summaryrefslogtreecommitdiff
path: root/drivers/regulator/ad5398.c
blob: 40f7dba42b5ad7c95a3e2643b3ad6e076cf2cbb4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Voltage and current regulation for AD5398 and AD5821
 *
 * Copyright 2010 Analog Devices Inc.
 *
 * Enter bugs at http://blackfin.uclinux.org/
 */

#include <linux/module.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>

#define AD5398_CURRENT_EN_MASK	0x8000

struct ad5398_chip_info {
	struct i2c_client *client;
	int min_uA;
	int max_uA;
	unsigned int current_level;
	unsigned int current_mask;
	unsigned int current_offset;
	struct regulator_dev *rdev;
};

static int ad5398_calc_current(struct ad5398_chip_info *chip,
	unsigned selector)
{
	unsigned range_uA = chip->max_uA - chip->min_uA;

	return chip->min_uA + (selector * range_uA / chip->current_level);
}

static int ad5398_read_reg(struct i2c_client *client, unsigned short *data)
{
	unsigned short val;
	int ret;

	ret = i2c_master_recv(client, (char *)&val, 2);
	if (ret < 0) {
		dev_err(&client->dev, "I2C read error\n");
		return ret;
	}
	*data = be16_to_cpu(val);

	return ret;
}

static int ad5398_write_reg(struct i2c_client *client, const unsigned short data)
{
	unsigned short val;
	int ret;

	val = cpu_to_be16(data);
	ret = i2c_master_send(client, (char *)&val, 2);
	if (ret != 2) {
		dev_err(&client->dev, "I2C write error\n");
		return ret < 0 ? ret : -EIO;
	}

	return 0;
}

static int ad5398_get_current_limit(struct regulator_dev *rdev)
{
	struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
	struct i2c_client *client = chip->client;
	unsigned short data;
	int ret;

	ret = ad5398_read_reg(client, &data);
	if (ret < 0)
		return ret;

	ret = (data & chip->current_mask) >> chip->current_offset;

	return ad5398_calc_current(chip, ret);
}

static int ad5398_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA)
{
	struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
	struct i2c_client *client = chip->client;
	unsigned range_uA = chip->max_uA - chip->min_uA;
	unsigned selector;
	unsigned short data;
	int ret;

	if (min_uA < chip->min_uA)
		min_uA = chip->min_uA;
	if (max_uA > chip->max_uA)
		max_uA = chip->max_uA;

	if (min_uA > chip->max_uA || max_uA < chip->min_uA)
		return -EINVAL;

	selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level,
				range_uA);
	if (ad5398_calc_current(chip, selector) > max_uA)
		return -EINVAL;

	dev_dbg(&client->dev, "changing current %duA\n",
		ad5398_calc_current(chip, selector));

	/* read chip enable bit */
	ret = ad5398_read_reg(client, &data);
	if (ret < 0)
		return ret;

	/* prepare register data */
	selector = (selector << chip->current_offset) & chip->current_mask;
	data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK);

	/* write the new current value back as well as enable bit */
	ret = ad5398_write_reg(client, data);

	return ret;
}

static int ad5398_is_enabled(struct regulator_dev *rdev)
{
	struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
	struct i2c_client *client = chip->client;
	unsigned short data;
	int ret;

	ret = ad5398_read_reg(client, &data);
	if (ret < 0)
		return ret;

	if (data & AD5398_CURRENT_EN_MASK)
		return 1;
	else
		return 0;
}

static int ad5398_enable(struct regulator_dev *rdev)
{
	struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
	struct i2c_client *client = chip->client;
	unsigned short data;
	int ret;

	ret = ad5398_read_reg(client, &data);
	if (ret < 0)
		return ret;

	if (data & AD5398_CURRENT_EN_MASK)
		return 0;

	data |= AD5398_CURRENT_EN_MASK;

	ret = ad5398_write_reg(client, data);

	return ret;
}

static int ad5398_disable(struct regulator_dev *rdev)
{
	struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
	struct i2c_client *client = chip->client;
	unsigned short data;
	int ret;

	ret = ad5398_read_reg(client, &data);
	if (ret < 0)
		return ret;

	if (!(data & AD5398_CURRENT_EN_MASK))
		return 0;

	data &= ~AD5398_CURRENT_EN_MASK;

	ret = ad5398_write_reg(client, data);

	return ret;
}

static const struct regulator_ops ad5398_ops = {
	.get_current_limit = ad5398_get_current_limit,
	.set_current_limit = ad5398_set_current_limit,
	.enable = ad5398_enable,
	.disable = ad5398_disable,
	.is_enabled = ad5398_is_enabled,
};

static const struct regulator_desc ad5398_reg = {
	.name = "isink",
	.id = 0,
	.ops = &ad5398_ops,
	.type = REGULATOR_CURRENT,
	.owner = THIS_MODULE,
};

struct ad5398_current_data_format {
	int current_bits;
	int current_offset;
	int min_uA;
	int max_uA;
};

static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};

static const struct i2c_device_id ad5398_id[] = {
	{ "ad5398", (kernel_ulong_t)&df_10_4_120 },
	{ "ad5821", (kernel_ulong_t)&df_10_4_120 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ad5398_id);

static int ad5398_probe(struct i2c_client *client)
{
	const struct i2c_device_id *id = i2c_client_get_device_id(client);
	struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
	struct regulator_config config = { };
	struct ad5398_chip_info *chip;
	const struct ad5398_current_data_format *df =
			(struct ad5398_current_data_format *)id->driver_data;

	if (!init_data)
		return -EINVAL;

	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
	if (!chip)
		return -ENOMEM;

	config.dev = &client->dev;
	config.init_data = init_data;
	config.driver_data = chip;

	chip->client = client;

	chip->min_uA = df->min_uA;
	chip->max_uA = df->max_uA;
	chip->current_level = 1 << df->current_bits;
	chip->current_offset = df->current_offset;
	chip->current_mask = (chip->current_level - 1) << chip->current_offset;

	chip->rdev = devm_regulator_register(&client->dev, &ad5398_reg,
					     &config);
	if (IS_ERR(chip->rdev)) {
		dev_err(&client->dev, "failed to register %s %s\n",
			id->name, ad5398_reg.name);
		return PTR_ERR(chip->rdev);
	}

	i2c_set_clientdata(client, chip);
	dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
	return 0;
}

static struct i2c_driver ad5398_driver = {
	.probe = ad5398_probe,
	.driver		= {
		.name	= "ad5398",
		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
	},
	.id_table	= ad5398_id,
};

static int __init ad5398_init(void)
{
	return i2c_add_driver(&ad5398_driver);
}
subsys_initcall(ad5398_init);

static void __exit ad5398_exit(void)
{
	i2c_del_driver(&ad5398_driver);
}
module_exit(ad5398_exit);

MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
MODULE_AUTHOR("Sonic Zhang");
MODULE_LICENSE("GPL");