drivers/iio/light/st_uvis25_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * STMicroelectronics uvis25 sensor driver
   4  *
   5  * Copyright 2017 STMicroelectronics Inc.
   6  *
   7  * Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/device.h>
  13 #include <linux/iio/sysfs.h>
  14 #include <linux/delay.h>
  15 #include <linux/pm.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/irqreturn.h>
  18 #include <linux/iio/trigger.h>
  19 #include <linux/iio/trigger_consumer.h>
  20 #include <linux/iio/triggered_buffer.h>
  21 #include <linux/iio/buffer.h>
  22 #include <linux/regmap.h>
  23
  24 #include "st_uvis25.h"
  25
  26 #define ST_UVIS25_REG_WHOAMI_ADDR       0x0f
  27 #define ST_UVIS25_REG_WHOAMI_VAL        0xca
  28 #define ST_UVIS25_REG_CTRL1_ADDR        0x20
  29 #define ST_UVIS25_REG_ODR_MASK          BIT(0)
  30 #define ST_UVIS25_REG_BDU_MASK          BIT(1)
  31 #define ST_UVIS25_REG_CTRL2_ADDR        0x21
  32 #define ST_UVIS25_REG_BOOT_MASK         BIT(7)
  33 #define ST_UVIS25_REG_CTRL3_ADDR        0x22
  34 #define ST_UVIS25_REG_HL_MASK           BIT(7)
  35 #define ST_UVIS25_REG_STATUS_ADDR       0x27
  36 #define ST_UVIS25_REG_UV_DA_MASK        BIT(0)
  37 #define ST_UVIS25_REG_OUT_ADDR          0x28
  38
  39 static const struct iio_chan_spec st_uvis25_channels[] = {
  40         {
  41                 .type = IIO_UVINDEX,
  42                 .address = ST_UVIS25_REG_OUT_ADDR,
  43                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
  44                 .scan_index = 0,
  45                 .scan_type = {
  46                         .sign = 'u',
  47                         .realbits = 8,
  48                         .storagebits = 8,
  49                 },
  50         },
  51         IIO_CHAN_SOFT_TIMESTAMP(1),
  52 };
  53
  54 static int st_uvis25_check_whoami(struct st_uvis25_hw *hw)
  55 {
  56         int err, data;
  57
  58         err = regmap_read(hw->regmap, ST_UVIS25_REG_WHOAMI_ADDR, &data);
  59         if (err < 0) {
  60                 dev_err(regmap_get_device(hw->regmap),
  61                         "failed to read whoami register\n");
  62                 return err;
  63         }
  64
  65         if (data != ST_UVIS25_REG_WHOAMI_VAL) {
  66                 dev_err(regmap_get_device(hw->regmap),
  67                         "wrong whoami {%02x vs %02x}\n",
  68                         data, ST_UVIS25_REG_WHOAMI_VAL);
  69                 return -ENODEV;
  70         }
  71
  72         return 0;
  73 }
  74
  75 static int st_uvis25_set_enable(struct st_uvis25_hw *hw, bool enable)
  76 {
  77         int err;
  78
  79         err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
  80                                  ST_UVIS25_REG_ODR_MASK, enable);
  81         if (err < 0)
  82                 return err;
  83
  84         hw->enabled = enable;
  85
  86         return 0;
  87 }
  88
  89 static int st_uvis25_read_oneshot(struct st_uvis25_hw *hw, u8 addr, int *val)
  90 {
  91         int err;
  92
  93         err = st_uvis25_set_enable(hw, true);
  94         if (err < 0)
  95                 return err;
  96
  97         msleep(1500);
  98
  99         /*
 100          * in order to avoid possible race conditions with interrupt
 101          * generation, disable the sensor first and then poll output
 102          * register. That sequence guarantees the interrupt will be reset
 103          * when irq line is unmasked
 104          */
 105         err = st_uvis25_set_enable(hw, false);
 106         if (err < 0)
 107                 return err;
 108
 109         err = regmap_read(hw->regmap, addr, val);
 110
 111         return err < 0 ? err : IIO_VAL_INT;
 112 }
 113
 114 static int st_uvis25_read_raw(struct iio_dev *iio_dev,
 115                               struct iio_chan_spec const *ch,
 116                               int *val, int *val2, long mask)
 117 {
 118         int ret;
 119
 120         ret = iio_device_claim_direct_mode(iio_dev);
 121         if (ret)
 122                 return ret;
 123
 124         switch (mask) {
 125         case IIO_CHAN_INFO_PROCESSED: {
 126                 struct st_uvis25_hw *hw = iio_priv(iio_dev);
 127
 128                 /*
 129                  * mask irq line during oneshot read since the sensor
 130                  * does not export the capability to disable data-ready line
 131                  * in the register map and it is enabled by default.
