_DIV6		S5P_CLKREG(0x318)
36#define S5P_CLKDIV_STAT0	S5P_CLKREG(0x1000)
37#define S5P_CLKDIV_STAT1	S5P_CLKREG(0x1004)
38#define S5P_CLKMUX_STAT0	S5P_CLKREG(0x1100)
39#define S5P_CLKMUX_STAT1	S5P_CLKREG(0x1104)
40
41#define S5P_ARM_MCS_CON		S5P_CLKREG(0x6100)
42
43/* CLKSRC0 */
44#define S5P_CLKSRC0_MUX200_SHIFT	(16)
45#define S5P_CLKSRC0_MUX200_MASK		(0x1 << S5P_CLKSRC0_MUX200_SHIFT)
46#define S5P_CLKSRC0_MUX166_MASK		(0x1<<20)
47#define S5P_CLKSRC0_MUX133_MASK		(0x1<<24)
48
49/* CLKSRC2 */
50#define S5P_CLKSRC2_G3D_SHIFT           (0)
51#define S5P_CLKSRC2_G3D_MASK            (0x3 << S5P_CLKSRC2_G3D_SHIFT)
52#define S5P_CLKSRC2_MFC_SHIFT           (4)
53#define S5P_CLKSRC2_MFC_MASK            (0x3 << S5P_CLKSRC2_MFC_SHIFT)
54
55/* CLKDIV0 */
56#define S5P_CLKDIV0_APLL_SHIFT		(0)
57#define S5P_CLKDIV0_APLL_MASK		(0x7 << S5P_CLKDIV0_APLL_SHIFT)
58#define S5P_CLKDIV0_A2M_SHIFT		(4)
59#define S5P_CLKDIV0_A2M_MASK		(0x7 << S5P_CLKDIV0_A2M_SHIFT)
60#define S5P_CLKDIV0_HCLK200_SHIFT	(8)
61#define S5P_CLKDIV0_HCLK200_MASK	(0x7 << S5P_CLKDIV0_HCLK200_SHIFT)
62#define S5P_CLKDIV0_PCLK100_SHIFT	(12)
63#define S5P_CLKDIV0_PCLK100_MASK	(0x7 << S5P_CLKDIV0_PCLK100_SHIFT)
64#define S5P_CLKDIV0_HCLK166_SHIFT	(16)
65#define S5P_CLKDIV0_HCLK166_MASK	(0xF << S5P_CLKDIV0_HCLK166_SHIFT)
66#define S5P_CLKDIV0_PCLK83_SHIFT	(20)
67#define S5P_CLKDIV0_PCLK83_MASK		(0x7 << S5P_CLKDIV0_PCLK83_SHIFT)
68#define S5P_CLKDIV0_HCLK133_SHIFT	(24)
69#define S5P_CLKDIV0_HCLK133_MASK	(0xF << S5P_CLKDIV0_HCLK133_SHIFT)
70#define S5P_CLKDIV0_PCLK66_SHIFT	(28)
71#define S5P_CLKDIV0_PCLK66_MASK		(0x7 << S5P_CLKDIV0_PCLK66_SHIFT)
72
73/* CLKDIV2 */
74#define S5P_CLKDIV2_G3D_SHIFT           (0)
75#define S5P_CLKDIV2_G3D_MASK            (0xF << S5P_CLKDIV2_G3D_SHIFT)
76#define S5P_CLKDIV2_MFC_SHIFT           (4)
77#define S5P_CLKDIV2_MFC_MASK            (0xF << S5P_CLKDIV2_MFC_SHIFT)
78
79/* CLKDIV6 */
80#define S5P_CLKDIV6_ONEDRAM_SHIFT       (28)
81#define S5P_CLKDIV6_ONEDRAM_MASK        (0xF << S5P_CLKDIV6_ONEDRAM_SHIFT)
82
83static struct clk *dmc0_clk;
84static struct clk *dmc1_clk;
85static DEFINE_MUTEX(set_freq_lock);
86
87/* APLL M,P,S values for 1G/800Mhz */
88#define APLL_VAL_1000	((1 << 31) | (125 << 16) | (3 << 8) | 1)
89#define APLL_VAL_800	((1 << 31) | (100 << 16) | (3 << 8) | 1)
90
91/* Use 800MHz when entering sleep mode */
92#define SLEEP_FREQ	(800 * 1000)
93
94/* Tracks if CPU frequency can be updated anymore */
95static bool no_cpufreq_access;
96
97/*
98 * DRAM configurations to calculate refresh counter for changing
99 * frequency of memory.
