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 /* Ensure natural alignment of buffer elements */
41 struct {
42 u16 channel;
43 s64 ts __aligned(8);
44 } scan;
45 };
46
47 #define REG_CONV_RES 0x00
48
adc081c_read_raw(struct iio_dev * iio,struct iio_chan_spec const * channel,int * value,int * shift,long mask)49 static int adc081c_read_raw(struct iio_dev *iio,
50 struct iio_chan_spec const *channel, int *value,
51 int *shift, long mask)
52 {
53 struct adc081c *adc = iio_priv(iio);
54 int err;
55
56 switch (mask) {
57 case IIO_CHAN_INFO_RAW:
58 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
59 if (err < 0)
60 return err;
61
62 *value = (err & 0xFFF) >> (12 - adc->bits);
63 return IIO_VAL_INT;
64
65 case IIO_CHAN_INFO_SCALE:
66 err = regulator_get_voltage(adc->ref);
67 if (err < 0)
68 return err;
69
70 *value = err / 1000;
71 *shift = adc->bits;
72
73 return IIO_VAL_FRACTIONAL_LOG2;
74
75 default:
76 break;
77 }
78
79 return -EINVAL;
80 }
81
82 #define ADCxx1C_CHAN(_bits) { \
83 .type = IIO_VOLTAGE, \
84 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
85 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
86 .scan_type = { \
87 .sign = 'u', \
88 .realbits = (_bits), \
89 .storagebits = 16, \
90 .shift = 12 - (_bits), \
91 .endianness = IIO_CPU, \
92 }, \
93 }
94
95 #define DEFINE_ADCxx1C_CHANNELS(_name, _bits) \
96 static const struct iio_chan_spec _name ## _channels[] = { \
97 ADCxx1C_CHAN((_bits)), \
98 IIO_CHAN_SOFT_TIMESTAMP(1), \
99 }; \
100
101 #define ADC081C_NUM_CHANNELS 2
102
103 struct adcxx1c_model {
104 const struct iio_chan_spec* channels;
105 int bits;
106 };
107
108 #define ADCxx1C_MODEL(_name, _bits) \
109 { \
110 .channels = _name ## _channels, \
111 .bits = (_bits), \
112 }
113
114 DEFINE_ADCxx1C_CHANNELS(adc081c, 8);
115 DEFINE_ADCxx1C_CHANNELS(adc101c, 10);
116 DEFINE_ADCxx1C_CHANNELS(adc121c, 12);
117
118 /* Model ids are indexes in _models array */
119 enum adcxx1c_model_id {
120 ADC081C = 0,
121 ADC101C = 1,
122 ADC121C = 2,
123 };
124
125 static struct adcxx1c_model adcxx1c_models[] = {
126 ADCxx1C_MODEL(adc081c, 8),
127 ADCxx1C_MODEL(adc101c, 10),
128 ADCxx1C_MODEL(adc121c, 12),
129 };
130
131 static const struct iio_info adc081c_info = {
132 .read_raw = adc081c_read_raw,
133 };
134
adc081c_trigger_handler(int irq,void * p)135 static irqreturn_t adc081c_trigger_handler(int irq, void *p)
136 {
137 struct iio_poll_func *pf = p;
138 struct iio_dev *indio_dev = pf->indio_dev;
139 struct adc081c *data = iio_priv(indio_dev);
140 int ret;
141
142 ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
143 if (ret < 0)
144 goto out;
145 data->scan.channel = ret;
146 iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
147 iio_get_time_ns(indio_dev));
148 out:
149 iio_trigger_notify_done(indio_dev->trig);
150 return IRQ_HANDLED;
151 }
152
adc081c_probe(struct i2c_client * client,const struct i2c_device_id * id)153 static int adc081c_probe(struct i2c_client *client,
154 const struct i2c_device_id *id)
155 {
156 struct iio_dev *iio;
157 struct adc081c *adc;
158 struct adcxx1c_model *model;
159 int err;
160
161 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
162 return -EOPNOTSUPP;
163
164 if (ACPI_COMPANION(&client->dev)) {
165 const struct acpi_device_id *ad_id;
166
167 ad_id = acpi_match_device(client->dev.driver->acpi_match_table,
168 &client->dev);
169 if (!ad_id)
170 return -ENODEV;
171 model = &adcxx1c_models[ad_id->driver_data];
172 } else {
173 model = &adcxx1c_models[id->driver_data];
174 }
175
176 iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
177 if (!iio)
178 return -ENOMEM;
179
180 adc = iio_priv(iio);
181 adc->i2c = client;
182 adc->bits = model->bits;
183
184 adc->ref = devm_regulator_get(&client->dev, "vref");
185 if (IS_ERR(adc->ref))
186 return PTR_ERR(adc->ref);
187
188 err = regulator_enable(adc->ref);
189 if (err < 0)
190 return err;
191
192 iio->dev.parent = &client->dev;
193 iio->dev.of_node = client->dev.of_node;
194 iio->name = dev_name(&client->dev);
195 iio->modes = INDIO_DIRECT_MODE;
196 iio->info = &adc081c_info;
197
198 iio->channels = model->channels;
199 iio->num_channels = ADC081C_NUM_CHANNELS;
200
201 err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL);
202 if (err < 0) {
203 dev_err(&client->dev, "iio triggered buffer setup failed\n");
204 goto err_regulator_disable;
205 }
206
207 err = iio_device_register(iio);
208 if (err < 0)
209 goto err_buffer_cleanup;
210
211 i2c_set_clientdata(client, iio);
212
213 return 0;
214
215 err_buffer_cleanup:
216 iio_triggered_buffer_cleanup(iio);
217 err_regulator_disable:
218 regulator_disable(adc->ref);
219
220 return err;
221 }
222
adc081c_remove(struct i2c_client * client)223 static int adc081c_remove(struct i2c_client *client)
224 {
225 struct iio_dev *iio = i2c_get_clientdata(client);
226 struct adc081c *adc = iio_priv(iio);
227
228 iio_device_unregister(iio);
229 iio_triggered_buffer_cleanup(iio);
230 regulator_disable(adc->ref);
231
232 return 0;
233 }
234
235 static const struct i2c_device_id adc081c_id[] = {
236 { "adc081c", ADC081C },
237 { "adc101c", ADC101C },
238 { "adc121c", ADC121C },
239 { }
240 };
241 MODULE_DEVICE_TABLE(i2c, adc081c_id);
242
243 #ifdef CONFIG_OF
244 static const struct of_device_id adc081c_of_match[] = {
245 { .compatible = "ti,adc081c" },
246 { .compatible = "ti,adc101c" },
247 { .compatible = "ti,adc121c" },
248 { }
249 };
250 MODULE_DEVICE_TABLE(of, adc081c_of_match);
251 #endif
252
253 #ifdef CONFIG_ACPI
254 static const struct acpi_device_id adc081c_acpi_match[] = {
255 { "ADC081C", ADC081C },
256 { "ADC101C", ADC101C },
257 { "ADC121C", ADC121C },
258 { }
259 };
260 MODULE_DEVICE_TABLE(acpi, adc081c_acpi_match);
261 #endif
262
263 static struct i2c_driver adc081c_driver = {
264 .driver = {
265 .name = "adc081c",
266 .of_match_table = of_match_ptr(adc081c_of_match),
267 .acpi_match_table = ACPI_PTR(adc081c_acpi_match),
268 },
269 .probe = adc081c_probe,
270 .remove = adc081c_remove,
271 .id_table = adc081c_id,
272 };
273 module_i2c_driver(adc081c_driver);
274
275 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
276 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
277 MODULE_LICENSE("GPL v2");
278