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/module.h>
  15 #include <linux/of_device.h>
  16 #include <linux/of_platform.h>
  17 #include <linux/platform_device.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  regulator *reg;
  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                 }
  75
  76                 *val = gain / 1000;
  77                 *val2 = (gain % 1000) * 1000;
  78
  79                 ret = IIO_VAL_INT_PLUS_MICRO_DB;
  80                 break;
  81         default:
  82                 ret = -EINVAL;
  83         }
  84         mutex_unlock(&st->lock);
  85
  86         return ret;
  87 };
  88
  89 static int hmc425a_write_raw(struct iio_dev *indio_dev,
  90                              struct iio_chan_spec const *chan, int val,
  91                              int val2, long mask)
  92 {
  93         struct hmc425a_state *st = iio_priv(indio_dev);
  94         struct hmc425a_chip_info *inf = st->chip_info;
  95         int code = 0, gain;
  96         int ret;
  97
  98         if (val < 0)
  99                 gain = (val * 1000) - (val2 / 1000);
 100         else
 101                 gain = (val * 1000) + (val2 / 1000);
 102
 103         if (gain > inf->gain_max || gain < inf->gain_min)
 104                 return -EINVAL;
 105
 106         switch (st->type) {
 107         case ID_HMC425A:
 108                 code = ~((abs(gain) / 500) & 0x3F);
 109                 break;
 110         }
 111
 112         mutex_lock(&st->lock);
 113         switch (mask) {
 114         case IIO_CHAN_INFO_HARDWAREGAIN:
 115                 st->gain = code;
 116
 117                 ret = hmc425a_write(indio_dev, st->gain);
 118                 break;
 119         default:
 120                 ret = -EINVAL;
 121         }
 122         mutex_unlock(&st->lock);
 123
 124         return ret;
 125 }
 126
 127 static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev,
 128                                      struct iio_chan_spec const *chan,
 129                                      long mask)
 130 {
 131         switch (mask) {
 132         case IIO_CHAN_INFO_HARDWAREGAIN:
 133                 return IIO_VAL_INT_PLUS_MICRO_DB;
 134         default:
 135                 return -EINVAL;
 136         }
 137 }
 138
 139 static const struct iio_info hmc425a_info = {
 140         .read_raw = &hmc425a_read_raw,
 141         .write_raw = &hmc425a_write_raw,
 142         .write_raw_get_fmt = &hmc425a_write_raw_get_fmt,
 143 };
 144
 145 #define HMC425A_CHAN(_channel)                                          \
 146 {                                                                       \
 147         .type = IIO_VOLTAGE,                                            \
 148         .output = 1,                                                    \
 149         .indexed = 1,                                                   \
 150         .channel = _channel,                                            \
 151         .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),          \
 152 }
 153
 154 static const struct iio_chan_spec hmc425a_channels[] = {
 155         HMC425A_CHAN(0),
 156 };
 157
 158 /* Match table for of_platform binding */
 159 static const struct of_device_id hmc425a_of_match[] = {
 160         { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
 161         {},
 162 };
 163 MODULE_DEVICE_TABLE(of, hmc425a_of_match);
 164
 165 static void hmc425a_reg_disable(void *data)
 166 {
 167         struct hmc425a_state *st = data;
 168
 169         regulator_disable(st->reg);
 170 }
 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 };
 183
 184 static int hmc425a_probe(struct platform_device *pdev)
 185 {
 186         struct iio_dev *indio_dev;
 187         struct hmc425a_state *st;
 188         int ret;
 189
 190         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
 191         if (!indio_dev)
 192                 return -ENOMEM;
 193
 194         st = iio_priv(indio_dev);
 195         st->type = (uintptr_t)of_device_get_match_data(&pdev->dev);
 196
 197         st->chip_info = &hmc425a_chip_info_tbl[st->type];
 198         indio_dev->num_channels = st->chip_info->num_channels;
 199         indio_dev->channels = st->chip_info->channels;
 200         indio_dev->name = st->chip_info->name;
 201         st->gain = st->chip_info->default_gain;
 202
 203         st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW);
 204         if (IS_ERR(st->gpios))
 205                 return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios),
 206                                      "failed to get gpios\n");
 207
 208         if (st->gpios->ndescs != st->chip_info->num_gpios) {
 209                 dev_err(&pdev->dev, "%d GPIOs needed to operate\n",
 210                         st->chip_info->num_gpios);
 211                 return -ENODEV;
 212         }
 213
 214         st->reg = devm_regulator_get(&pdev->dev, "vcc-supply");
 215         if (IS_ERR(st->reg))
 216                 return PTR_ERR(st->reg);
 217
 218         ret = regulator_enable(st->reg);
 219         if (ret)
 220                 return ret;
 221         ret = devm_add_action_or_reset(&pdev->dev, hmc425a_reg_disable, st);
 222         if (ret)
 223                 return ret;
 224
 225         mutex_init(&st->lock);
 226
 227         indio_dev->info = &hmc425a_info;
 228         indio_dev->modes = INDIO_DIRECT_MODE;
 229
 230         return devm_iio_device_register(&pdev->dev, indio_dev);
 231 }
 232
 233 static struct platform_driver hmc425a_driver = {
 234         .driver = {
 235                 .name = KBUILD_MODNAME,
 236                 .of_match_table = hmc425a_of_match,
 237         },
 238         .probe = hmc425a_probe,
 239 };
 240 module_platform_driver(hmc425a_driver);
 241
 242 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 243 MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
 244 MODULE_LICENSE("GPL v2");