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/init.h>
19 #include <linux/of.h>
20 #include <linux/of_address.h>
21 #include <linux/platform_device.h>
22
sun8i_a23_apb0_register(struct device_node * node,void __iomem * reg)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, 0, 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
sun8i_a23_apb0_setup(struct device_node * node)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_DRIVER(sun8i_a23_apb0, "allwinner,sun8i-a23-apb0-clk",
86 sun8i_a23_apb0_setup);
87
sun8i_a23_apb0_clk_probe(struct platform_device * pdev)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 return PTR_ERR_OR_ZERO(clk);
102 }
103
104 static const struct of_device_id sun8i_a23_apb0_clk_dt_ids[] = {
105 { .compatible = "allwinner,sun8i-a23-apb0-clk" },
106 { /* sentinel */ }
107 };
108
109 static struct platform_driver sun8i_a23_apb0_clk_driver = {
110 .driver = {
111 .name = "sun8i-a23-apb0-clk",
112 .of_match_table = sun8i_a23_apb0_clk_dt_ids,
113 },
114 .probe = sun8i_a23_apb0_clk_probe,
115 };
116 builtin_platform_driver(sun8i_a23_apb0_clk_driver);
117