100 */
101struct dram_conf {
102	unsigned long freq;	/* HZ */
103	unsigned long refresh;	/* DRAM refresh counter * 1000 */
104};
105
106/* DRAM configuration (DMC0 and DMC1) */
107static struct dram_conf s5pv210_dram_conf[2];
108
109enum perf_level {
110	L0, L1, L2, L3, L4,
111};
112
113enum s5pv210_mem_type {
114	LPDDR	= 0x1,
115	LPDDR2	= 0x2,
116	DDR2	= 0x4,
117};
118
119enum s5pv210_dmc_port {
120	DMC0 = 0,
121	DMC1,
122};
123
124static struct cpufreq_frequency_table s5pv210_freq_table[] = {
125	{0, L0, 1000*1000},
126	{0, L1, 800*1000},
127	{0, L2, 400*1000},
128	{0, L3, 200*1000},
129	{0, L4, 100*1000},
130	{0, 0, CPUFREQ_TABLE_END},
131};
132
133static struct regulator *arm_regulator;
134static struct regulator *int_regulator;
135
136struct s5pv210_dvs_conf {
137	int arm_volt;	/* uV */
138	int int_volt;	/* uV */
139};
140
141static const int arm_volt_max = 1350000;
142static const int int_volt_max = 1250000;
143
144static struct s5pv210_dvs_conf dvs_conf[] = {
145	[L0] = {
146		.arm_volt	= 1250000,
147		.int_volt	= 1100000,
148	},
149	[L1] = {
150		.arm_volt	= 1200000,
151		.int_volt	= 1100000,
152	},
153	[L2] = {
154		.arm_volt	= 1050000,
155		.int_volt	= 1100000,
156	},
157	[L3] = {
158		.arm_volt	= 950000,
159		.int_volt	= 1100000,
160	},
161	[L4] = {
162		.arm_volt	= 950000,
163		.int_volt	= 1000000,
164	},
165};
166
167static u32 clkdiv_val[5][11] = {
168	/*
169	 * Clock divider value for following
170	 * { APLL, A2M, HCLK_MSYS, PCLK_MSYS,
171	 *   HCLK_DSYS, PCLK_DSYS, HCLK_PSYS, PCLK_PSYS,
172	 *   ONEDRAM, MFC, G3D }
173	 */
174
175	/* L0 : [1000/200/100][166/83][133/66][200/200] */
176	{0, 4, 4, 1, 3, 1, 4, 1, 3, 0, 0},
177
178	/* L1 : [800/200/100][166/83][133/66][200/200] */
179	{0, 3, 3, 1, 3, 1, 4, 1, 3, 0, 0},
180
181	/* L2 : [400/200/100][166/83][133/66][200/200] */
182	{1, 3, 1, 1, 3, 1, 4, 1, 3, 0, 0},
183
184	/* L3 : [200/200/100][166/83][133/66][200/200] */
185	{3, 3, 1, 1, 3, 1, 4, 1, 3, 0, 0},
186
187	/* L4 : [100/100/100][83/83][66/66][100/100] */
188	{7, 7, 0, 0, 7, 0, 9, 0, 7, 0, 0},
189};
190
191/*
192 * This function set DRAM refresh counter
193 * according to operating frequency of DRAM
194 * ch: DMC port number 0 or 1
195 * freq: Operating frequency of DRAM(KHz)
196 */
197static void s5pv210_set_refresh(enum s5pv210_dmc_port ch, unsigned long freq)
198{
