1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Marvell Armada 37xx SoC xtal clocks
4  *
5  * Copyright (C) 2016 Marvell
6  *
7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
8  *
9  */
10 
11 #include <linux/clk-provider.h>
12 #include <linux/mfd/syscon.h>
13 #include <linux/platform_device.h>
14 #include <linux/regmap.h>
15 
16 #define NB_GPIO1_LATCH	0x8
17 #define XTAL_MODE	    BIT(9)
18 
19 static int armada_3700_xtal_clock_probe(struct platform_device *pdev)
20 {
21 	struct device_node *np = pdev->dev.of_node;
22 	const char *xtal_name = "xtal";
23 	struct device_node *parent;
24 	struct regmap *regmap;
25 	struct clk_hw *xtal_hw;
26 	unsigned int rate;
27 	u32 reg;
28 	int ret;
29 
30 	xtal_hw = devm_kzalloc(&pdev->dev, sizeof(*xtal_hw), GFP_KERNEL);
31 	if (!xtal_hw)
32 		return -ENOMEM;
33 
34 	platform_set_drvdata(pdev, xtal_hw);
35 
36 	parent = np->parent;
37 	if (!parent) {
38 		dev_err(&pdev->dev, "no parent\n");
39 		return -ENODEV;
40 	}
41 
42 	regmap = syscon_node_to_regmap(parent);
43 	if (IS_ERR(regmap)) {
44 		dev_err(&pdev->dev, "cannot get regmap\n");
45 		return PTR_ERR(regmap);
46 	}
47 
48 	ret = regmap_read(regmap, NB_GPIO1_LATCH, &reg);
49 	if (ret) {
50 		dev_err(&pdev->dev, "cannot read from regmap\n");
51 		return ret;
52 	}
53 
54 	if (reg & XTAL_MODE)
55 		rate = 40000000;
56 	else
57 		rate = 25000000;
58 
59 	of_property_read_string_index(np, "clock-output-names", 0, &xtal_name);
60 	xtal_hw = clk_hw_register_fixed_rate(NULL, xtal_name, NULL, 0, rate);
61 	if (IS_ERR(xtal_hw))
62 		return PTR_ERR(xtal_hw);
63 	ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, xtal_hw);
64 
65 	return ret;
66 }
67 
68 static int armada_3700_xtal_clock_remove(struct platform_device *pdev)
69 {
70 	of_clk_del_provider(pdev->dev.of_node);
71 
72 	return 0;
73 }
74 
75 static const struct of_device_id armada_3700_xtal_clock_of_match[] = {
76 	{ .compatible = "marvell,armada-3700-xtal-clock", },
77 	{ }
78 };
79 
80 static struct platform_driver armada_3700_xtal_clock_driver = {
81 	.probe = armada_3700_xtal_clock_probe,
82 	.remove = armada_3700_xtal_clock_remove,
83 	.driver		= {
84 		.name	= "marvell-armada-3700-xtal-clock",
85 		.of_match_table = armada_3700_xtal_clock_of_match,
86 	},
87 };
88 
89 builtin_platform_driver(armada_3700_xtal_clock_driver);
90