1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2014 Chen-Yu Tsai
4 * Author: Chen-Yu Tsai <wens@csie.org>
5 *
6 * Allwinner A23 APB0 clock driver
7 *
8 * Based on clk-sun6i-apb0.c
9 * Allwinner A31 APB0 clock driver
10 *
11 * Copyright (C) 2014 Free Electrons
12 * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
13 */
14
15#include <linux/clk-provider.h>
16#include <linux/init.h>
17#include <linux/io.h>
18#include <linux/of.h>
19#include <linux/of_address.h>
20#include <linux/platform_device.h>
21
22static struct clk *sun8i_a23_apb0_register(struct device_node *node,
23 void __iomem *reg)
24{
25 const char *clk_name = node->name;
26 const char *clk_parent;
27 struct clk *clk;
28 int ret;
29
30 clk_parent = of_clk_get_parent_name(np: node, index: 0);
31 if (!clk_parent)
32 return ERR_PTR(error: -EINVAL);
33
34 of_property_read_string(np: node, propname: "clock-output-names", out_string: &clk_name);
35
36 /* The A23 APB0 clock is a standard 2 bit wide divider clock */
37 clk = clk_register_divider(NULL, clk_name, clk_parent, 0, reg,
38 0, 2, 0, NULL);
39 if (IS_ERR(ptr: clk))
40 return clk;
41
42 ret = of_clk_add_provider(np: node, clk_src_get: of_clk_src_simple_get, data: clk);
43 if (ret)
44 goto err_unregister;
45
46 return clk;
47
48err_unregister:
49 clk_unregister_divider(clk);
50
51 return ERR_PTR(error: ret);
52}
53
54static void sun8i_a23_apb0_setup(struct device_node *node)
55{
56 void __iomem *reg;
57 struct resource res;
58 struct clk *clk;
59
60 reg = of_io_request_and_map(device: node, index: 0, name: of_node_full_name(np: node));
61 if (IS_ERR(ptr: reg)) {
62 /*
63 * This happens with clk nodes instantiated through mfd,
64 * as those do not have their resources assigned in the
65 * device tree. Do not print an error in this case.
66 */
67 if (PTR_ERR(ptr: reg) != -EINVAL)
68 pr_err("Could not get registers for a23-apb0-clk\n");
69
70 return;
71 }
72
73 clk = sun8i_a23_apb0_register(node, reg);
74 if (IS_ERR(ptr: clk))
75 goto err_unmap;
76
77 return;
78
79err_unmap:
80 iounmap(addr: reg);
81 of_address_to_resource(dev: node, index: 0, r: &res);
82 release_mem_region(res.start, resource_size(&res));
83}
84CLK_OF_DECLARE_DRIVER(sun8i_a23_apb0, "allwinner,sun8i-a23-apb0-clk",
85 sun8i_a23_apb0_setup);
86
87static int sun8i_a23_apb0_clk_probe(struct platform_device *pdev)
88{
89 struct device_node *np = pdev->dev.of_node;
90 void __iomem *reg;
91 struct clk *clk;
92
93 reg = devm_platform_ioremap_resource(pdev, index: 0);
94 if (IS_ERR(ptr: reg))
95 return PTR_ERR(ptr: reg);
96
97 clk = sun8i_a23_apb0_register(node: np, reg);
98 return PTR_ERR_OR_ZERO(ptr: clk);
99}
100
101static const struct of_device_id sun8i_a23_apb0_clk_dt_ids[] = {
102 { .compatible = "allwinner,sun8i-a23-apb0-clk" },
103 { /* sentinel */ }
104};
105
106static struct platform_driver sun8i_a23_apb0_clk_driver = {
107 .driver = {
108 .name = "sun8i-a23-apb0-clk",
109 .of_match_table = sun8i_a23_apb0_clk_dt_ids,
110 },
111 .probe = sun8i_a23_apb0_clk_probe,
112};
113builtin_platform_driver(sun8i_a23_apb0_clk_driver);
114

source code of linux/drivers/clk/sunxi/clk-sun8i-apb0.c