drivers/iio/position/iqs624-pos.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Azoteq IQS624/625 Angular Position Sensors
   4  *
   5  * Copyright (C) 2019 Jeff LaBundy <jeff@labundy.com>
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/iio/events.h>
  10 #include <linux/iio/iio.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mfd/iqs62x.h>
  13 #include <linux/module.h>
  14 #include <linux/mutex.h>
  15 #include <linux/notifier.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/regmap.h>
  18
  19 #define IQS624_POS_DEG_OUT                      0x16
  20
  21 #define IQS624_POS_SCALE1                       (314159 / 180)
  22 #define IQS624_POS_SCALE2                       100000
  23
  24 struct iqs624_pos_private {
  25         struct iqs62x_core *iqs62x;
  26         struct iio_dev *indio_dev;
  27         struct notifier_block notifier;
  28         struct mutex lock;
  29         bool angle_en;
  30         u16 angle;
  31 };
  32
  33 static int iqs624_pos_angle_en(struct iqs62x_core *iqs62x, bool angle_en)
  34 {
  35         unsigned int event_mask = IQS624_HALL_UI_WHL_EVENT;
  36
  37         /*
  38          * The IQS625 reports angular position in the form of coarse intervals,
  39          * so only interval change events are unmasked. Conversely, the IQS624
  40          * reports angular position down to one degree of resolution, so wheel
  41          * movement events are unmasked instead.
  42          */
  43         if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM)
  44                 event_mask = IQS624_HALL_UI_INT_EVENT;
  45
  46         return regmap_update_bits(iqs62x->regmap, IQS624_HALL_UI, event_mask,
  47                                   angle_en ? 0 : 0xFF);
  48 }
  49
  50 static int iqs624_pos_notifier(struct notifier_block *notifier,
  51                                unsigned long event_flags, void *context)
  52 {
  53         struct iqs62x_event_data *event_data = context;
  54         struct iqs624_pos_private *iqs624_pos;
  55         struct iqs62x_core *iqs62x;
  56         struct iio_dev *indio_dev;
  57         u16 angle = event_data->ui_data;
  58         s64 timestamp;
  59         int ret;
  60
  61         iqs624_pos = container_of(notifier, struct iqs624_pos_private,
  62                                   notifier);
  63         indio_dev = iqs624_pos->indio_dev;
  64         timestamp = iio_get_time_ns(indio_dev);
  65
  66         iqs62x = iqs624_pos->iqs62x;
  67         if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM)
  68                 angle = event_data->interval;
  69
  70         mutex_lock(&iqs624_pos->lock);
  71
  72         if (event_flags & BIT(IQS62X_EVENT_SYS_RESET)) {
  73                 ret = iqs624_pos_angle_en(iqs62x, iqs624_pos->angle_en);
  74                 if (ret) {
  75                         dev_err(indio_dev->dev.parent,
  76                                 "Failed to re-initialize device: %d\n", ret);
  77                         ret = NOTIFY_BAD;
  78                 } else {
  79                         ret = NOTIFY_OK;
  80                 }
  81         } else if (iqs624_pos->angle_en && (angle != iqs624_pos->angle)) {
  82                 iio_push_event(indio_dev,
  83                                IIO_UNMOD_EVENT_CODE(IIO_ANGL, 0,
  84                                                     IIO_EV_TYPE_CHANGE,
  85                                                     IIO_EV_DIR_NONE),
  86                                timestamp);
  87
  88                 iqs624_pos->angle = angle;
  89                 ret = NOTIFY_OK;
  90         } else {
  91                 ret = NOTIFY_DONE;
  92         }
  93
  94         mutex_unlock(&iqs624_pos->lock);
  95
  96         return ret;
  97 }
  98
  99 static void iqs624_pos_notifier_unregister(void *context)
 100 {
 101         struct iqs624_pos_private *iqs624_pos = context;
 102         struct iio_dev *indio_dev = iqs624_pos->indio_dev;
 103         int ret;
 104
 105         ret = blocking_notifier_chain_unregister(&iqs624_pos->iqs62x->nh,
 106                                                  &iqs624_pos->notifier);
 107         if (ret)
 108                 dev_err(indio_dev->dev.parent,
 109                         "Failed to unregister notifier: %d\n", ret);
 110 }
 111
 112 static int iqs624_pos_angle_get(struct iqs62x_core *iqs62x, unsigned int *val)
 113 {
 114         int ret;
 115         __le16 val_buf;
 116
 117         if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM)
 118                 return regmap_read(iqs62x->regmap, iqs62x->dev_desc->interval,
 119                                    val);
 120
 121         ret = regmap_raw_read(iqs62x->regmap, IQS624_POS_DEG_OUT, &val_buf,
 122                               sizeof(val_buf));
 123         if (ret)
 124                 return ret;
 125
 126         *val = le16_to_cpu(val_buf);
 127
 128         return 0;
 129 }
 130
 131 static int iqs624_pos_read_raw(struct iio_dev *indio_dev,
 132                                struct iio_chan_spec const *chan,
 133                                int *val, int *val2, long mask)
 134 {
 135         struct iqs624_pos_private *iqs624_pos = iio_priv(indio_dev);
 136         struct iqs62x_core *iqs62x = iqs624_pos->iqs62x;
 137         unsigned int scale = 1;
 138         int ret;
 139
 140         switch (mask) {
 141         case IIO_CHAN_INFO_RAW:
