xref: /openbmc/linux/drivers/regulator/ad5398.c (revision 2c684d89)
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 
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 
198 struct ad5398_current_data_format {
199 	int current_bits;
200 	int current_offset;
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 ad5398_probe(struct i2c_client *client,
215 				const struct i2c_device_id *id)
216 {
217 	struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
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 
223 	if (!init_data)
224 		return -EINVAL;
225 
226 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
227 	if (!chip)
228 		return -ENOMEM;
229 
230 	config.dev = &client->dev;
231 	config.init_data = init_data;
232 	config.driver_data = chip;
233 
234 	chip->client = client;
235 
236 	chip->min_uA = df->min_uA;
237 	chip->max_uA = df->max_uA;
238 	chip->current_level = 1 << df->current_bits;
239 	chip->current_offset = df->current_offset;
240 	chip->current_mask = (chip->current_level - 1) << chip->current_offset;
241 
242 	chip->rdev = devm_regulator_register(&client->dev, &ad5398_reg,
243 					     &config);
244 	if (IS_ERR(chip->rdev)) {
245 		dev_err(&client->dev, "failed to register %s %s\n",
246 			id->name, ad5398_reg.name);
247 		return PTR_ERR(chip->rdev);
248 	}
249 
250 	i2c_set_clientdata(client, chip);
251 	dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
252 	return 0;
253 }
254 
255 static struct i2c_driver ad5398_driver = {
256 	.probe = ad5398_probe,
257 	.driver		= {
258 		.name	= "ad5398",
259 	},
260 	.id_table	= ad5398_id,
261 };
262 
263 static int __init ad5398_init(void)
264 {
265 	return i2c_add_driver(&ad5398_driver);
266 }
267 subsys_initcall(ad5398_init);
268 
269 static void __exit ad5398_exit(void)
270 {
271 	i2c_del_driver(&ad5398_driver);
272 }
273 module_exit(ad5398_exit);
274 
275 MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
276 MODULE_AUTHOR("Sonic Zhang");
277 MODULE_LICENSE("GPL");
278