199	unsigned long tmp, tmp1;
200	void __iomem *reg = NULL;
201
202	if (ch == DMC0) {
203		reg = (dmc_base[0] + 0x30);
204	} else if (ch == DMC1) {
205		reg = (dmc_base[1] + 0x30);
206	} else {
207		pr_err("Cannot find DMC port\n");
208		return;
209	}
210
211	/* Find current DRAM frequency */
212	tmp = s5pv210_dram_conf[ch].freq;
213
214	tmp /= freq;
215
216	tmp1 = s5pv210_dram_conf[ch].refresh;
217
218	tmp1 /= tmp;
219
220	writel_relaxed(tmp1, reg);
221}
222
223static int s5pv210_target(struct cpufreq_policy *policy, unsigned int index)
224{
225	unsigned long reg;
226	unsigned int priv_index;
227	unsigned int pll_changing = 0;
228	unsigned int bus_speed_changing = 0;
229	unsigned int old_freq, new_freq;
230	int arm_volt, int_volt;
231	int ret = 0;
232
233	mutex_lock(&set_freq_lock);
234
235	if (no_cpufreq_access) {
236		pr_err("Denied access to %s as it is disabled temporarily\n",
237		       __func__);
238		ret = -EINVAL;
239		goto exit;
240	}
241
242	old_freq = policy->cur;
243	new_freq = s5pv210_freq_table[index].frequency;
244
245	/* Finding current running level index */
246	priv_index = cpufreq_table_find_index_h(policy, old_freq, false);
247
248	arm_volt = dvs_conf[index].arm_volt;
249	int_volt = dvs_conf[index].int_volt;
250
251	if (new_freq > old_freq) {
252		ret = regulator_set_voltage(arm_regulator,
253				arm_volt, arm_volt_max);
254		if (ret)
255			goto exit;
256
257		ret = regulator_set_voltage(int_regulator,
258				int_volt, int_volt_max);
259		if (ret)
260			goto exit;
261	}
262
263	/* Check if there need to change PLL */
264	if ((index == L0) || (priv_index == L0))
265		pll_changing = 1;
266
267	/* Check if there need to change System bus clock */
268	if ((index == L4) || (priv_index == L4))
269		bus_speed_changing = 1;
270
271	if (bus_speed_changing) {
272		/*
273		 * Reconfigure DRAM refresh counter value for minimum
274		 * temporary clock while changing divider.
275		 * expected clock is 83Mhz : 7.8usec/(1/83Mhz) = 0x287
276		 */
277		if (pll_changing)
278			s5pv210_set_refresh(DMC1, 83000);
279		else
280			s5pv210_set_refresh(DMC1, 100000);
281
282		s5pv210_set_refresh(DMC0, 83000);
283	}
284
285	/*
286	 * APLL should be changed in this level
287	 * APLL -> MPLL(for stable transition) -> APLL
288	 * Some clock source's clock API are not prepared.
289	 * Do not use clock API in below code.
