drivers/iio/adc/ad7091r-base.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * AD7091RX Analog to Digital converter driver
   4  *
   5  * Copyright 2014-2019 Analog Devices Inc.
   6  */
   7
   8 #include <linux/bitops.h>
   9 #include <linux/iio/events.h>
  10 #include <linux/iio/iio.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/module.h>
  13 #include <linux/regmap.h>
  14 #include <linux/regulator/consumer.h>
  15
  16 #include "ad7091r-base.h"
  17
  18 #define AD7091R_REG_RESULT  0
  19 #define AD7091R_REG_CHANNEL 1
  20 #define AD7091R_REG_CONF    2
  21 #define AD7091R_REG_ALERT   3
  22 #define AD7091R_REG_CH_LOW_LIMIT(ch) ((ch) * 3 + 4)
  23 #define AD7091R_REG_CH_HIGH_LIMIT(ch) ((ch) * 3 + 5)
  24 #define AD7091R_REG_CH_HYSTERESIS(ch) ((ch) * 3 + 6)
  25
  26 /* AD7091R_REG_RESULT */
  27 #define AD7091R_REG_RESULT_CH_ID(x)         (((x) >> 13) & 0x3)
  28 #define AD7091R_REG_RESULT_CONV_RESULT(x)   ((x) & 0xfff)
  29
  30 /* AD7091R_REG_CONF */
  31 #define AD7091R_REG_CONF_AUTO   BIT(8)
  32 #define AD7091R_REG_CONF_CMD    BIT(10)
  33
  34 #define AD7091R_REG_CONF_MODE_MASK  \
  35         (AD7091R_REG_CONF_AUTO | AD7091R_REG_CONF_CMD)
  36
  37 enum ad7091r_mode {
  38         AD7091R_MODE_SAMPLE,
  39         AD7091R_MODE_COMMAND,
  40         AD7091R_MODE_AUTOCYCLE,
  41 };
  42
  43 struct ad7091r_state {
  44         struct device *dev;
  45         struct regmap *map;
  46         struct regulator *vref;
  47         const struct ad7091r_chip_info *chip_info;
  48         enum ad7091r_mode mode;
  49         struct mutex lock; /*lock to prevent concurent reads */
  50 };
  51
  52 static int ad7091r_set_mode(struct ad7091r_state *st, enum ad7091r_mode mode)
  53 {
  54         int ret, conf;
  55
  56         switch (mode) {
  57         case AD7091R_MODE_SAMPLE:
  58                 conf = 0;
  59                 break;
  60         case AD7091R_MODE_COMMAND:
  61                 conf = AD7091R_REG_CONF_CMD;
  62                 break;
  63         case AD7091R_MODE_AUTOCYCLE:
  64                 conf = AD7091R_REG_CONF_AUTO;
  65                 break;
  66         default:
  67                 return -EINVAL;
  68         }
  69
  70         ret = regmap_update_bits(st->map, AD7091R_REG_CONF,
  71                                  AD7091R_REG_CONF_MODE_MASK, conf);
  72         if (ret)
  73                 return ret;
  74
  75         st->mode = mode;
  76
  77         return 0;
  78 }
  79
  80 static int ad7091r_set_channel(struct ad7091r_state *st, unsigned int channel)
  81 {
  82         unsigned int dummy;
  83         int ret;
  84
  85         /* AD7091R_REG_CHANNEL specified which channels to be converted */
  86         ret = regmap_write(st->map, AD7091R_REG_CHANNEL,
  87                         BIT(channel) | (BIT(channel) << 8));
  88         if (ret)
  89                 return ret;
  90
  91         /*
  92          * There is a latency of one conversion before the channel conversion
  93          * sequence is updated
  94          */
  95         return regmap_read(st->map, AD7091R_REG_RESULT, &dummy);
  96 }
  97
  98 static int ad7091r_read_one(struct iio_dev *iio_dev,
  99                 unsigned int channel, unsigned int *read_val)
 100 {
 101         struct ad7091r_state *st = iio_priv(iio_dev);
 102         unsigned int val;
 103         int ret;
 104
 105         ret = ad7091r_set_channel(st, channel);
 106         if (ret)
 107                 return ret;
 108
 109         ret = regmap_read(st->map, AD7091R_REG_RESULT, &val);
 110         if (ret)
 111                 return ret;
 112
 113         if (AD7091R_REG_RESULT_CH_ID(val) != channel)
 114                 return -EIO;
 115
 116         *read_val = AD7091R_REG_RESULT_CONV_RESULT(val);
 117
 118         return 0;
 119 }
 120
 121 static int ad7091r_read_raw(struct iio_dev *iio_dev,
 122                            struct iio_chan_spec const *chan,
 123                            int *val, int *val2, long m)
 124 {
 125         struct ad7091r_state *st = iio_priv(iio_dev);
 126         unsigned int read_val;
 127         int ret;
 128
 129         mutex_lock(&st->lock);
 130
 131         switch (m) {
 132         case IIO_CHAN_INFO_RAW:
 133                 if (st->mode != AD7091R_MODE_COMMAND) {
 134                         ret = -EBUSY;
 135                         goto unlock;
 136                 }
 137
 138                 ret = ad7091r_read_one(iio_dev, chan->channel, &read_val);
 139                 if (ret)
 140                         goto unlock;
 141
 142                 *val = read_val;
 143                 ret = IIO_VAL_INT;
 144                 break;
 145
 146         case IIO_CHAN_INFO_SCALE:
 147                 if (st->vref) {
 148                         ret = regulator_get_voltage(st->vref);
 149                         if (ret < 0)
 150                                 goto unlock;
 151
 152                         *val = ret / 1000;
 153                 } else {
 154                         *val = st->chip_info->vref_mV;