 132                  * If the line is unmasked during read_raw() it will be set
 133                  * active and never reset since the trigger is disabled
 134                  */
 135                 if (hw->irq > 0)
 136                         disable_irq(hw->irq);
 137                 ret = st_uvis25_read_oneshot(hw, ch->address, val);
 138                 if (hw->irq > 0)
 139                         enable_irq(hw->irq);
 140                 break;
 141         }
 142         default:
 143                 ret = -EINVAL;
 144                 break;
 145         }
 146
 147         iio_device_release_direct_mode(iio_dev);
 148
 149         return ret;
 150 }
 151
 152 static irqreturn_t st_uvis25_trigger_handler_thread(int irq, void *private)
 153 {
 154         struct st_uvis25_hw *hw = private;
 155         int err, status;
 156
 157         err = regmap_read(hw->regmap, ST_UVIS25_REG_STATUS_ADDR, &status);
 158         if (err < 0)
 159                 return IRQ_HANDLED;
 160
 161         if (!(status & ST_UVIS25_REG_UV_DA_MASK))
 162                 return IRQ_NONE;
 163
 164         iio_trigger_poll_nested(hw->trig);
 165
 166         return IRQ_HANDLED;
 167 }
 168
 169 static int st_uvis25_allocate_trigger(struct iio_dev *iio_dev)
 170 {
 171         struct st_uvis25_hw *hw = iio_priv(iio_dev);
 172         struct device *dev = regmap_get_device(hw->regmap);
 173         bool irq_active_low = false;
 174         unsigned long irq_type;
 175         int err;
 176
 177         irq_type = irq_get_trigger_type(hw->irq);
 178         switch (irq_type) {
 179         case IRQF_TRIGGER_HIGH:
 180         case IRQF_TRIGGER_RISING:
 181                 break;
 182         case IRQF_TRIGGER_LOW:
 183         case IRQF_TRIGGER_FALLING:
 184                 irq_active_low = true;
 185                 break;
 186         default:
 187                 dev_info(dev, "mode %lx unsupported\n", irq_type);
 188                 return -EINVAL;
 189         }
 190
 191         err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL3_ADDR,
 192                                  ST_UVIS25_REG_HL_MASK, irq_active_low);
 193         if (err < 0)
 194                 return err;
 195
 196         err = devm_request_threaded_irq(dev, hw->irq, NULL,
 197                                         st_uvis25_trigger_handler_thread,
 198                                         irq_type | IRQF_ONESHOT,
 199                                         iio_dev->name, hw);
 200         if (err) {
 201                 dev_err(dev, "failed to request trigger irq %d\n",
 202                         hw->irq);
 203                 return err;
 204         }
 205
 206         hw->trig = devm_iio_trigger_alloc(dev, "%s-trigger",
 207                                           iio_dev->name);
 208         if (!hw->trig)
 209                 return -ENOMEM;
 210
 211         iio_trigger_set_drvdata(hw->trig, iio_dev);
 212
 213         return devm_iio_trigger_register(dev, hw->trig);
 214 }
 215
 216 static int st_uvis25_buffer_preenable(struct iio_dev *iio_dev)
 217 {
 218         return st_uvis25_set_enable(iio_priv(iio_dev), true);
 219 }
 220
 221 static int st_uvis25_buffer_postdisable(struct iio_dev *iio_dev)
 222 {
 223         return st_uvis25_set_enable(iio_priv(iio_dev), false);
 224 }
 225
 226 static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = {
 227         .preenable = st_uvis25_buffer_preenable,
 228         .postdisable = st_uvis25_buffer_postdisable,
 229 };
 230
 231 static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p)
 232 {
 233         struct iio_poll_func *pf = p;
 234         struct iio_dev *iio_dev = pf->indio_dev;
 235         struct st_uvis25_hw *hw = iio_priv(iio_dev);
 236         unsigned int val;
 237         int err;
 238
 239         err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, &val);
