summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/clk/at91/clk-programmable.c
blob: 86c8a073dcc32a20b98f4c862d5622b11ffe1d57 (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
/*
 *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 */

#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/clk/at91_pmc.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/io.h>
#include <linux/wait.h>
#include <linux/sched.h>

#include "pmc.h"

#define PROG_SOURCE_MAX		5
#define PROG_ID_MAX		7

#define PROG_STATUS_MASK(id)	(1 << ((id) + 8))
#define PROG_PRES_MASK		0x7
#define PROG_MAX_RM9200_CSS	3

struct clk_programmable_layout {
	u8 pres_shift;
	u8 css_mask;
	u8 have_slck_mck;
};

struct clk_programmable {
	struct clk_hw hw;
	struct at91_pmc *pmc;
	u8 id;
	const struct clk_programmable_layout *layout;
};

#define to_clk_programmable(hw) container_of(hw, struct clk_programmable, hw)

static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
						  unsigned long parent_rate)
{
	u32 pres;
	struct clk_programmable *prog = to_clk_programmable(hw);
	struct at91_pmc *pmc = prog->pmc;
	const struct clk_programmable_layout *layout = prog->layout;

	pres = (pmc_read(pmc, AT91_PMC_PCKR(prog->id)) >> layout->pres_shift) &
	       PROG_PRES_MASK;
	return parent_rate >> pres;
}

static long clk_programmable_determine_rate(struct clk_hw *hw,
					    unsigned long rate,
					    unsigned long min_rate,
					    unsigned long max_rate,
					    unsigned long *best_parent_rate,
					    struct clk_hw **best_parent_hw)
{
	struct clk *parent = NULL;
	long best_rate = -EINVAL;
	unsigned long parent_rate;
	unsigned long tmp_rate;
	int shift;
	int i;

	for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
		parent = clk_get_parent_by_index(hw->clk, i);
		if (!parent)
			continue;

		parent_rate = __clk_get_rate(parent);
		for (shift = 0; shift < PROG_PRES_MASK; shift++) {
			tmp_rate = parent_rate >> shift;
			if (tmp_rate <= rate)
				break;
		}

		if (tmp_rate > rate)
			continue;

		if (best_rate < 0 || (rate - tmp_rate) < (rate - best_rate)) {
			best_rate = tmp_rate;
			*best_parent_rate = parent_rate;
			*best_parent_hw = __clk_get_hw(parent);
		}

		if (!best_rate)
			break;
	}

	return best_rate;
}

static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
{
	struct clk_programmable *prog = to_clk_programmable(hw);
	const struct clk_programmable_layout *layout = prog->layout;
	struct at91_pmc *pmc = prog->pmc;
	u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) & ~layout->css_mask;

	if (layout->have_slck_mck)
		tmp &= AT91_PMC_CSSMCK_MCK;

	if (index > layout->css_mask) {
		if (index > PROG_MAX_RM9200_CSS && layout->have_slck_mck) {
			tmp |= AT91_PMC_CSSMCK_MCK;
			return 0;
		} else {
			return -EINVAL;
		}
	}

	pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | index);
	return 0;
}

static u8 clk_programmable_get_parent(struct clk_hw *hw)
{
	u32 tmp;
	u8 ret;
	struct clk_programmable *prog = to_clk_programmable(hw);
	struct at91_pmc *pmc = prog->pmc;
	const struct clk_programmable_layout *layout = prog->layout;

	tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
	ret = tmp & layout->css_mask;
	if (layout->have_slck_mck && (tmp & AT91_PMC_CSSMCK_MCK) && !ret)
		ret = PROG_MAX_RM9200_CSS + 1;

	return ret;
}

static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
				     unsigned long parent_rate)
{
	struct clk_programmable *prog = to_clk_programmable(hw);
	struct at91_pmc *pmc = prog->pmc;
	const struct clk_programmable_layout *layout = prog->layout;
	unsigned long div = parent_rate / rate;
	int shift = 0;
	u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) &
		  ~(PROG_PRES_MASK << layout->pres_shift);

	if (!div)
		return -EINVAL;

	shift = fls(div) - 1;

	if (div != (1<<shift))
		return -EINVAL;

	if (shift >= PROG_PRES_MASK)
		return -EINVAL;

	pmc_write(pmc, AT91_PMC_PCKR(prog->id),
		  tmp | (shift << layout->pres_shift));

	return 0;
}

static const struct clk_ops programmable_ops = {
	.recalc_rate = clk_programmable_recalc_rate,
	.determine_rate = clk_programmable_determine_rate,
	.get_parent = clk_programmable_get_parent,
	.set_parent = clk_programmable_set_parent,
	.set_rate = clk_programmable_set_rate,
};

static struct clk * __init
at91_clk_register_programmable(struct at91_pmc *pmc,
			       const char *name, const char **parent_names,
			       u8 num_parents, u8 id,
			       const struct clk_programmable_layout *layout)
{
	struct clk_programmable *prog;
	struct clk *clk = NULL;
	struct clk_init_data init;

	if (id > PROG_ID_MAX)
		return ERR_PTR(-EINVAL);

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

	init.name = name;
	init.ops = &programmable_ops;
	init.parent_names = parent_names;
	init.num_parents = num_parents;
	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;

	prog->id = id;
	prog->layout = layout;
	prog->hw.init = &init;
	prog->pmc = pmc;

	clk = clk_register(NULL, &prog->hw);
	if (IS_ERR(clk))
		kfree(prog);

	return clk;
}

static const struct clk_programmable_layout at91rm9200_programmable_layout = {
	.pres_shift = 2,
	.css_mask = 0x3,
	.have_slck_mck = 0,
};

static const struct clk_programmable_layout at91sam9g45_programmable_layout = {
	.pres_shift = 2,
	.css_mask = 0x3,
	.have_slck_mck = 1,
};

static const struct clk_programmable_layout at91sam9x5_programmable_layout = {
	.pres_shift = 4,
	.css_mask = 0x7,
	.have_slck_mck = 0,
};

static void __init
of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,
		       const struct clk_programmable_layout *layout)
{
	int num;
	u32 id;
	int i;
	struct clk *clk;
	int num_parents;
	const char *parent_names[PROG_SOURCE_MAX];
	const char *name;
	struct device_node *progclknp;

	num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
	if (num_parents <= 0 || num_parents > PROG_SOURCE_MAX)
		return;

	for (i = 0; i < num_parents; ++i) {
		parent_names[i] = of_clk_get_parent_name(np, i);
		if (!parent_names[i])
			return;
	}

	num = of_get_child_count(np);
	if (!num || num > (PROG_ID_MAX + 1))
		return;

	for_each_child_of_node(np, progclknp) {
		if (of_property_read_u32(progclknp, "reg", &id))
			continue;

		if (of_property_read_string(np, "clock-output-names", &name))
			name = progclknp->name;

		clk = at91_clk_register_programmable(pmc, name,
						     parent_names, num_parents,
						     id, layout);
		if (IS_ERR(clk))
			continue;

		of_clk_add_provider(progclknp, of_clk_src_simple_get, clk);
	}
}


void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
					 struct at91_pmc *pmc)
{
	of_at91_clk_prog_setup(np, pmc, &at91rm9200_programmable_layout);
}

void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
					  struct at91_pmc *pmc)
{
	of_at91_clk_prog_setup(np, pmc, &at91sam9g45_programmable_layout);
}

void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
					 struct at91_pmc *pmc)
{
	of_at91_clk_prog_setup(np, pmc, &at91sam9x5_programmable_layout);
}