1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Voltage and current regulation for AD5398 and AD5821
4 *
5 * Copyright 2010 Analog Devices Inc.
6 *
7 * Enter bugs at http://blackfin.uclinux.org/
8 */
9
10 #include <linux/module.h>
11 #include <linux/err.h>
12 #include <linux/i2c.h>
13 #include <linux/slab.h>
14 #include <linux/platform_device.h>
15 #include <linux/regulator/driver.h>
16 #include <linux/regulator/machine.h>
17
18 #define AD5398_CURRENT_EN_MASK 0x8000
19
20 struct ad5398_chip_info {
21 struct i2c_client *client;
22 int min_uA;
23 int max_uA;
24 unsigned int current_level;
25 unsigned int current_mask;
26 unsigned int current_offset;
27 struct regulator_dev *rdev;
28 };
29
ad5398_calc_current(struct ad5398_chip_info * chip,unsigned selector)30 static int ad5398_calc_current(struct ad5398_chip_info *chip,
31 unsigned selector)
32 {
33 unsigned range_uA = chip->max_uA - chip->min_uA;
34
35 return chip->min_uA + (selector * range_uA / chip->current_level);
36 }
37
ad5398_read_reg(struct i2c_client * client,unsigned short * data)38 static int ad5398_read_reg(struct i2c_client *client, unsigned short *data)
39 {
40 unsigned short val;
41 int ret;
42
43 ret = i2c_master_recv(client, (char *)&val, 2);
44 if (ret < 0) {
45 dev_err(&client->dev, "I2C read error\n");
46 return ret;
47 }
48 *data = be16_to_cpu(val);
49
50 return ret;
51 }
52
ad5398_write_reg(struct i2c_client * client,const unsigned short data)53 static int ad5398_write_reg(struct i2c_client *client, const unsigned short data)
54 {
55 unsigned short val;
56 int ret;
57
58 val = cpu_to_be16(data);
59 ret = i2c_master_send(client, (char *)&val, 2);
60 if (ret != 2) {
61 dev_err(&client->dev, "I2C write error\n");
62 return ret < 0 ? ret : -EIO;
63 }
64
65 return 0;
66 }
67
ad5398_get_current_limit(struct regulator_dev * rdev)68 static int ad5398_get_current_limit(struct regulator_dev *rdev)
69 {
70 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
71 struct i2c_client *client = chip->client;
72 unsigned short data;
73 int ret;
74
75 ret = ad5398_read_reg(client, &data);
76 if (ret < 0)
77 return ret;
78
79 ret = (data & chip->current_mask) >> chip->current_offset;
80
81 return ad5398_calc_current(chip, ret);
82 }
83
ad5398_set_current_limit(struct regulator_dev * rdev,int min_uA,int max_uA)84 static int ad5398_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA)
85 {
86 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
87 struct i2c_client *client = chip->client;
88 unsigned range_uA = chip->max_uA - chip->min_uA;
89 unsigned selector;
90 unsigned short data;
91 int ret;
92
93 if (min_uA < chip->min_uA)
94 min_uA = chip->min_uA;
95 if (max_uA > chip->max_uA)
96 max_uA = chip->max_uA;
97
98 if (min_uA > chip->max_uA || max_uA < chip->min_uA)
99 return -EINVAL;
100
101 selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level,
102 range_uA);
103 if (ad5398_calc_current(chip, selector) > max_uA)
104 return -EINVAL;
105
106 dev_dbg(&client->dev, "changing current %duA\n",
107 ad5398_calc_current(chip, selector));
108
109 /* read chip enable bit */
110 ret = ad5398_read_reg(client, &data);
111 if (ret < 0)
112 return ret;
113
114 /* prepare register data */
115 selector = (selector << chip->current_offset) & chip->current_mask;
116 data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK);
117
118 /* write the new current value back as well as enable bit */
119 ret = ad5398_write_reg(client, data);
120
121 return ret;
122 }
123
ad5398_is_enabled(struct regulator_dev * rdev)124 static int ad5398_is_enabled(struct regulator_dev *rdev)
125 {
126 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
127 struct i2c_client *client = chip->client;
128 unsigned short data;
129 int ret;
130
131 ret = ad5398_read_reg(client, &data);
132 if (ret < 0)
133 return ret;
134
135 if (data & AD5398_CURRENT_EN_MASK)
136 return 1;
137 else
138 return 0;
139 }
140
ad5398_enable(struct regulator_dev * rdev)141 static int ad5398_enable(struct regulator_dev *rdev)
142 {
143 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
144 struct i2c_client *client = chip->client;
145 unsigned short data;
146 int ret;
147
148 ret = ad5398_read_reg(client, &data);
149 if (ret < 0)
150 return ret;
151
152 if (data & AD5398_CURRENT_EN_MASK)
153 return 0;
154
155 data |= AD5398_CURRENT_EN_MASK;
156
157 ret = ad5398_write_reg(client, data);
158
159 return ret;
160 }
161
ad5398_disable(struct regulator_dev * rdev)162 static int ad5398_disable(struct regulator_dev *rdev)
163 {
164 struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
165 struct i2c_client *client = chip->client;
166 unsigned short data;
167 int ret;
168
169 ret = ad5398_read_reg(client, &data);
170 if (ret < 0)
171 return ret;
172
173 if (!(data & AD5398_CURRENT_EN_MASK))
174 return 0;
175
176 data &= ~AD5398_CURRENT_EN_MASK;
177
178 ret = ad5398_write_reg(client, data);
179
180 return ret;
181 }
182
183 static const struct regulator_ops ad5398_ops = {
184 .get_current_limit = ad5398_get_current_limit,
185 .set_current_limit = ad5398_set_current_limit,
186 .enable = ad5398_enable,
187 .disable = ad5398_disable,
188 .is_enabled = ad5398_is_enabled,
189 };
190
191 static const struct regulator_desc ad5398_reg = {
192 .name = "isink",
193 .id = 0,
194 .ops = &ad5398_ops,
195 .type = REGULATOR_CURRENT,
196 .owner = THIS_MODULE,
197 };
198
199 struct ad5398_current_data_format {
200 int current_bits;
201 int current_offset;
202 int min_uA;
203 int max_uA;
204 };
205
206 static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
207
208 static const struct i2c_device_id ad5398_id[] = {
209 { "ad5398", (kernel_ulong_t)&df_10_4_120 },
210 { "ad5821", (kernel_ulong_t)&df_10_4_120 },
211 { }
212 };
213 MODULE_DEVICE_TABLE(i2c, ad5398_id);
214
ad5398_probe(struct i2c_client * client)215 static int ad5398_probe(struct i2c_client *client)
216 {
217 const struct i2c_device_id *id = i2c_client_get_device_id(client);
218 struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
219 struct regulator_config config = { };
220 struct ad5398_chip_info *chip;
221 const struct ad5398_current_data_format *df =
222 (struct ad5398_current_data_format *)id->driver_data;
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 = devm_regulator_register(&client->dev, &ad5398_reg,
244 &config);
245 if (IS_ERR(chip->rdev)) {
246 dev_err(&client->dev, "failed to register %s %s\n",
247 id->name, ad5398_reg.name);
248 return PTR_ERR(chip->rdev);
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
256 static struct i2c_driver ad5398_driver = {
257 .probe = ad5398_probe,
258 .driver = {
259 .name = "ad5398",
260 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
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