drivers/iio/adc/ti-ads124s08.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* TI ADS124S0X chip family driver
   3  * Copyright (C) 2018 Texas Instruments Incorporated - https://www.ti.com/
   4  */
   5
   6 #include <linux/err.h>
   7 #include <linux/delay.h>
   8 #include <linux/device.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/mod_devicetable.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysfs.h>
  14
  15 #include <linux/gpio/consumer.h>
  16 #include <linux/spi/spi.h>
  17
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/buffer.h>
  20 #include <linux/iio/trigger_consumer.h>
  21 #include <linux/iio/triggered_buffer.h>
  22 #include <linux/iio/sysfs.h>
  23
  24 #include <linux/unaligned.h>
  25
  26 /* Commands */
  27 #define ADS124S08_CMD_NOP       0x00
  28 #define ADS124S08_CMD_WAKEUP    0x02
  29 #define ADS124S08_CMD_PWRDWN    0x04
  30 #define ADS124S08_CMD_RESET     0x06
  31 #define ADS124S08_CMD_START     0x08
  32 #define ADS124S08_CMD_STOP      0x0a
  33 #define ADS124S08_CMD_SYOCAL    0x16
  34 #define ADS124S08_CMD_SYGCAL    0x17
  35 #define ADS124S08_CMD_SFOCAL    0x19
  36 #define ADS124S08_CMD_RDATA     0x12
  37 #define ADS124S08_CMD_RREG      0x20
  38 #define ADS124S08_CMD_WREG      0x40
  39
  40 /* Registers */
  41 #define ADS124S08_ID_REG        0x00
  42 #define ADS124S08_STATUS        0x01
  43 #define ADS124S08_INPUT_MUX     0x02
  44 #define ADS124S08_PGA           0x03
  45 #define ADS124S08_DATA_RATE     0x04
  46 #define ADS124S08_REF           0x05
  47 #define ADS124S08_IDACMAG       0x06
  48 #define ADS124S08_IDACMUX       0x07
  49 #define ADS124S08_VBIAS         0x08
  50 #define ADS124S08_SYS           0x09
  51 #define ADS124S08_OFCAL0        0x0a
  52 #define ADS124S08_OFCAL1        0x0b
  53 #define ADS124S08_OFCAL2        0x0c
  54 #define ADS124S08_FSCAL0        0x0d
  55 #define ADS124S08_FSCAL1        0x0e
  56 #define ADS124S08_FSCAL2        0x0f
  57 #define ADS124S08_GPIODAT       0x10
  58 #define ADS124S08_GPIOCON       0x11
  59
  60 /* ADS124S0x common channels */
  61 #define ADS124S08_AIN0          0x00
  62 #define ADS124S08_AIN1          0x01
  63 #define ADS124S08_AIN2          0x02
  64 #define ADS124S08_AIN3          0x03
  65 #define ADS124S08_AIN4          0x04
  66 #define ADS124S08_AIN5          0x05
  67 #define ADS124S08_AINCOM        0x0c
  68 /* ADS124S08 only channels */
  69 #define ADS124S08_AIN6          0x06
  70 #define ADS124S08_AIN7          0x07
  71 #define ADS124S08_AIN8          0x08
  72 #define ADS124S08_AIN9          0x09
  73 #define ADS124S08_AIN10         0x0a
  74 #define ADS124S08_AIN11         0x0b
  75 #define ADS124S08_MAX_CHANNELS  12
  76
  77 #define ADS124S08_POS_MUX_SHIFT 0x04
  78 #define ADS124S08_INT_REF               0x09
  79
  80 #define ADS124S08_START_REG_MASK        0x1f
  81 #define ADS124S08_NUM_BYTES_MASK        0x1f
  82
  83 #define ADS124S08_START_CONV    0x01
  84 #define ADS124S08_STOP_CONV     0x00
  85
  86 enum ads124s_id {
  87         ADS124S08_ID,
  88         ADS124S06_ID,
  89 };
  90
  91 struct ads124s_chip_info {
  92         const struct iio_chan_spec *channels;
  93         unsigned int num_channels;
  94 };
  95
  96 struct ads124s_private {
  97         const struct ads124s_chip_info  *chip_info;
  98         struct gpio_desc *reset_gpio;
  99         struct spi_device *spi;
 100         struct mutex lock;
 101         /*
 102          * Used to correctly align data.
 103          * Ensure timestamp is naturally aligned.
 104          * Note that the full buffer length may not be needed if not
 105          * all channels are enabled, as long as the alignment of the
 106          * timestamp is maintained.
