1 /*
2 *
3 * Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2, as
7 * published by the Free Software Foundation.
8 *
9 */
10
11 #include <linux/clk-provider.h>
12 #include <linux/err.h>
13 #include <linux/io.h>
14 #include <linux/of.h>
15 #include <linux/of_address.h>
16
17 #define MHZ (1000 * 1000)
18
19 #define BASE_CPU_SHIFT 1
20 #define BASE_CPU_MASK 0x7F
21
22 #define CPU_AHB_SHIFT 12
23 #define CPU_AHB_MASK 0x07
24
25 #define FIXED_BASE_SHIFT 8
26 #define FIXED_BASE_MASK 0x01
27
28 #define CLASSIC_BASE_SHIFT 16
29 #define CLASSIC_BASE_MASK 0x1F
30
31 #define CX_BASE_SHIFT 15
32 #define CX_BASE_MASK 0x3F
33
34 #define CX_UNKNOWN_SHIFT 21
35 #define CX_UNKNOWN_MASK 0x03
36
37 struct nspire_clk_info {
38 u32 base_clock;
39 u16 base_cpu_ratio;
40 u16 base_ahb_ratio;
41 };
42
43
44 #define EXTRACT(var, prop) (((var)>>prop##_SHIFT) & prop##_MASK)
nspire_clkinfo_cx(u32 val,struct nspire_clk_info * clk)45 static void nspire_clkinfo_cx(u32 val, struct nspire_clk_info *clk)
46 {
47 if (EXTRACT(val, FIXED_BASE))
48 clk->base_clock = 48 * MHZ;
49 else
50 clk->base_clock = 6 * EXTRACT(val, CX_BASE) * MHZ;
51
52 clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * EXTRACT(val, CX_UNKNOWN);
53 clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
54 }
55
nspire_clkinfo_classic(u32 val,struct nspire_clk_info * clk)56 static void nspire_clkinfo_classic(u32 val, struct nspire_clk_info *clk)
57 {
58 if (EXTRACT(val, FIXED_BASE))
59 clk->base_clock = 27 * MHZ;
60 else
61 clk->base_clock = (300 - 6 * EXTRACT(val, CLASSIC_BASE)) * MHZ;
62
63 clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * 2;
64 clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
65 }
66
nspire_ahbdiv_setup(struct device_node * node,void (* get_clkinfo)(u32,struct nspire_clk_info *))67 static void __init nspire_ahbdiv_setup(struct device_node *node,
68 void (*get_clkinfo)(u32, struct nspire_clk_info *))
69 {
70 u32 val;
71 void __iomem *io;
72 struct clk *clk;
73 const char *clk_name = node->name;
74 const char *parent_name;
75 struct nspire_clk_info info;
76
77 io = of_iomap(node, 0);
78 if (!io)
79 return;
80 val = readl(io);
81 iounmap(io);
82
83 get_clkinfo(val, &info);
84
85 of_property_read_string(node, "clock-output-names", &clk_name);
86 parent_name = of_clk_get_parent_name(node, 0);
87
88 clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
89 1, info.base_ahb_ratio);
90 if (!IS_ERR(clk))
91 of_clk_add_provider(node, of_clk_src_simple_get, clk);
92 }
93
nspire_ahbdiv_setup_cx(struct device_node * node)94 static void __init nspire_ahbdiv_setup_cx(struct device_node *node)
95 {
96 nspire_ahbdiv_setup(node, nspire_clkinfo_cx);
97 }
98
nspire_ahbdiv_setup_classic(struct device_node * node)99 static void __init nspire_ahbdiv_setup_classic(struct device_node *node)
100 {
101 nspire_ahbdiv_setup(node, nspire_clkinfo_classic);
102 }
103
104 CLK_OF_DECLARE(nspire_ahbdiv_cx, "lsi,nspire-cx-ahb-divider",
105 nspire_ahbdiv_setup_cx);
106 CLK_OF_DECLARE(nspire_ahbdiv_classic, "lsi,nspire-classic-ahb-divider",
107 nspire_ahbdiv_setup_classic);
108
nspire_clk_setup(struct device_node * node,void (* get_clkinfo)(u32,struct nspire_clk_info *))109 static void __init nspire_clk_setup(struct device_node *node,
110 void (*get_clkinfo)(u32, struct nspire_clk_info *))
111 {
112 u32 val;
113 void __iomem *io;
114 struct clk *clk;
115 const char *clk_name = node->name;
116 struct nspire_clk_info info;
117
118 io = of_iomap(node, 0);
119 if (!io)
120 return;
121 val = readl(io);
122 iounmap(io);
123
124 get_clkinfo(val, &info);
125
126 of_property_read_string(node, "clock-output-names", &clk_name);
127
128 clk = clk_register_fixed_rate(NULL, clk_name, NULL, CLK_IS_ROOT,
129 info.base_clock);
130 if (!IS_ERR(clk))
131 of_clk_add_provider(node, of_clk_src_simple_get, clk);
132 else
133 return;
134
135 pr_info("TI-NSPIRE Base: %uMHz CPU: %uMHz AHB: %uMHz\n",
136 info.base_clock / MHZ,
137 info.base_clock / info.base_cpu_ratio / MHZ,
138 info.base_clock / info.base_ahb_ratio / MHZ);
139 }
140
nspire_clk_setup_cx(struct device_node * node)141 static void __init nspire_clk_setup_cx(struct device_node *node)
142 {
143 nspire_clk_setup(node, nspire_clkinfo_cx);
144 }
145
nspire_clk_setup_classic(struct device_node * node)146 static void __init nspire_clk_setup_classic(struct device_node *node)
147 {
148 nspire_clk_setup(node, nspire_clkinfo_classic);
149 }
150
151 CLK_OF_DECLARE(nspire_clk_cx, "lsi,nspire-cx-clock", nspire_clk_setup_cx);
152 CLK_OF_DECLARE(nspire_clk_classic, "lsi,nspire-classic-clock",
153 nspire_clk_setup_classic);
154