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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 #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 
 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 
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 
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 
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 

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