drivers/iio/adc/lp8788_adc.c

   1 /*
   2  * TI LP8788 MFD - ADC driver
   3  *
   4  * Copyright 2012 Texas Instruments
   5  *
   6  * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/iio/iio.h>
  15 #include <linux/iio/driver.h>
  16 #include <linux/iio/machine.h>
  17 #include <linux/mfd/lp8788.h>
  18 #include <linux/module.h>
  19 #include <linux/mutex.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/slab.h>
  22
  23 /* register address */
  24 #define LP8788_ADC_CONF                 0x60
  25 #define LP8788_ADC_RAW                  0x61
  26 #define LP8788_ADC_DONE                 0x63
  27
  28 #define ADC_CONV_START                  1
  29
  30 struct lp8788_adc {
  31         struct lp8788 *lp;
  32         struct iio_map *map;
  33         struct mutex lock;
  34 };
  35
  36 static const int lp8788_scale[LPADC_MAX] = {
  37         [LPADC_VBATT_5P5] = 1343101,
  38         [LPADC_VIN_CHG]   = 3052503,
  39         [LPADC_IBATT]     = 610500,
  40         [LPADC_IC_TEMP]   = 61050,
  41         [LPADC_VBATT_6P0] = 1465201,
  42         [LPADC_VBATT_5P0] = 1221001,
  43         [LPADC_ADC1]      = 610500,
  44         [LPADC_ADC2]      = 610500,
  45         [LPADC_VDD]       = 1025641,
  46         [LPADC_VCOIN]     = 757020,
  47         [LPADC_ADC3]      = 610500,
  48         [LPADC_ADC4]      = 610500,
  49 };
  50
  51 static int lp8788_get_adc_result(struct lp8788_adc *adc, enum lp8788_adc_id id,
  52                                 int *val)
  53 {
  54         unsigned int msb;
  55         unsigned int lsb;
  56         unsigned int result;
  57         u8 data;
  58         u8 rawdata[2];
  59         int size = ARRAY_SIZE(rawdata);
  60         int retry = 5;
  61         int ret;
  62
  63         data = (id << 1) | ADC_CONV_START;
  64         ret = lp8788_write_byte(adc->lp, LP8788_ADC_CONF, data);
  65         if (ret)
  66                 goto err_io;
  67
  68         /* retry until adc conversion is done */
  69         data = 0;
  70         while (retry--) {
  71                 usleep_range(100, 200);
  72
  73                 ret = lp8788_read_byte(adc->lp, LP8788_ADC_DONE, &data);
  74                 if (ret)
  75                         goto err_io;
  76
  77                 /* conversion done */
  78                 if (data)
  79                         break;
  80         }
  81
  82         ret = lp8788_read_multi_bytes(adc->lp, LP8788_ADC_RAW, rawdata, size);
  83         if (ret)
  84                 goto err_io;
  85
  86         msb = (rawdata[0] << 4) & 0x00000ff0;
  87         lsb = (rawdata[1] >> 4) & 0x0000000f;
  88         result = msb | lsb;
  89         *val = result;
  90
  91         return 0;
  92
  93 err_io:
  94         return ret;
  95 }
  96
  97 static int lp8788_adc_read_raw(struct iio_dev *indio_dev,
  98                         struct iio_chan_spec const *chan,
  99                         int *val, int *val2, long mask)
 100 {
 101         struct lp8788_adc *adc = iio_priv(indio_dev);
 102         enum lp8788_adc_id id = chan->channel;
 103         int ret;
 104
 105         mutex_lock(&adc->lock);
 106
 107         switch (mask) {
 108         case IIO_CHAN_INFO_RAW:
 109                 ret = lp8788_get_adc_result(adc, id, val) ? -EIO : IIO_VAL_INT;
 110                 break;
 111         case IIO_CHAN_INFO_SCALE:
 112                 *val = lp8788_scale[id] / 1000000;
 113                 *val2 = lp8788_scale[id] % 1000000;
 114                 ret = IIO_VAL_INT_PLUS_MICRO;
 115                 break;
 116         default:
 117                 ret = -EINVAL;
 118                 break;
 119         }
 120
 121         mutex_unlock(&adc->lock);
 122
 123         return ret;
 124 }
 125
 126 static const struct iio_info lp8788_adc_info = {
 127         .read_raw = &lp8788_adc_read_raw,
 128         .driver_module = THIS_MODULE,
 129 };
 130
 131 #define LP8788_CHAN(_id, _type) {                               \
 132                 .type = _type,                                  \
 133                 .indexed = 1,                                   \
 134                 .channel = LPADC_##_id,                         \
 135                 .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |   \
 136                         IIO_CHAN_INFO_SCALE_SEPARATE_BIT,       \
 137                 .datasheet_name = #_id,                         \