290	 */
291	if (pll_changing) {
292		/*
293		 * 1. Temporary Change divider for MFC and G3D
294		 * SCLKA2M(200/1=200)->(200/4=50)Mhz
295		 */
296		reg = readl_relaxed(S5P_CLK_DIV2);
297		reg &= ~(S5P_CLKDIV2_G3D_MASK | S5P_CLKDIV2_MFC_MASK);
298		reg |= (3 << S5P_CLKDIV2_G3D_SHIFT) |
299			(3 << S5P_CLKDIV2_MFC_SHIFT);
300		writel_relaxed(reg, S5P_CLK_DIV2);
301
302		/* For MFC, G3D dividing */
303		do {
304			reg = readl_relaxed(S5P_CLKDIV_STAT0);
305		} while (reg & ((1 << 16) | (1 << 17)));
306
307		/*
308		 * 2. Change SCLKA2M(200Mhz)to SCLKMPLL in MFC_MUX, G3D MUX
309		 * (200/4=50)->(667/4=166)Mhz
310		 */
311		reg = readl_relaxed(S5P_CLK_SRC2);
312		reg &= ~(S5P_CLKSRC2_G3D_MASK | S5P_CLKSRC2_MFC_MASK);
313		reg |= (1 << S5P_CLKSRC2_G3D_SHIFT) |
314			(1 << S5P_CLKSRC2_MFC_SHIFT);
315		writel_relaxed(reg, S5P_CLK_SRC2);
316
317		do {
318			reg = readl_relaxed(S5P_CLKMUX_STAT1);
319		} while (reg & ((1 << 7) | (1 << 3)));
320
321		/*
322		 * 3. DMC1 refresh count for 133Mhz if (index == L4) is
323		 * true refresh counter is already programmed in upper
324		 * code. 0x287@83Mhz
325		 */
326		if (!bus_speed_changing)
327			s5pv210_set_refresh(DMC1, 133000);
328
329		/* 4. SCLKAPLL -> SCLKMPLL */
330		reg = readl_relaxed(S5P_CLK_SRC0);
331		reg &= ~(S5P_CLKSRC0_MUX200_MASK);
332		reg |= (0x1 << S5P_CLKSRC0_MUX200_SHIFT);
333		writel_relaxed(reg, S5P_CLK_SRC0);
334
335		do {
336			reg = readl_relaxed(S5P_CLKMUX_STAT0);
337		} while (reg & (0x1 << 18));
338
339	}
340
341	/* Change divider */
342	reg = readl_relaxed(S5P_CLK_DIV0);
343
344	reg &= ~(S5P_CLKDIV0_APLL_MASK | S5P_CLKDIV0_A2M_MASK |
345		S5P_CLKDIV0_HCLK200_MASK | S5P_CLKDIV0_PCLK100_MASK |
346		S5P_CLKDIV0_HCLK166_MASK | S5P_CLKDIV0_PCLK83_MASK |
347		S5P_CLKDIV0_HCLK133_MASK | S5P_CLKDIV0_PCLK66_MASK);
348
349	reg |= ((clkdiv_val[index][0] << S5P_CLKDIV0_APLL_SHIFT) |
350		(clkdiv_val[index][1] << S5P_CLKDIV0_A2M_SHIFT) |
351		(clkdiv_val[index][2] << S5P_CLKDIV0_HCLK200_SHIFT) |
352		(clkdiv_val[index][3] << S5P_CLKDIV0_PCLK100_SHIFT) |
353		(clkdiv_val[index][4] << S5P_CLKDIV0_HCLK166_SHIFT) |
354		(clkdiv_val[index][5] << S5P_CLKDIV0_PCLK83_SHIFT) |
355		(clkdiv_val[index][6] << S5P_CLKDIV0_HCLK133_SHIFT) |
356		(clkdiv_val[index][7] << S5P_CLKDIV0_PCLK66_SHIFT));
357
358	writel_relaxed(reg, S5P_CLK_DIV0);
359
360	do {
361		reg = readl_relaxed(S5P_CLKDIV_STAT0);
362	} while (reg & 0xff);
363
364	/* ARM MCS value changed */
365	reg = readl_relaxed(S5P_ARM_MCS_CON);
366	reg &= ~0x3;
367	if (index >= L3)
368		reg |= 0x3;
369	else
370		reg |= 0x1;
371
372	writel_relaxed(reg, S5P_ARM_MCS_CON);
373
374	if (pll_changing) {
375		/* 5. Set Lock time = 30us*24Mhz = 0x2cf */
376		writel_relaxed(0x2cf, S5P_APLL_LOCK);
377
378		/*
379		 * 6. Turn on APLL
380		 * 6-1. Set PMS values
381		 * 6-2. Wait until the PLL is locked
382		 */
383		if (index == L0)
384			writel_relaxed(APLL_VAL_1000, S5P_APLL_CON);
385		else
386			writel_relaxed(APLL_VAL_800, S5P_APLL_CON);
387
388		do {
