drivers/iio/adc/axp288_adc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * axp288_adc.c - X-Powers AXP288 PMIC ADC Driver
   4  *
   5  * Copyright (C) 2014 Intel Corporation
   6  *
   7  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/device.h>
  13 #include <linux/regmap.h>
  14 #include <linux/mfd/axp20x.h>
  15 #include <linux/platform_device.h>
  16
  17 #include <linux/iio/iio.h>
  18 #include <linux/iio/machine.h>
  19 #include <linux/iio/driver.h>
  20
  21 /*
  22  * This mask enables all ADCs except for the battery temp-sensor (TS), that is
  23  * left as-is to avoid breaking charging on devices without a temp-sensor.
  24  */
  25 #define AXP288_ADC_EN_MASK                              0xF0
  26 #define AXP288_ADC_TS_ENABLE                            0x01
  27
  28 #define AXP288_ADC_TS_CURRENT_ON_OFF_MASK               GENMASK(1, 0)
  29 #define AXP288_ADC_TS_CURRENT_OFF                       (0 << 0)
  30 #define AXP288_ADC_TS_CURRENT_ON_WHEN_CHARGING          (1 << 0)
  31 #define AXP288_ADC_TS_CURRENT_ON_ONDEMAND               (2 << 0)
  32 #define AXP288_ADC_TS_CURRENT_ON                        (3 << 0)
  33
  34 enum axp288_adc_id {
  35         AXP288_ADC_TS,
  36         AXP288_ADC_PMIC,
  37         AXP288_ADC_GP,
  38         AXP288_ADC_BATT_CHRG_I,
  39         AXP288_ADC_BATT_DISCHRG_I,
  40         AXP288_ADC_BATT_V,
  41         AXP288_ADC_NR_CHAN,
  42 };
  43
  44 struct axp288_adc_info {
  45         int irq;
  46         struct regmap *regmap;
  47         bool ts_enabled;
  48 };
  49
  50 static const struct iio_chan_spec axp288_adc_channels[] = {
  51         {
  52                 .indexed = 1,
  53                 .type = IIO_TEMP,
  54                 .channel = 0,
  55                 .address = AXP288_TS_ADC_H,
  56                 .datasheet_name = "TS_PIN",
  57                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  58         }, {
  59                 .indexed = 1,
  60                 .type = IIO_TEMP,
  61                 .channel = 1,
  62                 .address = AXP288_PMIC_ADC_H,
  63                 .datasheet_name = "PMIC_TEMP",
  64                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  65         }, {
  66                 .indexed = 1,
  67                 .type = IIO_TEMP,
  68                 .channel = 2,
  69                 .address = AXP288_GP_ADC_H,
  70                 .datasheet_name = "GPADC",
  71                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  72         }, {
  73                 .indexed = 1,
  74                 .type = IIO_CURRENT,
  75                 .channel = 3,
  76                 .address = AXP20X_BATT_CHRG_I_H,
  77                 .datasheet_name = "BATT_CHG_I",
  78                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  79         }, {
  80                 .indexed = 1,
  81                 .type = IIO_CURRENT,
  82                 .channel = 4,
  83                 .address = AXP20X_BATT_DISCHRG_I_H,
  84                 .datasheet_name = "BATT_DISCHRG_I",
  85                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  86         }, {
  87                 .indexed = 1,
  88                 .type = IIO_VOLTAGE,
  89                 .channel = 5,
  90                 .address = AXP20X_BATT_V_H,
  91                 .datasheet_name = "BATT_V",
  92                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  93         },
  94 };
  95
  96 /* for consumer drivers */
  97 static struct iio_map axp288_adc_default_maps[] = {
  98         IIO_MAP("TS_PIN", "axp288-batt", "axp288-batt-temp"),
  99         IIO_MAP("PMIC_TEMP", "axp288-pmic", "axp288-pmic-temp"),
 100         IIO_MAP("GPADC", "axp288-gpadc", "axp288-system-temp"),
 101         IIO_MAP("BATT_CHG_I", "axp288-chrg", "axp288-chrg-curr"),
 102         IIO_MAP("BATT_DISCHRG_I", "axp288-chrg", "axp288-chrg-d-curr"),
 103         IIO_MAP("BATT_V", "axp288-batt", "axp288-batt-volt"),
 104         {},
 105 };
 106
 107 static int axp288_adc_read_channel(int *val, unsigned long address,
 108                                 struct regmap *regmap)
 109 {
 110         u8 buf[2];
 111
 112         if (regmap_bulk_read(regmap, address, buf, 2))
 113                 return -EIO;
 114         *val = (buf[0] << 4) + ((buf[1] >> 4) & 0x0F);
 115
 116         return IIO_VAL_INT;
 117 }
 118
 119 /*
 120  * The current-source used for the battery temp-sensor (TS) is shared
 121  * with the GPADC. For proper fuel-gauge and charger operation the TS
 122  * current-source needs to be permanently on. But to read the GPADC we
 123  * need to temporary switch the TS current-source to ondemand, so that
 124  * the GPADC can use it, otherwise we will always read an all 0 value.
