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Linux/drivers/iio/adc/ti-adc081c.c

  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 
 26 #include <linux/iio/iio.h>
 27 #include <linux/iio/buffer.h>
 28 #include <linux/iio/trigger_consumer.h>
 29 #include <linux/iio/triggered_buffer.h>
 30 #include <linux/regulator/consumer.h>
 31 
 32 struct adc081c {
 33         struct i2c_client *i2c;
 34         struct regulator *ref;
 35 
 36         /* 8, 10 or 12 */
 37         int bits;
 38 };
 39 
 40 #define REG_CONV_RES 0x00
 41 
 42 static int adc081c_read_raw(struct iio_dev *iio,
 43                             struct iio_chan_spec const *channel, int *value,
 44                             int *shift, long mask)
 45 {
 46         struct adc081c *adc = iio_priv(iio);
 47         int err;
 48 
 49         switch (mask) {
 50         case IIO_CHAN_INFO_RAW:
 51                 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
 52                 if (err < 0)
 53                         return err;
 54 
 55                 *value = (err & 0xFFF) >> (12 - adc->bits);
 56                 return IIO_VAL_INT;
 57 
 58         case IIO_CHAN_INFO_SCALE:
 59                 err = regulator_get_voltage(adc->ref);
 60                 if (err < 0)
 61                         return err;
 62 
 63                 *value = err / 1000;
 64                 *shift = adc->bits;
 65 
 66                 return IIO_VAL_FRACTIONAL_LOG2;
 67 
 68         default:
 69                 break;
 70         }
 71 
 72         return -EINVAL;
 73 }
 74 
 75 #define ADCxx1C_CHAN(_bits) {                                   \
 76         .type = IIO_VOLTAGE,                                    \
 77         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
 78         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 79         .scan_type = {                                          \
 80                 .sign = 'u',                                    \
 81                 .realbits = (_bits),                            \
 82                 .storagebits = 16,                              \
 83                 .shift = 12 - (_bits),                          \
 84                 .endianness = IIO_CPU,                          \
 85         },                                                      \
 86 }
 87 
 88 #define DEFINE_ADCxx1C_CHANNELS(_name, _bits)                           \
 89         static const struct iio_chan_spec _name ## _channels[] = {      \
 90                 ADCxx1C_CHAN((_bits)),                                  \
 91                 IIO_CHAN_SOFT_TIMESTAMP(1),                             \
 92         };                                                              \
 93 
 94 #define ADC081C_NUM_CHANNELS 2
 95 
 96 struct adcxx1c_model {
 97         const struct iio_chan_spec* channels;
 98         int bits;
 99 };
100 
101 #define ADCxx1C_MODEL(_name, _bits)                                     \
102         {                                                               \
103                 .channels = _name ## _channels,                         \
104                 .bits = (_bits),                                        \
105         }
106 
107 DEFINE_ADCxx1C_CHANNELS(adc081c,  8);
108 DEFINE_ADCxx1C_CHANNELS(adc101c, 10);
109 DEFINE_ADCxx1C_CHANNELS(adc121c, 12);
110 
111 /* Model ids are indexes in _models array */
112 enum adcxx1c_model_id {
113         ADC081C = 0,
114         ADC101C = 1,
115         ADC121C = 2,
116 };
117 
118 static struct adcxx1c_model adcxx1c_models[] = {
119         ADCxx1C_MODEL(adc081c,  8),
120         ADCxx1C_MODEL(adc101c, 10),
121         ADCxx1C_MODEL(adc121c, 12),
122 };
123 
124 static const struct iio_info adc081c_info = {
125         .read_raw = adc081c_read_raw,
126         .driver_module = THIS_MODULE,
127 };
128 
129 static irqreturn_t adc081c_trigger_handler(int irq, void *p)
130 {
131         struct iio_poll_func *pf = p;
132         struct iio_dev *indio_dev = pf->indio_dev;
133         struct adc081c *data = iio_priv(indio_dev);
134         u16 buf[8]; /* 2 bytes data + 6 bytes padding + 8 bytes timestamp */
135         int ret;
136 
137         ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
138         if (ret < 0)
139                 goto out;
140         buf[0] = ret;
141         iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
142 out:
143         iio_trigger_notify_done(indio_dev->trig);
144         return IRQ_HANDLED;
145 }
146 
147 static int adc081c_probe(struct i2c_client *client,
148                          const struct i2c_device_id *id)
149 {
150         struct iio_dev *iio;
151         struct adc081c *adc;
152         struct adcxx1c_model *model = &adcxx1c_models[id->driver_data];
153         int err;
154 
155         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
156                 return -EOPNOTSUPP;
157 
158         iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
159         if (!iio)
160                 return -ENOMEM;
161 
162         adc = iio_priv(iio);
163         adc->i2c = client;
164         adc->bits = model->bits;
165 
166         adc->ref = devm_regulator_get(&client->dev, "vref");
167         if (IS_ERR(adc->ref))
168                 return PTR_ERR(adc->ref);
169 
170         err = regulator_enable(adc->ref);
171         if (err < 0)
172                 return err;
173 
174         iio->dev.parent = &client->dev;
175         iio->name = dev_name(&client->dev);
176         iio->modes = INDIO_DIRECT_MODE;
177         iio->info = &adc081c_info;
178 
179         iio->channels = model->channels;
180         iio->num_channels = ADC081C_NUM_CHANNELS;
181 
182         err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL);
183         if (err < 0) {
184                 dev_err(&client->dev, "iio triggered buffer setup failed\n");
185                 goto err_regulator_disable;
186         }
187 
188         err = iio_device_register(iio);
189         if (err < 0)
190                 goto err_buffer_cleanup;
191 
192         i2c_set_clientdata(client, iio);
193 
194         return 0;
195 
196 err_buffer_cleanup:
197         iio_triggered_buffer_cleanup(iio);
198 err_regulator_disable:
199         regulator_disable(adc->ref);
200 
201         return err;
202 }
203 
204 static int adc081c_remove(struct i2c_client *client)
205 {
206         struct iio_dev *iio = i2c_get_clientdata(client);
207         struct adc081c *adc = iio_priv(iio);
208 
209         iio_device_unregister(iio);
210         iio_triggered_buffer_cleanup(iio);
211         regulator_disable(adc->ref);
212 
213         return 0;
214 }
215 
216 static const struct i2c_device_id adc081c_id[] = {
217         { "adc081c", ADC081C },
218         { "adc101c", ADC101C },
219         { "adc121c", ADC121C },
220         { }
221 };
222 MODULE_DEVICE_TABLE(i2c, adc081c_id);
223 
224 #ifdef CONFIG_OF
225 static const struct of_device_id adc081c_of_match[] = {
226         { .compatible = "ti,adc081c" },
227         { .compatible = "ti,adc101c" },
228         { .compatible = "ti,adc121c" },
229         { }
230 };
231 MODULE_DEVICE_TABLE(of, adc081c_of_match);
232 #endif
233 
234 static struct i2c_driver adc081c_driver = {
235         .driver = {
236                 .name = "adc081c",
237                 .of_match_table = of_match_ptr(adc081c_of_match),
238         },
239         .probe = adc081c_probe,
240         .remove = adc081c_remove,
241         .id_table = adc081c_id,
242 };
243 module_i2c_driver(adc081c_driver);
244 
245 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
246 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
247 MODULE_LICENSE("GPL v2");
248 

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