xref: /openbmc/linux/drivers/regulator/fixed.c (revision b34e08d5)
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.h>
28 #include <linux/slab.h>
29 #include <linux/of.h>
30 #include <linux/of_gpio.h>
31 #include <linux/regulator/of_regulator.h>
32 #include <linux/regulator/machine.h>
33 
34 struct fixed_voltage_data {
35 	struct regulator_desc desc;
36 	struct regulator_dev *dev;
37 };
38 
39 
40 /**
41  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
42  * @dev: device requesting for fixed_voltage_config
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  */
48 static struct fixed_voltage_config *
49 of_get_fixed_voltage_config(struct device *dev)
50 {
51 	struct fixed_voltage_config *config;
52 	struct device_node *np = dev->of_node;
53 	const __be32 *delay;
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);
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 	config->gpio = of_get_named_gpio(np, "gpio", 0);
81 	/*
82 	 * of_get_named_gpio() currently returns ENODEV rather than
83 	 * EPROBE_DEFER. This code attempts to be compatible with both
84 	 * for now; the ENODEV check can be removed once the API is fixed.
85 	 * of_get_named_gpio() doesn't differentiate between a missing
86 	 * property (which would be fine here, since the GPIO is optional)
87 	 * and some other error. Patches have been posted for both issues.
88 	 * Once they are check in, we should replace this with:
89 	 * if (config->gpio < 0 && config->gpio != -ENOENT)
90 	 */
91 	if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER))
92 		return ERR_PTR(-EPROBE_DEFER);
93 
94 	delay = of_get_property(np, "startup-delay-us", NULL);
95 	if (delay)
96 		config->startup_delay = be32_to_cpu(*delay);
97 
98 	if (of_find_property(np, "enable-active-high", NULL))
99 		config->enable_high = true;
100 
101 	if (of_find_property(np, "gpio-open-drain", NULL))
102 		config->gpio_is_open_drain = true;
103 
104 	if (of_find_property(np, "vin-supply", NULL))
105 		config->input_supply = "vin";
106 
107 	return config;
108 }
109 
110 static struct regulator_ops fixed_voltage_ops = {
111 };
112 
113 static int reg_fixed_voltage_probe(struct platform_device *pdev)
114 {
115 	struct fixed_voltage_config *config;
116 	struct fixed_voltage_data *drvdata;
117 	struct regulator_config cfg = { };
118 	int ret;
119 
120 	if (pdev->dev.of_node) {
121 		config = of_get_fixed_voltage_config(&pdev->dev);
122 		if (IS_ERR(config))
123 			return PTR_ERR(config);
124 	} else {
125 		config = dev_get_platdata(&pdev->dev);
126 	}
127 
128 	if (!config)
129 		return -ENOMEM;
130 
131 	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
132 			       GFP_KERNEL);
133 	if (!drvdata)
134 		return -ENOMEM;
135 
136 	drvdata->desc.name = devm_kstrdup(&pdev->dev,
137 					  config->supply_name,
138 					  GFP_KERNEL);
139 	if (drvdata->desc.name == NULL) {
140 		dev_err(&pdev->dev, "Failed to allocate supply name\n");
141 		return -ENOMEM;
142 	}
143 	drvdata->desc.type = REGULATOR_VOLTAGE;
144 	drvdata->desc.owner = THIS_MODULE;
145 	drvdata->desc.ops = &fixed_voltage_ops;
146 
147 	drvdata->desc.enable_time = config->startup_delay;
148 
149 	if (config->input_supply) {
150 		drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
151 					    config->input_supply,
152 					    GFP_KERNEL);
153 		if (!drvdata->desc.supply_name) {
154 			dev_err(&pdev->dev,
155 				"Failed to allocate input supply\n");
156 			return -ENOMEM;
157 		}
158 	}
159 
160 	if (config->microvolts)
161 		drvdata->desc.n_voltages = 1;
162 
163 	drvdata->desc.fixed_uV = config->microvolts;
164 
165 	if (config->gpio >= 0)
166 		cfg.ena_gpio = config->gpio;
167 	cfg.ena_gpio_invert = !config->enable_high;
168 	if (config->enabled_at_boot) {
169 		if (config->enable_high)
170 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
171 		else
172 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
173 	} else {
174 		if (config->enable_high)
175 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
176 		else
177 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
178 	}
179 	if (config->gpio_is_open_drain)
180 		cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
181 
182 	cfg.dev = &pdev->dev;
183 	cfg.init_data = config->init_data;
184 	cfg.driver_data = drvdata;
185 	cfg.of_node = pdev->dev.of_node;
186 
187 	drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
188 					       &cfg);
189 	if (IS_ERR(drvdata->dev)) {
190 		ret = PTR_ERR(drvdata->dev);
191 		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
192 		return ret;
193 	}
194 
195 	platform_set_drvdata(pdev, drvdata);
196 
197 	dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
198 		drvdata->desc.fixed_uV);
199 
200 	return 0;
201 }
202 
203 #if defined(CONFIG_OF)
204 static const struct of_device_id fixed_of_match[] = {
205 	{ .compatible = "regulator-fixed", },
206 	{},
207 };
208 MODULE_DEVICE_TABLE(of, fixed_of_match);
209 #endif
210 
211 static struct platform_driver regulator_fixed_voltage_driver = {
212 	.probe		= reg_fixed_voltage_probe,
213 	.driver		= {
214 		.name		= "reg-fixed-voltage",
215 		.owner		= THIS_MODULE,
216 		.of_match_table = of_match_ptr(fixed_of_match),
217 	},
218 };
219 
220 static int __init regulator_fixed_voltage_init(void)
221 {
222 	return platform_driver_register(&regulator_fixed_voltage_driver);
223 }
224 subsys_initcall(regulator_fixed_voltage_init);
225 
226 static void __exit regulator_fixed_voltage_exit(void)
227 {
228 	platform_driver_unregister(&regulator_fixed_voltage_driver);
229 }
230 module_exit(regulator_fixed_voltage_exit);
231 
232 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
233 MODULE_DESCRIPTION("Fixed voltage regulator");
234 MODULE_LICENSE("GPL");
235 MODULE_ALIAS("platform:reg-fixed-voltage");
236