drivers/iio/adc/ti-adc161s626.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * ti-adc161s626.c - Texas Instruments ADC161S626 1-channel differential ADC
   4  *
   5  * ADC Devices Supported:
   6  *  adc141s626 - 14-bit ADC
   7  *  adc161s626 - 16-bit ADC
   8  *
   9  * Copyright (C) 2016-2018
  10  * Author: Matt Ranostay <matt.ranostay@konsulko.com>
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/err.h>
  16 #include <linux/spi/spi.h>
  17 #include <linux/iio/iio.h>
  18 #include <linux/iio/trigger.h>
  19 #include <linux/iio/buffer.h>
  20 #include <linux/iio/trigger_consumer.h>
  21 #include <linux/iio/triggered_buffer.h>
  22 #include <linux/regulator/consumer.h>
  23
  24 #define TI_ADC_DRV_NAME "ti-adc161s626"
  25
  26 enum {
  27         TI_ADC141S626,
  28         TI_ADC161S626,
  29 };
  30
  31 static const struct iio_chan_spec ti_adc141s626_channels[] = {
  32         {
  33                 .type = IIO_VOLTAGE,
  34                 .channel = 0,
  35                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  36                                       BIT(IIO_CHAN_INFO_SCALE) |
  37                                       BIT(IIO_CHAN_INFO_OFFSET),
  38                 .scan_index = 0,
  39                 .scan_type = {
  40                         .sign = 's',
  41                         .realbits = 14,
  42                         .storagebits = 16,
  43                 },
  44         },
  45         IIO_CHAN_SOFT_TIMESTAMP(1),
  46 };
  47
  48 static const struct iio_chan_spec ti_adc161s626_channels[] = {
  49         {
  50                 .type = IIO_VOLTAGE,
  51                 .channel = 0,
  52                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  53                                       BIT(IIO_CHAN_INFO_SCALE) |
  54                                       BIT(IIO_CHAN_INFO_OFFSET),
  55                 .scan_index = 0,
  56                 .scan_type = {
  57                         .sign = 's',
  58                         .realbits = 16,
  59                         .storagebits = 16,
  60                 },
  61         },
  62         IIO_CHAN_SOFT_TIMESTAMP(1),
  63 };
  64
  65 struct ti_adc_data {
  66         struct iio_dev *indio_dev;
  67         struct spi_device *spi;
  68         struct regulator *ref;
  69
  70         u8 read_size;
  71         u8 shift;
  72
  73         u8 buffer[16] ____cacheline_aligned;
  74 };
  75
  76 static int ti_adc_read_measurement(struct ti_adc_data *data,
  77                                    struct iio_chan_spec const *chan, int *val)
  78 {
  79         int ret;
  80
  81         switch (data->read_size) {
  82         case 2: {
  83                 __be16 buf;
  84
  85                 ret = spi_read(data->spi, (void *) &buf, 2);
  86                 if (ret)
  87                         return ret;
  88
  89                 *val = be16_to_cpu(buf);
  90                 break;
  91         }
  92         case 3: {
  93                 __be32 buf;
  94
  95                 ret = spi_read(data->spi, (void *) &buf, 3);
  96                 if (ret)
  97                         return ret;
  98
  99                 *val = be32_to_cpu(buf) >> 8;
 100                 break;
 101         }
 102         default:
 103                 return -EINVAL;
 104         }
 105
 106         *val = sign_extend32(*val >> data->shift, chan->scan_type.realbits - 1);
 107
 108         return 0;
 109 }
 110
 111 static irqreturn_t ti_adc_trigger_handler(int irq, void *private)
 112 {
 113         struct iio_poll_func *pf = private;
 114         struct iio_dev *indio_dev = pf->indio_dev;
 115         struct ti_adc_data *data = iio_priv(indio_dev);
 116         int ret;
 117
 118         ret = ti_adc_read_measurement(data, &indio_dev->channels[0],
 119                                      (int *) &data->buffer);
 120         if (!ret)
 121                 iio_push_to_buffers_with_timestamp(indio_dev,
 122                                         data->buffer,
 123                                         iio_get_time_ns(indio_dev));
 124
 125         iio_trigger_notify_done(indio_dev->trig);
 126
 127         return IRQ_HANDLED;
 128 }
 129
 130 static int ti_adc_read_raw(struct iio_dev *indio_dev,
 131                            struct iio_chan_spec const *chan,
 132                            int *val, int *val2, long mask)
 133 {
 134         struct ti_adc_data *data = iio_priv(indio_dev);
 135         int ret;
 136
 137         switch (mask) {
 138         case IIO_CHAN_INFO_RAW:
 139                 ret = iio_device_claim_direct_mode(indio_dev);
 140                 if (ret)
 141                         return ret;
 142
 143                 ret = ti_adc_read_measurement(data, chan, val);
 144                 iio_device_release_direct_mode(indio_dev);
 145
 146                 if (ret)
 147                         return ret;
 148
 149                 return IIO_VAL_INT;
 150         case IIO_CHAN_INFO_SCALE:
 151                 ret = regulator_get_voltage(data->ref);
 152                 if (ret < 0)
 153                         return ret;
 154
 155                 *val = ret / 1000;
 156                 *val2 = chan->scan_type.realbits;
 157
 158                 return IIO_VAL_FRACTIONAL_LOG2;
 159         case IIO_CHAN_INFO_OFFSET:
 160                 *val = 1 << (chan->scan_type.realbits - 1);
 161                 return IIO_VAL_INT;
 162         }
 163
 164         return 0;
 165 }
 166
 167 static const struct iio_info ti_adc_info = {
 168         .read_raw = ti_adc_read_raw,
 169 };
 170
 171 static int ti_adc_probe(struct spi_device *spi)
 172 {
 173         struct iio_dev *indio_dev;
 174         struct ti_adc_data *data;
 175         int ret;
 176
 177         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
 178         if (!indio_dev)
 179                 return -ENOMEM;
 180
 181         indio_dev->info = &ti_adc_info;
 182         indio_dev->dev.parent = &spi->dev;
 183         indio_dev->dev.of_node = spi->dev.of_node;
 184         indio_dev->name = TI_ADC_DRV_NAME;
 185         indio_dev->modes = INDIO_DIRECT_MODE;
 186         spi_set_drvdata(spi, indio_dev);
 187
 188         data = iio_priv(indio_dev);
 189         data->spi = spi;
 190
 191         switch (spi_get_device_id(spi)->driver_data) {
 192         case TI_ADC141S626:
 193                 indio_dev->channels = ti_adc141s626_channels;
 194                 indio_dev->num_channels = ARRAY_SIZE(ti_adc141s626_channels);
 195                 data->shift = 0;
 196                 data->read_size = 2;
 197                 break;
 198         case TI_ADC161S626:
 199                 indio_dev->channels = ti_adc161s626_channels;
 200                 indio_dev->num_channels = ARRAY_SIZE(ti_adc161s626_channels);
 201                 data->shift = 6;
 202                 data->read_size = 3;
 203                 break;
 204         }
 205
 206         data->ref = devm_regulator_get(&spi->dev, "vdda");
 207         if (!IS_ERR(data->ref)) {
 208                 ret = regulator_enable(data->ref);
 209                 if (ret < 0)
 210                         return ret;
 211         }
 212
 213         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 214                                          ti_adc_trigger_handler, NULL);
 215         if (ret)
 216                 goto error_regulator_disable;
 217
 218         ret = iio_device_register(indio_dev);
 219         if (ret)
 220                 goto error_unreg_buffer;
 221
 222         return 0;
 223
 224 error_unreg_buffer:
 225         iio_triggered_buffer_cleanup(indio_dev);
 226
 227 error_regulator_disable:
 228         regulator_disable(data->ref);
 229
 230         return ret;
 231 }
 232
 233 static int ti_adc_remove(struct spi_device *spi)
 234 {
 235         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 236         struct ti_adc_data *data = iio_priv(indio_dev);
 237
 238         iio_device_unregister(indio_dev);
 239         iio_triggered_buffer_cleanup(indio_dev);
 240         regulator_disable(data->ref);
 241
 242         return 0;
 243 }
 244
 245 static const struct of_device_id ti_adc_dt_ids[] = {
 246         { .compatible = "ti,adc141s626", },
 247         { .compatible = "ti,adc161s626", },
 248         {}
 249 };
 250 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
 251
 252 static const struct spi_device_id ti_adc_id[] = {
 253         {"adc141s626", TI_ADC141S626},
 254         {"adc161s626", TI_ADC161S626},
 255         {},
 256 };
 257 MODULE_DEVICE_TABLE(spi, ti_adc_id);
 258
 259 static struct spi_driver ti_adc_driver = {
 260         .driver = {
 261                 .name   = TI_ADC_DRV_NAME,
 262                 .of_match_table = of_match_ptr(ti_adc_dt_ids),
 263         },
 264         .probe          = ti_adc_probe,
 265         .remove         = ti_adc_remove,
 266         .id_table       = ti_adc_id,
 267 };
 268 module_spi_driver(ti_adc_driver);
 269
 270 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
 271 MODULE_DESCRIPTION("Texas Instruments ADC1x1S 1-channel differential ADC");
 272 MODULE_LICENSE("GPL");