 155                 }
 156
 157                 *val2 = chan->scan_type.realbits;
 158                 ret = IIO_VAL_FRACTIONAL_LOG2;
 159                 break;
 160
 161         default:
 162                 ret = -EINVAL;
 163                 break;
 164         }
 165
 166 unlock:
 167         mutex_unlock(&st->lock);
 168         return ret;
 169 }
 170
 171 static const struct iio_info ad7091r_info = {
 172         .read_raw = ad7091r_read_raw,
 173 };
 174
 175 static irqreturn_t ad7091r_event_handler(int irq, void *private)
 176 {
 177         struct ad7091r_state *st = (struct ad7091r_state *) private;
 178         struct iio_dev *iio_dev = dev_get_drvdata(st->dev);
 179         unsigned int i, read_val;
 180         int ret;
 181         s64 timestamp = iio_get_time_ns(iio_dev);
 182
 183         ret = regmap_read(st->map, AD7091R_REG_ALERT, &read_val);
 184         if (ret)
 185                 return IRQ_HANDLED;
 186
 187         for (i = 0; i < st->chip_info->num_channels; i++) {
 188                 if (read_val & BIT(i * 2))
 189                         iio_push_event(iio_dev,
 190                                         IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
 191                                                 IIO_EV_TYPE_THRESH,
 192                                                 IIO_EV_DIR_RISING), timestamp);
 193                 if (read_val & BIT(i * 2 + 1))
 194                         iio_push_event(iio_dev,
 195                                         IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
 196                                                 IIO_EV_TYPE_THRESH,
 197                                                 IIO_EV_DIR_FALLING), timestamp);
 198         }
 199
 200         return IRQ_HANDLED;
 201 }
 202
 203 static void ad7091r_remove(void *data)
 204 {
 205         struct ad7091r_state *st = data;
 206
 207         regulator_disable(st->vref);
 208 }
 209
 210 int ad7091r_probe(struct device *dev, const char *name,
 211                 const struct ad7091r_chip_info *chip_info,
 212                 struct regmap *map, int irq)
 213 {
 214         struct iio_dev *iio_dev;
 215         struct ad7091r_state *st;
 216         int ret;
 217
 218         iio_dev = devm_iio_device_alloc(dev, sizeof(*st));
 219         if (!iio_dev)
 220                 return -ENOMEM;
 221
 222         st = iio_priv(iio_dev);
 223         st->dev = dev;
 224         st->chip_info = chip_info;
 225         st->map = map;
 226
 227         iio_dev->name = name;
 228         iio_dev->info = &ad7091r_info;
 229         iio_dev->modes = INDIO_DIRECT_MODE;
 230
 231         iio_dev->num_channels = chip_info->num_channels;
 232         iio_dev->channels = chip_info->channels;
 233
 234         if (irq) {
 235                 ret = devm_request_threaded_irq(dev, irq, NULL,
 236                                 ad7091r_event_handler,
 237                                 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, name, st);
 238                 if (ret)
 239                         return ret;
 240         }
 241
 242         st->vref = devm_regulator_get_optional(dev, "vref");
 243         if (IS_ERR(st->vref)) {
 244                 if (PTR_ERR(st->vref) == -EPROBE_DEFER)
 245                         return -EPROBE_DEFER;
 246                 st->vref = NULL;
 247         } else {
 248                 ret = regulator_enable(st->vref);
 249                 if (ret)
 250                         return ret;
 251                 ret = devm_add_action_or_reset(dev, ad7091r_remove, st);
 252                 if (ret)
 253                         return ret;
 254         }
 255
 256         /* Use command mode by default to convert only desired channels*/
 257         ret = ad7091r_set_mode(st, AD7091R_MODE_COMMAND);
 258         if (ret)
 259                 return ret;
 260
 261         return devm_iio_device_register(dev, iio_dev);
 262 }
 263 EXPORT_SYMBOL_GPL(ad7091r_probe);
 264
 265 static bool ad7091r_writeable_reg(struct device *dev, unsigned int reg)
 266 {
 267         switch (reg) {
 268         case AD7091R_REG_RESULT:
 269         case AD7091R_REG_ALERT:
 270                 return false;
 271         default:
 272                 return true;
 273         }
 274 }
 275
 276 static bool ad7091r_volatile_reg(struct device *dev, unsigned int reg)
 277 {
 278         switch (reg) {
 279         case AD7091R_REG_RESULT:
 280         case AD7091R_REG_ALERT:
 281                 return true;
 282         default:
 283                 return false;
 284         }
 285 }
 286
 287 const struct regmap_config ad7091r_regmap_config = {
 288         .reg_bits = 8,
 289         .val_bits = 16,
 290         .writeable_reg = ad7091r_writeable_reg,
 291         .volatile_reg = ad7091r_volatile_reg,
 292 };
 293 EXPORT_SYMBOL_GPL(ad7091r_regmap_config);
 294
 295 MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
 296 MODULE_DESCRIPTION("Analog Devices AD7091Rx multi-channel converters");
 297 MODULE_LICENSE("GPL v2");