1 /*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License version 2 as
4 * published by the Free Software Foundation.
5 *
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
10 *
11 * Copyright (C) 2012 ARM Limited
12 */
13
14 #define DRVNAME "vexpress-regulator"
15 #define pr_fmt(fmt) DRVNAME ": " fmt
16
17 #include <linux/device.h>
18 #include <linux/err.h>
19 #include <linux/module.h>
20 #include <linux/of_device.h>
21 #include <linux/regulator/driver.h>
22 #include <linux/regulator/machine.h>
23 #include <linux/regulator/of_regulator.h>
24 #include <linux/vexpress.h>
25
26 struct vexpress_regulator {
27 struct regulator_desc desc;
28 struct regulator_dev *regdev;
29 struct regmap *regmap;
30 };
31
vexpress_regulator_get_voltage(struct regulator_dev * regdev)32 static int vexpress_regulator_get_voltage(struct regulator_dev *regdev)
33 {
34 struct vexpress_regulator *reg = rdev_get_drvdata(regdev);
35 u32 uV;
36 int err = regmap_read(reg->regmap, 0, &uV);
37
38 return err ? err : uV;
39 }
40
vexpress_regulator_set_voltage(struct regulator_dev * regdev,int min_uV,int max_uV,unsigned * selector)41 static int vexpress_regulator_set_voltage(struct regulator_dev *regdev,
42 int min_uV, int max_uV, unsigned *selector)
43 {
44 struct vexpress_regulator *reg = rdev_get_drvdata(regdev);
45
46 return regmap_write(reg->regmap, 0, min_uV);
47 }
48
49 static struct regulator_ops vexpress_regulator_ops_ro = {
50 .get_voltage = vexpress_regulator_get_voltage,
51 };
52
53 static struct regulator_ops vexpress_regulator_ops = {
54 .get_voltage = vexpress_regulator_get_voltage,
55 .set_voltage = vexpress_regulator_set_voltage,
56 };
57
vexpress_regulator_probe(struct platform_device * pdev)58 static int vexpress_regulator_probe(struct platform_device *pdev)
59 {
60 struct vexpress_regulator *reg;
61 struct regulator_init_data *init_data;
62 struct regulator_config config = { };
63
64 reg = devm_kzalloc(&pdev->dev, sizeof(*reg), GFP_KERNEL);
65 if (!reg)
66 return -ENOMEM;
67
68 reg->regmap = devm_regmap_init_vexpress_config(&pdev->dev);
69 if (IS_ERR(reg->regmap))
70 return PTR_ERR(reg->regmap);
71
72 reg->desc.name = dev_name(&pdev->dev);
73 reg->desc.type = REGULATOR_VOLTAGE;
74 reg->desc.owner = THIS_MODULE;
75 reg->desc.continuous_voltage_range = true;
76
77 init_data = of_get_regulator_init_data(&pdev->dev, pdev->dev.of_node,
78 ®->desc);
79 if (!init_data)
80 return -EINVAL;
81
82 init_data->constraints.apply_uV = 0;
83 if (init_data->constraints.min_uV && init_data->constraints.max_uV)
84 reg->desc.ops = &vexpress_regulator_ops;
85 else
86 reg->desc.ops = &vexpress_regulator_ops_ro;
87
88 config.dev = &pdev->dev;
89 config.init_data = init_data;
90 config.driver_data = reg;
91 config.of_node = pdev->dev.of_node;
92
93 reg->regdev = devm_regulator_register(&pdev->dev, ®->desc, &config);
94 if (IS_ERR(reg->regdev))
95 return PTR_ERR(reg->regdev);
96
97 platform_set_drvdata(pdev, reg);
98
99 return 0;
100 }
101
102 static const struct of_device_id vexpress_regulator_of_match[] = {
103 { .compatible = "arm,vexpress-volt", },
104 { }
105 };
106 MODULE_DEVICE_TABLE(of, vexpress_regulator_of_match);
107
108 static struct platform_driver vexpress_regulator_driver = {
109 .probe = vexpress_regulator_probe,
110 .driver = {
111 .name = DRVNAME,
112 .of_match_table = vexpress_regulator_of_match,
113 },
114 };
115
116 module_platform_driver(vexpress_regulator_driver);
117
118 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
119 MODULE_DESCRIPTION("Versatile Express regulator");
120 MODULE_LICENSE("GPL");
121 MODULE_ALIAS("platform:vexpress-regulator");
122