 107          */
 108         u32 buffer[ADS124S08_MAX_CHANNELS + sizeof(s64)/sizeof(u32)] __aligned(8);
 109         u8 data[5] __aligned(IIO_DMA_MINALIGN);
 110 };
 111
 112 #define ADS124S08_CHAN(index)                                   \
 113 {                                                               \
 114         .type = IIO_VOLTAGE,                                    \
 115         .indexed = 1,                                           \
 116         .channel = index,                                       \
 117         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 118         .scan_index = index,                                    \
 119         .scan_type = {                                          \
 120                 .sign = 'u',                                    \
 121                 .realbits = 32,                                 \
 122                 .storagebits = 32,                              \
 123         },                                                      \
 124 }
 125
 126 static const struct iio_chan_spec ads124s06_channels[] = {
 127         ADS124S08_CHAN(0),
 128         ADS124S08_CHAN(1),
 129         ADS124S08_CHAN(2),
 130         ADS124S08_CHAN(3),
 131         ADS124S08_CHAN(4),
 132         ADS124S08_CHAN(5),
 133 };
 134
 135 static const struct iio_chan_spec ads124s08_channels[] = {
 136         ADS124S08_CHAN(0),
 137         ADS124S08_CHAN(1),
 138         ADS124S08_CHAN(2),
 139         ADS124S08_CHAN(3),
 140         ADS124S08_CHAN(4),
 141         ADS124S08_CHAN(5),
 142         ADS124S08_CHAN(6),
 143         ADS124S08_CHAN(7),
 144         ADS124S08_CHAN(8),
 145         ADS124S08_CHAN(9),
 146         ADS124S08_CHAN(10),
 147         ADS124S08_CHAN(11),
 148 };
 149
 150 static const struct ads124s_chip_info ads124s_chip_info_tbl[] = {
 151         [ADS124S08_ID] = {
 152                 .channels = ads124s08_channels,
 153                 .num_channels = ARRAY_SIZE(ads124s08_channels),
 154         },
 155         [ADS124S06_ID] = {
 156                 .channels = ads124s06_channels,
 157                 .num_channels = ARRAY_SIZE(ads124s06_channels),
 158         },
 159 };
 160
 161 static int ads124s_write_cmd(struct iio_dev *indio_dev, u8 command)
 162 {
 163         struct ads124s_private *priv = iio_priv(indio_dev);
 164
 165         priv->data[0] = command;
 166
 167         return spi_write(priv->spi, &priv->data[0], 1);
 168 }
 169
 170 static int ads124s_write_reg(struct iio_dev *indio_dev, u8 reg, u8 data)
 171 {
 172         struct ads124s_private *priv = iio_priv(indio_dev);
 173
 174         priv->data[0] = ADS124S08_CMD_WREG | reg;
 175         priv->data[1] = 0x0;
 176         priv->data[2] = data;
 177
 178         return spi_write(priv->spi, &priv->data[0], 3);
 179 }
 180
 181 static int ads124s_reset(struct iio_dev *indio_dev)
 182 {
 183         struct ads124s_private *priv = iio_priv(indio_dev);
 184
 185         if (priv->reset_gpio) {
 186                 gpiod_set_value(priv->reset_gpio, 0);
 187                 udelay(200);
 188                 gpiod_set_value(priv->reset_gpio, 1);
 189         } else {
 190                 return ads124s_write_cmd(indio_dev, ADS124S08_CMD_RESET);
 191         }
 192
 193         return 0;
 194 };
 195
 196 static int ads124s_read(struct iio_dev *indio_dev)
 197 {
 198         struct ads124s_private *priv = iio_priv(indio_dev);
 199         int ret;
 200         struct spi_transfer t[] = {
 201                 {
 202                         .tx_buf = &priv->data[0],
 203                         .len = 4,
 204                         .cs_change = 1,
 205                 }, {
 206                         .tx_buf = &priv->data[1],
 207                         .rx_buf = &priv->data[1],
 208                         .len = 4,
 209                 },
 210         };
 211
 212         priv->data[0] = ADS124S08_CMD_RDATA;
 213         memset(&priv->data[1], ADS124S08_CMD_NOP, sizeof(priv->data) - 1);
 214
 215         ret = spi_sync_transfer(priv->spi, t, ARRAY_SIZE(t));
 216         if (ret < 0)
 217                 return ret;
 218
 219         return get_unaligned_be24(&priv->data[2]);
 220 }
 221
 222 static int ads124s_read_raw(struct iio_dev *indio_dev,
 223                             struct iio_chan_spec const *chan,
 224                             int *val, int *val2, long m)
 225 {
 226         struct ads124s_private *priv = iio_priv(indio_dev);
 227         int ret;
 228
 229         mutex_lock(&priv->lock);
 230         switch (m) {
 231         case IIO_CHAN_INFO_RAW:
 232                 ret = ads124s_write_reg(indio_dev, ADS124S08_INPUT_MUX,
 233                                         chan->channel);
 234                 if (ret) {
 235                         dev_err(&priv->spi->dev, "Set ADC CH failed\n");
 236                         goto out;
 237                 }
 238
 239                 ret = ads124s_write_cmd(indio_dev, ADS124S08_START_CONV);