 142                 ret = iqs624_pos_angle_get(iqs62x, val);
 143                 if (ret)
 144                         return ret;
 145
 146                 return IIO_VAL_INT;
 147
 148         case IIO_CHAN_INFO_SCALE:
 149                 if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM) {
 150                         ret = regmap_read(iqs62x->regmap, IQS624_INTERVAL_DIV,
 151                                           &scale);
 152                         if (ret)
 153                                 return ret;
 154                 }
 155
 156                 *val = scale * IQS624_POS_SCALE1;
 157                 *val2 = IQS624_POS_SCALE2;
 158                 return IIO_VAL_FRACTIONAL;
 159
 160         default:
 161                 return -EINVAL;
 162         }
 163 }
 164
 165 static int iqs624_pos_read_event_config(struct iio_dev *indio_dev,
 166                                         const struct iio_chan_spec *chan,
 167                                         enum iio_event_type type,
 168                                         enum iio_event_direction dir)
 169 {
 170         struct iqs624_pos_private *iqs624_pos = iio_priv(indio_dev);
 171         int ret;
 172
 173         mutex_lock(&iqs624_pos->lock);
 174         ret = iqs624_pos->angle_en;
 175         mutex_unlock(&iqs624_pos->lock);
 176
 177         return ret;
 178 }
 179
 180 static int iqs624_pos_write_event_config(struct iio_dev *indio_dev,
 181                                          const struct iio_chan_spec *chan,
 182                                          enum iio_event_type type,
 183                                          enum iio_event_direction dir,
 184                                          int state)
 185 {
 186         struct iqs624_pos_private *iqs624_pos = iio_priv(indio_dev);
 187         struct iqs62x_core *iqs62x = iqs624_pos->iqs62x;
 188         unsigned int val;
 189         int ret;
 190
 191         mutex_lock(&iqs624_pos->lock);
 192
 193         ret = iqs624_pos_angle_get(iqs62x, &val);
 194         if (ret)
 195                 goto err_mutex;
 196
 197         ret = iqs624_pos_angle_en(iqs62x, state);
 198         if (ret)
 199                 goto err_mutex;
 200
 201         iqs624_pos->angle = val;
 202         iqs624_pos->angle_en = state;
 203
 204 err_mutex:
 205         mutex_unlock(&iqs624_pos->lock);
 206
 207         return ret;
 208 }
 209
 210 static const struct iio_info iqs624_pos_info = {
 211         .read_raw = &iqs624_pos_read_raw,
 212         .read_event_config = iqs624_pos_read_event_config,
 213         .write_event_config = iqs624_pos_write_event_config,
 214 };
 215
 216 static const struct iio_event_spec iqs624_pos_events[] = {
 217         {
 218                 .type = IIO_EV_TYPE_CHANGE,
 219                 .dir = IIO_EV_DIR_NONE,
 220                 .mask_separate = BIT(IIO_EV_INFO_ENABLE),
 221         },
 222 };
 223
 224 static const struct iio_chan_spec iqs624_pos_channels[] = {
 225         {
 226                 .type = IIO_ANGL,
 227                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 228                                       BIT(IIO_CHAN_INFO_SCALE),
 229                 .event_spec = iqs624_pos_events,
 230                 .num_event_specs = ARRAY_SIZE(iqs624_pos_events),
 231         },
 232 };
 233
 234 static int iqs624_pos_probe(struct platform_device *pdev)
 235 {
 236         struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
 237         struct iqs624_pos_private *iqs624_pos;
 238         struct iio_dev *indio_dev;
 239         int ret;
 240
 241         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*iqs624_pos));
 242         if (!indio_dev)
 243                 return -ENOMEM;
 244
 245         iqs624_pos = iio_priv(indio_dev);
 246         iqs624_pos->iqs62x = iqs62x;
 247         iqs624_pos->indio_dev = indio_dev;
 248
 249         indio_dev->modes = INDIO_DIRECT_MODE;
 250         indio_dev->channels = iqs624_pos_channels;
 251         indio_dev->num_channels = ARRAY_SIZE(iqs624_pos_channels);
 252         indio_dev->name = iqs62x->dev_desc->dev_name;
 253         indio_dev->info = &iqs624_pos_info;
 254
 255         mutex_init(&iqs624_pos->lock);
 256
 257         iqs624_pos->notifier.notifier_call = iqs624_pos_notifier;
 258         ret = blocking_notifier_chain_register(&iqs624_pos->iqs62x->nh,
 259                                                &iqs624_pos->notifier);
 260         if (ret) {
 261                 dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
 262                 return ret;
 263         }
 264
 265         ret = devm_add_action_or_reset(&pdev->dev,
 266                                        iqs624_pos_notifier_unregister,
 267                                        iqs624_pos);
 268         if (ret)
 269                 return ret;
 270
 271         return devm_iio_device_register(&pdev->dev, indio_dev);
 272 }
 273
 274 static struct platform_driver iqs624_pos_platform_driver = {
 275         .driver = {
 276                 .name = "iqs624-pos",
 277         },
 278         .probe = iqs624_pos_probe,
 279 };
 280 module_platform_driver(iqs624_pos_platform_driver);
 281
 282 MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
 283 MODULE_DESCRIPTION("Azoteq IQS624/625 Angular Position Sensors");
 284 MODULE_LICENSE("GPL");
 285 MODULE_ALIAS("platform:iqs624-pos");