drivers/iio/adc/ltc2497-core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ltc2497-core.c - Common code for Analog Devices/Linear Technology
   4  * LTC2496 and LTC2497 ADCs
   5  *
   6  * Copyright (C) 2017 Analog Devices Inc.
   7  */
   8
   9 #include <linux/delay.h>
  10 #include <linux/iio/iio.h>
  11 #include <linux/iio/driver.h>
  12 #include <linux/module.h>
  13 #include <linux/regulator/consumer.h>
  14
  15 #include "ltc2497.h"
  16
  17 #define LTC2497_SGL                     BIT(4)
  18 #define LTC2497_DIFF                    0
  19 #define LTC2497_SIGN                    BIT(3)
  20
  21 static int ltc2497core_wait_conv(struct ltc2497core_driverdata *ddata)
  22 {
  23         s64 time_elapsed;
  24
  25         time_elapsed = ktime_ms_delta(ktime_get(), ddata->time_prev);
  26
  27         if (time_elapsed < LTC2497_CONVERSION_TIME_MS) {
  28                 /* delay if conversion time not passed
  29                  * since last read or write
  30                  */
  31                 if (msleep_interruptible(
  32                     LTC2497_CONVERSION_TIME_MS - time_elapsed))
  33                         return -ERESTARTSYS;
  34
  35                 return 0;
  36         }
  37
  38         if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) {
  39                 /* We're in automatic mode -
  40                  * so the last reading is still not outdated
  41                  */
  42                 return 0;
  43         }
  44
  45         return 1;
  46 }
  47
  48 static int ltc2497core_read(struct ltc2497core_driverdata *ddata, u8 address, int *val)
  49 {
  50         int ret;
  51
  52         ret = ltc2497core_wait_conv(ddata);
  53         if (ret < 0)
  54                 return ret;
  55
  56         if (ret || ddata->addr_prev != address) {
  57                 ret = ddata->result_and_measure(ddata, address, NULL);
  58                 if (ret < 0)
  59                         return ret;
  60                 ddata->addr_prev = address;
  61
  62                 if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS))
  63                         return -ERESTARTSYS;
  64         }
  65
  66         ret = ddata->result_and_measure(ddata, address, val);
  67         if (ret < 0)
  68                 return ret;
  69
  70         ddata->time_prev = ktime_get();
  71
  72         return ret;
  73 }
  74
  75 static int ltc2497core_read_raw(struct iio_dev *indio_dev,
  76                             struct iio_chan_spec const *chan,
  77                             int *val, int *val2, long mask)
  78 {
  79         struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
  80         int ret;
  81
  82         switch (mask) {
  83         case IIO_CHAN_INFO_RAW:
  84                 mutex_lock(&indio_dev->mlock);
  85                 ret = ltc2497core_read(ddata, chan->address, val);
  86                 mutex_unlock(&indio_dev->mlock);
  87                 if (ret < 0)
  88                         return ret;
  89
  90                 return IIO_VAL_INT;
  91
  92         case IIO_CHAN_INFO_SCALE:
  93                 ret = regulator_get_voltage(ddata->ref);
  94                 if (ret < 0)
  95                         return ret;
  96
  97                 *val = ret / 1000;
  98                 *val2 = 17;
  99
 100                 return IIO_VAL_FRACTIONAL_LOG2;
 101
 102         default:
 103                 return -EINVAL;
 104         }
 105 }
 106
 107 #define LTC2497_CHAN(_chan, _addr, _ds_name) { \
 108         .type = IIO_VOLTAGE, \
 109         .indexed = 1, \
 110         .channel = (_chan), \
 111         .address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \
 112         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 113         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 114         .datasheet_name = (_ds_name), \
 115 }
 116
 117 #define LTC2497_CHAN_DIFF(_chan, _addr) { \
 118         .type = IIO_VOLTAGE, \
 119         .indexed = 1, \
 120         .channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \
 121         .channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\
 122         .address = (_addr | _chan), \
 123         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 124         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 125         .differential = 1, \
 126 }
 127
 128 static const struct iio_chan_spec ltc2497core_channel[] = {
