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
21 struct 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
ad5398_calc_current(struct ad5398_chip_info * chip,unsigned selector)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
ad5398_read_reg(struct i2c_client * client,unsigned short * data)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
ad5398_write_reg(struct i2c_client * client,const unsigned short data)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 != 2) {
62 dev_err(&client->dev, "I2C write error\n");
63 return ret < 0 ? ret : -EIO;
64 }
65
66 return 0;
67 }
68
ad5398_get_current_limit(struct regulator_dev * rdev)69 static int ad5398_get_current_limit(struct regulator_dev *rdev)
70 {
71 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
72 struct i2c_client *client = chip->client;
73 unsigned short data;
74 int ret;
75
76 ret = ad5398_read_reg(client, &data);
77 if (ret < 0)
78 return ret;
79
80 ret = (data & chip->current_mask) >> chip->current_offset;
81
82 return ad5398_calc_current(chip, ret);
83 }
84
ad5398_set_current_limit(struct regulator_dev * rdev,int min_uA,int max_uA)85 static int ad5398_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA)
86 {
87 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
88 struct i2c_client *client = chip->client;
89 unsigned range_uA = chip->max_uA - chip->min_uA;
90 unsigned selector;
91 unsigned short data;
92 int ret;
93
94 if (min_uA < chip->min_uA)
95 min_uA = chip->min_uA;
96 if (max_uA > chip->max_uA)
97 max_uA = chip->max_uA;
98
99 if (min_uA > chip->max_uA || max_uA < chip->min_uA)
100 return -EINVAL;
101
102 selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level,
103 range_uA);
104 if (ad5398_calc_current(chip, selector) > max_uA)
105 return -EINVAL;
106
107 dev_dbg(&client->dev, "changing current %duA\n",
108 ad5398_calc_current(chip, selector));
109
110 /* read chip enable bit */
111 ret = ad5398_read_reg(client, &data);
112 if (ret < 0)
113 return ret;
114
115 /* prepare register data */
116 selector = (selector << chip->current_offset) & chip->current_mask;
117 data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK);
118
119 /* write the new current value back as well as enable bit */
120 ret = ad5398_write_reg(client, data);
121
122 return ret;
123 }
124
ad5398_is_enabled(struct regulator_dev * rdev)125 static int ad5398_is_enabled(struct regulator_dev *rdev)
126 {
127 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
128 struct i2c_client *client = chip->client;
129 unsigned short data;
130 int ret;
131
132 ret = ad5398_read_reg(client, &data);
133 if (ret < 0)
134 return ret;
135
136 if (data & AD5398_CURRENT_EN_MASK)
137 return 1;
138 else
139 return 0;
140 }
141
ad5398_enable(struct regulator_dev * rdev)142 static int ad5398_enable(struct regulator_dev *rdev)
143 {
144 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
145 struct i2c_client *client = chip->client;
146 unsigned short data;
147 int ret;
148
149 ret = ad5398_read_reg(client, &data);
150 if (ret < 0)
151 return ret;
152
153 if (data & AD5398_CURRENT_EN_MASK)
154 return 0;
155
156 data |= AD5398_CURRENT_EN_MASK;
157
158 ret = ad5398_write_reg(client, data);
159
160 return ret;
161 }
162
ad5398_disable(struct regulator_dev * rdev)163 static int ad5398_disable(struct regulator_dev *rdev)
164 {
165 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
166 struct i2c_client *client = chip->client;
167 unsigned short data;
168 int ret;
169
170 ret = ad5398_read_reg(client, &data);
171 if (ret < 0)
172 return ret;
173
174 if (!(data & AD5398_CURRENT_EN_MASK))
175 return 0;
176
177 data &= ~AD5398_CURRENT_EN_MASK;
178
179 ret = ad5398_write_reg(client, data);
180
181 return ret;
182 }
183
184 static const struct regulator_ops ad5398_ops = {
185 .get_current_limit = ad5398_get_current_limit,
186 .set_current_limit = ad5398_set_current_limit,
187 .enable = ad5398_enable,
188 .disable = ad5398_disable,
189 .is_enabled = ad5398_is_enabled,
190 };
191
192 static const struct regulator_desc ad5398_reg = {
193 .name = "isink",
194 .id = 0,
195 .ops = &ad5398_ops,
196 .type = REGULATOR_CURRENT,
197 .owner = THIS_MODULE,
198 };
199
200 struct ad5398_current_data_format {
201 int current_bits;
202 int current_offset;
203 int min_uA;
204 int max_uA;
205 };
206
207 static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
208
209 static const struct i2c_device_id ad5398_id[] = {
210 { "ad5398", (kernel_ulong_t)&df_10_4_120 },
211 { "ad5821", (kernel_ulong_t)&df_10_4_120 },
212 { }
213 };
214 MODULE_DEVICE_TABLE(i2c, ad5398_id);
215
ad5398_probe(struct i2c_client * client,const struct i2c_device_id * id)216 static int ad5398_probe(struct i2c_client *client,
217 const struct i2c_device_id *id)
218 {
219 struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
220 struct regulator_config config = { };
221 struct ad5398_chip_info *chip;
222 const struct ad5398_current_data_format *df =
223 (struct ad5398_current_data_format *)id->driver_data;
224
225 if (!init_data)
226 return -EINVAL;
227
228 chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
229 if (!chip)
230 return -ENOMEM;
231
232 config.dev = &client->dev;
233 config.init_data = init_data;
234 config.driver_data = chip;
235
236 chip->client = client;
237
238 chip->min_uA = df->min_uA;
239 chip->max_uA = df->max_uA;
240 chip->current_level = 1 << df->current_bits;
241 chip->current_offset = df->current_offset;
242 chip->current_mask = (chip->current_level - 1) << chip->current_offset;
243
244 chip->rdev = devm_regulator_register(&client->dev, &ad5398_reg,
245 &config);
246 if (IS_ERR(chip->rdev)) {
247 dev_err(&client->dev, "failed to register %s %s\n",
248 id->name, ad5398_reg.name);
249 return PTR_ERR(chip->rdev);
250 }
251
252 i2c_set_clientdata(client, chip);
253 dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
254 return 0;
255 }
256
257 static struct i2c_driver ad5398_driver = {
258 .probe = ad5398_probe,
259 .driver = {
260 .name = "ad5398",
261 },
262 .id_table = ad5398_id,
263 };
264
ad5398_init(void)265 static int __init ad5398_init(void)
266 {
267 return i2c_add_driver(&ad5398_driver);
268 }
269 subsys_initcall(ad5398_init);
270
ad5398_exit(void)271 static void __exit ad5398_exit(void)
272 {
273 i2c_del_driver(&ad5398_driver);
274 }
275 module_exit(ad5398_exit);
276
277 MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
278 MODULE_AUTHOR("Sonic Zhang");
279 MODULE_LICENSE("GPL");
280