389			reg = readl_relaxed(S5P_APLL_CON);
390		} while (!(reg & (0x1 << 29)));
391
392		/*
393		 * 7. Change source clock from SCLKMPLL(667Mhz)
394		 * to SCLKA2M(200Mhz) in MFC_MUX and G3D MUX
395		 * (667/4=166)->(200/4=50)Mhz
396		 */
397		reg = readl_relaxed(S5P_CLK_SRC2);
398		reg &= ~(S5P_CLKSRC2_G3D_MASK | S5P_CLKSRC2_MFC_MASK);
399		reg |= (0 << S5P_CLKSRC2_G3D_SHIFT) |
400			(0 << S5P_CLKSRC2_MFC_SHIFT);
401		writel_relaxed(reg, S5P_CLK_SRC2);
402
403		do {
404			reg = readl_relaxed(S5P_CLKMUX_STAT1);
405		} while (reg & ((1 << 7) | (1 << 3)));
406
407		/*
408		 * 8. Change divider for MFC and G3D
409		 * (200/4=50)->(200/1=200)Mhz
410		 */
411		reg = readl_relaxed(S5P_CLK_DIV2);
412		reg &= ~(S5P_CLKDIV2_G3D_MASK | S5P_CLKDIV2_MFC_MASK);
413		reg |= (clkdiv_val[index][10] << S5P_CLKDIV2_G3D_SHIFT) |
414			(clkdiv_val[index][9] << S5P_CLKDIV2_MFC_SHIFT);
415		writel_relaxed(reg, S5P_CLK_DIV2);
416
417		/* For MFC, G3D dividing */
418		do {
419			reg = readl_relaxed(S5P_CLKDIV_STAT0);
420		} while (reg & ((1 << 16) | (1 << 17)));
421
422		/* 9. Change MPLL to APLL in MSYS_MUX */
423		reg = readl_relaxed(S5P_CLK_SRC0);
424		reg &= ~(S5P_CLKSRC0_MUX200_MASK);
425		reg |= (0x0 << S5P_CLKSRC0_MUX200_SHIFT);
426		writel_relaxed(reg, S5P_CLK_SRC0);
427
428		do {
429			reg = readl_relaxed(S5P_CLKMUX_STAT0);
430		} while (reg & (0x1 << 18));
431
432		/*
433		 * 10. DMC1 refresh counter
434		 * L4 : DMC1 = 100Mhz 7.8us/(1/100) = 0x30c
435		 * Others : DMC1 = 200Mhz 7.8us/(1/200) = 0x618
436		 */
437		if (!bus_speed_changing)
438			s5pv210_set_refresh(DMC1, 200000);
439	}
440
441	/*
442	 * L4 level needs to change memory bus speed, hence ONEDRAM clock
443	 * divider and memory refresh parameter should be changed
444	 */
445	if (bus_speed_changing) {
446		reg = readl_relaxed(S5P_CLK_DIV6);
447		reg &= ~S5P_CLKDIV6_ONEDRAM_MASK;
448		reg |= (clkdiv_val[index][8] << S5P_CLKDIV6_ONEDRAM_SHIFT);
449		writel_relaxed(reg, S5P_CLK_DIV6);
450
451		do {
452			reg = readl_relaxed(S5P_CLKDIV_STAT1);
453		} while (reg & (1 << 15));
454
455		/* Reconfigure DRAM refresh counter value */
456		if (index != L4) {
457			/*
458			 * DMC0 : 166Mhz
459			 * DMC1 : 200Mhz
460			 */
461			s5pv210_set_refresh(DMC0, 166000);
462			s5pv210_set_refresh(DMC1, 200000);
463		} else {
464			/*
465			 * DMC0 : 83Mhz
466			 * DMC1 : 100Mhz
467			 */
468			s5pv210_set_refresh(DMC0, 83000);
469			s5pv210_set_refresh(DMC1, 100000);
470		}
471	}
472
473	if (new_freq < old_freq) {
474		regulator_set_voltage(int_regulator,
475				int_volt, int_volt_max);
476
477		regulator_set_voltage(arm_regulator,
478				arm_volt, arm_volt_max);
479	}
480
481	pr_debug("Perf changed[L%d]\n", index);
482
483exit:
484	mutex_unlock(&set_freq_lock);
485	return ret;
486}
487
488static int check_mem_type(void __iomem *dmc_reg)
489{
490	unsigned long val;
491
492	val = readl_relaxed(dmc_reg + 0x4);
493	val = (val & (0xf << 8));
494
495	return val >> 8;
496}
497
498static int s5pv210_cpu_init(struct cpufreq_policy *policy)
499{
