drivers/iio/adc/ti-adc161s626.c

   1 /*
   2  * ti-adc161s626.c - Texas Instruments ADC161S626 1-channel differential ADC
   3  *
   4  * ADC Devices Supported:
   5  *  adc141s626 - 14-bit ADC
   6  *  adc161s626 - 16-bit ADC
   7  *
   8  * Copyright (C) 2016 Matt Ranostay <mranostay@gmail.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU General Public License for more details.
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/err.h>
  24 #include <linux/spi/spi.h>
  25 #include <linux/iio/iio.h>
  26 #include <linux/iio/trigger.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 #define TI_ADC_DRV_NAME "ti-adc161s626"
  33
  34 enum {
  35         TI_ADC141S626,
  36         TI_ADC161S626,
  37 };
  38
  39 static const struct iio_chan_spec ti_adc141s626_channels[] = {
  40         {
  41                 .type = IIO_VOLTAGE,
  42                 .channel = 0,
  43                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  44                                       BIT(IIO_CHAN_INFO_SCALE) |
  45                                       BIT(IIO_CHAN_INFO_OFFSET),
  46                 .scan_index = 0,
  47                 .scan_type = {
  48                         .sign = 's',
  49                         .realbits = 14,
  50                         .storagebits = 16,
  51                 },
  52         },
  53         IIO_CHAN_SOFT_TIMESTAMP(1),
  54 };
  55
  56 static const struct iio_chan_spec ti_adc161s626_channels[] = {
  57         {
  58                 .type = IIO_VOLTAGE,
  59                 .channel = 0,
  60                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  61                                       BIT(IIO_CHAN_INFO_SCALE) |
  62                                       BIT(IIO_CHAN_INFO_OFFSET),
  63                 .scan_index = 0,
  64                 .scan_type = {
  65                         .sign = 's',
  66                         .realbits = 16,
  67                         .storagebits = 16,
  68                 },
  69         },
  70         IIO_CHAN_SOFT_TIMESTAMP(1),
  71 };
  72
  73 struct ti_adc_data {
  74         struct iio_dev *indio_dev;
  75         struct spi_device *spi;
  76         struct regulator *ref;
  77
  78         u8 read_size;
  79         u8 shift;
  80
  81         u8 buffer[16] ____cacheline_aligned;
  82 };
  83
  84 static int ti_adc_read_measurement(struct ti_adc_data *data,
  85                                    struct iio_chan_spec const *chan, int *val)
  86 {
  87         int ret;
  88
  89         switch (data->read_size) {
  90         case 2: {
  91                 __be16 buf;
  92
  93                 ret = spi_read(data->spi, (void *) &buf, 2);
  94                 if (ret)
  95                         return ret;
  96
  97                 *val = be16_to_cpu(buf);
  98                 break;
  99         }
 100         case 3: {
 101                 __be32 buf;
 102
 103                 ret = spi_read(data->spi, (void *) &buf, 3);
 104                 if (ret)
 105                         return ret;
 106
 107                 *val = be32_to_cpu(buf) >> 8;
 108                 break;
 109         }
 110         default:
 111                 return -EINVAL;
 112         }
 113
 114         *val = sign_extend32(*val >> data->shift, chan->scan_type.realbits - 1);
 115
 116         return 0;
 117 }
 118
 119 static irqreturn_t ti_adc_trigger_handler(int irq, void *private)
 120 {
 121         struct iio_poll_func *pf = private;
 122         struct iio_dev *indio_dev = pf->indio_dev;
 123         struct ti_adc_data *data = iio_priv(indio_dev);
 124         int ret;
 125
 126         ret = ti_adc_read_measurement(data, &indio_dev->channels[0],
 127                                      (int *) &data->buffer);
 128         if (!ret)
 129                 iio_push_to_buffers_with_timestamp(indio_dev,
 130                                         data->buffer,
 131                                         iio_get_time_ns(indio_dev));
 132
 133         iio_trigger_notify_done(indio_dev->trig);
 134
 135         return IRQ_HANDLED;
 136 }
 137
 138 static int ti_adc_read_raw(struct iio_dev *indio_dev,
 139                            struct iio_chan_spec const *chan,
 140                            int *val, int *val2, long mask)
 141 {
 142         struct ti_adc_data *data = iio_priv(indio_dev);
 143         int ret;
 144
 145         switch (mask) {
 146         case IIO_CHAN_INFO_RAW:
 147                 ret = iio_device_claim_direct_mode(indio_dev);
 148                 if (ret)