 129         LTC2497_CHAN(0, LTC2497_SGL, "CH0"),
 130         LTC2497_CHAN(1, LTC2497_SGL, "CH1"),
 131         LTC2497_CHAN(2, LTC2497_SGL, "CH2"),
 132         LTC2497_CHAN(3, LTC2497_SGL, "CH3"),
 133         LTC2497_CHAN(4, LTC2497_SGL, "CH4"),
 134         LTC2497_CHAN(5, LTC2497_SGL, "CH5"),
 135         LTC2497_CHAN(6, LTC2497_SGL, "CH6"),
 136         LTC2497_CHAN(7, LTC2497_SGL, "CH7"),
 137         LTC2497_CHAN(8, LTC2497_SGL, "CH8"),
 138         LTC2497_CHAN(9, LTC2497_SGL, "CH9"),
 139         LTC2497_CHAN(10, LTC2497_SGL, "CH10"),
 140         LTC2497_CHAN(11, LTC2497_SGL, "CH11"),
 141         LTC2497_CHAN(12, LTC2497_SGL, "CH12"),
 142         LTC2497_CHAN(13, LTC2497_SGL, "CH13"),
 143         LTC2497_CHAN(14, LTC2497_SGL, "CH14"),
 144         LTC2497_CHAN(15, LTC2497_SGL, "CH15"),
 145         LTC2497_CHAN_DIFF(0, LTC2497_DIFF),
 146         LTC2497_CHAN_DIFF(1, LTC2497_DIFF),
 147         LTC2497_CHAN_DIFF(2, LTC2497_DIFF),
 148         LTC2497_CHAN_DIFF(3, LTC2497_DIFF),
 149         LTC2497_CHAN_DIFF(4, LTC2497_DIFF),
 150         LTC2497_CHAN_DIFF(5, LTC2497_DIFF),
 151         LTC2497_CHAN_DIFF(6, LTC2497_DIFF),
 152         LTC2497_CHAN_DIFF(7, LTC2497_DIFF),
 153         LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN),
 154         LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN),
 155         LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN),
 156         LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN),
 157         LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN),
 158         LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN),
 159         LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN),
 160         LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN),
 161 };
 162
 163 static const struct iio_info ltc2497core_info = {
 164         .read_raw = ltc2497core_read_raw,
 165 };
 166
 167 int ltc2497core_probe(struct device *dev, struct iio_dev *indio_dev)
 168 {
 169         struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
 170         int ret;
 171
 172         indio_dev->name = dev_name(dev);
 173         indio_dev->info = &ltc2497core_info;
 174         indio_dev->modes = INDIO_DIRECT_MODE;
 175         indio_dev->channels = ltc2497core_channel;
 176         indio_dev->num_channels = ARRAY_SIZE(ltc2497core_channel);
 177
 178         ret = ddata->result_and_measure(ddata, LTC2497_CONFIG_DEFAULT, NULL);
 179         if (ret < 0)
 180                 return ret;
 181
 182         ddata->ref = devm_regulator_get(dev, "vref");
 183         if (IS_ERR(ddata->ref))
 184                 return dev_err_probe(dev, PTR_ERR(ddata->ref),
 185                                      "Failed to get vref regulator\n");
 186
 187         ret = regulator_enable(ddata->ref);
 188         if (ret < 0) {
 189                 dev_err(dev, "Failed to enable vref regulator: %pe\n",
 190                         ERR_PTR(ret));
 191                 return ret;
 192         }
 193
 194         if (dev->platform_data) {
 195                 struct iio_map *plat_data;
 196
 197                 plat_data = (struct iio_map *)dev->platform_data;
 198
 199                 ret = iio_map_array_register(indio_dev, plat_data);
 200                 if (ret) {
 201                         dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
 202                         goto err_regulator_disable;
 203                 }
 204         }
 205
 206         ddata->addr_prev = LTC2497_CONFIG_DEFAULT;
 207         ddata->time_prev = ktime_get();
 208
 209         ret = iio_device_register(indio_dev);
 210         if (ret < 0)
 211                 goto err_array_unregister;
 212
 213         return 0;
 214
 215 err_array_unregister:
 216         iio_map_array_unregister(indio_dev);
 217
 218 err_regulator_disable:
 219         regulator_disable(ddata->ref);
 220
 221         return ret;
 222 }
 223 EXPORT_SYMBOL_NS(ltc2497core_probe, LTC2497);
 224
 225 void ltc2497core_remove(struct iio_dev *indio_dev)
 226 {
 227         struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
 228
 229         iio_device_unregister(indio_dev);
 230
 231         iio_map_array_unregister(indio_dev);
 232
 233         regulator_disable(ddata->ref);
 234 }
 235 EXPORT_SYMBOL_NS(ltc2497core_remove, LTC2497);
 236
 237 MODULE_DESCRIPTION("common code for LTC2496/LTC2497 drivers");
 238 MODULE_LICENSE("GPL v2");