1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Copyright (C) 2012 ARM Limited
4 
5 #define DRVNAME "vexpress-regulator"
6 #define pr_fmt(fmt) DRVNAME ": " fmt
7 
8 #include <linux/device.h>
9 #include <linux/err.h>
10 #include <linux/module.h>
11 #include <linux/of_device.h>
12 #include <linux/regulator/driver.h>
13 #include <linux/regulator/machine.h>
14 #include <linux/regulator/of_regulator.h>
15 #include <linux/vexpress.h>
16 
17 static int vexpress_regulator_get_voltage(struct regulator_dev *regdev)
18 {
19 	unsigned int uV;
20 	int err = regmap_read(regdev->regmap, 0, &uV);
21 
22 	return err ? err : uV;
23 }
24 
25 static int vexpress_regulator_set_voltage(struct regulator_dev *regdev,
26 		int min_uV, int max_uV, unsigned *selector)
27 {
28 	return regmap_write(regdev->regmap, 0, min_uV);
29 }
30 
31 static const struct regulator_ops vexpress_regulator_ops_ro = {
32 	.get_voltage = vexpress_regulator_get_voltage,
33 };
34 
35 static const struct regulator_ops vexpress_regulator_ops = {
36 	.get_voltage = vexpress_regulator_get_voltage,
37 	.set_voltage = vexpress_regulator_set_voltage,
38 };
39 
40 static int vexpress_regulator_probe(struct platform_device *pdev)
41 {
42 	struct regulator_desc *desc;
43 	struct regulator_init_data *init_data;
44 	struct regulator_config config = { };
45 	struct regulator_dev *rdev;
46 	struct regmap *regmap;
47 
48 	desc = devm_kzalloc(&pdev->dev, sizeof(*desc), GFP_KERNEL);
49 	if (!desc)
50 		return -ENOMEM;
51 
52 	regmap = devm_regmap_init_vexpress_config(&pdev->dev);
53 	if (IS_ERR(regmap))
54 		return PTR_ERR(regmap);
55 
56 	desc->name = dev_name(&pdev->dev);
57 	desc->type = REGULATOR_VOLTAGE;
58 	desc->owner = THIS_MODULE;
59 	desc->continuous_voltage_range = true;
60 
61 	init_data = of_get_regulator_init_data(&pdev->dev, pdev->dev.of_node,
62 					       desc);
63 	if (!init_data)
64 		return -EINVAL;
65 
66 	init_data->constraints.apply_uV = 0;
67 	if (init_data->constraints.min_uV && init_data->constraints.max_uV)
68 		desc->ops = &vexpress_regulator_ops;
69 	else
70 		desc->ops = &vexpress_regulator_ops_ro;
71 
72 	config.regmap = regmap;
73 	config.dev = &pdev->dev;
74 	config.init_data = init_data;
75 	config.of_node = pdev->dev.of_node;
76 
77 	rdev = devm_regulator_register(&pdev->dev, desc, &config);
78 	return PTR_ERR_OR_ZERO(rdev);
79 }
80 
81 static const struct of_device_id vexpress_regulator_of_match[] = {
82 	{ .compatible = "arm,vexpress-volt", },
83 	{ }
84 };
85 MODULE_DEVICE_TABLE(of, vexpress_regulator_of_match);
86 
87 static struct platform_driver vexpress_regulator_driver = {
88 	.probe = vexpress_regulator_probe,
89 	.driver	= {
90 		.name = DRVNAME,
91 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
92 		.of_match_table = vexpress_regulator_of_match,
93 	},
94 };
95 
96 module_platform_driver(vexpress_regulator_driver);
97 
98 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
99 MODULE_DESCRIPTION("Versatile Express regulator");
100 MODULE_LICENSE("GPL");
101 MODULE_ALIAS("platform:vexpress-regulator");
102