 138 }
 139
 140 static const struct iio_chan_spec lp8788_adc_channels[] = {
 141         [LPADC_VBATT_5P5] = LP8788_CHAN(VBATT_5P5, IIO_VOLTAGE),
 142         [LPADC_VIN_CHG]   = LP8788_CHAN(VIN_CHG, IIO_VOLTAGE),
 143         [LPADC_IBATT]     = LP8788_CHAN(IBATT, IIO_CURRENT),
 144         [LPADC_IC_TEMP]   = LP8788_CHAN(IC_TEMP, IIO_TEMP),
 145         [LPADC_VBATT_6P0] = LP8788_CHAN(VBATT_6P0, IIO_VOLTAGE),
 146         [LPADC_VBATT_5P0] = LP8788_CHAN(VBATT_5P0, IIO_VOLTAGE),
 147         [LPADC_ADC1]      = LP8788_CHAN(ADC1, IIO_VOLTAGE),
 148         [LPADC_ADC2]      = LP8788_CHAN(ADC2, IIO_VOLTAGE),
 149         [LPADC_VDD]       = LP8788_CHAN(VDD, IIO_VOLTAGE),
 150         [LPADC_VCOIN]     = LP8788_CHAN(VCOIN, IIO_VOLTAGE),
 151         [LPADC_ADC3]      = LP8788_CHAN(ADC3, IIO_VOLTAGE),
 152         [LPADC_ADC4]      = LP8788_CHAN(ADC4, IIO_VOLTAGE),
 153 };
 154
 155 /* default maps used by iio consumer (lp8788-charger driver) */
 156 static struct iio_map lp8788_default_iio_maps[] = {
 157         {
 158                 .consumer_dev_name = "lp8788-charger",
 159                 .consumer_channel = "lp8788_vbatt_5p0",
 160                 .adc_channel_label = "VBATT_5P0",
 161         },
 162         {
 163                 .consumer_dev_name = "lp8788-charger",
 164                 .consumer_channel = "lp8788_adc1",
 165                 .adc_channel_label = "ADC1",
 166         },
 167         { }
 168 };
 169
 170 static int lp8788_iio_map_register(struct iio_dev *indio_dev,
 171                                 struct lp8788_platform_data *pdata,
 172                                 struct lp8788_adc *adc)
 173 {
 174         struct iio_map *map;
 175         int ret;
 176
 177         map = (!pdata || !pdata->adc_pdata) ?
 178                 lp8788_default_iio_maps : pdata->adc_pdata;
 179
 180         ret = iio_map_array_register(indio_dev, map);
 181         if (ret) {
 182                 dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
 183                 return ret;
 184         }
 185
 186         adc->map = map;
 187         return 0;
 188 }
 189
 190 static int lp8788_adc_probe(struct platform_device *pdev)
 191 {
 192         struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
 193         struct iio_dev *indio_dev;
 194         struct lp8788_adc *adc;
 195         int ret;
 196
 197         indio_dev = iio_device_alloc(sizeof(*adc));
 198         if (!indio_dev)
 199                 return -ENOMEM;
 200
 201         adc = iio_priv(indio_dev);
 202         adc->lp = lp;
 203         platform_set_drvdata(pdev, indio_dev);
 204
 205         indio_dev->dev.of_node = pdev->dev.of_node;
 206         ret = lp8788_iio_map_register(indio_dev, lp->pdata, adc);
 207         if (ret)
 208                 goto err_iio_map;
 209
 210         mutex_init(&adc->lock);
 211
 212         indio_dev->dev.parent = &pdev->dev;
 213         indio_dev->name = pdev->name;
 214         indio_dev->modes = INDIO_DIRECT_MODE;
 215         indio_dev->info = &lp8788_adc_info;
 216         indio_dev->channels = lp8788_adc_channels;
 217         indio_dev->num_channels = ARRAY_SIZE(lp8788_adc_channels);
 218
 219         ret = iio_device_register(indio_dev);
 220         if (ret) {
 221                 dev_err(&pdev->dev, "iio dev register err: %d\n", ret);
 222                 goto err_iio_device;
 223         }
 224
 225         return 0;
 226
 227 err_iio_device:
 228         iio_map_array_unregister(indio_dev);
 229 err_iio_map:
 230         iio_device_free(indio_dev);
 231         return ret;
 232 }
 233
 234 static int lp8788_adc_remove(struct platform_device *pdev)
 235 {
 236         struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 237
 238         iio_device_unregister(indio_dev);
 239         iio_map_array_unregister(indio_dev);
 240         iio_device_free(indio_dev);
 241
 242         return 0;
 243 }
 244
 245 static struct platform_driver lp8788_adc_driver = {
 246         .probe = lp8788_adc_probe,
 247         .remove = lp8788_adc_remove,
 248         .driver = {
 249                 .name = LP8788_DEV_ADC,
 250                 .owner = THIS_MODULE,
 251         },
 252 };
 253 module_platform_driver(lp8788_adc_driver);
 254
 255 MODULE_DESCRIPTION("Texas Instruments LP8788 ADC Driver");
 256 MODULE_AUTHOR("Milo Kim");
 257 MODULE_LICENSE("GPL");
 258 MODULE_ALIAS("platform:lp8788-adc");