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