drivers/iio/light/cm3605.c

   1 /*
   2  * CM3605 Ambient Light and Proximity Sensor
   3  *
   4  * Copyright (C) 2016 Linaro Ltd.
   5  * Author: Linus Walleij <linus.walleij@linaro.org>
   6  *
   7  * This hardware was found in the very first Nexus One handset from Google/HTC
   8  * and an early endavour into mobile light and proximity sensors.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/iio/iio.h>
  13 #include <linux/iio/sysfs.h>
  14 #include <linux/iio/events.h>
  15 #include <linux/iio/consumer.h> /* To get our ADC channel */
  16 #include <linux/iio/types.h> /* To deal with our ADC channel */
  17 #include <linux/init.h>
  18 #include <linux/leds.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/of.h>
  21 #include <linux/regulator/consumer.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/math64.h>
  25 #include <linux/pm.h>
  26
  27 #define CM3605_PROX_CHANNEL 0
  28 #define CM3605_ALS_CHANNEL 1
  29 #define CM3605_AOUT_TYP_MAX_MV 1550
  30 /* It should not go above 1.650V according to the data sheet */
  31 #define CM3605_AOUT_MAX_MV 1650
  32
  33 /**
  34  * struct cm3605 - CM3605 state
  35  * @dev: pointer to parent device
  36  * @vdd: regulator controlling VDD
  37  * @aset: sleep enable GPIO, high = sleep
  38  * @aout: IIO ADC channel to convert the AOUT signal
  39  * @als_max: maximum LUX detection (depends on RSET)
  40  * @dir: proximity direction: start as FALLING
  41  * @led: trigger for the infrared LED used by the proximity sensor
  42  */
  43 struct cm3605 {
  44         struct device *dev;
  45         struct regulator *vdd;
  46         struct gpio_desc *aset;
  47         struct iio_channel *aout;
  48         s32 als_max;
  49         enum iio_event_direction dir;
  50         struct led_trigger *led;
  51 };
  52
  53 static irqreturn_t cm3605_prox_irq(int irq, void *d)
  54 {
  55         struct iio_dev *indio_dev = d;
  56         struct cm3605 *cm3605 = iio_priv(indio_dev);
  57         u64 ev;
  58
  59         ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, CM3605_PROX_CHANNEL,
  60                                   IIO_EV_TYPE_THRESH, cm3605->dir);
  61         iio_push_event(indio_dev, ev, iio_get_time_ns(indio_dev));
  62
  63         /* Invert the edge for each event */
  64         if (cm3605->dir == IIO_EV_DIR_RISING)
  65                 cm3605->dir = IIO_EV_DIR_FALLING;
  66         else
  67                 cm3605->dir = IIO_EV_DIR_RISING;
  68
  69         return IRQ_HANDLED;
  70 }
  71
  72 static int cm3605_get_lux(struct cm3605 *cm3605)
  73 {
  74         int ret, res;
  75         s64 lux;
  76
  77         ret = iio_read_channel_processed(cm3605->aout, &res);
  78         if (ret < 0)
  79                 return ret;
  80
  81         dev_dbg(cm3605->dev, "read %d mV from ADC\n", res);
  82
  83         /*
  84          * AOUT has an offset of ~30mV then linear at dark
  85          * then goes from 2.54 up to 650 LUX yielding 1.55V
  86          * (1550 mV) so scale the returned value to this interval
  87          * using simple linear interpolation.
  88          */
  89         if (res < 30)
  90                 return 0;
  91         if (res > CM3605_AOUT_MAX_MV)
  92                 dev_err(cm3605->dev, "device out of range\n");
  93
  94         /* Remove bias */
  95         lux = res - 30;
  96
  97         /* Linear interpolation between 0 and ALS typ max */
  98         lux *= cm3605->als_max;
  99         lux = div64_s64(lux, CM3605_AOUT_TYP_MAX_MV);
 100
 101         return lux;
 102 }
 103
 104 static int cm3605_read_raw(struct iio_dev *indio_dev,
 105                            struct iio_chan_spec const *chan,
 106                            int *val, int *val2, long mask)
 107 {
 108         struct cm3605 *cm3605 = iio_priv(indio_dev);
 109         int ret;
 110
 111         switch (mask) {
 112         case IIO_CHAN_INFO_RAW:
 113                 switch (chan->type) {
 114                 case IIO_LIGHT:
 115                         ret = cm3605_get_lux(cm3605);
 116                         if (ret < 0)
 117                                 return ret;
 118                         *val = ret;
 119                         return IIO_VAL_INT;
 120                 default:
 121                         return -EINVAL;
 122                 }
 123         default:
 124                 return -EINVAL;
 125         }
 126 }
 127
 128 static const struct iio_info cm3605_info = {
 129         .read_raw = cm3605_read_raw,
 130 };
 131
 132 static const struct iio_event_spec cm3605_events[] = {
