summaryrefslogtreecommitdiffstats
path: root/drivers/clk/spear/clk-vco-pll.c
blob: c08dec30bfa629dd5599822f74f0054be114b0e4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
/*
 * Copyright (C) 2012 ST Microelectronics
 * Viresh Kumar <vireshk@kernel.org>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 *
 * VCO-PLL clock implementation
 */

#define pr_fmt(fmt) "clk-vco-pll: " fmt

#include <linux/clk-provider.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/err.h>
#include "clk.h"

/*
 * DOC: VCO-PLL clock
 *
 * VCO and PLL rate are derived from following equations:
 *
 * In normal mode
 * vco = (2 * M[15:8] * Fin)/N
 *
 * In Dithered mode
 * vco = (2 * M[15:0] * Fin)/(256 * N)
 *
 * pll_rate = pll/2^p
 *
 * vco and pll are very closely bound to each other, "vco needs to program:
 * mode, m & n" and "pll needs to program p", both share common enable/disable
 * logic.
 *
 * clk_register_vco_pll() registers instances of both vco & pll.
 * CLK_SET_RATE_PARENT flag is forced for pll, as it will always pass its
 * set_rate to vco. A single rate table exists for both the clocks, which
 * configures m, n and p.
 */

/* PLL_CTR register masks */
#define PLL_MODE_NORMAL		0
#define PLL_MODE_FRACTION	1
#define PLL_MODE_DITH_DSM	2
#define PLL_MODE_DITH_SSM	3
#define PLL_MODE_MASK		3
#define PLL_MODE_SHIFT		3
#define PLL_ENABLE		2

#define PLL_LOCK_SHIFT		0
#define PLL_LOCK_MASK		1

/* PLL FRQ register masks */
#define PLL_NORM_FDBK_M_MASK	0xFF
#define PLL_NORM_FDBK_M_SHIFT	24
#define PLL_DITH_FDBK_M_MASK	0xFFFF
#define PLL_DITH_FDBK_M_SHIFT	16
#define PLL_DIV_P_MASK		0x7
#define PLL_DIV_P_SHIFT		8
#define PLL_DIV_N_MASK		0xFF
#define PLL_DIV_N_SHIFT		0

#define to_clk_vco(_hw) container_of(_hw, struct clk_vco, hw)
#define to_clk_pll(_hw) container_of(_hw, struct clk_pll, hw)

/* Calculates pll clk rate for specific value of mode, m, n and p */
static unsigned long pll_calc_rate(struct pll_rate_tbl *rtbl,
		unsigned long prate, int index, unsigned long *pll_rate)
{
	unsigned long rate = prate;
	unsigned int mode;

	mode = rtbl[index].mode ? 256 : 1;
	rate = (((2 * rate / 10000) * rtbl[index].m) / (mode * rtbl[index].n));

	if (pll_rate)
		*pll_rate = (rate / (1 << rtbl[index].p)) * 10000;

	return rate * 10000;
}

static long clk_pll_round_rate_index(struct clk_hw *hw, unsigned long drate,
				unsigned long *prate, int *index)
{
	struct clk_pll *pll = to_clk_pll(hw);
	unsigned long prev_rate, vco_prev_rate, rate = 0;
	unsigned long vco_parent_rate =
		clk_hw_get_rate(clk_hw_get_parent(clk_hw_get_parent(hw)));

	if (!prate) {
		pr_err("%s: prate is must for pll clk\n", __func__);
		return -EINVAL;
	}

	for (*index = 0; *index < pll->vco->rtbl_cnt; (*index)++) {
		prev_rate = rate;
		vco_prev_rate = *prate;
		*prate = pll_calc_rate(pll->vco->rtbl, vco_parent_rate, *index,
				&rate);
		if (drate < rate) {
			/* previous clock was best */
			if (*index) {
				rate = prev_rate;
				*prate = vco_prev_rate;
				(*index)--;
			}
			break;
		}
	}

	return rate;
}

static long clk_pll_round_rate(struct clk_hw *hw, unsigned long drate,
				unsigned long *prate)
{
	int unused;

