Root/drivers/regulator/ad5398.c

1/*
2 * Voltage and current regulation for AD5398 and AD5821
3 *
4 * Copyright 2010 Analog Devices Inc.
5 *
6 * Enter bugs at http://blackfin.uclinux.org/
7 *
8 * Licensed under the GPL-2 or later.
9 */
10
11#include <linux/module.h>
12#include <linux/err.h>
13#include <linux/i2c.h>
14#include <linux/slab.h>
15#include <linux/platform_device.h>
16#include <linux/regulator/driver.h>
17#include <linux/regulator/machine.h>
18
19#define AD5398_CURRENT_EN_MASK 0x8000
20
21struct ad5398_chip_info {
22    struct i2c_client *client;
23    int min_uA;
24    int max_uA;
25    unsigned int current_level;
26    unsigned int current_mask;
27    unsigned int current_offset;
28    struct regulator_dev *rdev;
29};
30
31static int ad5398_calc_current(struct ad5398_chip_info *chip,
32    unsigned selector)
33{
34    unsigned range_uA = chip->max_uA - chip->min_uA;
35
36    return chip->min_uA + (selector * range_uA / chip->current_level);
37}
38
39static int ad5398_read_reg(struct i2c_client *client, unsigned short *data)
40{
41    unsigned short val;
42    int ret;
43
44    ret = i2c_master_recv(client, (char *)&val, 2);
45    if (ret < 0) {
46        dev_err(&client->dev, "I2C read error\n");
47        return ret;
48    }
49    *data = be16_to_cpu(val);
50
51    return ret;
52}
53
54static int ad5398_write_reg(struct i2c_client *client, const unsigned short data)
55{
56    unsigned short val;
57    int ret;
58
59    val = cpu_to_be16(data);
60    ret = i2c_master_send(client, (char *)&val, 2);
61    if (ret < 0)
62        dev_err(&client->dev, "I2C write error\n");
63
64    return ret;
65}
66
67static int ad5398_get_current_limit(struct regulator_dev *rdev)
68{
69    struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
70    struct i2c_client *client = chip->client;
71    unsigned short data;
72    int ret;
73
74    ret = ad5398_read_reg(client, &data);
75    if (ret < 0)
76        return ret;
77
78    ret = (data & chip->current_mask) >> chip->current_offset;
79
80    return ad5398_calc_current(chip, ret);
81}
82
83static int ad5398_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA)
84{
85    struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
86    struct i2c_client *client = chip->client;
87    unsigned range_uA = chip->max_uA - chip->min_uA;
88    unsigned selector;
89    unsigned short data;
90    int ret;
91
92    if (min_uA < chip->min_uA)
93        min_uA = chip->min_uA;
94    if (max_uA > chip->max_uA)
95        max_uA = chip->max_uA;
96
97    if (min_uA > chip->max_uA || max_uA < chip->min_uA)
98        return -EINVAL;
99
100    selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level,
101                range_uA);
102    if (ad5398_calc_current(chip, selector) > max_uA)
103        return -EINVAL;
104
105    dev_dbg(&client->dev, "changing current %duA\n",
106        ad5398_calc_current(chip, selector));
107
108    /* read chip enable bit */
109    ret = ad5398_read_reg(client, &data);
110    if (ret < 0)
111        return ret;
112
113    /* prepare register data */
114    selector = (selector << chip->current_offset) & chip->current_mask;
115    data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK);
116
117    /* write the new current value back as well as enable bit */
118    ret = ad5398_write_reg(client, data);
119
120    return ret;
121}
122
123static int ad5398_is_enabled(struct regulator_dev *rdev)
124{
125    struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
126    struct i2c_client *client = chip->client;
127    unsigned short data;
128    int ret;
129
130    ret = ad5398_read_reg(client, &data);
131    if (ret < 0)
132        return ret;
133
134    if (data & AD5398_CURRENT_EN_MASK)
135        return 1;
136    else
137        return 0;
138}
139
140static int ad5398_enable(struct regulator_dev *rdev)
141{
142    struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
143    struct i2c_client *client = chip->client;
144    unsigned short data;
