drivers/iio/amplifiers/hmc425a.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * HMC425A and similar Gain Amplifiers
   4  *
   5  * Copyright 2020 Analog Devices Inc.
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/err.h>
  10 #include <linux/gpio/consumer.h>
  11 #include <linux/iio/iio.h>
  12 #include <linux/iio/sysfs.h>
  13 #include <linux/kernel.h>
  14 #include <linux/mod_devicetable.h>
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/property.h>
  18 #include <linux/slab.h>
  19 #include <linux/regulator/consumer.h>
  20 #include <linux/sysfs.h>
  21
  22 enum hmc425a_type {
  23         ID_HMC425A,
  24 };
  25
  26 struct hmc425a_chip_info {
  27         const char                      *name;
  28         const struct iio_chan_spec      *channels;
  29         unsigned int                    num_channels;
  30         unsigned int                    num_gpios;
  31         int                             gain_min;
  32         int                             gain_max;
  33         int                             default_gain;
  34 };
  35
  36 struct hmc425a_state {
  37         struct  mutex lock; /* protect sensor state */
  38         struct  hmc425a_chip_info *chip_info;
  39         struct  gpio_descs *gpios;
  40         enum    hmc425a_type type;
  41         u32     gain;
  42 };
  43
  44 static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
  45 {
  46         struct hmc425a_state *st = iio_priv(indio_dev);
  47         DECLARE_BITMAP(values, BITS_PER_TYPE(value));
  48
  49         values[0] = value;
  50
  51         gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,
  52                                        NULL, values);
  53         return 0;
  54 }
  55
  56 static int hmc425a_read_raw(struct iio_dev *indio_dev,
  57                             struct iio_chan_spec const *chan, int *val,
  58                             int *val2, long m)
  59 {
  60         struct hmc425a_state *st = iio_priv(indio_dev);
  61         int code, gain = 0;
  62         int ret;
  63
  64         mutex_lock(&st->lock);
  65         switch (m) {
  66         case IIO_CHAN_INFO_HARDWAREGAIN:
  67                 code = st->gain;
  68
  69                 switch (st->type) {
  70                 case ID_HMC425A:
  71                         gain = ~code * -500;
  72                         break;
  73                 }
  74
  75                 *val = gain / 1000;
  76                 *val2 = (gain % 1000) * 1000;
  77
  78                 ret = IIO_VAL_INT_PLUS_MICRO_DB;
  79                 break;
  80         default:
  81                 ret = -EINVAL;
  82         }
  83         mutex_unlock(&st->lock);
  84
  85         return ret;
  86 };
  87
  88 static int hmc425a_write_raw(struct iio_dev *indio_dev,
  89                              struct iio_chan_spec const *chan, int val,
  90                              int val2, long mask)
  91 {
  92         struct hmc425a_state *st = iio_priv(indio_dev);
  93         struct hmc425a_chip_info *inf = st->chip_info;
  94         int code = 0, gain;
  95         int ret;
  96
  97         if (val < 0)
  98                 gain = (val * 1000) - (val2 / 1000);
  99         else
 100                 gain = (val * 1000) + (val2 / 1000);
 101
 102         if (gain > inf->gain_max || gain < inf->gain_min)
 103                 return -EINVAL;
 104
 105         switch (st->type) {
 106         case ID_HMC425A:
 107                 code = ~((abs(gain) / 500) & 0x3F);
 108                 break;
 109         }
 110
 111         mutex_lock(&st->lock);
 112         switch (mask) {
 113         case IIO_CHAN_INFO_HARDWAREGAIN:
 114                 st->gain = code;
 115
 116                 ret = hmc425a_write(indio_dev, st->gain);
 117                 break;
 118         default:
 119                 ret = -EINVAL;
 120         }
 121         mutex_unlock(&st->lock);
 122
 123         return ret;
 124 }
 125
 126 static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev,
 127                                      struct iio_chan_spec const *chan,
 128                                      long mask)
 129 {
 130         switch (mask) {
 131         case IIO_CHAN_INFO_HARDWAREGAIN:
 132                 return IIO_VAL_INT_PLUS_MICRO_DB;
 133         default:
 134                 return -EINVAL;
 135         }
 136 }
 137
 138 static const struct iio_info hmc425a_info = {
 139         .read_raw = &hmc425a_read_raw,
 140         .write_raw = &hmc425a_write_raw,
 141         .write_raw_get_fmt = &hmc425a_write_raw_get_fmt,
 142 };
 143
 144 #define HMC425A_CHAN(_channel)                                          \
 145 {                                                                       \
 146         .type = IIO_VOLTAGE,                                            \
 147         .output = 1,                                                    \
 148         .indexed = 1,                                                   \
 149         .channel = _channel,                                            \
 150         .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),          \
 151 }
 152
 153 static const struct iio_chan_spec hmc425a_channels[] = {
 154         HMC425A_CHAN(0),
 155 };
 156
 157 /* Match table for of_platform binding */
 158 static const struct of_device_id hmc425a_of_match[] = {
 159         { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
 160         {},
 161 };
 162 MODULE_DEVICE_TABLE(of, hmc425a_of_match);
 163
 164 static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
 165         [ID_HMC425A] = {
 166                 .name = "hmc425a",
 167                 .channels = hmc425a_channels,
 168                 .num_channels = ARRAY_SIZE(hmc425a_channels),
 169                 .num_gpios = 6,
 170                 .gain_min = -31500,
 171                 .gain_max = 0,
 172                 .default_gain = -0x40, /* set default gain -31.5db*/
 173         },
 174 };
 175
 176 static int hmc425a_probe(struct platform_device *pdev)
 177 {
 178         struct iio_dev *indio_dev;
 179         struct hmc425a_state *st;
 180         int ret;
 181
 182         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
 183         if (!indio_dev)
 184                 return -ENOMEM;
 185
 186         st = iio_priv(indio_dev);
 187         st->type = (uintptr_t)device_get_match_data(&pdev->dev);
 188
 189         st->chip_info = &hmc425a_chip_info_tbl[st->type];
 190         indio_dev->num_channels = st->chip_info->num_channels;
 191         indio_dev->channels = st->chip_info->channels;
 192         indio_dev->name = st->chip_info->name;
 193         st->gain = st->chip_info->default_gain;
 194
 195         st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW);
 196         if (IS_ERR(st->gpios))
 197                 return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios),
 198                                      "failed to get gpios\n");
 199
 200         if (st->gpios->ndescs != st->chip_info->num_gpios) {
 201                 dev_err(&pdev->dev, "%d GPIOs needed to operate\n",
 202                         st->chip_info->num_gpios);
 203                 return -ENODEV;
 204         }
 205
 206         ret = devm_regulator_get_enable(&pdev->dev, "vcc-supply");
 207         if (ret)
 208                 return ret;
 209
 210         mutex_init(&st->lock);
 211
 212         indio_dev->info = &hmc425a_info;
 213         indio_dev->modes = INDIO_DIRECT_MODE;
 214
 215         return devm_iio_device_register(&pdev->dev, indio_dev);
 216 }
 217
 218 static struct platform_driver hmc425a_driver = {
 219         .driver = {
 220                 .name = KBUILD_MODNAME,
 221                 .of_match_table = hmc425a_of_match,
 222         },
 223         .probe = hmc425a_probe,
 224 };
 225 module_platform_driver(hmc425a_driver);
 226
 227 MODULE_AUTHOR("Michael Hennerich <[email protected]>");
 228 MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
 229 MODULE_LICENSE("GPL v2");