	return clk_pll_round_rate_index(hw, drate, prate, &unused);
}

static unsigned long clk_pll_recalc_rate(struct clk_hw *hw, unsigned long
		parent_rate)
{
	struct clk_pll *pll = to_clk_pll(hw);
	unsigned long flags = 0;
	unsigned int p;

	if (pll->vco->lock)
		spin_lock_irqsave(pll->vco->lock, flags);

	p = readl_relaxed(pll->vco->cfg_reg);

	if (pll->vco->lock)
		spin_unlock_irqrestore(pll->vco->lock, flags);

	p = (p >> PLL_DIV_P_SHIFT) & PLL_DIV_P_MASK;

	return parent_rate / (1 << p);
}

static int clk_pll_set_rate(struct clk_hw *hw, unsigned long drate,
				unsigned long prate)
{
	struct clk_pll *pll = to_clk_pll(hw);
	struct pll_rate_tbl *rtbl = pll->vco->rtbl;
	unsigned long flags = 0, val;
	int uninitialized_var(i);

	clk_pll_round_rate_index(hw, drate, NULL, &i);

	if (pll->vco->lock)
		spin_lock_irqsave(pll->vco->lock, flags);

	val = readl_relaxed(pll->vco->cfg_reg);
	val &= ~(PLL_DIV_P_MASK << PLL_DIV_P_SHIFT);
	val |= (rtbl[i].p & PLL_DIV_P_MASK) << PLL_DIV_P_SHIFT;
	writel_relaxed(val, pll->vco->cfg_reg);

	if (pll->vco->lock)
		spin_unlock_irqrestore(pll->vco->lock, flags);

	return 0;
}

static const struct clk_ops clk_pll_ops = {
	.recalc_rate = clk_pll_recalc_rate,
	.round_rate = clk_pll_round_rate,
	.set_rate = clk_pll_set_rate,
};

static inline unsigned long vco_calc_rate(struct clk_hw *hw,
		unsigned long prate, int index)
{
	struct clk_vco *vco = to_clk_vco(hw);

	return pll_calc_rate(vco->rtbl, prate, index, NULL);
}

static long clk_vco_round_rate(struct clk_hw *hw, unsigned long drate,
		unsigned long *prate)
{
	struct clk_vco *vco = to_clk_vco(hw);
	int unused;

	return clk_round_rate_index(hw, drate, *prate, vco_calc_rate,
			vco->rtbl_cnt, &unused);
}

static unsigned long clk_vco_recalc_rate(struct clk_hw *hw,
		unsigned long parent_rate)
{
	struct clk_vco *vco = to_clk_vco(hw);
	unsigned long flags = 0;
	unsigned int num = 2, den = 0, val, mode = 0;

	if (vco->lock)
		spin_lock_irqsave(vco->lock, flags);

	mode = (readl_relaxed(vco->mode_reg) >> PLL_MODE_SHIFT) & PLL_MODE_MASK;

	val = readl_relaxed(vco->cfg_reg);

	if (vco->lock)
		spin_unlock_irqrestore(vco->lock, flags);

	den = (val >> PLL_DIV_N_SHIFT) & PLL_DIV_N_MASK;

	/* calculate numerator & denominator */
	if (!mode) {
		/* Normal mode */
		num *= (val >> PLL_NORM_FDBK_M_SHIFT) & PLL_NORM_FDBK_M_MASK;
	} else {
		/* Dithered mode */
		num *= (val >> PLL_DITH_FDBK_M_SHIFT) & PLL_DITH_FDBK_M_MASK;
		den *= 256;
	}

	if (!den) {
		WARN(1, "%s: denominator can't be zero\n", __func__);
		return 0;
	}

	return (((parent_rate / 10000) * num) / den) * 10000;
}

/* Configures new clock rate of vco */
static int clk_vco_set_rate(struct clk_hw *hw, unsigned long drate,
				unsigned long prate)
{
	struct clk_vco *vco = to_clk_vco(hw);
	struct pll_rate_tbl *rtbl = vco->rtbl;
	unsigned long flags = 0, val;
	int i;

	clk_round_rate_index(hw, drate, prate, vco_calc_rate, vco->rtbl_cnt,
			&i);

	if (vco->lock)
		spin_lock_irqsave(vco->lock, flags);

