xref: /openbmc/linux/drivers/gpu/drm/sun4i/sun6i_drc.c (revision d665e3c9)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 Free Electrons
4  *
5  * Maxime Ripard <maxime.ripard@free-electrons.com>
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/component.h>
10 #include <linux/module.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/platform_device.h>
13 #include <linux/regmap.h>
14 #include <linux/reset.h>
15 
16 struct sun6i_drc {
17 	struct clk		*bus_clk;
18 	struct clk		*mod_clk;
19 	struct reset_control	*reset;
20 };
21 
sun6i_drc_bind(struct device * dev,struct device * master,void * data)22 static int sun6i_drc_bind(struct device *dev, struct device *master,
23 			 void *data)
24 {
25 	struct sun6i_drc *drc;
26 	int ret;
27 
28 	drc = devm_kzalloc(dev, sizeof(*drc), GFP_KERNEL);
29 	if (!drc)
30 		return -ENOMEM;
31 	dev_set_drvdata(dev, drc);
32 
33 	drc->reset = devm_reset_control_get(dev, NULL);
34 	if (IS_ERR(drc->reset)) {
35 		dev_err(dev, "Couldn't get our reset line\n");
36 		return PTR_ERR(drc->reset);
37 	}
38 
39 	ret = reset_control_deassert(drc->reset);
40 	if (ret) {
41 		dev_err(dev, "Couldn't deassert our reset line\n");
42 		return ret;
43 	}
44 
45 	drc->bus_clk = devm_clk_get(dev, "ahb");
46 	if (IS_ERR(drc->bus_clk)) {
47 		dev_err(dev, "Couldn't get our bus clock\n");
48 		ret = PTR_ERR(drc->bus_clk);
49 		goto err_assert_reset;
50 	}
51 	clk_prepare_enable(drc->bus_clk);
52 
53 	drc->mod_clk = devm_clk_get(dev, "mod");
54 	if (IS_ERR(drc->mod_clk)) {
55 		dev_err(dev, "Couldn't get our mod clock\n");
56 		ret = PTR_ERR(drc->mod_clk);
57 		goto err_disable_bus_clk;
58 	}
59 
60 	ret = clk_set_rate_exclusive(drc->mod_clk, 300000000);
61 	if (ret) {
62 		dev_err(dev, "Couldn't set the module clock frequency\n");
63 		goto err_disable_bus_clk;
64 	}
65 
66 	clk_prepare_enable(drc->mod_clk);
67 
68 	return 0;
69 
70 err_disable_bus_clk:
71 	clk_disable_unprepare(drc->bus_clk);
72 err_assert_reset:
73 	reset_control_assert(drc->reset);
74 	return ret;
75 }
76 
sun6i_drc_unbind(struct device * dev,struct device * master,void * data)77 static void sun6i_drc_unbind(struct device *dev, struct device *master,
78 			    void *data)
79 {
80 	struct sun6i_drc *drc = dev_get_drvdata(dev);
81 
82 	clk_rate_exclusive_put(drc->mod_clk);
83 	clk_disable_unprepare(drc->mod_clk);
84 	clk_disable_unprepare(drc->bus_clk);
85 	reset_control_assert(drc->reset);
86 }
87 
88 static const struct component_ops sun6i_drc_ops = {
89 	.bind	= sun6i_drc_bind,
90 	.unbind	= sun6i_drc_unbind,
91 };
92 
sun6i_drc_probe(struct platform_device * pdev)93 static int sun6i_drc_probe(struct platform_device *pdev)
94 {
95 	return component_add(&pdev->dev, &sun6i_drc_ops);
96 }
97 
sun6i_drc_remove(struct platform_device * pdev)98 static void sun6i_drc_remove(struct platform_device *pdev)
99 {
100 	component_del(&pdev->dev, &sun6i_drc_ops);
101 }
102 
103 static const struct of_device_id sun6i_drc_of_table[] = {
104 	{ .compatible = "allwinner,sun6i-a31-drc" },
105 	{ .compatible = "allwinner,sun6i-a31s-drc" },
106 	{ .compatible = "allwinner,sun8i-a23-drc" },
107 	{ .compatible = "allwinner,sun8i-a33-drc" },
108 	{ .compatible = "allwinner,sun9i-a80-drc" },
109 	{ }
110 };
111 MODULE_DEVICE_TABLE(of, sun6i_drc_of_table);
112 
113 static struct platform_driver sun6i_drc_platform_driver = {
114 	.probe		= sun6i_drc_probe,
115 	.remove_new	= sun6i_drc_remove,
116 	.driver		= {
117 		.name		= "sun6i-drc",
118 		.of_match_table	= sun6i_drc_of_table,
119 	},
120 };
121 module_platform_driver(sun6i_drc_platform_driver);
122 
123 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
124 MODULE_DESCRIPTION("Allwinner A31 Dynamic Range Control (DRC) Driver");
125 MODULE_LICENSE("GPL");
126