Root/drivers/regulator/gpio-regulator.c

1/*
2 * gpio-regulator.c
3 *
4 * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
5 *
6 * based on fixed.c
7 *
8 * Copyright 2008 Wolfson Microelectronics PLC.
9 *
10 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
11 *
12 * Copyright (c) 2009 Nokia Corporation
13 * Roger Quadros <ext-roger.quadros@nokia.com>
14 *
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License as
17 * published by the Free Software Foundation; either version 2 of the
18 * License, or (at your option) any later version.
19 *
20 * This is useful for systems with mixed controllable and
21 * non-controllable regulators, as well as for allowing testing on
22 * systems with no controllable regulators.
23 */
24
25#include <linux/err.h>
26#include <linux/mutex.h>
27#include <linux/module.h>
28#include <linux/platform_device.h>
29#include <linux/regulator/driver.h>
30#include <linux/regulator/machine.h>
31#include <linux/regulator/gpio-regulator.h>
32#include <linux/gpio.h>
33#include <linux/slab.h>
34
35struct gpio_regulator_data {
36    struct regulator_desc desc;
37    struct regulator_dev *dev;
38
39    struct gpio *gpios;
40    int nr_gpios;
41
42    struct gpio_regulator_state *states;
43    int nr_states;
44
45    int state;
46};
47
48static int gpio_regulator_get_value(struct regulator_dev *dev)
49{
50    struct gpio_regulator_data *data = rdev_get_drvdata(dev);
51    int ptr;
52
53    for (ptr = 0; ptr < data->nr_states; ptr++)
54        if (data->states[ptr].gpios == data->state)
55            return data->states[ptr].value;
56
57    return -EINVAL;
58}
59
60static int gpio_regulator_set_voltage(struct regulator_dev *dev,
61                    int min_uV, int max_uV,
62                    unsigned *selector)
63{
64    struct gpio_regulator_data *data = rdev_get_drvdata(dev);
65    int ptr, target = 0, state, best_val = INT_MAX;
66
67    for (ptr = 0; ptr < data->nr_states; ptr++)
68        if (data->states[ptr].value < best_val &&
69            data->states[ptr].value >= min_uV &&
70            data->states[ptr].value <= max_uV) {
71            target = data->states[ptr].gpios;
72            best_val = data->states[ptr].value;
73            if (selector)
74                *selector = ptr;
75        }
76
77    if (best_val == INT_MAX)
78        return -EINVAL;
79
80    for (ptr = 0; ptr < data->nr_gpios; ptr++) {
81        state = (target & (1 << ptr)) >> ptr;
82        gpio_set_value(data->gpios[ptr].gpio, state);
83    }
84    data->state = target;
85
86    return 0;
87}
88
89static int gpio_regulator_list_voltage(struct regulator_dev *dev,
90                      unsigned selector)
91{
92    struct gpio_regulator_data *data = rdev_get_drvdata(dev);
93
94    if (selector >= data->nr_states)
95        return -EINVAL;
96
97    return data->states[selector].value;
98}
99
100static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
101                    int min_uA, int max_uA)
102{
103    struct gpio_regulator_data *data = rdev_get_drvdata(dev);
104    int ptr, target = 0, state, best_val = 0;
105
106    for (ptr = 0; ptr < data->nr_states; ptr++)
107        if (data->states[ptr].value > best_val &&
108            data->states[ptr].value >= min_uA &&
109            data->states[ptr].value <= max_uA) {
110            target = data->states[ptr].gpios;
111            best_val = data->states[ptr].value;
112        }
113
114    if (best_val == 0)
115        return -EINVAL;
116
117    for (ptr = 0; ptr < data->nr_gpios; ptr++) {
118        state = (target & (1 << ptr)) >> ptr;
119        gpio_set_value(data->gpios[ptr].gpio, state);
120    }
121    data->state = target;
122
123    return 0;
124}
125
126static struct regulator_ops gpio_regulator_voltage_ops = {
127    .get_voltage = gpio_regulator_get_value,
128    .set_voltage = gpio_regulator_set_voltage,
129    .list_voltage = gpio_regulator_list_voltage,
130};
131
132static struct regulator_ops gpio_regulator_current_ops = {
133    .get_current_limit = gpio_regulator_get_value,
134    .set_current_limit = gpio_regulator_set_current_limit,
135};
136
137static int __devinit gpio_regulator_probe(struct platform_device *pdev)
138{
139    struct gpio_regulator_config *config = pdev->dev.platform_data;
140    struct gpio_regulator_data *drvdata;
141    struct regulator_config cfg = { };
142    int ptr, ret, state;
143
144    drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
145                   GFP_KERNEL);
146    if (drvdata == NULL) {
147        dev_err(&pdev->dev, "Failed to allocate device data\n");
148        return -ENOMEM;
149    }
150
151    drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
