1 /*
2 * TI ADC081C/ADC101C/ADC121C 8/10/12-bit ADC driver
3 *
4 * Copyright (C) 2012 Avionic Design GmbH
5 * Copyright (C) 2016 Intel
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * Datasheets:
12 * http://www.ti.com/lit/ds/symlink/adc081c021.pdf
13 * http://www.ti.com/lit/ds/symlink/adc101c021.pdf
14 * http://www.ti.com/lit/ds/symlink/adc121c021.pdf
15 *
16 * The devices have a very similar interface and differ mostly in the number of
17 * bits handled. For the 8-bit and 10-bit models the least-significant 4 or 2
18 * bits of value registers are reserved.
19 */
20
21 #include <linux/err.h>
22 #include <linux/i2c.h>
23 #include <linux/module.h>
24 #include <linux/of.h>
25 #include <linux/acpi.h>
26
27 #include <linux/iio/iio.h>
28 #include <linux/iio/buffer.h>
29 #include <linux/iio/trigger_consumer.h>
30 #include <linux/iio/triggered_buffer.h>
31 #include <linux/regulator/consumer.h>
32
33 struct adc081c {
34 struct i2c_client *i2c;
35 struct regulator *ref;
36
37 /* 8, 10 or 12 */
38 int bits;
39 };
40
41 #define REG_CONV_RES 0x00
42
adc081c_read_raw(struct iio_dev * iio,struct iio_chan_spec const * channel,int * value,int * shift,long mask)43 static int adc081c_read_raw(struct iio_dev *iio,
44 struct iio_chan_spec const *channel, int *value,
45 int *shift, long mask)
46 {
47 struct adc081c *adc = iio_priv(iio);
48 int err;
49
50 switch (mask) {
51 case IIO_CHAN_INFO_RAW:
52 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
53 if (err < 0)
54 return err;
55
56 *value = (err & 0xFFF) >> (12 - adc->bits);
57 return IIO_VAL_INT;
58
59 case IIO_CHAN_INFO_SCALE:
60 err = regulator_get_voltage(adc->ref);
61 if (err < 0)
62 return err;
63
64 *value = err / 1000;
65 *shift = adc->bits;
66
67 return IIO_VAL_FRACTIONAL_LOG2;
68
69 default:
70 break;
71 }
72
73 return -EINVAL;
74 }
75
76 #define ADCxx1C_CHAN(_bits) { \
77 .type = IIO_VOLTAGE, \
78 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
79 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
80 .scan_type = { \
81 .sign = 'u', \
82 .realbits = (_bits), \
83 .storagebits = 16, \
84 .shift = 12 - (_bits), \
85 .endianness = IIO_CPU, \
86 }, \
87 }
88
89 #define DEFINE_ADCxx1C_CHANNELS(_name, _bits) \
90 static const struct iio_chan_spec _name ## _channels[] = { \
91 ADCxx1C_CHAN((_bits)), \
92 IIO_CHAN_SOFT_TIMESTAMP(1), \
93 }; \
94
95 #define ADC081C_NUM_CHANNELS 2
96
97 struct adcxx1c_model {
98 const struct iio_chan_spec* channels;
99 int bits;
100 };
101
102 #define ADCxx1C_MODEL(_name, _bits) \
103 { \
104 .channels = _name ## _channels, \
105 .bits = (_bits), \
106 }
107
108 DEFINE_ADCxx1C_CHANNELS(adc081c, 8);
109 DEFINE_ADCxx1C_CHANNELS(adc101c, 10);
110 DEFINE_ADCxx1C_CHANNELS(adc121c, 12);
111
112 /* Model ids are indexes in _models array */
113 enum adcxx1c_model_id {
114 ADC081C = 0,
115 ADC101C = 1,
116 ADC121C = 2,
117 };
118
119 static struct adcxx1c_model adcxx1c_models[] = {
120 ADCxx1C_MODEL(adc081c, 8),
121 ADCxx1C_MODEL(adc101c, 10),
122 ADCxx1C_MODEL(adc121c, 12),
123 };
124
125 static const struct iio_info adc081c_info = {
126 .read_raw = adc081c_read_raw,
127 .driver_module = THIS_MODULE,
128 };
129
adc081c_trigger_handler(int irq,void * p)130 static irqreturn_t adc081c_trigger_handler(int irq, void *p)
131 {
132 struct iio_poll_func *pf = p;
133 struct iio_dev *indio_dev = pf->indio_dev;
134 struct adc081c *data = iio_priv(indio_dev);
135 u16 buf[8]; /* 2 bytes data + 6 bytes padding + 8 bytes timestamp */
136 int ret;
137
138 ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
139 if (ret < 0)
140 goto out;
