drivers/iio/adc/max34408.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * IIO driver for Maxim MAX34409/34408 ADC, 4-Channels/2-Channels, 8bits, I2C
   4  *
   5  * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdf
   6  *
   7  * TODO: ALERT interrupt, Overcurrent delay, Shutdown delay
   8  */
   9
  10 #include <linux/bitfield.h>
  11 #include <linux/init.h>
  12 #include <linux/i2c.h>
  13 #include <linux/module.h>
  14 #include <linux/mod_devicetable.h>
  15 #include <linux/property.h>
  16 #include <linux/regmap.h>
  17
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/types.h>
  20
  21 #define MAX34408_STATUS_REG             0x0
  22 #define MAX34408_CONTROL_REG            0x1
  23 #define MAX34408_OCDELAY_REG            0x2
  24 #define MAX34408_SDDELAY_REG            0x3
  25
  26 #define MAX34408_ADC1_REG               0x4
  27 #define MAX34408_ADC2_REG               0x5
  28 /* ADC3 & ADC4 always returns 0x0 on 34408 */
  29 #define MAX34409_ADC3_REG               0x6
  30 #define MAX34409_ADC4_REG               0x7
  31
  32 #define MAX34408_OCT1_REG               0x8
  33 #define MAX34408_OCT2_REG               0x9
  34 #define MAX34409_OCT3_REG               0xA
  35 #define MAX34409_OCT4_REG               0xB
  36
  37 #define MAX34408_DID_REG                0xC
  38 #define MAX34408_DCYY_REG               0xD
  39 #define MAX34408_DCWW_REG               0xE
  40
  41 /* Bit masks for status register */
  42 #define MAX34408_STATUS_OC_MSK          GENMASK(1, 0)
  43 #define MAX34409_STATUS_OC_MSK          GENMASK(3, 0)
  44 #define MAX34408_STATUS_SHTDN           BIT(4)
  45 #define MAX34408_STATUS_ENA             BIT(5)
  46
  47 /* Bit masks for control register */
  48 #define MAX34408_CONTROL_AVG0           BIT(0)
  49 #define MAX34408_CONTROL_AVG1           BIT(1)
  50 #define MAX34408_CONTROL_AVG2           BIT(2)
  51 #define MAX34408_CONTROL_ALERT          BIT(3)
  52
  53 #define MAX34408_DEFAULT_AVG            0x4
  54
  55 /* Bit masks for over current delay */
  56 #define MAX34408_OCDELAY_OCD_MSK        GENMASK(6, 0)
  57 #define MAX34408_OCDELAY_RESET          BIT(7)
  58
  59 /* Bit masks for shutdown delay */
  60 #define MAX34408_SDDELAY_SHD_MSK        GENMASK(6, 0)
  61 #define MAX34408_SDDELAY_RESET          BIT(7)
  62
  63 #define MAX34408_DEFAULT_RSENSE         1000
  64
  65 /**
  66  * struct max34408_data - max34408/max34409 specific data.
  67  * @regmap:     device register map.
  68  * @dev:        max34408 device.
  69  * @lock:       lock for protecting access to device hardware registers, mostly
  70  *              for read modify write cycles for control registers.
  71  * @input_rsense:       Rsense values in uOhm, will be overwritten by
  72  *                      values from channel nodes.
  73  */
  74 struct max34408_data {
  75         struct regmap *regmap;
  76         struct device *dev;
  77         struct mutex lock;
  78         u32 input_rsense[4];
  79 };
  80
  81 static const struct regmap_config max34408_regmap_config = {
  82         .reg_bits       = 8,
  83         .val_bits       = 8,
  84         .max_register   = MAX34408_DCWW_REG,
  85 };
  86
  87 struct max34408_adc_model_data {
  88         const char *model_name;
  89         const struct iio_chan_spec *channels;
  90         const int num_channels;
  91 };
  92
  93 #define MAX34008_CHANNEL(_index, _address)                      \
  94         {                                                       \
  95                 .type = IIO_CURRENT,                            \
  96                 .info_mask_separate     = BIT(IIO_CHAN_INFO_RAW) | \
  97                                           BIT(IIO_CHAN_INFO_SCALE) | \
  98                                           BIT(IIO_CHAN_INFO_OFFSET), \
  99                 .channel = (_index),                            \
 100                 .address = (_address),                          \
 101                 .indexed = 1,                                   \
 102         }
 103
 104 static const struct iio_chan_spec max34408_channels[] = {
 105         MAX34008_CHANNEL(0, MAX34408_ADC1_REG),
 106         MAX34008_CHANNEL(1, MAX34408_ADC2_REG),
 107 };
 108
 109 static const struct iio_chan_spec max34409_channels[] = {
 110         MAX34008_CHANNEL(0, MAX34408_ADC1_REG),
 111         MAX34008_CHANNEL(1, MAX34408_ADC2_REG),
 112         MAX34008_CHANNEL(2, MAX34409_ADC3_REG),
 113         MAX34008_CHANNEL(3, MAX34409_ADC4_REG),
 114 };
 115
 116 static int max34408_read_adc_avg(struct max34408_data *max34408,
 117                                  const struct iio_chan_spec *chan, int *val)
 118 {
 119         unsigned int ctrl;
 120         int rc;
 121
 122         guard(mutex)(&max34408->lock);
 123         rc = regmap_read(max34408->regmap, MAX34408_CONTROL_REG, (u32 *)&ctrl);
 124         if (rc)
 125                 return rc;
 126
 127         /* set averaging (0b100) default values*/
 128         rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG,
 129                           MAX34408_DEFAULT_AVG);
 130         if (rc) {
 131                 dev_err(max34408->dev,
 132                         "Error (%d) writing control register\n", rc);
 133                 return rc;
 134         }
 135
 136         rc = regmap_read(max34408->regmap, chan->address, val);
 137         if (rc)
 138                 return rc;
 139
 140         /* back to old values */
 141         rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG, ctrl);
 142         if (rc)
 143                 dev_err(max34408->dev,
 144                         "Error (%d) writing control register\n", rc);
 145
 146         return rc;
 147 }
 148
 149 static int max34408_read_raw(struct iio_dev *indio_dev,
 150                              struct iio_chan_spec const *chan,
 151                              int *val, int *val2, long mask)
 152 {
 153         struct max34408_data *max34408 = iio_priv(indio_dev);
 154         int rc;
 155
 156         switch (mask) {
 157         case IIO_CHAN_INFO_RAW:
 158                 rc = max34408_read_adc_avg(max34408, chan, val);
 159                 if (rc)
 160                         return rc;
 161                 return IIO_VAL_INT;
 162         case IIO_CHAN_INFO_SCALE:
 163                 /*
 164                  * calculate current for 8bit ADC with Rsense
 165                  * value.
