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ad5398.c
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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>
18 
19 #define AD5398_CURRENT_EN_MASK 0x8000
20 
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;
29 };
30 
31 static 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 
39 static 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 
54 static 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 
67 static 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 
83 static 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 
123 static 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 
140 static 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 
161 static 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 
182 static 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 
190 static 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 
201  int min_uA;
202  int max_uA;
203 };
204 
205 static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
206 
207 static 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 };
212 MODULE_DEVICE_TABLE(i2c, ad5398_id);
213 
214 static 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 
255 err:
256  return ret;
257 }
258 
259 static 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 
267 static 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 
276 static int __init ad5398_init(void)
277 {
278  return i2c_add_driver(&ad5398_driver);
279 }
280 subsys_initcall(ad5398_init);
281 
282 static void __exit ad5398_exit(void)
283 {
284  i2c_del_driver(&ad5398_driver);
285 }
286 module_exit(ad5398_exit);
287 
288 MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
289 MODULE_AUTHOR("Sonic Zhang");
290 MODULE_LICENSE("GPL");
291 MODULE_ALIAS("i2c:ad5398-regulator");