500	unsigned long mem_type;
501	int ret;
502
503	policy->clk = clk_get(NULL, "armclk");
504	if (IS_ERR(policy->clk))
505		return PTR_ERR(policy->clk);
506
507	dmc0_clk = clk_get(NULL, "sclk_dmc0");
508	if (IS_ERR(dmc0_clk)) {
509		ret = PTR_ERR(dmc0_clk);
510		goto out_dmc0;
511	}
512
513	dmc1_clk = clk_get(NULL, "hclk_msys");
514	if (IS_ERR(dmc1_clk)) {
515		ret = PTR_ERR(dmc1_clk);
516		goto out_dmc1;
517	}
518
519	if (policy->cpu != 0) {
520		ret = -EINVAL;
521		goto out_dmc1;
522	}
523
524	/*
525	 * check_mem_type : This driver only support LPDDR & LPDDR2.
526	 * other memory type is not supported.
527	 */
528	mem_type = check_mem_type(dmc_base[0]);
529
530	if ((mem_type != LPDDR) && (mem_type != LPDDR2)) {
531		pr_err("CPUFreq doesn't support this memory type\n");
532		ret = -EINVAL;
533		goto out_dmc1;
534	}
535
536	/* Find current refresh counter and frequency each DMC */
537	s5pv210_dram_conf[0].refresh = (readl_relaxed(dmc_base[0] + 0x30) * 1000);
538	s5pv210_dram_conf[0].freq = clk_get_rate(dmc0_clk);
539
540	s5pv210_dram_conf[1].refresh = (readl_relaxed(dmc_base[1] + 0x30) * 1000);
541	s5pv210_dram_conf[1].freq = clk_get_rate(dmc1_clk);
542
543	policy->suspend_freq = SLEEP_FREQ;
544	cpufreq_generic_init(policy, s5pv210_freq_table, 40000);
545	return 0;
546
547out_dmc1:
548	clk_put(dmc0_clk);
549out_dmc0:
550	clk_put(policy->clk);
551	return ret;
552}
553
554static int s5pv210_cpufreq_reboot_notifier_event(struct notifier_block *this,
555						 unsigned long event, void *ptr)
556{
557	int ret;
558	struct cpufreq_policy *policy;
559
560	policy = cpufreq_cpu_get(0);
561	if (!policy) {
562		pr_debug("cpufreq: get no policy for cpu0\n");
563		return NOTIFY_BAD;
564	}
565
566	ret = cpufreq_driver_target(policy, SLEEP_FREQ, 0);
567	cpufreq_cpu_put(policy);
568
569	if (ret < 0)
570		return NOTIFY_BAD;
571
572	no_cpufreq_access = true;
573	return NOTIFY_DONE;
574}
575
576static struct cpufreq_driver s5pv210_driver = {
577	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
578	.verify		= cpufreq_generic_frequency_table_verify,
579	.target_index	= s5pv210_target,
580	.get		= cpufreq_generic_get,
581	.init		= s5pv210_cpu_init,
582	.name		= "s5pv210",
583	.suspend	= cpufreq_generic_suspend,
584	.resume		= cpufreq_generic_suspend, /* We need to set SLEEP FREQ again */
585};
586
587static struct notifier_block s5pv210_cpufreq_reboot_notifier = {
588	.notifier_call = s5pv210_cpufreq_reboot_notifier_event,
589};
590
591static int s5pv210_cpufreq_probe(struct platform_device *pdev)
592{
593	struct device *dev = &pdev->dev;
594	struct device_node *np;
595	int id, result = 0;
596
597	/*
598	 * HACK: This is a temporary workaround to get access to clock
599	 * and DMC controller registers directly and remove static mappings
600	 * and dependencies on platform headers. It is necessary to enable
601	 * S5PV210 multi-platform support and will be removed together with
602	 * this whole driver as soon as S5PV210 gets migrated to use
603	 * cpufreq-dt driver.