 166                  * 10 mV * 1000 / Rsense uOhm = max current
 167                  * (max current * adc val * 1000) / (2^8 - 1) mA
 168                  */
 169                 *val = 10000 / max34408->input_rsense[chan->channel];
 170                 *val2 = 8;
 171                 return IIO_VAL_FRACTIONAL_LOG2;
 172         default:
 173                 return -EINVAL;
 174         }
 175 }
 176
 177 static const struct iio_info max34408_info = {
 178         .read_raw       = max34408_read_raw,
 179 };
 180
 181 static const struct max34408_adc_model_data max34408_model_data = {
 182         .model_name = "max34408",
 183         .channels = max34408_channels,
 184         .num_channels = 2,
 185 };
 186
 187 static const struct max34408_adc_model_data max34409_model_data = {
 188         .model_name = "max34409",
 189         .channels = max34409_channels,
 190         .num_channels = 4,
 191 };
 192
 193 static int max34408_probe(struct i2c_client *client)
 194 {
 195         const struct max34408_adc_model_data *model_data;
 196         struct device *dev = &client->dev;
 197         struct max34408_data *max34408;
 198         struct fwnode_handle *node;
 199         struct iio_dev *indio_dev;
 200         struct regmap *regmap;
 201         int rc, i = 0;
 202
 203         model_data = i2c_get_match_data(client);
 204         if (!model_data)
 205                 return -EINVAL;
 206
 207         regmap = devm_regmap_init_i2c(client, &max34408_regmap_config);
 208         if (IS_ERR(regmap)) {
 209                 dev_err_probe(dev, PTR_ERR(regmap),
 210                               "regmap_init failed\n");
 211                 return PTR_ERR(regmap);
 212         }
 213
 214         indio_dev = devm_iio_device_alloc(dev, sizeof(*max34408));
 215         if (!indio_dev)
 216                 return -ENOMEM;
 217
 218         max34408 = iio_priv(indio_dev);
 219         max34408->regmap = regmap;
 220         max34408->dev = dev;
 221         mutex_init(&max34408->lock);
 222
 223         device_for_each_child_node(dev, node) {
 224                 fwnode_property_read_u32(node, "maxim,rsense-val-micro-ohms",
 225                                          &max34408->input_rsense[i]);
 226                 i++;
 227         }
 228
 229         /* disable ALERT and averaging */
 230         rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG, 0x0);
 231         if (rc)
 232                 return rc;
 233
 234         indio_dev->channels = model_data->channels;
 235         indio_dev->num_channels = model_data->num_channels;
 236         indio_dev->name = model_data->model_name;
 237
 238         indio_dev->info = &max34408_info;
 239         indio_dev->modes = INDIO_DIRECT_MODE;
 240
 241         return devm_iio_device_register(dev, indio_dev);
 242 }
 243
 244 static const struct of_device_id max34408_of_match[] = {
 245         {
 246                 .compatible = "maxim,max34408",
 247                 .data = &max34408_model_data,
 248         },
 249         {
 250                 .compatible = "maxim,max34409",
 251                 .data = &max34409_model_data,
 252         },
 253         { }
 254 };
 255 MODULE_DEVICE_TABLE(of, max34408_of_match);
 256
 257 static const struct i2c_device_id max34408_id[] = {
 258         { "max34408", (kernel_ulong_t)&max34408_model_data },
 259         { "max34409", (kernel_ulong_t)&max34409_model_data },
 260         { }
 261 };
 262 MODULE_DEVICE_TABLE(i2c, max34408_id);
 263
 264 static struct i2c_driver max34408_driver = {
 265         .driver = {
 266                 .name   = "max34408",
 267                 .of_match_table = max34408_of_match,
 268         },
 269         .probe = max34408_probe,
 270         .id_table = max34408_id,
 271 };
 272 module_i2c_driver(max34408_driver);
 273
 274 MODULE_AUTHOR("Ivan Mikhaylov <fr0st61te@gmail.com>");
 275 MODULE_DESCRIPTION("Maxim MAX34408/34409 ADC driver");
 276 MODULE_LICENSE("GPL");