1 /*
2  * Copyright (C) 2014 Free Electrons
3  *
4  * License Terms: GNU General Public License v2
5  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
6  *
7  * Allwinner A31 APB0 clock gates driver
8  *
9  */
10 
11 #include <linux/clk-provider.h>
12 #include <linux/clkdev.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/of_device.h>
16 #include <linux/platform_device.h>
17 
18 #define SUN6I_APB0_GATES_MAX_SIZE	32
19 
20 struct gates_data {
21 	DECLARE_BITMAP(mask, SUN6I_APB0_GATES_MAX_SIZE);
22 };
23 
24 static const struct gates_data sun6i_a31_apb0_gates __initconst = {
25 	.mask = {0x7F},
26 };
27 
28 static const struct gates_data sun8i_a23_apb0_gates __initconst = {
29 	.mask = {0x5D},
30 };
31 
32 static const struct of_device_id sun6i_a31_apb0_gates_clk_dt_ids[] = {
33 	{ .compatible = "allwinner,sun6i-a31-apb0-gates-clk", .data = &sun6i_a31_apb0_gates },
34 	{ .compatible = "allwinner,sun8i-a23-apb0-gates-clk", .data = &sun8i_a23_apb0_gates },
35 	{ /* sentinel */ }
36 };
37 
38 static int sun6i_a31_apb0_gates_clk_probe(struct platform_device *pdev)
39 {
40 	struct device_node *np = pdev->dev.of_node;
41 	struct clk_onecell_data *clk_data;
42 	const struct of_device_id *device;
43 	const struct gates_data *data;
44 	const char *clk_parent;
45 	const char *clk_name;
46 	struct resource *r;
47 	void __iomem *reg;
48 	int ngates;
49 	int i;
50 	int j = 0;
51 
52 	if (!np)
53 		return -ENODEV;
54 
55 	device = of_match_device(sun6i_a31_apb0_gates_clk_dt_ids, &pdev->dev);
56 	if (!device)
57 		return -ENODEV;
58 	data = device->data;
59 
60 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
61 	reg = devm_ioremap_resource(&pdev->dev, r);
62 	if (IS_ERR(reg))
63 		return PTR_ERR(reg);
64 
65 	clk_parent = of_clk_get_parent_name(np, 0);
66 	if (!clk_parent)
67 		return -EINVAL;
68 
69 	clk_data = devm_kzalloc(&pdev->dev, sizeof(struct clk_onecell_data),
70 				GFP_KERNEL);
71 	if (!clk_data)
72 		return -ENOMEM;
73 
74 	/* Worst-case size approximation and memory allocation */
75 	ngates = find_last_bit(data->mask, SUN6I_APB0_GATES_MAX_SIZE);
76 	clk_data->clks = devm_kcalloc(&pdev->dev, (ngates + 1),
77 				      sizeof(struct clk *), GFP_KERNEL);
78 	if (!clk_data->clks)
79 		return -ENOMEM;
80 
81 	for_each_set_bit(i, data->mask, SUN6I_APB0_GATES_MAX_SIZE) {
82 		of_property_read_string_index(np, "clock-output-names",
83 					      j, &clk_name);
84 
85 		clk_data->clks[i] = clk_register_gate(&pdev->dev, clk_name,
86 						      clk_parent, 0, reg, i,
87 						      0, NULL);
88 		WARN_ON(IS_ERR(clk_data->clks[i]));
89 		clk_register_clkdev(clk_data->clks[i], clk_name, NULL);
90 
91 		j++;
92 	}
93 
94 	clk_data->clk_num = ngates + 1;
95 
96 	return of_clk_add_provider(np, of_clk_src_onecell_get, clk_data);
97 }
98 
99 static struct platform_driver sun6i_a31_apb0_gates_clk_driver = {
100 	.driver = {
101 		.name = "sun6i-a31-apb0-gates-clk",
102 		.owner = THIS_MODULE,
103 		.of_match_table = sun6i_a31_apb0_gates_clk_dt_ids,
104 	},
105 	.probe = sun6i_a31_apb0_gates_clk_probe,
106 };
107 module_platform_driver(sun6i_a31_apb0_gates_clk_driver);
108 
109 MODULE_AUTHOR("Boris BREZILLON <boris.brezillon@free-electrons.com>");
110 MODULE_DESCRIPTION("Allwinner A31 APB0 gate clocks driver");
111 MODULE_LICENSE("GPL v2");
112