 240         if (err < 0)
 241                 goto out;
 242
 243         hw->scan.chan = val;
 244
 245         iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan,
 246                                            iio_get_time_ns(iio_dev));
 247
 248 out:
 249         iio_trigger_notify_done(hw->trig);
 250
 251         return IRQ_HANDLED;
 252 }
 253
 254 static int st_uvis25_allocate_buffer(struct iio_dev *iio_dev)
 255 {
 256         struct st_uvis25_hw *hw = iio_priv(iio_dev);
 257
 258         return devm_iio_triggered_buffer_setup(regmap_get_device(hw->regmap),
 259                                                iio_dev, NULL,
 260                                                st_uvis25_buffer_handler_thread,
 261                                                &st_uvis25_buffer_ops);
 262 }
 263
 264 static const struct iio_info st_uvis25_info = {
 265         .read_raw = st_uvis25_read_raw,
 266 };
 267
 268 static int st_uvis25_init_sensor(struct st_uvis25_hw *hw)
 269 {
 270         int err;
 271
 272         err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL2_ADDR,
 273                                  ST_UVIS25_REG_BOOT_MASK, 1);
 274         if (err < 0)
 275                 return err;
 276
 277         msleep(2000);
 278
 279         return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
 280                                   ST_UVIS25_REG_BDU_MASK, 1);
 281 }
 282
 283 int st_uvis25_probe(struct device *dev, int irq, struct regmap *regmap)
 284 {
 285         struct st_uvis25_hw *hw;
 286         struct iio_dev *iio_dev;
 287         int err;
 288
 289         iio_dev = devm_iio_device_alloc(dev, sizeof(*hw));
 290         if (!iio_dev)
 291                 return -ENOMEM;
 292
 293         dev_set_drvdata(dev, iio_dev);
 294
 295         hw = iio_priv(iio_dev);
 296         hw->irq = irq;
 297         hw->regmap = regmap;
 298
 299         err = st_uvis25_check_whoami(hw);
 300         if (err < 0)
 301                 return err;
 302
 303         iio_dev->modes = INDIO_DIRECT_MODE;
 304         iio_dev->channels = st_uvis25_channels;
 305         iio_dev->num_channels = ARRAY_SIZE(st_uvis25_channels);
 306         iio_dev->name = ST_UVIS25_DEV_NAME;
 307         iio_dev->info = &st_uvis25_info;
 308
 309         err = st_uvis25_init_sensor(hw);
 310         if (err < 0)
 311                 return err;
 312
 313         if (hw->irq > 0) {
 314                 err = st_uvis25_allocate_buffer(iio_dev);
 315                 if (err < 0)
 316                         return err;
 317
 318                 err = st_uvis25_allocate_trigger(iio_dev);
 319                 if (err)
 320                         return err;
 321         }
 322
 323         return devm_iio_device_register(dev, iio_dev);
 324 }
 325 EXPORT_SYMBOL_NS(st_uvis25_probe, "IIO_UVIS25");
 326
 327 static int st_uvis25_suspend(struct device *dev)
 328 {
 329         struct iio_dev *iio_dev = dev_get_drvdata(dev);
 330         struct st_uvis25_hw *hw = iio_priv(iio_dev);
 331
 332         return regmap_clear_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
 333                                  ST_UVIS25_REG_ODR_MASK);
 334 }
 335
 336 static int st_uvis25_resume(struct device *dev)
 337 {
 338         struct iio_dev *iio_dev = dev_get_drvdata(dev);
 339         struct st_uvis25_hw *hw = iio_priv(iio_dev);
 340
 341         if (hw->enabled)
 342                 return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
 343                                           ST_UVIS25_REG_ODR_MASK, 1);
 344
 345         return 0;
 346 }
 347
 348 EXPORT_NS_SIMPLE_DEV_PM_OPS(st_uvis25_pm_ops, st_uvis25_suspend, st_uvis25_resume, IIO_UVIS25);
 349
 350 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>");
 351 MODULE_DESCRIPTION("STMicroelectronics uvis25 sensor driver");
 352 MODULE_LICENSE("GPL v2");