1 /* $NetBSD: sunxi_ccu_phase.c,v 1.1 2017/07/17 23:26:17 jmcneill Exp $ */
2
3 /*-
4 * Copyright (c) 2017 Jared McNeill <jmcneill@invisible.ca>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: sunxi_ccu_phase.c,v 1.1 2017/07/17 23:26:17 jmcneill Exp $");
31
32 #include <sys/param.h>
33 #include <sys/bus.h>
34
35 #include <dev/clk/clk_backend.h>
36
37 #include <arm/sunxi/sunxi_ccu.h>
38
39 static u_int
sunxi_ccu_phase_get_parent_rate(struct clk * clkp)40 sunxi_ccu_phase_get_parent_rate(struct clk *clkp)
41 {
42 struct clk *clkp_parent;
43
44 clkp_parent = clk_get_parent(clkp);
45 if (clkp_parent == NULL)
46 return 0;
47
48 return clk_get_rate(clkp_parent);
49 }
50
51 static u_int
sunxi_ccu_phase_div(u_int n,u_int d)52 sunxi_ccu_phase_div(u_int n, u_int d)
53 {
54 return (n + (d/2)) / d;
55 }
56
57 u_int
sunxi_ccu_phase_get_rate(struct sunxi_ccu_softc * sc,struct sunxi_ccu_clk * clk)58 sunxi_ccu_phase_get_rate(struct sunxi_ccu_softc *sc,
59 struct sunxi_ccu_clk *clk)
60 {
61 struct sunxi_ccu_phase *phase = &clk->u.phase;
62 struct clk *clkp = &clk->base;
63 u_int p_rate, gp_rate, p_div, delay;
64 uint32_t val;
65
66 KASSERT(clk->type == SUNXI_CCU_PHASE);
67
68 p_rate = sunxi_ccu_phase_get_parent_rate(clkp);
69 if (p_rate == 0)
70 return 0;
71 gp_rate = sunxi_ccu_phase_get_parent_rate(clk_get_parent(clkp));
72 if (gp_rate == 0)
73 return 0;
74
75 p_div = gp_rate / p_rate;
76
77 val = CCU_READ(sc, phase->reg);
78 delay = __SHIFTOUT(val, phase->mask);
79
80 return delay * sunxi_ccu_phase_div(360, p_div);
81 }
82
83 int
sunxi_ccu_phase_set_rate(struct sunxi_ccu_softc * sc,struct sunxi_ccu_clk * clk,u_int new_rate)84 sunxi_ccu_phase_set_rate(struct sunxi_ccu_softc *sc,
85 struct sunxi_ccu_clk *clk, u_int new_rate)
86 {
87 struct sunxi_ccu_phase *phase = &clk->u.phase;
88 struct clk *clkp = &clk->base;
89 u_int p_rate, gp_rate, p_div, delay;
90 uint32_t val;
91
92 KASSERT(clk->type == SUNXI_CCU_PHASE);
93
94 clkp = &clk->base;
95
96 p_rate = sunxi_ccu_phase_get_parent_rate(clkp);
97 if (p_rate == 0)
98 return 0;
99 gp_rate = sunxi_ccu_phase_get_parent_rate(clk_get_parent(clkp));
100 if (gp_rate == 0)
101 return 0;
102
103 p_div = gp_rate / p_rate;
104
105 delay = new_rate == 180 ? 0 :
106 sunxi_ccu_phase_div(new_rate,
107 sunxi_ccu_phase_div(360, p_div));
108
109 val = CCU_READ(sc, phase->reg);
110 val &= ~phase->mask;
111 val |= __SHIFTIN(delay, phase->mask);
112 CCU_WRITE(sc, phase->reg, val);
113
114 return 0;
115 }
116
117 const char *
sunxi_ccu_phase_get_parent(struct sunxi_ccu_softc * sc,struct sunxi_ccu_clk * clk)118 sunxi_ccu_phase_get_parent(struct sunxi_ccu_softc *sc,
119 struct sunxi_ccu_clk *clk)
120 {
121 struct sunxi_ccu_phase *phase = &clk->u.phase;
122
123 KASSERT(clk->type == SUNXI_CCU_PHASE);
124
125 return phase->parent;
126 }
127