drivers/iio/adc/lp8788_adc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * TI LP8788 MFD - ADC driver
   4  *
   5  * Copyright 2012 Texas Instruments
   6  *
   7  * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
   8  */
   9
  10 #include <linux/delay.h>
  11 #include <linux/iio/iio.h>
  12 #include <linux/iio/driver.h>
  13 #include <linux/iio/machine.h>
  14 #include <linux/mfd/lp8788.h>
  15 #include <linux/module.h>
  16 #include <linux/mutex.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/slab.h>
  19
  20 /* register address */
  21 #define LP8788_ADC_CONF                 0x60
  22 #define LP8788_ADC_RAW                  0x61
  23 #define LP8788_ADC_DONE                 0x63
  24
  25 #define ADC_CONV_START                  1
  26
  27 struct lp8788_adc {
  28         struct lp8788 *lp;
  29         const struct iio_map *map;
  30         struct mutex lock;
  31 };
  32
  33 static const int lp8788_scale[LPADC_MAX] = {
  34         [LPADC_VBATT_5P5] = 1343101,
  35         [LPADC_VIN_CHG]   = 3052503,
  36         [LPADC_IBATT]     = 610500,
  37         [LPADC_IC_TEMP]   = 61050,
  38         [LPADC_VBATT_6P0] = 1465201,
  39         [LPADC_VBATT_5P0] = 1221001,
  40         [LPADC_ADC1]      = 610500,
  41         [LPADC_ADC2]      = 610500,
  42         [LPADC_VDD]       = 1025641,
  43         [LPADC_VCOIN]     = 757020,
  44         [LPADC_ADC3]      = 610500,
  45         [LPADC_ADC4]      = 610500,
  46 };
  47
  48 static int lp8788_get_adc_result(struct lp8788_adc *adc, enum lp8788_adc_id id,
  49                                 int *val)
  50 {
  51         unsigned int msb;
  52         unsigned int lsb;
  53         unsigned int result;
  54         u8 data;
  55         u8 rawdata[2];
  56         int size = ARRAY_SIZE(rawdata);
  57         int retry = 5;
  58         int ret;
  59
  60         data = (id << 1) | ADC_CONV_START;
  61         ret = lp8788_write_byte(adc->lp, LP8788_ADC_CONF, data);
  62         if (ret)
  63                 goto err_io;
  64
  65         /* retry until adc conversion is done */
  66         data = 0;
  67         while (retry--) {
  68                 usleep_range(100, 200);
  69
  70                 ret = lp8788_read_byte(adc->lp, LP8788_ADC_DONE, &data);
  71                 if (ret)
  72                         goto err_io;
  73
  74                 /* conversion done */
  75                 if (data)
  76                         break;
  77         }
  78
  79         ret = lp8788_read_multi_bytes(adc->lp, LP8788_ADC_RAW, rawdata, size);
  80         if (ret)
  81                 goto err_io;
  82
  83         msb = (rawdata[0] << 4) & 0x00000ff0;
  84         lsb = (rawdata[1] >> 4) & 0x0000000f;
  85         result = msb | lsb;
  86         *val = result;
  87
  88         return 0;
  89
  90 err_io:
  91         return ret;
  92 }
  93
  94 static int lp8788_adc_read_raw(struct iio_dev *indio_dev,
  95                         struct iio_chan_spec const *chan,
  96                         int *val, int *val2, long mask)
  97 {
  98         struct lp8788_adc *adc = iio_priv(indio_dev);
  99         enum lp8788_adc_id id = chan->channel;
 100         int ret;
 101
 102         mutex_lock(&adc->lock);
 103
 104         switch (mask) {
 105         case IIO_CHAN_INFO_RAW:
 106                 ret = lp8788_get_adc_result(adc, id, val) ? -EIO : IIO_VAL_INT;
 107                 break;
 108         case IIO_CHAN_INFO_SCALE:
 109                 *val = lp8788_scale[id] / 1000000;
 110                 *val2 = lp8788_scale[id] % 1000000;
 111                 ret = IIO_VAL_INT_PLUS_MICRO;
 112                 break;
 113         default:
 114                 ret = -EINVAL;
 115                 break;
 116         }
 117
 118         mutex_unlock(&adc->lock);
 119
 120         return ret;
 121 }
 122
 123 static const struct iio_info lp8788_adc_info = {