 125  */
 126 static int axp288_adc_set_ts(struct axp288_adc_info *info,
 127                              unsigned int mode, unsigned long address)
 128 {
 129         int ret;
 130
 131         /* No need to switch the current-source if the TS pin is disabled */
 132         if (!info->ts_enabled)
 133                 return 0;
 134
 135         /* Channels other than GPADC do not need the current source */
 136         if (address != AXP288_GP_ADC_H)
 137                 return 0;
 138
 139         ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
 140                                  AXP288_ADC_TS_CURRENT_ON_OFF_MASK, mode);
 141         if (ret)
 142                 return ret;
 143
 144         /* When switching to the GPADC pin give things some time to settle */
 145         if (mode == AXP288_ADC_TS_CURRENT_ON_ONDEMAND)
 146                 usleep_range(6000, 10000);
 147
 148         return 0;
 149 }
 150
 151 static int axp288_adc_read_raw(struct iio_dev *indio_dev,
 152                         struct iio_chan_spec const *chan,
 153                         int *val, int *val2, long mask)
 154 {
 155         int ret;
 156         struct axp288_adc_info *info = iio_priv(indio_dev);
 157
 158         mutex_lock(&indio_dev->mlock);
 159         switch (mask) {
 160         case IIO_CHAN_INFO_RAW:
 161                 if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON_ONDEMAND,
 162                                         chan->address)) {
 163                         dev_err(&indio_dev->dev, "GPADC mode\n");
 164                         ret = -EINVAL;
 165                         break;
 166                 }
 167                 ret = axp288_adc_read_channel(val, chan->address, info->regmap);
 168                 if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON,
 169                                                 chan->address))
 170                         dev_err(&indio_dev->dev, "TS pin restore\n");
 171                 break;
 172         default:
 173                 ret = -EINVAL;
 174         }
 175         mutex_unlock(&indio_dev->mlock);
 176
 177         return ret;
 178 }
 179
 180 static int axp288_adc_initialize(struct axp288_adc_info *info)
 181 {
 182         int ret, adc_enable_val;
 183
 184         /*
 185          * Determine if the TS pin is enabled and set the TS current-source
 186          * accordingly.
 187          */
 188         ret = regmap_read(info->regmap, AXP20X_ADC_EN1, &adc_enable_val);
 189         if (ret)
 190                 return ret;
 191
 192         if (adc_enable_val & AXP288_ADC_TS_ENABLE) {
 193                 info->ts_enabled = true;
 194                 ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
 195                                          AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
 196                                          AXP288_ADC_TS_CURRENT_ON);
 197         } else {
 198                 info->ts_enabled = false;
 199                 ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
 200                                          AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
 201                                          AXP288_ADC_TS_CURRENT_OFF);
 202         }
 203         if (ret)
 204                 return ret;
 205
 206         /* Turn on the ADC for all channels except TS, leave TS as is */
 207         return regmap_update_bits(info->regmap, AXP20X_ADC_EN1,
 208                                   AXP288_ADC_EN_MASK, AXP288_ADC_EN_MASK);
 209 }
 210
 211 static const struct iio_info axp288_adc_iio_info = {
 212         .read_raw = &axp288_adc_read_raw,
 213 };
 214
 215 static int axp288_adc_probe(struct platform_device *pdev)
 216 {
 217         int ret;
 218         struct axp288_adc_info *info;
 219         struct iio_dev *indio_dev;
 220         struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
 221
 222         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
 223         if (!indio_dev)
 224                 return -ENOMEM;
 225
 226         info = iio_priv(indio_dev);
 227         info->irq = platform_get_irq(pdev, 0);
 228         if (info->irq < 0) {
 229                 dev_err(&pdev->dev, "no irq resource?\n");
 230                 return info->irq;
 231         }
 232         platform_set_drvdata(pdev, indio_dev);
 233         info->regmap = axp20x->regmap;
 234         /*
 235          * Set ADC to enabled state at all time, including system suspend.
 236          * otherwise internal fuel gauge functionality may be affected.
 237          */
 238         ret = axp288_adc_initialize(info);
 239         if (ret) {
 240                 dev_err(&pdev->dev, "unable to enable ADC device\n");
 241                 return ret;
 242         }
 243
 244         indio_dev->dev.parent = &pdev->dev;
 245         indio_dev->name = pdev->name;
 246         indio_dev->channels = axp288_adc_channels;
 247         indio_dev->num_channels = ARRAY_SIZE(axp288_adc_channels);
 248         indio_dev->info = &axp288_adc_iio_info;
 249         indio_dev->modes = INDIO_DIRECT_MODE;
 250         ret = iio_map_array_register(indio_dev, axp288_adc_default_maps);
 251         if (ret < 0)
 252                 return ret;
 253
 254         ret = iio_device_register(indio_dev);
 255         if (ret < 0) {
 256                 dev_err(&pdev->dev, "unable to register iio device\n");
 257                 goto err_array_unregister;
 258         }
 259         return 0;
 260
 261 err_array_unregister:
 262         iio_map_array_unregister(indio_dev);
 263
 264         return ret;
 265 }
 266
 267 static int axp288_adc_remove(struct platform_device *pdev)
 268 {
 269         struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 270
 271         iio_device_unregister(indio_dev);
 272         iio_map_array_unregister(indio_dev);
 273
 274         return 0;
 275 }
 276
 277 static const struct platform_device_id axp288_adc_id_table[] = {
 278         { .name = "axp288_adc" },
 279         {},
 280 };
 281
 282 static struct platform_driver axp288_adc_driver = {
 283         .probe = axp288_adc_probe,
 284         .remove = axp288_adc_remove,
 285         .id_table = axp288_adc_id_table,
 286         .driver = {
 287                 .name = "axp288_adc",
 288         },
 289 };
 290
 291 MODULE_DEVICE_TABLE(platform, axp288_adc_id_table);
 292
 293 module_platform_driver(axp288_adc_driver);
 294
 295 MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
 296 MODULE_DESCRIPTION("X-Powers AXP288 ADC Driver");
 297 MODULE_LICENSE("GPL");