141 buf[0] = ret;
142 iio_push_to_buffers_with_timestamp(indio_dev, buf,
143 iio_get_time_ns(indio_dev));
144 out:
145 iio_trigger_notify_done(indio_dev->trig);
146 return IRQ_HANDLED;
147 }
148
adc081c_probe(struct i2c_client * client,const struct i2c_device_id * id)149 static int adc081c_probe(struct i2c_client *client,
150 const struct i2c_device_id *id)
151 {
152 struct iio_dev *iio;
153 struct adc081c *adc;
154 struct adcxx1c_model *model;
155 int err;
156
157 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
158 return -EOPNOTSUPP;
159
160 if (ACPI_COMPANION(&client->dev)) {
161 const struct acpi_device_id *ad_id;
162
163 ad_id = acpi_match_device(client->dev.driver->acpi_match_table,
164 &client->dev);
165 if (!ad_id)
166 return -ENODEV;
167 model = &adcxx1c_models[ad_id->driver_data];
168 } else {
169 model = &adcxx1c_models[id->driver_data];
170 }
171
172 iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
173 if (!iio)
174 return -ENOMEM;
175
176 adc = iio_priv(iio);
177 adc->i2c = client;
178 adc->bits = model->bits;
179
180 adc->ref = devm_regulator_get(&client->dev, "vref");
181 if (IS_ERR(adc->ref))
182 return PTR_ERR(adc->ref);
183
184 err = regulator_enable(adc->ref);
185 if (err < 0)
186 return err;
187
188 iio->dev.parent = &client->dev;
189 iio->dev.of_node = client->dev.of_node;
190 iio->name = dev_name(&client->dev);
191 iio->modes = INDIO_DIRECT_MODE;
192 iio->info = &adc081c_info;
193
194 iio->channels = model->channels;
195 iio->num_channels = ADC081C_NUM_CHANNELS;
196
197 err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL);
198 if (err < 0) {
199 dev_err(&client->dev, "iio triggered buffer setup failed\n");
200 goto err_regulator_disable;
201 }
202
203 err = iio_device_register(iio);
204 if (err < 0)
205 goto err_buffer_cleanup;
206
207 i2c_set_clientdata(client, iio);
208
209 return 0;
210
211 err_buffer_cleanup:
212 iio_triggered_buffer_cleanup(iio);
213 err_regulator_disable:
214 regulator_disable(adc->ref);
215
216 return err;
217 }
218
adc081c_remove(struct i2c_client * client)219 static int adc081c_remove(struct i2c_client *client)
220 {
221 struct iio_dev *iio = i2c_get_clientdata(client);
222 struct adc081c *adc = iio_priv(iio);
223
224 iio_device_unregister(iio);
225 iio_triggered_buffer_cleanup(iio);
226 regulator_disable(adc->ref);
227
228 return 0;
229 }
230
231 static const struct i2c_device_id adc081c_id[] = {
232 { "adc081c", ADC081C },
233 { "adc101c", ADC101C },
234 { "adc121c", ADC121C },
235 { }
236 };
237 MODULE_DEVICE_TABLE(i2c, adc081c_id);
238
239 #ifdef CONFIG_OF
240 static const struct of_device_id adc081c_of_match[] = {
241 { .compatible = "ti,adc081c" },
242 { .compatible = "ti,adc101c" },
243 { .compatible = "ti,adc121c" },
244 { }
245 };
246 MODULE_DEVICE_TABLE(of, adc081c_of_match);
247 #endif
248
249 #ifdef CONFIG_ACPI
250 static const struct acpi_device_id adc081c_acpi_match[] = {
251 { "ADC081C", ADC081C },
252 { "ADC101C", ADC101C },
253 { "ADC121C", ADC121C },
254 { }
255 };
256 MODULE_DEVICE_TABLE(acpi, adc081c_acpi_match);
257 #endif
258
259 static struct i2c_driver adc081c_driver = {
260 .driver = {
261 .name = "adc081c",
262 .of_match_table = of_match_ptr(adc081c_of_match),
263 .acpi_match_table = ACPI_PTR(adc081c_acpi_match),
264 },
265 .probe = adc081c_probe,
266 .remove = adc081c_remove,
267 .id_table = adc081c_id,
268 };
269 module_i2c_driver(adc081c_driver);
270
271 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
272 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
273 MODULE_LICENSE("GPL v2");
274