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/bitops.h>
   9 #include <linux/device.h>
  10 #include <linux/err.h>
  11 #include <linux/gpio/consumer.h>
  12 #include <linux/iio/iio.h>
  13 #include <linux/iio/sysfs.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mod_devicetable.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/property.h>
  19 #include <linux/slab.h>
  20 #include <linux/regulator/consumer.h>
  21 #include <linux/sysfs.h>
  22
  23 enum hmc425a_type {
  24         ID_HMC425A,
  25         ID_HMC540S,
  26         ID_ADRF5740
  27 };
  28
  29 struct hmc425a_chip_info {
  30         const char                      *name;
  31         const struct iio_chan_spec      *channels;
  32         unsigned int                    num_channels;
  33         unsigned int                    num_gpios;
  34         int                             gain_min;
  35         int                             gain_max;
  36         int                             default_gain;
  37 };
  38
  39 struct hmc425a_state {
  40         struct  mutex lock; /* protect sensor state */
  41         struct  hmc425a_chip_info *chip_info;
  42         struct  gpio_descs *gpios;
  43         enum    hmc425a_type type;
  44         u32     gain;
  45 };
  46
  47 static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
  48 {
  49         struct hmc425a_state *st = iio_priv(indio_dev);
  50         DECLARE_BITMAP(values, BITS_PER_TYPE(value));
  51
  52         values[0] = value;
  53
  54         gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,
  55                                        NULL, values);
  56         return 0;
  57 }
  58
  59 static int hmc425a_read_raw(struct iio_dev *indio_dev,
  60                             struct iio_chan_spec const *chan, int *val,
  61                             int *val2, long m)
  62 {
  63         struct hmc425a_state *st = iio_priv(indio_dev);
  64         int code, gain = 0;
  65         int ret;
  66
  67         mutex_lock(&st->lock);
  68         switch (m) {
  69         case IIO_CHAN_INFO_HARDWAREGAIN:
  70                 code = st->gain;
  71
  72                 switch (st->type) {
  73                 case ID_HMC425A:
  74                         gain = ~code * -500;
  75                         break;
  76                 case ID_HMC540S:
  77                         gain = ~code * -1000;
  78                         break;
  79                 case ID_ADRF5740:
  80                         code = code & BIT(3) ? code & ~BIT(2) : code;
  81                         gain = code * -2000;
  82                         break;
  83                 }
  84
  85                 *val = gain / 1000;
  86                 *val2 = (gain % 1000) * 1000;
  87
  88                 ret = IIO_VAL_INT_PLUS_MICRO_DB;
  89                 break;
  90         default:
  91                 ret = -EINVAL;
  92         }
  93         mutex_unlock(&st->lock);
  94
  95         return ret;
  96 };
  97
  98 static int hmc425a_write_raw(struct iio_dev *indio_dev,
  99                              struct iio_chan_spec const *chan, int val,
 100                              int val2, long mask)
 101 {
 102         struct hmc425a_state *st = iio_priv(indio_dev);
 103         struct hmc425a_chip_info *inf = st->chip_info;
 104         int code = 0, gain;
 105         int ret;
 106
 107         if (val < 0)
 108                 gain = (val * 1000) - (val2 / 1000);
 109         else
 110                 gain = (val * 1000) + (val2 / 1000);
 111
 112         if (gain > inf->gain_max || gain < inf->gain_min)
 113                 return -EINVAL;
 114
 115         switch (st->type) {
 116         case ID_HMC425A:
 117                 code = ~((abs(gain) / 500) & 0x3F);
 118                 break;
 119         case ID_HMC540S:
 120                 code = ~((abs(gain) / 1000) & 0xF);
 121                 break;
 122         case ID_ADRF5740:
 123                 code = (abs(gain) / 2000) & 0xF;
 124                 code = code & BIT(3) ? code | BIT(2) : code;
 125                 break;
 126         }
 127
 128         mutex_lock(&st->lock);
 129         switch (mask) {
 130         case IIO_CHAN_INFO_HARDWAREGAIN:
 131                 st->gain = code;
 132
 133                 ret = hmc425a_write(indio_dev, st->gain);
 134                 break;
 135         default:
 136                 ret = -EINVAL;
 137         }
 138         mutex_unlock(&st->lock);
 139
 140         return ret;
 141 }
 142
 143 static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev,
 144                                      struct iio_chan_spec const *chan,
 145                                      long mask)
 146 {
 147         switch (mask) {
 148         case IIO_CHAN_INFO_HARDWAREGAIN:
 149                 return IIO_VAL_INT_PLUS_MICRO_DB;
 150         default:
 151                 return -EINVAL;
 152         }
 153 }
 154
 155 static const struct iio_info hmc425a_info = {
 156         .read_raw = &hmc425a_read_raw,
 157         .write_raw = &hmc425a_write_raw,
 158         .write_raw_get_fmt = &hmc425a_write_raw_get_fmt,
 159 };
 160
 161 #define HMC425A_CHAN(_channel)                                          \
 162 {                                                                       \
 163         .type = IIO_VOLTAGE,                                            \
 164         .output = 1,                                                    \
 165         .indexed = 1,                                                   \
 166         .channel = _channel,                                            \
 167         .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),          \
 168 }
 169
 170 static const struct iio_chan_spec hmc425a_channels[] = {
 171         HMC425A_CHAN(0),
 172 };
 173
 174 /* Match table for of_platform binding */
 175 static const struct of_device_id hmc425a_of_match[] = {
 176         { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
 177         { .compatible = "adi,hmc540s", .data = (void *)ID_HMC540S },
 178         { .compatible = "adi,adrf5740", .data = (void *)ID_ADRF5740 },
 179         {},
 180 };
 181 MODULE_DEVICE_TABLE(of, hmc425a_of_match);
 182
 183 static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
 184         [ID_HMC425A] = {
 185                 .name = "hmc425a",
 186                 .channels = hmc425a_channels,
 187                 .num_channels = ARRAY_SIZE(hmc425a_channels),
 188                 .num_gpios = 6,
 189                 .gain_min = -31500,
 190                 .gain_max = 0,
 191                 .default_gain = -0x40, /* set default gain -31.5db*/
 192         },
 193         [ID_HMC540S] = {
 194                 .name = "hmc540s",
 195                 .channels = hmc425a_channels,
 196                 .num_channels = ARRAY_SIZE(hmc425a_channels),
 197                 .num_gpios = 4,
 198                 .gain_min = -15000,
 199                 .gain_max = 0,
 200                 .default_gain = -0x10, /* set default gain -15.0db*/
 201         },
 202         [ID_ADRF5740] = {
 203                 .name = "adrf5740",
 204                 .channels = hmc425a_channels,
 205                 .num_channels = ARRAY_SIZE(hmc425a_channels),
 206                 .num_gpios = 4,
 207                 .gain_min = -22000,
 208                 .gain_max = 0,
 209                 .default_gain = 0xF, /* set default gain -22.0db*/
 210         },
 211 };
 212
 213 static int hmc425a_probe(struct platform_device *pdev)
 214 {
 215         struct iio_dev *indio_dev;
 216         struct hmc425a_state *st;
 217         int ret;
 218
 219         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
 220         if (!indio_dev)
 221                 return -ENOMEM;
 222
 223         st = iio_priv(indio_dev);
 224         st->type = (uintptr_t)device_get_match_data(&pdev->dev);
 225
 226         st->chip_info = &hmc425a_chip_info_tbl[st->type];
 227         indio_dev->num_channels = st->chip_info->num_channels;
 228         indio_dev->channels = st->chip_info->channels;
 229         indio_dev->name = st->chip_info->name;
 230         st->gain = st->chip_info->default_gain;
 231
 232         st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW);
 233         if (IS_ERR(st->gpios))
 234                 return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios),
 235                                      "failed to get gpios\n");
 236
 237         if (st->gpios->ndescs != st->chip_info->num_gpios) {
 238                 dev_err(&pdev->dev, "%d GPIOs needed to operate\n",
 239                         st->chip_info->num_gpios);
 240                 return -ENODEV;
 241         }
 242
 243         ret = devm_regulator_get_enable(&pdev->dev, "vcc-supply");
 244         if (ret)
 245                 return ret;
 246
 247         mutex_init(&st->lock);
 248
 249         indio_dev->info = &hmc425a_info;
 250         indio_dev->modes = INDIO_DIRECT_MODE;
 251
 252         /* Set default gain */
 253         hmc425a_write(indio_dev, st->gain);
 254
 255         return devm_iio_device_register(&pdev->dev, indio_dev);
 256 }
 257
 258 static struct platform_driver hmc425a_driver = {
 259         .driver = {
 260                 .name = KBUILD_MODNAME,
 261                 .of_match_table = hmc425a_of_match,
 262         },
 263         .probe = hmc425a_probe,
 264 };
 265 module_platform_driver(hmc425a_driver);
 266
 267 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 268 MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
 269 MODULE_LICENSE("GPL v2");