1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * r8a7740 Core CPG Clocks
4  *
5  * Copyright (C) 2014  Ulrich Hecht
6  */
7 
8 #include <linux/clk-provider.h>
9 #include <linux/clk/renesas.h>
10 #include <linux/init.h>
11 #include <linux/io.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/of.h>
15 #include <linux/of_address.h>
16 #include <linux/spinlock.h>
17 
18 struct r8a7740_cpg {
19 	struct clk_onecell_data data;
20 	spinlock_t lock;
21 };
22 
23 #define CPG_FRQCRA	0x00
24 #define CPG_FRQCRB	0x04
25 #define CPG_PLLC2CR	0x2c
26 #define CPG_USBCKCR	0x8c
27 #define CPG_FRQCRC	0xe0
28 
29 #define CLK_ENABLE_ON_INIT BIT(0)
30 
31 struct div4_clk {
32 	const char *name;
33 	unsigned int reg;
34 	unsigned int shift;
35 	int flags;
36 };
37 
38 static struct div4_clk div4_clks[] = {
39 	{ "i", CPG_FRQCRA, 20, CLK_ENABLE_ON_INIT },
40 	{ "zg", CPG_FRQCRA, 16, CLK_ENABLE_ON_INIT },
41 	{ "b", CPG_FRQCRA,  8, CLK_ENABLE_ON_INIT },
42 	{ "m1", CPG_FRQCRA,  4, CLK_ENABLE_ON_INIT },
43 	{ "hp", CPG_FRQCRB,  4, 0 },
44 	{ "hpp", CPG_FRQCRC, 20, 0 },
45 	{ "usbp", CPG_FRQCRC, 16, 0 },
46 	{ "s", CPG_FRQCRC, 12, 0 },
47 	{ "zb", CPG_FRQCRC,  8, 0 },
48 	{ "m3", CPG_FRQCRC,  4, 0 },
49 	{ "cp", CPG_FRQCRC,  0, 0 },
50 	{ NULL, 0, 0, 0 },
51 };
52 
53 static const struct clk_div_table div4_div_table[] = {
54 	{ 0, 2 }, { 1, 3 }, { 2, 4 }, { 3, 6 }, { 4, 8 }, { 5, 12 },
55 	{ 6, 16 }, { 7, 18 }, { 8, 24 }, { 9, 32 }, { 10, 36 }, { 11, 48 },
56 	{ 13, 72 }, { 14, 96 }, { 0, 0 }
57 };
58 
59 static u32 cpg_mode __initdata;
60 
61 static struct clk * __init
r8a7740_cpg_register_clock(struct device_node * np,struct r8a7740_cpg * cpg,void __iomem * base,const char * name)62 r8a7740_cpg_register_clock(struct device_node *np, struct r8a7740_cpg *cpg,
63 			   void __iomem *base, const char *name)
64 {
65 	const struct clk_div_table *table = NULL;
66 	const char *parent_name;
67 	unsigned int shift, reg;
68 	unsigned int mult = 1;
69 	unsigned int div = 1;
70 
71 	if (!strcmp(name, "r")) {
72 		switch (cpg_mode & (BIT(2) | BIT(1))) {
73 		case BIT(1) | BIT(2):
74 			/* extal1 */
75 			parent_name = of_clk_get_parent_name(np, 0);
76 			div = 2048;
77 			break;
78 		case BIT(2):
79 			/* extal1 */
80 			parent_name = of_clk_get_parent_name(np, 0);
81 			div = 1024;
82 			break;
83 		default:
84 			/* extalr */
85 			parent_name = of_clk_get_parent_name(np, 2);
86 			break;
87 		}
88 	} else if (!strcmp(name, "system")) {
89 		parent_name = of_clk_get_parent_name(np, 0);
90 		if (cpg_mode & BIT(1))
91 			div = 2;
92 	} else if (!strcmp(name, "pllc0")) {
93 		/* PLLC0/1 are configurable multiplier clocks. Register them as
94 		 * fixed factor clocks for now as there's no generic multiplier
95 		 * clock implementation and we currently have no need to change
96 		 * the multiplier value.
