1 /*
2  * Copyright (C) 2014 Chen-Yu Tsai
3  * Author: Chen-Yu Tsai <wens@csie.org>
4  *
5  * Allwinner A23 APB0 clock driver
6  *
7  * License Terms: GNU General Public License v2
8  *
9  * Based on clk-sun6i-apb0.c
10  * Allwinner A31 APB0 clock driver
11  *
12  * Copyright (C) 2014 Free Electrons
13  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
14  *
15  */
16 
17 #include <linux/clk-provider.h>
18 #include <linux/module.h>
19 #include <linux/of.h>
20 #include <linux/of_address.h>
21 #include <linux/platform_device.h>
22 
23 static struct clk *sun8i_a23_apb0_register(struct device_node *node,
24 					   void __iomem *reg)
25 {
26 	const char *clk_name = node->name;
27 	const char *clk_parent;
28 	struct clk *clk;
29 	int ret;
30 
31 	clk_parent = of_clk_get_parent_name(node, 0);
32 	if (!clk_parent)
33 		return ERR_PTR(-EINVAL);
34 
35 	of_property_read_string(node, "clock-output-names", &clk_name);
36 
37 	/* The A23 APB0 clock is a standard 2 bit wide divider clock */
38 	clk = clk_register_divider(NULL, clk_name, clk_parent, 0, reg,
39 				   0, 2, CLK_DIVIDER_POWER_OF_TWO, NULL);
40 	if (IS_ERR(clk))
41 		return clk;
42 
43 	ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
44 	if (ret)
45 		goto err_unregister;
46 
47 	return clk;
48 
49 err_unregister:
50 	clk_unregister_divider(clk);
51 
52 	return ERR_PTR(ret);
53 }
54 
55 static void sun8i_a23_apb0_setup(struct device_node *node)
56 {
57 	void __iomem *reg;
58 	struct resource res;
59 	struct clk *clk;
60 
61 	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
62 	if (IS_ERR(reg)) {
63 		/*
64 		 * This happens with clk nodes instantiated through mfd,
65 		 * as those do not have their resources assigned in the
66 		 * device tree. Do not print an error in this case.
67 		 */
68 		if (PTR_ERR(reg) != -EINVAL)
69 			pr_err("Could not get registers for a23-apb0-clk\n");
70 
71 		return;
72 	}
73 
74 	clk = sun8i_a23_apb0_register(node, reg);
75 	if (IS_ERR(clk))
76 		goto err_unmap;
77 
78 	return;
79 
80 err_unmap:
81 	iounmap(reg);
82 	of_address_to_resource(node, 0, &res);
83 	release_mem_region(res.start, resource_size(&res));
84 }
85 CLK_OF_DECLARE(sun8i_a23_apb0, "allwinner,sun8i-a23-apb0-clk",
86 	       sun8i_a23_apb0_setup);
87 
88 static int sun8i_a23_apb0_clk_probe(struct platform_device *pdev)
89 {
90 	struct device_node *np = pdev->dev.of_node;
91 	struct resource *r;
92 	void __iomem *reg;
93 	struct clk *clk;
94 
95 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
96 	reg = devm_ioremap_resource(&pdev->dev, r);
97 	if (IS_ERR(reg))
98 		return PTR_ERR(reg);
99 
100 	clk = sun8i_a23_apb0_register(np, reg);
101 	if (IS_ERR(clk))
102 		return PTR_ERR(clk);
103 
104 	return 0;
105 }
106 
107 static const struct of_device_id sun8i_a23_apb0_clk_dt_ids[] = {
108 	{ .compatible = "allwinner,sun8i-a23-apb0-clk" },
109 	{ /* sentinel */ }
110 };
111 MODULE_DEVICE_TABLE(of, sun8i_a23_apb0_clk_dt_ids);
112 
113 static struct platform_driver sun8i_a23_apb0_clk_driver = {
114 	.driver = {
115 		.name = "sun8i-a23-apb0-clk",
116 		.of_match_table = sun8i_a23_apb0_clk_dt_ids,
117 	},
118 	.probe = sun8i_a23_apb0_clk_probe,
119 };
120 module_platform_driver(sun8i_a23_apb0_clk_driver);
121 
122 MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
123 MODULE_DESCRIPTION("Allwinner A23 APB0 clock Driver");
124 MODULE_LICENSE("GPL v2");
125