145    int ret;
146
147    ret = ad5398_read_reg(client, &data);
148    if (ret < 0)
149        return ret;
150
151    if (data & AD5398_CURRENT_EN_MASK)
152        return 0;
153
154    data |= AD5398_CURRENT_EN_MASK;
155
156    ret = ad5398_write_reg(client, data);
157
158    return ret;
159}
160
161static int ad5398_disable(struct regulator_dev *rdev)
162{
163    struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
164    struct i2c_client *client = chip->client;
165    unsigned short data;
166    int ret;
167
168    ret = ad5398_read_reg(client, &data);
169    if (ret < 0)
170        return ret;
171
172    if (!(data & AD5398_CURRENT_EN_MASK))
173        return 0;
174
175    data &= ~AD5398_CURRENT_EN_MASK;
176
177    ret = ad5398_write_reg(client, data);
178
179    return ret;
180}
181
182static struct regulator_ops ad5398_ops = {
183    .get_current_limit = ad5398_get_current_limit,
184    .set_current_limit = ad5398_set_current_limit,
185    .enable = ad5398_enable,
186    .disable = ad5398_disable,
187    .is_enabled = ad5398_is_enabled,
188};
189
190static const struct regulator_desc ad5398_reg = {
191    .name = "isink",
192    .id = 0,
193    .ops = &ad5398_ops,
194    .type = REGULATOR_CURRENT,
195    .owner = THIS_MODULE,
196};
197
198struct ad5398_current_data_format {
199    int current_bits;
200    int current_offset;
201    int min_uA;
202    int max_uA;
203};
204
205static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
206
207static const struct i2c_device_id ad5398_id[] = {
208    { "ad5398", (kernel_ulong_t)&df_10_4_120 },
209    { "ad5821", (kernel_ulong_t)&df_10_4_120 },
210    { }
211};
212MODULE_DEVICE_TABLE(i2c, ad5398_id);
213
214static int __devinit ad5398_probe(struct i2c_client *client,
215                const struct i2c_device_id *id)
216{
217    struct regulator_init_data *init_data = client->dev.platform_data;
218    struct regulator_config config = { };
219    struct ad5398_chip_info *chip;
220    const struct ad5398_current_data_format *df =
221            (struct ad5398_current_data_format *)id->driver_data;
222    int ret;
223
224    if (!init_data)
225        return -EINVAL;
226
227    chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
228    if (!chip)
229        return -ENOMEM;
230
231    config.dev = &client->dev;
232    config.init_data = init_data;
233    config.driver_data = chip;
234
235    chip->client = client;
236
237    chip->min_uA = df->min_uA;
238    chip->max_uA = df->max_uA;
239    chip->current_level = 1 << df->current_bits;
240    chip->current_offset = df->current_offset;
241    chip->current_mask = (chip->current_level - 1) << chip->current_offset;
242
243    chip->rdev = regulator_register(&ad5398_reg, &config);
244    if (IS_ERR(chip->rdev)) {
245        ret = PTR_ERR(chip->rdev);
246        dev_err(&client->dev, "failed to register %s %s\n",
247            id->name, ad5398_reg.name);
248        goto err;
249    }
250
251    i2c_set_clientdata(client, chip);
252    dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
253    return 0;
254
255err:
256    return ret;
257}
258
259static int __devexit ad5398_remove(struct i2c_client *client)
260{
261    struct ad5398_chip_info *chip = i2c_get_clientdata(client);
262
263    regulator_unregister(chip->rdev);
264    return 0;
265}
266
267static struct i2c_driver ad5398_driver = {
268    .probe = ad5398_probe,
269    .remove = __devexit_p(ad5398_remove),
270    .driver = {
271        .name = "ad5398",
272    },
273    .id_table = ad5398_id,
274};
275
276static int __init ad5398_init(void)
277{
278    return i2c_add_driver(&ad5398_driver);
279}
280subsys_initcall(ad5398_init);
281
282static void __exit ad5398_exit(void)
283{
284    i2c_del_driver(&ad5398_driver);
285}
286module_exit(ad5398_exit);
287
288MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
289MODULE_AUTHOR("Sonic Zhang");
290MODULE_LICENSE("GPL");
291MODULE_ALIAS("i2c:ad5398-regulator");
292

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