97 		 */
98 		u32 value = readl(base + CPG_FRQCRC);
99 		parent_name = "system";
100 		mult = ((value >> 24) & 0x7f) + 1;
101 	} else if (!strcmp(name, "pllc1")) {
102 		u32 value = readl(base + CPG_FRQCRA);
103 		parent_name = "system";
104 		mult = ((value >> 24) & 0x7f) + 1;
105 		div = 2;
106 	} else if (!strcmp(name, "pllc2")) {
107 		u32 value = readl(base + CPG_PLLC2CR);
108 		parent_name = "system";
109 		mult = ((value >> 24) & 0x3f) + 1;
110 	} else if (!strcmp(name, "usb24s")) {
111 		u32 value = readl(base + CPG_USBCKCR);
112 		if (value & BIT(7))
113 			/* extal2 */
114 			parent_name = of_clk_get_parent_name(np, 1);
115 		else
116 			parent_name = "system";
117 		if (!(value & BIT(6)))
118 			div = 2;
119 	} else {
120 		struct div4_clk *c;
121 		for (c = div4_clks; c->name; c++) {
122 			if (!strcmp(name, c->name)) {
123 				parent_name = "pllc1";
124 				table = div4_div_table;
125 				reg = c->reg;
126 				shift = c->shift;
127 				break;
128 			}
129 		}
130 		if (!c->name)
131 			return ERR_PTR(-EINVAL);
132 	}
133 
134 	if (!table) {
135 		return clk_register_fixed_factor(NULL, name, parent_name, 0,
136 						 mult, div);
137 	} else {
138 		return clk_register_divider_table(NULL, name, parent_name, 0,
139 						  base + reg, shift, 4, 0,
140 						  table, &cpg->lock);
141 	}
142 }
143 
r8a7740_cpg_clocks_init(struct device_node * np)144 static void __init r8a7740_cpg_clocks_init(struct device_node *np)
145 {
146 	struct r8a7740_cpg *cpg;
147 	void __iomem *base;
148 	struct clk **clks;
149 	unsigned int i;
150 	int num_clks;
151 
152 	if (of_property_read_u32(np, "renesas,mode", &cpg_mode))
153 		pr_warn("%s: missing renesas,mode property\n", __func__);
154 
155 	num_clks = of_property_count_strings(np, "clock-output-names");
156 	if (num_clks < 0) {
157 		pr_err("%s: failed to count clocks\n", __func__);
158 		return;
159 	}
160 
161 	cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
162 	clks = kcalloc(num_clks, sizeof(*clks), GFP_KERNEL);
163 	if (cpg == NULL || clks == NULL) {
164 		/* We're leaking memory on purpose, there's no point in cleaning
165 		 * up as the system won't boot anyway.
166 		 */
167 		return;
168 	}
169 
170 	spin_lock_init(&cpg->lock);
171 
172 	cpg->data.clks = clks;
173 	cpg->data.clk_num = num_clks;
174 
175 	base = of_iomap(np, 0);
176 	if (WARN_ON(base == NULL))
177 		return;
178 
179 	for (i = 0; i < num_clks; ++i) {
180 		const char *name;
181 		struct clk *clk;
182 
183 		of_property_read_string_index(np, "clock-output-names", i,
184 					      &name);
185 
186 		clk = r8a7740_cpg_register_clock(np, cpg, base, name);
187 		if (IS_ERR(clk))
188 			pr_err("%s: failed to register %pOFn %s clock (%ld)\n",
189 			       __func__, np, name, PTR_ERR(clk));
190 		else
191 			cpg->data.clks[i] = clk;
192 	}
193 
194 	of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
195 }
196 CLK_OF_DECLARE(r8a7740_cpg_clks, "renesas,r8a7740-cpg-clocks",
197 	       r8a7740_cpg_clocks_init);
198