1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2015 Altera Corporation. All rights reserved
4  */
5 #include <linux/slab.h>
6 #include <linux/clk-provider.h>
7 #include <linux/io.h>
8 #include <linux/of.h>
9 
10 #include "clk.h"
11 
12 #define CLK_MGR_FREE_SHIFT		16
13 #define CLK_MGR_FREE_MASK		0x7
14 
15 #define SOCFPGA_MPU_FREE_CLK		"mpu_free_clk"
16 #define SOCFPGA_NOC_FREE_CLK		"noc_free_clk"
17 #define SOCFPGA_SDMMC_FREE_CLK		"sdmmc_free_clk"
18 #define to_socfpga_periph_clk(p) container_of(p, struct socfpga_periph_clk, hw.hw)
19 
clk_periclk_recalc_rate(struct clk_hw * hwclk,unsigned long parent_rate)20 static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
21 					     unsigned long parent_rate)
22 {
23 	struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
24 	u32 div;
25 
26 	if (socfpgaclk->fixed_div) {
27 		div = socfpgaclk->fixed_div;
28 	} else if (socfpgaclk->div_reg) {
29 		div = readl(socfpgaclk->div_reg) >> socfpgaclk->shift;
30 		div &= GENMASK(socfpgaclk->width - 1, 0);
31 		div += 1;
32 	} else {
33 		div = ((readl(socfpgaclk->hw.reg) & 0x7ff) + 1);
34 	}
35 
36 	return parent_rate / div;
37 }
38 
clk_periclk_get_parent(struct clk_hw * hwclk)39 static u8 clk_periclk_get_parent(struct clk_hw *hwclk)
40 {
41 	struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
42 	u32 clk_src;
43 	const char *name = clk_hw_get_name(hwclk);
44 
45 	clk_src = readl(socfpgaclk->hw.reg);
46 	if (streq(name, SOCFPGA_MPU_FREE_CLK) ||
47 	    streq(name, SOCFPGA_NOC_FREE_CLK) ||
48 	    streq(name, SOCFPGA_SDMMC_FREE_CLK))
49 		return (clk_src >> CLK_MGR_FREE_SHIFT) &
50 			CLK_MGR_FREE_MASK;
51 	else
52 		return 0;
53 }
54 
55 static const struct clk_ops periclk_ops = {
56 	.recalc_rate = clk_periclk_recalc_rate,
57 	.get_parent = clk_periclk_get_parent,
58 };
59 
__socfpga_periph_init(struct device_node * node,const struct clk_ops * ops)60 static __init void __socfpga_periph_init(struct device_node *node,
61 	const struct clk_ops *ops)
62 {
63 	u32 reg;
64 	struct clk_hw *hw_clk;
65 	struct socfpga_periph_clk *periph_clk;
66 	const char *clk_name = node->name;
67 	const char *parent_name[SOCFPGA_MAX_PARENTS];
68 	struct clk_init_data init;
69 	int rc;
70 	u32 fixed_div;
71 	u32 div_reg[3];
72 
73 	of_property_read_u32(node, "reg", &reg);
74 
75 	periph_clk = kzalloc(sizeof(*periph_clk), GFP_KERNEL);
76 	if (WARN_ON(!periph_clk))
77 		return;
78 
79 	periph_clk->hw.reg = clk_mgr_a10_base_addr + reg;
80 
81 	rc = of_property_read_u32_array(node, "div-reg", div_reg, 3);
82 	if (!rc) {
83 		periph_clk->div_reg = clk_mgr_a10_base_addr + div_reg[0];
84 		periph_clk->shift = div_reg[1];
85 		periph_clk->width = div_reg[2];
86 	} else {
87 		periph_clk->div_reg = NULL;
88 	}
89 
90 	rc = of_property_read_u32(node, "fixed-divider", &fixed_div);
91 	if (rc)
92 		periph_clk->fixed_div = 0;
93 	else
94 		periph_clk->fixed_div = fixed_div;
95 
96 	of_property_read_string(node, "clock-output-names", &clk_name);
97 
98 	init.name = clk_name;
99 	init.ops = ops;
100 	init.flags = 0;
101 
102 	init.num_parents = of_clk_parent_fill(node, parent_name, SOCFPGA_MAX_PARENTS);
103 	init.parent_names = parent_name;
104 
105 	periph_clk->hw.hw.init = &init;
106 
107 	hw_clk = &periph_clk->hw.hw;
108 
109 	if (clk_hw_register(NULL, hw_clk)) {
110 		kfree(periph_clk);
111 		return;
112 	}
113 	rc = of_clk_add_provider(node, of_clk_src_simple_get, hw_clk);
114 	if (rc < 0) {
115 		pr_err("Could not register clock provider for node:%s\n",
116 		       clk_name);
117 		goto err_clk;
118 	}
119 
120 	return;
121 
122 err_clk:
123 	clk_hw_unregister(hw_clk);
124 }
125 
socfpga_a10_periph_init(struct device_node * node)126 void __init socfpga_a10_periph_init(struct device_node *node)
127 {
128 	__socfpga_periph_init(node, &periclk_ops);
129 }
130