 124         .read_raw = &lp8788_adc_read_raw,
 125 };
 126
 127 #define LP8788_CHAN(_id, _type) {                               \
 128                 .type = _type,                                  \
 129                 .indexed = 1,                                   \
 130                 .channel = LPADC_##_id,                         \
 131                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
 132                         BIT(IIO_CHAN_INFO_SCALE),               \
 133                 .datasheet_name = #_id,                         \
 134 }
 135
 136 static const struct iio_chan_spec lp8788_adc_channels[] = {
 137         [LPADC_VBATT_5P5] = LP8788_CHAN(VBATT_5P5, IIO_VOLTAGE),
 138         [LPADC_VIN_CHG]   = LP8788_CHAN(VIN_CHG, IIO_VOLTAGE),
 139         [LPADC_IBATT]     = LP8788_CHAN(IBATT, IIO_CURRENT),
 140         [LPADC_IC_TEMP]   = LP8788_CHAN(IC_TEMP, IIO_TEMP),
 141         [LPADC_VBATT_6P0] = LP8788_CHAN(VBATT_6P0, IIO_VOLTAGE),
 142         [LPADC_VBATT_5P0] = LP8788_CHAN(VBATT_5P0, IIO_VOLTAGE),
 143         [LPADC_ADC1]      = LP8788_CHAN(ADC1, IIO_VOLTAGE),
 144         [LPADC_ADC2]      = LP8788_CHAN(ADC2, IIO_VOLTAGE),
 145         [LPADC_VDD]       = LP8788_CHAN(VDD, IIO_VOLTAGE),
 146         [LPADC_VCOIN]     = LP8788_CHAN(VCOIN, IIO_VOLTAGE),
 147         [LPADC_ADC3]      = LP8788_CHAN(ADC3, IIO_VOLTAGE),
 148         [LPADC_ADC4]      = LP8788_CHAN(ADC4, IIO_VOLTAGE),
 149 };
 150
 151 /* default maps used by iio consumer (lp8788-charger driver) */
 152 static const struct iio_map lp8788_default_iio_maps[] = {
 153         IIO_MAP("VBATT_5P0", "lp8788-charger", "lp8788_vbatt_5p0"),
 154         IIO_MAP("ADC1", "lp8788-charger", "lp8788_adc1"),
 155         { }
 156 };
 157
 158 static int lp8788_iio_map_register(struct device *dev,
 159                                 struct iio_dev *indio_dev,
 160                                 struct lp8788_platform_data *pdata,
 161                                 struct lp8788_adc *adc)
 162 {
 163         const struct iio_map *map;
 164         int ret;
 165
 166         map = (!pdata || !pdata->adc_pdata) ?
 167                 lp8788_default_iio_maps : pdata->adc_pdata;
 168
 169         ret = devm_iio_map_array_register(dev, indio_dev, map);
 170         if (ret) {
 171                 dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
 172                 return ret;
 173         }
 174
 175         adc->map = map;
 176         return 0;
 177 }
 178
 179 static int lp8788_adc_probe(struct platform_device *pdev)
 180 {
 181         struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
 182         struct iio_dev *indio_dev;
 183         struct lp8788_adc *adc;
 184         int ret;
 185
 186         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
 187         if (!indio_dev)
 188                 return -ENOMEM;
 189
 190         adc = iio_priv(indio_dev);
 191         adc->lp = lp;
 192
 193         ret = lp8788_iio_map_register(&pdev->dev, indio_dev, lp->pdata, adc);
 194         if (ret)
 195                 return ret;
 196
 197         mutex_init(&adc->lock);
 198
 199         indio_dev->name = pdev->name;
 200         indio_dev->modes = INDIO_DIRECT_MODE;
 201         indio_dev->info = &lp8788_adc_info;
 202         indio_dev->channels = lp8788_adc_channels;
 203         indio_dev->num_channels = ARRAY_SIZE(lp8788_adc_channels);
 204
 205         return devm_iio_device_register(&pdev->dev, indio_dev);
 206 }
 207
 208 static struct platform_driver lp8788_adc_driver = {
 209         .probe = lp8788_adc_probe,
 210         .driver = {
 211                 .name = LP8788_DEV_ADC,
 212         },
 213 };
 214 module_platform_driver(lp8788_adc_driver);
 215
 216 MODULE_DESCRIPTION("Texas Instruments LP8788 ADC Driver");
 217 MODULE_AUTHOR("Milo Kim");
 218 MODULE_LICENSE("GPL");
 219 MODULE_ALIAS("platform:lp8788-adc");