	val = readl_relaxed(vco->mode_reg);
	val &= ~(PLL_MODE_MASK << PLL_MODE_SHIFT);
	val |= (rtbl[i].mode & PLL_MODE_MASK) << PLL_MODE_SHIFT;
	writel_relaxed(val, vco->mode_reg);

	val = readl_relaxed(vco->cfg_reg);
	val &= ~(PLL_DIV_N_MASK << PLL_DIV_N_SHIFT);
	val |= (rtbl[i].n & PLL_DIV_N_MASK) << PLL_DIV_N_SHIFT;

	val &= ~(PLL_DITH_FDBK_M_MASK << PLL_DITH_FDBK_M_SHIFT);
	if (rtbl[i].mode)
		val |= (rtbl[i].m & PLL_DITH_FDBK_M_MASK) <<
			PLL_DITH_FDBK_M_SHIFT;
	else
		val |= (rtbl[i].m & PLL_NORM_FDBK_M_MASK) <<
			PLL_NORM_FDBK_M_SHIFT;

	writel_relaxed(val, vco->cfg_reg);

	if (vco->lock)
		spin_unlock_irqrestore(vco->lock, flags);

	return 0;
}

static const struct clk_ops clk_vco_ops = {
	.recalc_rate = clk_vco_recalc_rate,
	.round_rate = clk_vco_round_rate,
	.set_rate = clk_vco_set_rate,
};

struct clk *clk_register_vco_pll(const char *vco_name, const char *pll_name,
		const char *vco_gate_name, const char *parent_name,
		unsigned long flags, void __iomem *mode_reg, void __iomem
		*cfg_reg, struct pll_rate_tbl *rtbl, u8 rtbl_cnt,
		spinlock_t *lock, struct clk **pll_clk,
		struct clk **vco_gate_clk)
{
	struct clk_vco *vco;
	struct clk_pll *pll;
	struct clk *vco_clk, *tpll_clk, *tvco_gate_clk;
	struct clk_init_data vco_init, pll_init;
	const char **vco_parent_name;

	if (!vco_name || !pll_name || !parent_name || !mode_reg || !cfg_reg ||
			!rtbl || !rtbl_cnt) {
		pr_err("Invalid arguments passed");
		return ERR_PTR(-EINVAL);
	}

	vco = kzalloc(sizeof(*vco), GFP_KERNEL);
	if (!vco)
		return ERR_PTR(-ENOMEM);

	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
	if (!pll)
		goto free_vco;

	/* struct clk_vco assignments */
	vco->mode_reg = mode_reg;
	vco->cfg_reg = cfg_reg;
	vco->rtbl = rtbl;
	vco->rtbl_cnt = rtbl_cnt;
	vco->lock = lock;
	vco->hw.init = &vco_init;

	pll->vco = vco;
	pll->hw.init = &pll_init;

	if (vco_gate_name) {
		tvco_gate_clk = clk_register_gate(NULL, vco_gate_name,
				parent_name, 0, mode_reg, PLL_ENABLE, 0, lock);
		if (IS_ERR_OR_NULL(tvco_gate_clk))
			goto free_pll;

		if (vco_gate_clk)
			*vco_gate_clk = tvco_gate_clk;
		vco_parent_name = &vco_gate_name;
	} else {
		vco_parent_name = &parent_name;
	}

	vco_init.name = vco_name;
	vco_init.ops = &clk_vco_ops;
	vco_init.flags = flags;
	vco_init.parent_names = vco_parent_name;
	vco_init.num_parents = 1;

	pll_init.name = pll_name;
	pll_init.ops = &clk_pll_ops;
	pll_init.flags = CLK_SET_RATE_PARENT;
	pll_init.parent_names = &vco_name;
	pll_init.num_parents = 1;

	vco_clk = clk_register(NULL, &vco->hw);
	if (IS_ERR_OR_NULL(vco_clk))
		goto free_pll;

	tpll_clk = clk_register(NULL, &pll->hw);
	if (IS_ERR_OR_NULL(tpll_clk))
		goto free_pll;

	if (pll_clk)
		*pll_clk = tpll_clk;

	return vco_clk;

free_pll:
	kfree(pll);
free_vco:
	kfree(vco);

	pr_err("Failed to register vco pll clock\n");

	return ERR_PTR(-ENOMEM);
}