1/*
2 * fixed.c
3 *
4 * Copyright 2008 Wolfson Microelectronics PLC.
5 *
6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
7 *
8 * Copyright (c) 2009 Nokia Corporation
9 * Roger Quadros <ext-roger.quadros@nokia.com>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License as
13 * published by the Free Software Foundation; either version 2 of the
14 * License, or (at your option) any later version.
15 *
16 * This is useful for systems with mixed controllable and
17 * non-controllable regulators, as well as for allowing testing on
18 * systems with no controllable regulators.
19 */
20
21#include <linux/err.h>
22#include <linux/mutex.h>
23#include <linux/module.h>
24#include <linux/platform_device.h>
25#include <linux/regulator/driver.h>
26#include <linux/regulator/fixed.h>
27#include <linux/gpio/consumer.h>
28#include <linux/slab.h>
29#include <linux/of.h>
30#include <linux/regulator/of_regulator.h>
31#include <linux/regulator/machine.h>
32
33struct fixed_voltage_data {
34 struct regulator_desc desc;
35 struct regulator_dev *dev;
36};
37
38
39/**
40 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
41 * @dev: device requesting for fixed_voltage_config
42 * @desc: regulator description
43 *
44 * Populates fixed_voltage_config structure by extracting data from device
45 * tree node, returns a pointer to the populated structure of NULL if memory
46 * alloc fails.
47 */
48static struct fixed_voltage_config *
49of_get_fixed_voltage_config(struct device *dev,
50 const struct regulator_desc *desc)
51{
52 struct fixed_voltage_config *config;
53 struct device_node *np = dev->of_node;
54 struct regulator_init_data *init_data;
55
56 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
57 GFP_KERNEL);
58 if (!config)
59 return ERR_PTR(-ENOMEM);
60
61 config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
62 if (!config->init_data)
63 return ERR_PTR(-EINVAL);
64
65 init_data = config->init_data;
66 init_data->constraints.apply_uV = 0;
67
68 config->supply_name = init_data->constraints.name;
69 if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
70 config->microvolts = init_data->constraints.min_uV;
71 } else {
72 dev_err(dev,
73 "Fixed regulator specified with variable voltages\n");
74 return ERR_PTR(-EINVAL);
75 }
76
77 if (init_data->constraints.boot_on)
78 config->enabled_at_boot = true;
79
80 of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
81
82 if (of_find_property(np, "vin-supply", NULL))
83 config->input_supply = "vin";
84
85 return config;
86}
87
88static struct regulator_ops fixed_voltage_ops = {
89};
90
91static int reg_fixed_voltage_probe(struct platform_device *pdev)
92{
93 struct fixed_voltage_config *config;
94 struct fixed_voltage_data *drvdata;
95 struct regulator_config cfg = { };
96 enum gpiod_flags gflags;
97 int ret;
98
99 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
100 GFP_KERNEL);
101 if (!drvdata)
102 return -ENOMEM;
103
104 if (pdev->dev.of_node) {
105 config = of_get_fixed_voltage_config(&pdev->dev,
106 &drvdata->desc);
107 if (IS_ERR(config))
108 return PTR_ERR(config);
109 } else {
110 config = dev_get_platdata(&pdev->dev);
111 }
112
113 if (!config)
114 return -ENOMEM;
115
116 drvdata->desc.name = devm_kstrdup(&pdev->dev,
117 config->supply_name,
118 GFP_KERNEL);
119 if (drvdata->desc.name == NULL) {
120 dev_err(&pdev->dev, "Failed to allocate supply name\n");
121 return -ENOMEM;
122 }
123 drvdata->desc.type = REGULATOR_VOLTAGE;
124 drvdata->desc.owner = THIS_MODULE;
125 drvdata->desc.ops = &fixed_voltage_ops;
126
127 drvdata->desc.enable_time = config->startup_delay;
128
129 if (config->input_supply) {
130 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
131 config->input_supply,
132 GFP_KERNEL);
133 if (!drvdata->desc.supply_name) {
134 dev_err(&pdev->dev,
135 "Failed to allocate input supply\n");
136 return -ENOMEM;
137 }
138 }
139
140 if (config->microvolts)
141 drvdata->desc.n_voltages = 1;
142
143 drvdata->desc.fixed_uV = config->microvolts;
144
145 /*
146 * The signal will be inverted by the GPIO core if flagged so in the
147 * decriptor.
148 */
149 if (config->enabled_at_boot)
150 gflags = GPIOD_OUT_HIGH;
151 else
152 gflags = GPIOD_OUT_LOW;
153
154 /*
155 * Some fixed regulators share the enable line between two
156 * regulators which makes it necessary to get a handle on the
157 * same descriptor for two different consumers. This will get
158 * the GPIO descriptor, but only the first call will initialize
159 * it so any flags such as inversion or open drain will only
160 * be set up by the first caller and assumed identical on the
161 * next caller.
162 *
163 * FIXME: find a better way to deal with this.
164 */
165 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
166
167 /*
168 * Do not use devm* here: the regulator core takes over the
169 * lifecycle management of the GPIO descriptor.
170 */
171 cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
172 if (IS_ERR(cfg.ena_gpiod))
173 return PTR_ERR(cfg.ena_gpiod);
174
175 cfg.dev = &pdev->dev;
176 cfg.init_data = config->init_data;
177 cfg.driver_data = drvdata;
178 cfg.of_node = pdev->dev.of_node;
179
180 drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
181 &cfg);
182 if (IS_ERR(drvdata->dev)) {
183 ret = PTR_ERR(drvdata->dev);
184 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
185 return ret;
186 }
187
188 platform_set_drvdata(pdev, drvdata);
189
190 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
191 drvdata->desc.fixed_uV);
192
193 return 0;
194}
195
196#if defined(CONFIG_OF)
197static const struct of_device_id fixed_of_match[] = {
198 { .compatible = "regulator-fixed", },
199 {},
200};
201MODULE_DEVICE_TABLE(of, fixed_of_match);
202#endif
203
204static struct platform_driver regulator_fixed_voltage_driver = {
205 .probe = reg_fixed_voltage_probe,
206 .driver = {
207 .name = "reg-fixed-voltage",
208 .of_match_table = of_match_ptr(fixed_of_match),
209 },
210};
211
212static int __init regulator_fixed_voltage_init(void)
213{
214 return platform_driver_register(&regulator_fixed_voltage_driver);
215}
216subsys_initcall(regulator_fixed_voltage_init);
217
218static void __exit regulator_fixed_voltage_exit(void)
219{
220 platform_driver_unregister(&regulator_fixed_voltage_driver);
221}
222module_exit(regulator_fixed_voltage_exit);
223
224MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
225MODULE_DESCRIPTION("Fixed voltage regulator");
226MODULE_LICENSE("GPL");
227MODULE_ALIAS("platform:reg-fixed-voltage");
228