drivers/iio/amplifiers/ad8366.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AD8366 SPI Dual-Digital Variable Gain Amplifier (VGA)
   4  *
   5  * Copyright 2012 Analog Devices Inc.
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/kernel.h>
  10 #include <linux/slab.h>
  11 #include <linux/sysfs.h>
  12 #include <linux/spi/spi.h>
  13 #include <linux/regulator/consumer.h>
  14 #include <linux/err.h>
  15 #include <linux/module.h>
  16 #include <linux/bitrev.h>
  17
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/sysfs.h>
  20
  21 struct ad8366_state {
  22         struct spi_device       *spi;
  23         struct regulator        *reg;
  24         unsigned char           ch[2];
  25         /*
  26          * DMA (thus cache coherency maintenance) requires the
  27          * transfer buffers to live in their own cache lines.
  28          */
  29         unsigned char           data[2] ____cacheline_aligned;
  30 };
  31
  32 static int ad8366_write(struct iio_dev *indio_dev,
  33                         unsigned char ch_a, unsigned char ch_b)
  34 {
  35         struct ad8366_state *st = iio_priv(indio_dev);
  36         int ret;
  37
  38         ch_a = bitrev8(ch_a & 0x3F);
  39         ch_b = bitrev8(ch_b & 0x3F);
  40
  41         st->data[0] = ch_b >> 4;
  42         st->data[1] = (ch_b << 4) | (ch_a >> 2);
  43
  44         ret = spi_write(st->spi, st->data, ARRAY_SIZE(st->data));
  45         if (ret < 0)
  46                 dev_err(&indio_dev->dev, "write failed (%d)", ret);
  47
  48         return ret;
  49 }
  50
  51 static int ad8366_read_raw(struct iio_dev *indio_dev,
  52                            struct iio_chan_spec const *chan,
  53                            int *val,
  54                            int *val2,
  55                            long m)
  56 {
  57         struct ad8366_state *st = iio_priv(indio_dev);
  58         int ret;
  59         unsigned code;
  60
  61         mutex_lock(&indio_dev->mlock);
  62         switch (m) {
  63         case IIO_CHAN_INFO_HARDWAREGAIN:
  64                 code = st->ch[chan->channel];
  65
  66                 /* Values in dB */
  67                 code = code * 253 + 4500;
  68                 *val = code / 1000;
  69                 *val2 = (code % 1000) * 1000;
  70
  71                 ret = IIO_VAL_INT_PLUS_MICRO_DB;
  72                 break;
  73         default:
  74                 ret = -EINVAL;
  75         }
  76         mutex_unlock(&indio_dev->mlock);
  77
  78         return ret;
  79 };
  80
  81 static int ad8366_write_raw(struct iio_dev *indio_dev,
  82                             struct iio_chan_spec const *chan,
  83                             int val,
  84                             int val2,
  85                             long mask)
  86 {
  87         struct ad8366_state *st = iio_priv(indio_dev);
  88         unsigned code;
  89         int ret;
  90
  91         if (val < 0 || val2 < 0)
  92                 return -EINVAL;
  93
  94         /* Values in dB */
  95         code = (((u8)val * 1000) + ((u32)val2 / 1000));
  96
  97         if (code > 20500 || code < 4500)
  98                 return -EINVAL;
  99
 100         code = (code - 4500) / 253;
 101
 102         mutex_lock(&indio_dev->mlock);
 103         switch (mask) {
 104         case IIO_CHAN_INFO_HARDWAREGAIN:
 105                 st->ch[chan->channel] = code;
 106                 ret = ad8366_write(indio_dev, st->ch[0], st->ch[1]);
 107                 break;
 108         default:
 109                 ret = -EINVAL;
 110         }
 111         mutex_unlock(&indio_dev->mlock);
 112
 113         return ret;
 114 }
 115
 116 static const struct iio_info ad8366_info = {
 117         .read_raw = &ad8366_read_raw,
 118         .write_raw = &ad8366_write_raw,
 119 };
 120
 121 #define AD8366_CHAN(_channel) {                         \
 122         .type = IIO_VOLTAGE,                            \
 123         .output = 1,                                    \
 124         .indexed = 1,                                   \
 125         .channel = _channel,                            \
 126         .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),\
 127 }
 128
 129 static const struct iio_chan_spec ad8366_channels[] = {
 130         AD8366_CHAN(0),
 131         AD8366_CHAN(1),
 132 };
 133
 134 static int ad8366_probe(struct spi_device *spi)
 135 {
 136         struct iio_dev *indio_dev;
 137         struct ad8366_state *st;
 138         int ret;
 139
 140         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 141         if (indio_dev == NULL)
 142                 return -ENOMEM;
 143
 144         st = iio_priv(indio_dev);
 145
 146         st->reg = devm_regulator_get(&spi->dev, "vcc");
 147         if (!IS_ERR(st->reg)) {
 148                 ret = regulator_enable(st->reg);
 149                 if (ret)
 150                         return ret;
 151         }
 152
 153         spi_set_drvdata(spi, indio_dev);
 154         st->spi = spi;
 155
 156         indio_dev->dev.parent = &spi->dev;
 157         indio_dev->name = spi_get_device_id(spi)->name;
 158         indio_dev->info = &ad8366_info;
 159         indio_dev->modes = INDIO_DIRECT_MODE;
 160         indio_dev->channels = ad8366_channels;
 161         indio_dev->num_channels = ARRAY_SIZE(ad8366_channels);
 162
 163         ret = ad8366_write(indio_dev, 0 , 0);
 164         if (ret < 0)
 165                 goto error_disable_reg;
 166
 167         ret = iio_device_register(indio_dev);
 168         if (ret)
 169                 goto error_disable_reg;
 170
 171         return 0;
 172
 173 error_disable_reg:
 174         if (!IS_ERR(st->reg))
 175                 regulator_disable(st->reg);
 176
 177         return ret;
 178 }
 179
 180 static int ad8366_remove(struct spi_device *spi)
 181 {
 182         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 183         struct ad8366_state *st = iio_priv(indio_dev);
 184         struct regulator *reg = st->reg;
 185
 186         iio_device_unregister(indio_dev);
 187
 188         if (!IS_ERR(reg))
 189                 regulator_disable(reg);
 190
 191         return 0;
 192 }
 193
 194 static const struct spi_device_id ad8366_id[] = {
 195         {"ad8366", 0},
 196         {}
 197 };
 198 MODULE_DEVICE_TABLE(spi, ad8366_id);
 199
 200 static struct spi_driver ad8366_driver = {
 201         .driver = {
 202                 .name   = KBUILD_MODNAME,
 203         },
 204         .probe          = ad8366_probe,
 205         .remove         = ad8366_remove,
 206         .id_table       = ad8366_id,
 207 };
 208
 209 module_spi_driver(ad8366_driver);
 210
 211 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 212 MODULE_DESCRIPTION("Analog Devices AD8366 VGA");
 213 MODULE_LICENSE("GPL v2");