This source file includes following definitions.
- ltc2497_wait_conv
- ltc2497_read
- ltc2497_read_raw
- ltc2497_probe
- ltc2497_remove
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10 #include <linux/delay.h>
11 #include <linux/i2c.h>
12 #include <linux/iio/iio.h>
13 #include <linux/iio/driver.h>
14 #include <linux/iio/sysfs.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/regulator/consumer.h>
18
19 #define LTC2497_ENABLE 0xA0
20 #define LTC2497_SGL BIT(4)
21 #define LTC2497_DIFF 0
22 #define LTC2497_SIGN BIT(3)
23 #define LTC2497_CONFIG_DEFAULT LTC2497_ENABLE
24 #define LTC2497_CONVERSION_TIME_MS 150ULL
25
26 struct ltc2497_st {
27 struct i2c_client *client;
28 struct regulator *ref;
29 ktime_t time_prev;
30 u8 addr_prev;
31
32
33
34
35 __be32 buf ____cacheline_aligned;
36 };
37
38 static int ltc2497_wait_conv(struct ltc2497_st *st)
39 {
40 s64 time_elapsed;
41
42 time_elapsed = ktime_ms_delta(ktime_get(), st->time_prev);
43
44 if (time_elapsed < LTC2497_CONVERSION_TIME_MS) {
45
46
47
48 if (msleep_interruptible(
49 LTC2497_CONVERSION_TIME_MS - time_elapsed))
50 return -ERESTARTSYS;
51
52 return 0;
53 }
54
55 if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) {
56
57
58
59 return 0;
60 }
61
62 return 1;
63 }
64
65 static int ltc2497_read(struct ltc2497_st *st, u8 address, int *val)
66 {
67 struct i2c_client *client = st->client;
68 int ret;
69
70 ret = ltc2497_wait_conv(st);
71 if (ret < 0)
72 return ret;
73
74 if (ret || st->addr_prev != address) {
75 ret = i2c_smbus_write_byte(st->client,
76 LTC2497_ENABLE | address);
77 if (ret < 0)
78 return ret;
79 st->addr_prev = address;
80 if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS))
81 return -ERESTARTSYS;
82 }
83 ret = i2c_master_recv(client, (char *)&st->buf, 3);
84 if (ret < 0) {
85 dev_err(&client->dev, "i2c_master_recv failed\n");
86 return ret;
87 }
88 st->time_prev = ktime_get();
89
90
91
92
93 *val = (be32_to_cpu(st->buf) >> 14) - (1 << 17);
94
95 return ret;
96 }
97
98 static int ltc2497_read_raw(struct iio_dev *indio_dev,
99 struct iio_chan_spec const *chan,
100 int *val, int *val2, long mask)
101 {
102 struct ltc2497_st *st = iio_priv(indio_dev);
103 int ret;
104
105 switch (mask) {
106 case IIO_CHAN_INFO_RAW:
107 mutex_lock(&indio_dev->mlock);
108 ret = ltc2497_read(st, chan->address, val);
109 mutex_unlock(&indio_dev->mlock);
110 if (ret < 0)
111 return ret;
112
113 return IIO_VAL_INT;
114
115 case IIO_CHAN_INFO_SCALE:
116 ret = regulator_get_voltage(st->ref);
117 if (ret < 0)
118 return ret;
119
120 *val = ret / 1000;
121 *val2 = 17;
122
123 return IIO_VAL_FRACTIONAL_LOG2;
124
125 default:
126 return -EINVAL;
127 }
128 }
129
130 #define LTC2497_CHAN(_chan, _addr, _ds_name) { \
131 .type = IIO_VOLTAGE, \
132 .indexed = 1, \
133 .channel = (_chan), \
134 .address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \
135 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
136 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
137 .datasheet_name = (_ds_name), \
138 }
139
140 #define LTC2497_CHAN_DIFF(_chan, _addr) { \
141 .type = IIO_VOLTAGE, \
142 .indexed = 1, \
143 .channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \
144 .channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\
145 .address = (_addr | _chan), \
146 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
147 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
148 .differential = 1, \
149 }
150
151 static const struct iio_chan_spec ltc2497_channel[] = {
152 LTC2497_CHAN(0, LTC2497_SGL, "CH0"),
153 LTC2497_CHAN(1, LTC2497_SGL, "CH1"),
154 LTC2497_CHAN(2, LTC2497_SGL, "CH2"),
155 LTC2497_CHAN(3, LTC2497_SGL, "CH3"),
156 LTC2497_CHAN(4, LTC2497_SGL, "CH4"),
157 LTC2497_CHAN(5, LTC2497_SGL, "CH5"),
158 LTC2497_CHAN(6, LTC2497_SGL, "CH6"),
159 LTC2497_CHAN(7, LTC2497_SGL, "CH7"),
160 LTC2497_CHAN(8, LTC2497_SGL, "CH8"),
161 LTC2497_CHAN(9, LTC2497_SGL, "CH9"),
162 LTC2497_CHAN(10, LTC2497_SGL, "CH10"),
