1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * System clock support for AT91 architectures.
4 *
5 * Copyright (C) Microchip Technology Inc. and its subsidiaries
6 *
7 * Author: Claudiu Beznea <claudiu.beznea@microchip.com>
8 *
9 * Based on drivers/clk/at91/clk-system.c from Linux.
10 */
11 #include <asm/processor.h>
12 #include <clk-uclass.h>
13 #include <dm.h>
14 #include <linux/io.h>
15 #include <linux/clk-provider.h>
16 #include <linux/clk/at91_pmc.h>
17
18 #include "pmc.h"
19
20 #define UBOOT_DM_CLK_AT91_SYSTEM "at91-system-clk"
21
22 #define SYSTEM_MAX_ID 31
23
24 struct clk_system {
25 void __iomem *base;
26 struct clk clk;
27 u8 id;
28 };
29
30 #define to_clk_system(_c) container_of(_c, struct clk_system, clk)
31
is_pck(int id)32 static inline int is_pck(int id)
33 {
34 return (id >= 8) && (id <= 15);
35 }
36
clk_system_ready(void __iomem * base,int id)37 static inline bool clk_system_ready(void __iomem *base, int id)
38 {
39 unsigned int status;
40
41 pmc_read(base, AT91_PMC_SR, &status);
42
43 return !!(status & (1 << id));
44 }
45
clk_system_enable(struct clk * clk)46 static int clk_system_enable(struct clk *clk)
47 {
48 struct clk_system *sys = to_clk_system(clk);
49
50 pmc_write(sys->base, AT91_PMC_SCER, 1 << sys->id);
51
52 if (!is_pck(sys->id))
53 return 0;
54
55 while (!clk_system_ready(sys->base, sys->id)) {
56 debug("waiting for pck%u\n", sys->id);
57 cpu_relax();
58 }
59
60 return 0;
61 }
62
clk_system_disable(struct clk * clk)63 static int clk_system_disable(struct clk *clk)
64 {
65 struct clk_system *sys = to_clk_system(clk);
66
67 pmc_write(sys->base, AT91_PMC_SCDR, 1 << sys->id);
68
69 return 0;
70 }
71
72 static const struct clk_ops system_ops = {
73 .enable = clk_system_enable,
74 .disable = clk_system_disable,
75 .get_rate = clk_generic_get_rate,
76 };
77
at91_clk_register_system(void __iomem * base,const char * name,const char * parent_name,u8 id)78 struct clk *at91_clk_register_system(void __iomem *base, const char *name,
79 const char *parent_name, u8 id)
80 {
81 struct clk_system *sys;
82 struct clk *clk;
83 int ret;
84
85 if (!base || !name || !parent_name || id > SYSTEM_MAX_ID)
86 return ERR_PTR(-EINVAL);
87
88 sys = kzalloc(sizeof(*sys), GFP_KERNEL);
89 if (!sys)
90 return ERR_PTR(-ENOMEM);
91
92 sys->id = id;
93 sys->base = base;
94
95 clk = &sys->clk;
96 clk->flags = CLK_GET_RATE_NOCACHE;
97 ret = clk_register(clk, UBOOT_DM_CLK_AT91_SYSTEM, name, parent_name);
98 if (ret) {
99 kfree(sys);
100 clk = ERR_PTR(ret);
101 }
102
103 return clk;
104 }
105
106 U_BOOT_DRIVER(at91_system_clk) = {
107 .name = UBOOT_DM_CLK_AT91_SYSTEM,
108 .id = UCLASS_CLK,
109 .ops = &system_ops,
110 .flags = DM_FLAG_PRE_RELOC,
111 };
112