152    if (drvdata->desc.name == NULL) {
153        dev_err(&pdev->dev, "Failed to allocate supply name\n");
154        ret = -ENOMEM;
155        goto err;
156    }
157
158    drvdata->gpios = kmemdup(config->gpios,
159                 config->nr_gpios * sizeof(struct gpio),
160                 GFP_KERNEL);
161    if (drvdata->gpios == NULL) {
162        dev_err(&pdev->dev, "Failed to allocate gpio data\n");
163        ret = -ENOMEM;
164        goto err_name;
165    }
166
167    drvdata->states = kmemdup(config->states,
168                  config->nr_states *
169                     sizeof(struct gpio_regulator_state),
170                  GFP_KERNEL);
171    if (drvdata->states == NULL) {
172        dev_err(&pdev->dev, "Failed to allocate state data\n");
173        ret = -ENOMEM;
174        goto err_memgpio;
175    }
176    drvdata->nr_states = config->nr_states;
177
178    drvdata->desc.owner = THIS_MODULE;
179    drvdata->desc.enable_time = config->startup_delay;
180
181    /* handle regulator type*/
182    switch (config->type) {
183    case REGULATOR_VOLTAGE:
184        drvdata->desc.type = REGULATOR_VOLTAGE;
185        drvdata->desc.ops = &gpio_regulator_voltage_ops;
186        drvdata->desc.n_voltages = config->nr_states;
187        break;
188    case REGULATOR_CURRENT:
189        drvdata->desc.type = REGULATOR_CURRENT;
190        drvdata->desc.ops = &gpio_regulator_current_ops;
191        break;
192    default:
193        dev_err(&pdev->dev, "No regulator type set\n");
194        ret = -EINVAL;
195        goto err_memgpio;
196        break;
197    }
198
199    drvdata->nr_gpios = config->nr_gpios;
200    ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
201    if (ret) {
202        dev_err(&pdev->dev,
203           "Could not obtain regulator setting GPIOs: %d\n", ret);
204        goto err_memstate;
205    }
206
207    /* build initial state from gpio init data. */
208    state = 0;
209    for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
210        if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
211            state |= (1 << ptr);
212    }
213    drvdata->state = state;
214
215    cfg.dev = &pdev->dev;
216    cfg.init_data = config->init_data;
217    cfg.driver_data = drvdata;
218
219    if (config->enable_gpio >= 0)
220        cfg.ena_gpio = config->enable_gpio;
221    cfg.ena_gpio_invert = !config->enable_high;
222    if (config->enabled_at_boot) {
223        if (config->enable_high)
224            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
225        else
226            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
227    } else {
228        if (config->enable_high)
229            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
230        else
231            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
232    }
233
234    drvdata->dev = regulator_register(&drvdata->desc, &cfg);
235    if (IS_ERR(drvdata->dev)) {
236        ret = PTR_ERR(drvdata->dev);
237        dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
238        goto err_stategpio;
239    }
240
241    platform_set_drvdata(pdev, drvdata);
242
243    return 0;
244
245err_stategpio:
246    gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
247err_memstate:
248    kfree(drvdata->states);
249err_memgpio:
250    kfree(drvdata->gpios);
251err_name:
252    kfree(drvdata->desc.name);
253err:
254    return ret;
255}
256
257static int __devexit gpio_regulator_remove(struct platform_device *pdev)
258{
259    struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
260
261    regulator_unregister(drvdata->dev);
262
263    gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
264
265    kfree(drvdata->states);
266    kfree(drvdata->gpios);
267
268    kfree(drvdata->desc.name);
269
270    return 0;
271}
272
273static struct platform_driver gpio_regulator_driver = {
274    .probe = gpio_regulator_probe,
275    .remove = __devexit_p(gpio_regulator_remove),
276    .driver = {
277        .name = "gpio-regulator",
278        .owner = THIS_MODULE,
279    },
280};
281
282static int __init gpio_regulator_init(void)
283{
284    return platform_driver_register(&gpio_regulator_driver);
285}
286subsys_initcall(gpio_regulator_init);
287
288static void __exit gpio_regulator_exit(void)
289{
290    platform_driver_unregister(&gpio_regulator_driver);
291}
292module_exit(gpio_regulator_exit);
293
294MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
295MODULE_DESCRIPTION("gpio voltage regulator");
296MODULE_LICENSE("GPL");
297MODULE_ALIAS("platform:gpio-regulator");
298

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