summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-omap2/dpll44xx.c
blob: 52f9438b92f2a5d165b548b323bacb8680588bae (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
/*
 * OMAP4-specific DPLL control functions
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Rajendra Nayak
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/bitops.h>

#include "soc.h"
#include "clock.h"
#include "clock44xx.h"
#include "cm-regbits-44xx.h"

/*
 * Maximum DPLL input frequency (FINT) and output frequency (FOUT) that
 * can supported when using the DPLL low-power mode. Frequencies are
 * defined in OMAP4430/60 Public TRM section 3.6.3.3.2 "Enable Control,
 * Status, and Low-Power Operation Mode".
 */
#define OMAP4_DPLL_LP_FINT_MAX	1000000
#define OMAP4_DPLL_LP_FOUT_MAX	100000000

/* Supported only on OMAP4 */
int omap4_dpllmx_gatectrl_read(struct clk_hw_omap *clk)
{
	u32 v;
	u32 mask;

	if (!clk || !clk->clksel_reg || !cpu_is_omap44xx())
		return -EINVAL;

	mask = clk->flags & CLOCK_CLKOUTX2 ?
			OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK :
			OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK;

	v = omap2_clk_readl(clk, clk->clksel_reg);
	v &= mask;
	v >>= __ffs(mask);

	return v;
}

void omap4_dpllmx_allow_gatectrl(struct clk_hw_omap *clk)
{
	u32 v;
	u32 mask;

	if (!clk || !clk->clksel_reg || !cpu_is_omap44xx())
		return;

	mask = clk->flags & CLOCK_CLKOUTX2 ?
			OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK :
			OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK;

	v = omap2_clk_readl(clk, clk->clksel_reg);
	/* Clear the bit to allow gatectrl */
	v &= ~mask;
	omap2_clk_writel(v, clk, clk->clksel_reg);
}

void omap4_dpllmx_deny_gatectrl(struct clk_hw_omap *clk)
{
	u32 v;
	u32 mask;

	if (!clk || !clk->clksel_reg || !cpu_is_omap44xx())
		return;

	mask = clk->flags & CLOCK_CLKOUTX2 ?
			OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK :
			OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK;

	v = omap2_clk_readl(clk, clk->clksel_reg);
	/* Set the bit to deny gatectrl */
	v |= mask;
	omap2_clk_writel(v, clk, clk->clksel_reg);
}

const struct clk_hw_omap_ops clkhwops_omap4_dpllmx = {
	.allow_idle	= omap4_dpllmx_allow_gatectrl,
	.deny_idle      = omap4_dpllmx_deny_gatectrl,
};

/**
 * omap4_dpll_lpmode_recalc - compute DPLL low-power setting
 * @dd: pointer to the dpll data structure
 *
 * Calculates if low-power mode can be enabled based upon the last
 * multiplier and divider values calculated. If low-power mode can be
 * enabled, then the bit to enable low-power mode is stored in the
 * last_rounded_lpmode variable. This implementation is based upon the
 * criteria for enabling low-power mode as described in the OMAP4430/60
 * Public TRM section 3.6.3.3.2 "Enable Control, Status, and Low-Power
 * Operation Mode".
 */
static void omap4_dpll_lpmode_recalc(struct dpll_data *dd)
{
	long fint, fout;

	fint = __clk_get_rate(dd->clk_ref) / (dd->last_rounded_n + 1);
	fout = fint * dd->last_rounded_m;

	if ((fint < OMAP4_DPLL_LP_FINT_MAX) && (fout < OMAP4_DPLL_LP_FOUT_MAX))
		dd->last_rounded_lpmode = 1;
	else
		dd->last_rounded_lpmode = 0;
}

/**
 * omap4_dpll_regm4xen_recalc - compute DPLL rate, considering REGM4XEN bit
 * @clk: struct clk * of the DPLL to compute the rate for
 *
 * Compute the output rate for the OMAP4 DPLL represented by @clk.
 * Takes the REGM4XEN bit into consideration, which is needed for the
 * OMAP4 ABE DPLL.  Returns the DPLL's output rate (before M-dividers)
 * upon success, or 0 upon error.
 */
unsigned long omap4_dpll_regm4xen_recalc(struct clk_hw *hw,
			unsigned long parent_rate)
{
	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
	u32 v;
	unsigned long rate;
	struct dpll_data *dd;

	if (!clk || !clk->dpll_data)
		return 0;

	dd = clk->dpll_data;

	rate = omap2_get_dpll_rate(clk);

	/* regm4xen adds a multiplier of 4 to DPLL calculations */
	v = omap2_clk_readl(clk, dd->control_reg);
	if (v & OMAP4430_DPLL_REGM4XEN_MASK)
		rate *= OMAP4430_REGM4XEN_MULT;

	return rate;
}

/**
 * omap4_dpll_regm4xen_round_rate - round DPLL rate, considering REGM4XEN bit
 * @clk: struct clk * of the DPLL to round a rate for
 * @target_rate: the desired rate of the DPLL
 *
 * Compute the rate that would be programmed into the DPLL hardware
 * for @clk if set_rate() were to be provided with the rate
 * @target_rate.  Takes the REGM4XEN bit into consideration, which is
 * needed for the OMAP4 ABE DPLL.  Returns the rounded rate (before
 * M-dividers) upon success, -EINVAL if @clk is null or not a DPLL, or
 * ~0 if an error occurred in omap2_dpll_round_rate().
 */
long omap4_dpll_regm4xen_round_rate(struct clk_hw *hw,
				    unsigned long target_rate,
				    unsigned long *parent_rate)
{
	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
	struct dpll_data *dd;
	long r;

	if (!clk || !clk->dpll_data)
		return -EINVAL;

	dd = clk->dpll_data;

	dd->last_rounded_m4xen = 0;

	/*
	 * First try to compute the DPLL configuration for
	 * target rate without using the 4X multiplier.
	 */
	r = omap2_dpll_round_rate(hw, target_rate, NULL);
	if (r != ~0)
		goto out;

	/*
	 * If we did not find a valid DPLL configuration, try again, but
	 * this time see if using the 4X multiplier can help. Enabling the
	 * 4X multiplier is equivalent to dividing the target rate by 4.
	 */
	r = omap2_dpll_round_rate(hw, target_rate / OMAP4430_REGM4XEN_MULT,
				  NULL);
	if (r == ~0)
		return r;

	dd->last_rounded_rate *= OMAP4430_REGM4XEN_MULT;
	dd->last_rounded_m4xen = 1;

out:
	omap4_dpll_lpmode_recalc(dd);

	return dd->last_rounded_rate;
}
OpenPOWER on IntegriCloud