604	 */
605	arm_regulator = regulator_get(NULL, "vddarm");
606	if (IS_ERR(arm_regulator))
607		return dev_err_probe(dev, PTR_ERR(arm_regulator),
608				     "failed to get regulator vddarm\n");
609
610	int_regulator = regulator_get(NULL, "vddint");
611	if (IS_ERR(int_regulator)) {
612		result = dev_err_probe(dev, PTR_ERR(int_regulator),
613				       "failed to get regulator vddint\n");
614		goto err_int_regulator;
615	}
616
617	np = of_find_compatible_node(NULL, NULL, "samsung,s5pv210-clock");
618	if (!np) {
619		dev_err(dev, "failed to find clock controller DT node\n");
620		result = -ENODEV;
621		goto err_clock;
622	}
623
624	clk_base = of_iomap(np, 0);
625	of_node_put(np);
626	if (!clk_base) {
627		dev_err(dev, "failed to map clock registers\n");
628		result = -EFAULT;
629		goto err_clock;
630	}
631
632	for_each_compatible_node(np, NULL, "samsung,s5pv210-dmc") {
633		id = of_alias_get_id(np, "dmc");
634		if (id < 0 || id >= ARRAY_SIZE(dmc_base)) {
635			dev_err(dev, "failed to get alias of dmc node '%pOFn'\n", np);
636			of_node_put(np);
637			result = id;
638			goto err_clk_base;
639		}
640
641		dmc_base[id] = of_iomap(np, 0);
642		if (!dmc_base[id]) {
643			dev_err(dev, "failed to map dmc%d registers\n", id);
644			of_node_put(np);
645			result = -EFAULT;
646			goto err_dmc;
647		}
648	}
649
650	for (id = 0; id < ARRAY_SIZE(dmc_base); ++id) {
651		if (!dmc_base[id]) {
652			dev_err(dev, "failed to find dmc%d node\n", id);
653			result = -ENODEV;
654			goto err_dmc;
655		}
656	}
657
658	register_reboot_notifier(&s5pv210_cpufreq_reboot_notifier);
659
660	return cpufreq_register_driver(&s5pv210_driver);
661
662err_dmc:
663	for (id = 0; id < ARRAY_SIZE(dmc_base); ++id)
664		if (dmc_base[id]) {
665			iounmap(dmc_base[id]);
666			dmc_base[id] = NULL;
667		}
668
669err_clk_base:
670	iounmap(clk_base);
671
672err_clock:
673	regulator_put(int_regulator);
674
675err_int_regulator:
676	regulator_put(arm_regulator);
677
678	return result;
679}
680
681static struct platform_driver s5pv210_cpufreq_platdrv = {
682	.driver = {
683		.name	= "s5pv210-cpufreq",
684	},
685	.probe = s5pv210_cpufreq_probe,
686};
687builtin_platform_driver(s5pv210_cpufreq_platdrv);
688