 240                 if (ret) {
 241                         dev_err(&priv->spi->dev, "Start conversions failed\n");
 242                         goto out;
 243                 }
 244
 245                 ret = ads124s_read(indio_dev);
 246                 if (ret < 0) {
 247                         dev_err(&priv->spi->dev, "Read ADC failed\n");
 248                         goto out;
 249                 }
 250
 251                 *val = ret;
 252
 253                 ret = ads124s_write_cmd(indio_dev, ADS124S08_STOP_CONV);
 254                 if (ret) {
 255                         dev_err(&priv->spi->dev, "Stop conversions failed\n");
 256                         goto out;
 257                 }
 258
 259                 ret = IIO_VAL_INT;
 260                 break;
 261         default:
 262                 ret = -EINVAL;
 263                 break;
 264         }
 265 out:
 266         mutex_unlock(&priv->lock);
 267         return ret;
 268 }
 269
 270 static const struct iio_info ads124s_info = {
 271         .read_raw = &ads124s_read_raw,
 272 };
 273
 274 static irqreturn_t ads124s_trigger_handler(int irq, void *p)
 275 {
 276         struct iio_poll_func *pf = p;
 277         struct iio_dev *indio_dev = pf->indio_dev;
 278         struct ads124s_private *priv = iio_priv(indio_dev);
 279         int scan_index, j = 0;
 280         int ret;
 281
 282         iio_for_each_active_channel(indio_dev, scan_index) {
 283                 ret = ads124s_write_reg(indio_dev, ADS124S08_INPUT_MUX,
 284                                         scan_index);
 285                 if (ret)
 286                         dev_err(&priv->spi->dev, "Set ADC CH failed\n");
 287
 288                 ret = ads124s_write_cmd(indio_dev, ADS124S08_START_CONV);
 289                 if (ret)
 290                         dev_err(&priv->spi->dev, "Start ADC conversions failed\n");
 291
 292                 priv->buffer[j] = ads124s_read(indio_dev);
 293                 ret = ads124s_write_cmd(indio_dev, ADS124S08_STOP_CONV);
 294                 if (ret)
 295                         dev_err(&priv->spi->dev, "Stop ADC conversions failed\n");
 296
 297                 j++;
 298         }
 299
 300         iio_push_to_buffers_with_timestamp(indio_dev, priv->buffer,
 301                         pf->timestamp);
 302
 303         iio_trigger_notify_done(indio_dev->trig);
 304
 305         return IRQ_HANDLED;
 306 }
 307
 308 static int ads124s_probe(struct spi_device *spi)
 309 {
 310         struct ads124s_private *ads124s_priv;
 311         struct iio_dev *indio_dev;
 312         const struct spi_device_id *spi_id = spi_get_device_id(spi);
 313         int ret;
 314
 315         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ads124s_priv));
 316         if (indio_dev == NULL)
 317                 return -ENOMEM;
 318
 319         ads124s_priv = iio_priv(indio_dev);
 320
 321         ads124s_priv->reset_gpio = devm_gpiod_get_optional(&spi->dev,
 322                                                    "reset", GPIOD_OUT_LOW);
 323         if (IS_ERR(ads124s_priv->reset_gpio))
 324                 dev_info(&spi->dev, "Reset GPIO not defined\n");
 325
 326         ads124s_priv->chip_info = &ads124s_chip_info_tbl[spi_id->driver_data];
 327
 328         ads124s_priv->spi = spi;
 329
 330         indio_dev->name = spi_id->name;
 331         indio_dev->modes = INDIO_DIRECT_MODE;
 332         indio_dev->channels = ads124s_priv->chip_info->channels;
 333         indio_dev->num_channels = ads124s_priv->chip_info->num_channels;
 334         indio_dev->info = &ads124s_info;
 335
 336         mutex_init(&ads124s_priv->lock);
 337
 338         ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
 339                                               ads124s_trigger_handler, NULL);
 340         if (ret) {
 341                 dev_err(&spi->dev, "iio triggered buffer setup failed\n");
 342                 return ret;
 343         }
 344
 345         ads124s_reset(indio_dev);
 346
 347         return devm_iio_device_register(&spi->dev, indio_dev);
 348 }
 349
 350 static const struct spi_device_id ads124s_id[] = {
 351         { "ads124s06", ADS124S06_ID },
 352         { "ads124s08", ADS124S08_ID },
 353         { }
 354 };
 355 MODULE_DEVICE_TABLE(spi, ads124s_id);
 356
 357 static const struct of_device_id ads124s_of_table[] = {
 358         { .compatible = "ti,ads124s06" },
 359         { .compatible = "ti,ads124s08" },
 360         { }
 361 };
 362 MODULE_DEVICE_TABLE(of, ads124s_of_table);
 363
 364 static struct spi_driver ads124s_driver = {
 365         .driver = {
 366                 .name   = "ads124s08",
 367                 .of_match_table = ads124s_of_table,
 368         },
 369         .probe          = ads124s_probe,
 370         .id_table       = ads124s_id,
 371 };
 372 module_spi_driver(ads124s_driver);
 373
 374 MODULE_AUTHOR("Dan Murphy <dmuprhy@ti.com>");
 375 MODULE_DESCRIPTION("TI TI_ADS12S0X ADC");
 376 MODULE_LICENSE("GPL v2");