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/mod_devicetable.h>
12 #include <linux/platform_device.h>
13 #include <linux/regulator/driver.h>
14 #include <linux/regulator/machine.h>
15 #include <linux/regulator/of_regulator.h>
16 #include <linux/vexpress.h>
17 
18 static int vexpress_regulator_get_voltage(struct regulator_dev *regdev)
19 {
20 	unsigned int uV;
21 	int err = regmap_read(regdev->regmap, 0, &uV);
22 
23 	return err ? err : uV;
24 }
25 
26 static int vexpress_regulator_set_voltage(struct regulator_dev *regdev,
27 		int min_uV, int max_uV, unsigned *selector)
28 {
29 	return regmap_write(regdev->regmap, 0, min_uV);
30 }
31 
32 static const struct regulator_ops vexpress_regulator_ops_ro = {
33 	.get_voltage = vexpress_regulator_get_voltage,
34 };
35 
36 static const struct regulator_ops vexpress_regulator_ops = {
37 	.get_voltage = vexpress_regulator_get_voltage,
38 	.set_voltage = vexpress_regulator_set_voltage,
39 };
40 
41 static int vexpress_regulator_probe(struct platform_device *pdev)
42 {
43 	struct regulator_desc *desc;
44 	struct regulator_init_data *init_data;
45 	struct regulator_config config = { };
46 	struct regulator_dev *rdev;
47 	struct regmap *regmap;
48 
49 	desc = devm_kzalloc(&pdev->dev, sizeof(*desc), GFP_KERNEL);
50 	if (!desc)
51 		return -ENOMEM;
52 
53 	regmap = devm_regmap_init_vexpress_config(&pdev->dev);
54 	if (IS_ERR(regmap))
55 		return PTR_ERR(regmap);
56 
57 	desc->name = dev_name(&pdev->dev);
58 	desc->type = REGULATOR_VOLTAGE;
59 	desc->owner = THIS_MODULE;
60 	desc->continuous_voltage_range = true;
61 
62 	init_data = of_get_regulator_init_data(&pdev->dev, pdev->dev.of_node,
63 					       desc);
64 	if (!init_data)
65 		return -EINVAL;
66 
67 	init_data->constraints.apply_uV = 0;
68 	if (init_data->constraints.min_uV && init_data->constraints.max_uV)
69 		desc->ops = &vexpress_regulator_ops;
70 	else
71 		desc->ops = &vexpress_regulator_ops_ro;
72 
73 	config.regmap = regmap;
74 	config.dev = &pdev->dev;
75 	config.init_data = init_data;
76 	config.of_node = pdev->dev.of_node;
77 
78 	rdev = devm_regulator_register(&pdev->dev, desc, &config);
79 	return PTR_ERR_OR_ZERO(rdev);
80 }
81 
82 static const struct of_device_id vexpress_regulator_of_match[] = {
83 	{ .compatible = "arm,vexpress-volt", },
84 	{ }
85 };
86 MODULE_DEVICE_TABLE(of, vexpress_regulator_of_match);
87 
88 static struct platform_driver vexpress_regulator_driver = {
89 	.probe = vexpress_regulator_probe,
90 	.driver	= {
91 		.name = DRVNAME,
92 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
93 		.of_match_table = vexpress_regulator_of_match,
94 	},
95 };
96 
97 module_platform_driver(vexpress_regulator_driver);
98 
99 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
100 MODULE_DESCRIPTION("Versatile Express regulator");
101 MODULE_LICENSE("GPL");
102 MODULE_ALIAS("platform:vexpress-regulator");
103