xref: /openbmc/linux/drivers/clk/socfpga/clk-pll.c (revision b4e18b29)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright 2011-2012 Calxeda, Inc.
4  *  Copyright (C) 2012-2013 Altera Corporation <www.altera.com>
5  *
6  * Based from clk-highbank.c
7  */
8 #include <linux/slab.h>
9 #include <linux/clk-provider.h>
10 #include <linux/io.h>
11 #include <linux/of.h>
12 #include <linux/of_address.h>
13 
14 #include "clk.h"
15 
16 /* Clock bypass bits */
17 #define MAINPLL_BYPASS		(1<<0)
18 #define SDRAMPLL_BYPASS		(1<<1)
19 #define SDRAMPLL_SRC_BYPASS	(1<<2)
20 #define PERPLL_BYPASS		(1<<3)
21 #define PERPLL_SRC_BYPASS	(1<<4)
22 
23 #define SOCFPGA_PLL_BG_PWRDWN		0
24 #define SOCFPGA_PLL_EXT_ENA		1
25 #define SOCFPGA_PLL_PWR_DOWN		2
26 #define SOCFPGA_PLL_DIVF_MASK		0x0000FFF8
27 #define SOCFPGA_PLL_DIVF_SHIFT		3
28 #define SOCFPGA_PLL_DIVQ_MASK		0x003F0000
29 #define SOCFPGA_PLL_DIVQ_SHIFT		16
30 
31 #define CLK_MGR_PLL_CLK_SRC_SHIFT	22
32 #define CLK_MGR_PLL_CLK_SRC_MASK	0x3
33 
34 #define to_socfpga_clk(p) container_of(p, struct socfpga_pll, hw.hw)
35 
36 void __iomem *clk_mgr_base_addr;
37 
38 static unsigned long clk_pll_recalc_rate(struct clk_hw *hwclk,
39 					 unsigned long parent_rate)
40 {
41 	struct socfpga_pll *socfpgaclk = to_socfpga_clk(hwclk);
42 	unsigned long divf, divq, reg;
43 	unsigned long long vco_freq;
44 	unsigned long bypass;
45 
46 	reg = readl(socfpgaclk->hw.reg);
47 	bypass = readl(clk_mgr_base_addr + CLKMGR_BYPASS);
48 	if (bypass & MAINPLL_BYPASS)
49 		return parent_rate;
50 
51 	divf = (reg & SOCFPGA_PLL_DIVF_MASK) >> SOCFPGA_PLL_DIVF_SHIFT;
52 	divq = (reg & SOCFPGA_PLL_DIVQ_MASK) >> SOCFPGA_PLL_DIVQ_SHIFT;
53 	vco_freq = (unsigned long long)parent_rate * (divf + 1);
54 	do_div(vco_freq, (1 + divq));
55 	return (unsigned long)vco_freq;
56 }
57 
58 static u8 clk_pll_get_parent(struct clk_hw *hwclk)
59 {
60 	u32 pll_src;
61 	struct socfpga_pll *socfpgaclk = to_socfpga_clk(hwclk);
62 
63 	pll_src = readl(socfpgaclk->hw.reg);
64 	return (pll_src >> CLK_MGR_PLL_CLK_SRC_SHIFT) &
65 			CLK_MGR_PLL_CLK_SRC_MASK;
66 }
67 
68 static const struct clk_ops clk_pll_ops = {
69 	.recalc_rate = clk_pll_recalc_rate,
70 	.get_parent = clk_pll_get_parent,
71 };
72 
73 static __init struct clk *__socfpga_pll_init(struct device_node *node,
74 	const struct clk_ops *ops)
75 {
76 	u32 reg;
77 	struct clk *clk;
78 	struct socfpga_pll *pll_clk;
79 	const char *clk_name = node->name;
80 	const char *parent_name[SOCFPGA_MAX_PARENTS];
81 	struct clk_init_data init;
82 	struct device_node *clkmgr_np;
83 	int rc;
84 
85 	of_property_read_u32(node, "reg", &reg);
86 
87 	pll_clk = kzalloc(sizeof(*pll_clk), GFP_KERNEL);
88 	if (WARN_ON(!pll_clk))
89 		return NULL;
90 
91 	clkmgr_np = of_find_compatible_node(NULL, NULL, "altr,clk-mgr");
92 	clk_mgr_base_addr = of_iomap(clkmgr_np, 0);
93 	of_node_put(clkmgr_np);
94 	BUG_ON(!clk_mgr_base_addr);
95 	pll_clk->hw.reg = clk_mgr_base_addr + reg;
96 
97 	of_property_read_string(node, "clock-output-names", &clk_name);
98 
99 	init.name = clk_name;
100 	init.ops = ops;
101 	init.flags = 0;
102 
103 	init.num_parents = of_clk_parent_fill(node, parent_name, SOCFPGA_MAX_PARENTS);
104 	init.parent_names = parent_name;
105 	pll_clk->hw.hw.init = &init;
106 
107 	pll_clk->hw.bit_idx = SOCFPGA_PLL_EXT_ENA;
108 
109 	clk = clk_register(NULL, &pll_clk->hw.hw);
110 	if (WARN_ON(IS_ERR(clk))) {
111 		kfree(pll_clk);
112 		return NULL;
113 	}
114 	rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
115 	return clk;
116 }
117 
118 void __init socfpga_pll_init(struct device_node *node)
119 {
120 	__socfpga_pll_init(node, &clk_pll_ops);
121 }
122