 149                         return ret;
 150
 151                 ret = ti_adc_read_measurement(data, chan, val);
 152                 iio_device_release_direct_mode(indio_dev);
 153
 154                 if (ret)
 155                         return ret;
 156
 157                 return IIO_VAL_INT;
 158         case IIO_CHAN_INFO_SCALE:
 159                 ret = regulator_get_voltage(data->ref);
 160                 if (ret < 0)
 161                         return ret;
 162
 163                 *val = ret / 1000;
 164                 *val2 = chan->scan_type.realbits;
 165
 166                 return IIO_VAL_FRACTIONAL_LOG2;
 167         case IIO_CHAN_INFO_OFFSET:
 168                 *val = 1 << (chan->scan_type.realbits - 1);
 169                 return IIO_VAL_INT;
 170         }
 171
 172         return 0;
 173 }
 174
 175 static const struct iio_info ti_adc_info = {
 176         .driver_module = THIS_MODULE,
 177         .read_raw = ti_adc_read_raw,
 178 };
 179
 180 static int ti_adc_probe(struct spi_device *spi)
 181 {
 182         struct iio_dev *indio_dev;
 183         struct ti_adc_data *data;
 184         int ret;
 185
 186         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
 187         if (!indio_dev)
 188                 return -ENOMEM;
 189
 190         indio_dev->info = &ti_adc_info;
 191         indio_dev->dev.parent = &spi->dev;
 192         indio_dev->dev.of_node = spi->dev.of_node;
 193         indio_dev->name = TI_ADC_DRV_NAME;
 194         indio_dev->modes = INDIO_DIRECT_MODE;
 195         spi_set_drvdata(spi, indio_dev);
 196
 197         data = iio_priv(indio_dev);
 198         data->spi = spi;
 199
 200         switch (spi_get_device_id(spi)->driver_data) {
 201         case TI_ADC141S626:
 202                 indio_dev->channels = ti_adc141s626_channels;
 203                 indio_dev->num_channels = ARRAY_SIZE(ti_adc141s626_channels);
 204                 data->shift = 0;
 205                 data->read_size = 2;
 206                 break;
 207         case TI_ADC161S626:
 208                 indio_dev->channels = ti_adc161s626_channels;
 209                 indio_dev->num_channels = ARRAY_SIZE(ti_adc161s626_channels);
 210                 data->shift = 6;
 211                 data->read_size = 3;
 212                 break;
 213         }
 214
 215         data->ref = devm_regulator_get(&spi->dev, "vdda");
 216         if (!IS_ERR(data->ref)) {
 217                 ret = regulator_enable(data->ref);
 218                 if (ret < 0)
 219                         return ret;
 220         }
 221
 222         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 223                                          ti_adc_trigger_handler, NULL);
 224         if (ret)
 225                 goto error_regulator_disable;
 226
 227         ret = iio_device_register(indio_dev);
 228         if (ret)
 229                 goto error_unreg_buffer;
 230
 231         return 0;
 232
 233 error_unreg_buffer:
 234         iio_triggered_buffer_cleanup(indio_dev);
 235
 236 error_regulator_disable:
 237         regulator_disable(data->ref);
 238
 239         return ret;
 240 }
 241
 242 static int ti_adc_remove(struct spi_device *spi)
 243 {
 244         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 245         struct ti_adc_data *data = iio_priv(indio_dev);
 246
 247         iio_device_unregister(indio_dev);
 248         iio_triggered_buffer_cleanup(indio_dev);
 249         regulator_disable(data->ref);
 250
 251         return 0;
 252 }
 253
 254 static const struct of_device_id ti_adc_dt_ids[] = {
 255         { .compatible = "ti,adc141s626", },
 256         { .compatible = "ti,adc161s626", },
 257         {}
 258 };
 259 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
 260
 261 static const struct spi_device_id ti_adc_id[] = {
 262         {"adc141s626", TI_ADC141S626},
 263         {"adc161s626", TI_ADC161S626},
 264         {},
 265 };
 266 MODULE_DEVICE_TABLE(spi, ti_adc_id);
 267
 268 static struct spi_driver ti_adc_driver = {
 269         .driver = {
 270                 .name   = TI_ADC_DRV_NAME,
 271                 .of_match_table = of_match_ptr(ti_adc_dt_ids),
 272         },
 273         .probe          = ti_adc_probe,
 274         .remove         = ti_adc_remove,
 275         .id_table       = ti_adc_id,
 276 };
 277 module_spi_driver(ti_adc_driver);
 278
 279 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
 280 MODULE_DESCRIPTION("Texas Instruments ADC1x1S 1-channel differential ADC");
 281 MODULE_LICENSE("GPL");