163 LTC2497_CHAN(11, LTC2497_SGL, "CH11"),
164 LTC2497_CHAN(12, LTC2497_SGL, "CH12"),
165 LTC2497_CHAN(13, LTC2497_SGL, "CH13"),
166 LTC2497_CHAN(14, LTC2497_SGL, "CH14"),
167 LTC2497_CHAN(15, LTC2497_SGL, "CH15"),
168 LTC2497_CHAN_DIFF(0, LTC2497_DIFF),
169 LTC2497_CHAN_DIFF(1, LTC2497_DIFF),
170 LTC2497_CHAN_DIFF(2, LTC2497_DIFF),
171 LTC2497_CHAN_DIFF(3, LTC2497_DIFF),
172 LTC2497_CHAN_DIFF(4, LTC2497_DIFF),
173 LTC2497_CHAN_DIFF(5, LTC2497_DIFF),
174 LTC2497_CHAN_DIFF(6, LTC2497_DIFF),
175 LTC2497_CHAN_DIFF(7, LTC2497_DIFF),
176 LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN),
177 LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN),
178 LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN),
179 LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN),
180 LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN),
181 LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN),
182 LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN),
183 LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN),
184 };
185
186 static const struct iio_info ltc2497_info = {
187 .read_raw = ltc2497_read_raw,
188 };
189
190 static int ltc2497_probe(struct i2c_client *client,
191 const struct i2c_device_id *id)
192 {
193 struct iio_dev *indio_dev;
194 struct ltc2497_st *st;
195 struct iio_map *plat_data;
196 int ret;
197
198 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
199 I2C_FUNC_SMBUS_WRITE_BYTE))
200 return -EOPNOTSUPP;
201
202 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
203 if (!indio_dev)
204 return -ENOMEM;
205
206 st = iio_priv(indio_dev);
207 i2c_set_clientdata(client, indio_dev);
208 st->client = client;
209
210 indio_dev->dev.parent = &client->dev;
211 indio_dev->name = id->name;
212 indio_dev->info = <c2497_info;
213 indio_dev->modes = INDIO_DIRECT_MODE;
214 indio_dev->channels = ltc2497_channel;
215 indio_dev->num_channels = ARRAY_SIZE(ltc2497_channel);
216
217 st->ref = devm_regulator_get(&client->dev, "vref");
218 if (IS_ERR(st->ref))
219 return PTR_ERR(st->ref);
220
221 ret = regulator_enable(st->ref);
222 if (ret < 0)
223 return ret;
224
225 if (client->dev.platform_data) {
226 plat_data = ((struct iio_map *)client->dev.platform_data);
227 ret = iio_map_array_register(indio_dev, plat_data);
228 if (ret) {
229 dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
230 goto err_regulator_disable;
231 }
232 }
233
234 ret = i2c_smbus_write_byte(st->client, LTC2497_CONFIG_DEFAULT);
235 if (ret < 0)
236 goto err_array_unregister;
237
238 st->addr_prev = LTC2497_CONFIG_DEFAULT;
239 st->time_prev = ktime_get();
240
241 ret = iio_device_register(indio_dev);
242 if (ret < 0)
243 goto err_array_unregister;
244
245 return 0;
246
247 err_array_unregister:
248 iio_map_array_unregister(indio_dev);
249
250 err_regulator_disable:
251 regulator_disable(st->ref);
252
253 return ret;
254 }
255
256 static int ltc2497_remove(struct i2c_client *client)
257 {
258 struct iio_dev *indio_dev = i2c_get_clientdata(client);
259 struct ltc2497_st *st = iio_priv(indio_dev);
260
261 iio_map_array_unregister(indio_dev);
262 iio_device_unregister(indio_dev);
263 regulator_disable(st->ref);
264
265 return 0;
266 }
267
268 static const struct i2c_device_id ltc2497_id[] = {
269 { "ltc2497", 0 },
270 { }
271 };
272 MODULE_DEVICE_TABLE(i2c, ltc2497_id);
273
274 static const struct of_device_id ltc2497_of_match[] = {
275 { .compatible = "lltc,ltc2497", },
276 {},
277 };
278 MODULE_DEVICE_TABLE(of, ltc2497_of_match);
279
280 static struct i2c_driver ltc2497_driver = {
281 .driver = {
282 .name = "ltc2497",
283 .of_match_table = of_match_ptr(ltc2497_of_match),
284 },
285 .probe = ltc2497_probe,
286 .remove = ltc2497_remove,
287 .id_table = ltc2497_id,
288 };
289 module_i2c_driver(ltc2497_driver);
290
291 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
292 MODULE_DESCRIPTION("Linear Technology LTC2497 ADC driver");
293 MODULE_LICENSE("GPL v2");