1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * RZ/A1 Core CPG Clocks
4 *
5 * Copyright (C) 2013 Ideas On Board SPRL
6 * Copyright (C) 2014 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
7 */
8
9 #include <linux/clk-provider.h>
10 #include <linux/clk/renesas.h>
11 #include <linux/init.h>
12 #include <linux/io.h>
13 #include <linux/kernel.h>
14 #include <linux/of.h>
15 #include <linux/of_address.h>
16 #include <linux/slab.h>
17
18 struct rz_cpg {
19 struct clk_onecell_data data;
20 void __iomem *reg;
21 };
22
23 #define CPG_FRQCR 0x10
24 #define CPG_FRQCR2 0x14
25
26 #define PPR0 0xFCFE3200
27 #define PIBC0 0xFCFE7000
28
29 #define MD_CLK(x) ((x >> 2) & 1) /* P0_2 */
30
31 /* -----------------------------------------------------------------------------
32 * Initialization
33 */
34
rz_cpg_read_mode_pins(void)35 static u16 __init rz_cpg_read_mode_pins(void)
36 {
37 void __iomem *ppr0, *pibc0;
38 u16 modes;
39
40 ppr0 = ioremap(PPR0, 2);
41 pibc0 = ioremap(PIBC0, 2);
42 BUG_ON(!ppr0 || !pibc0);
43 iowrite16(4, pibc0); /* enable input buffer */
44 modes = ioread16(ppr0);
45 iounmap(ppr0);
46 iounmap(pibc0);
47
48 return modes;
49 }
50
51 static struct clk * __init
rz_cpg_register_clock(struct device_node * np,struct rz_cpg * cpg,const char * name)52 rz_cpg_register_clock(struct device_node *np, struct rz_cpg *cpg, const char *name)
53 {
54 u32 val;
55 unsigned mult;
56 static const unsigned frqcr_tab[4] = { 3, 2, 0, 1 };
57
58 if (strcmp(name, "pll") == 0) {
59 unsigned int cpg_mode = MD_CLK(rz_cpg_read_mode_pins());
60 const char *parent_name = of_clk_get_parent_name(np, cpg_mode);
61
62 mult = cpg_mode ? (32 / 4) : 30;
63
64 return clk_register_fixed_factor(NULL, name, parent_name, 0, mult, 1);
65 }
66
67 /* If mapping regs failed, skip non-pll clocks. System will boot anyhow */
68 if (!cpg->reg)
69 return ERR_PTR(-ENXIO);
70
71 /* FIXME:"i" and "g" are variable clocks with non-integer dividers (e.g. 2/3)
72 * and the constraint that always g <= i. To get the rz platform started,
73 * let them run at fixed current speed and implement the details later.
74 */
75 if (strcmp(name, "i") == 0)
76 val = (readl(cpg->reg + CPG_FRQCR) >> 8) & 3;
77 else if (strcmp(name, "g") == 0)
78 val = readl(cpg->reg + CPG_FRQCR2) & 3;
79 else
80 return ERR_PTR(-EINVAL);
81
82 mult = frqcr_tab[val];
83 return clk_register_fixed_factor(NULL, name, "pll", 0, mult, 3);
84 }
85
rz_cpg_clocks_init(struct device_node * np)86 static void __init rz_cpg_clocks_init(struct device_node *np)
87 {
88 struct rz_cpg *cpg;
89 struct clk **clks;
90 unsigned i;
91 int num_clks;
92
93 num_clks = of_property_count_strings(np, "clock-output-names");
94 if (WARN(num_clks <= 0, "can't count CPG clocks\n"))
95 return;
96
97 cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
98 clks = kcalloc(num_clks, sizeof(*clks), GFP_KERNEL);
99 BUG_ON(!cpg || !clks);
100
101 cpg->data.clks = clks;
102 cpg->data.clk_num = num_clks;
103
104 cpg->reg = of_iomap(np, 0);
105
106 for (i = 0; i < num_clks; ++i) {
107 const char *name;
108 struct clk *clk;
109
110 of_property_read_string_index(np, "clock-output-names", i, &name);
111
112 clk = rz_cpg_register_clock(np, cpg, name);
113 if (IS_ERR(clk))
114 pr_err("%s: failed to register %pOFn %s clock (%ld)\n",
115 __func__, np, name, PTR_ERR(clk));
116 else
117 cpg->data.clks[i] = clk;
118 }
119
120 of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
121
122 cpg_mstp_add_clk_domain(np);
123 }
124 CLK_OF_DECLARE(rz_cpg_clks, "renesas,rz-cpg-clocks", rz_cpg_clocks_init);
125