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 
22 static 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(node, 0);
31 	if (!clk_parent)
32 		return ERR_PTR(-EINVAL);
33 
34 	of_property_read_string(node, "clock-output-names", &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(clk))
40 		return clk;
41 
42 	ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
43 	if (ret)
44 		goto err_unregister;
45 
46 	return clk;
47 
48 err_unregister:
49 	clk_unregister_divider(clk);
50 
51 	return ERR_PTR(ret);
52 }
53 
54 static 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(node, 0, of_node_full_name(node));
61 	if (IS_ERR(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(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(clk))
75 		goto err_unmap;
76 
77 	return;
78 
79 err_unmap:
80 	iounmap(reg);
81 	of_address_to_resource(node, 0, &res);
82 	release_mem_region(res.start, resource_size(&res));
83 }
84 CLK_OF_DECLARE_DRIVER(sun8i_a23_apb0, "allwinner,sun8i-a23-apb0-clk",
85 		      sun8i_a23_apb0_setup);
86 
87 static int sun8i_a23_apb0_clk_probe(struct platform_device *pdev)
88 {
89 	struct device_node *np = pdev->dev.of_node;
90 	struct resource *r;
91 	void __iomem *reg;
92 	struct clk *clk;
93 
94 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
95 	reg = devm_ioremap_resource(&pdev->dev, r);
96 	if (IS_ERR(reg))
97 		return PTR_ERR(reg);
98 
99 	clk = sun8i_a23_apb0_register(np, reg);
100 	return PTR_ERR_OR_ZERO(clk);
101 }
102 
103 static const struct of_device_id sun8i_a23_apb0_clk_dt_ids[] = {
104 	{ .compatible = "allwinner,sun8i-a23-apb0-clk" },
105 	{ /* sentinel */ }
106 };
107 
108 static struct platform_driver sun8i_a23_apb0_clk_driver = {
109 	.driver = {
110 		.name = "sun8i-a23-apb0-clk",
111 		.of_match_table = sun8i_a23_apb0_clk_dt_ids,
112 	},
113 	.probe = sun8i_a23_apb0_clk_probe,
114 };
115 builtin_platform_driver(sun8i_a23_apb0_clk_driver);
116