1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2014 Free Electrons
4  *
5  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
6  *
7  * Allwinner A31 APB0 clock driver
8  */
9 
10 #include <linux/clk-provider.h>
11 #include <linux/init.h>
12 #include <linux/of.h>
13 #include <linux/platform_device.h>
14 
15 /*
16  * The APB0 clk has a configurable divisor.
17  *
18  * We must use a clk_div_table and not a regular power of 2
19  * divisor here, because the first 2 values divide the clock
20  * by 2.
21  */
22 static const struct clk_div_table sun6i_a31_apb0_divs[] = {
23 	{ .val = 0, .div = 2, },
24 	{ .val = 1, .div = 2, },
25 	{ .val = 2, .div = 4, },
26 	{ .val = 3, .div = 8, },
27 	{ /* sentinel */ },
28 };
29 
30 static int sun6i_a31_apb0_clk_probe(struct platform_device *pdev)
31 {
32 	struct device_node *np = pdev->dev.of_node;
33 	const char *clk_name = np->name;
34 	const char *clk_parent;
35 	struct resource *r;
36 	void __iomem *reg;
37 	struct clk *clk;
38 
39 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
40 	reg = devm_ioremap_resource(&pdev->dev, r);
41 	if (IS_ERR(reg))
42 		return PTR_ERR(reg);
43 
44 	clk_parent = of_clk_get_parent_name(np, 0);
45 	if (!clk_parent)
46 		return -EINVAL;
47 
48 	of_property_read_string(np, "clock-output-names", &clk_name);
49 
50 	clk = clk_register_divider_table(&pdev->dev, clk_name, clk_parent,
51 					 0, reg, 0, 2, 0, sun6i_a31_apb0_divs,
52 					 NULL);
53 	if (IS_ERR(clk))
54 		return PTR_ERR(clk);
55 
56 	return of_clk_add_provider(np, of_clk_src_simple_get, clk);
57 }
58 
59 static const struct of_device_id sun6i_a31_apb0_clk_dt_ids[] = {
60 	{ .compatible = "allwinner,sun6i-a31-apb0-clk" },
61 	{ /* sentinel */ }
62 };
63 
64 static struct platform_driver sun6i_a31_apb0_clk_driver = {
65 	.driver = {
66 		.name = "sun6i-a31-apb0-clk",
67 		.of_match_table = sun6i_a31_apb0_clk_dt_ids,
68 	},
69 	.probe = sun6i_a31_apb0_clk_probe,
70 };
71 builtin_platform_driver(sun6i_a31_apb0_clk_driver);
72