 133         {
 134                 .type = IIO_EV_TYPE_THRESH,
 135                 .dir = IIO_EV_DIR_EITHER,
 136                 .mask_separate = BIT(IIO_EV_INFO_ENABLE),
 137         },
 138 };
 139
 140 static const struct iio_chan_spec cm3605_channels[] = {
 141         {
 142                 .type = IIO_PROXIMITY,
 143                 .event_spec = cm3605_events,
 144                 .num_event_specs = ARRAY_SIZE(cm3605_events),
 145         },
 146         {
 147                 .type = IIO_LIGHT,
 148                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 149                 .channel = CM3605_ALS_CHANNEL,
 150         },
 151 };
 152
 153 static int cm3605_probe(struct platform_device *pdev)
 154 {
 155         struct cm3605 *cm3605;
 156         struct iio_dev *indio_dev;
 157         struct device *dev = &pdev->dev;
 158         struct device_node *np = dev->of_node;
 159         enum iio_chan_type ch_type;
 160         u32 rset;
 161         int ret;
 162
 163         indio_dev = devm_iio_device_alloc(dev, sizeof(*cm3605));
 164         if (!indio_dev)
 165                 return -ENOMEM;
 166         platform_set_drvdata(pdev, indio_dev);
 167
 168         cm3605 = iio_priv(indio_dev);
 169         cm3605->dev = dev;
 170         cm3605->dir = IIO_EV_DIR_FALLING;
 171
 172         ret = of_property_read_u32(np, "capella,aset-resistance-ohms", &rset);
 173         if (ret) {
 174                 dev_info(dev, "no RSET specified, assuming 100K\n");
 175                 rset = 100000;
 176         }
 177         switch (rset) {
 178         case 50000:
 179                 cm3605->als_max = 650;
 180                 break;
 181         case 100000:
 182                 cm3605->als_max = 300;
 183                 break;
 184         case 300000:
 185                 cm3605->als_max = 100;
 186                 break;
 187         case 600000:
 188                 cm3605->als_max = 50;
 189                 break;
 190         default:
 191                 dev_info(dev, "non-standard resistance\n");
 192                 return -EINVAL;
 193         }
 194
 195         cm3605->aout = devm_iio_channel_get(dev, "aout");
 196         if (IS_ERR(cm3605->aout)) {
 197                 if (PTR_ERR(cm3605->aout) == -ENODEV) {
 198                         dev_err(dev, "no ADC, deferring...\n");
 199                         return -EPROBE_DEFER;
 200                 }
 201                 dev_err(dev, "failed to get AOUT ADC channel\n");
 202                 return PTR_ERR(cm3605->aout);
 203         }
 204         ret = iio_get_channel_type(cm3605->aout, &ch_type);
 205         if (ret < 0)
 206                 return ret;
 207         if (ch_type != IIO_VOLTAGE) {
 208                 dev_err(dev, "wrong type of IIO channel specified for AOUT\n");
 209                 return -EINVAL;
 210         }
 211
 212         cm3605->vdd = devm_regulator_get(dev, "vdd");
 213         if (IS_ERR(cm3605->vdd)) {
 214                 dev_err(dev, "failed to get VDD regulator\n");
 215                 return PTR_ERR(cm3605->vdd);
 216         }
 217         ret = regulator_enable(cm3605->vdd);
 218         if (ret) {
 219                 dev_err(dev, "failed to enable VDD regulator\n");
 220                 return ret;
 221         }
 222
 223         cm3605->aset = devm_gpiod_get(dev, "aset", GPIOD_OUT_HIGH);
 224         if (IS_ERR(cm3605->aset)) {
 225                 dev_err(dev, "no ASET GPIO\n");
 226                 ret = PTR_ERR(cm3605->aset);
 227                 goto out_disable_vdd;
 228         }
 229
 230         ret = devm_request_threaded_irq(dev, platform_get_irq(pdev, 0),
 231                         cm3605_prox_irq, NULL, 0, "cm3605", indio_dev);
 232         if (ret) {
 233                 dev_err(dev, "unable to request IRQ\n");
 234                 goto out_disable_aset;
 235         }
 236
 237         /* Just name the trigger the same as the driver */
 238         led_trigger_register_simple("cm3605", &cm3605->led);
 239         led_trigger_event(cm3605->led, LED_FULL);
 240
 241         indio_dev->dev.parent = dev;
 242         indio_dev->info = &cm3605_info;
 243         indio_dev->name = "cm3605";
 244         indio_dev->channels = cm3605_channels;
 245         indio_dev->num_channels = ARRAY_SIZE(cm3605_channels);
 246         indio_dev->modes = INDIO_DIRECT_MODE;
 247
 248         ret = iio_device_register(indio_dev);
 249         if (ret)
 250                 goto out_remove_trigger;
 251         dev_info(dev, "Capella Microsystems CM3605 enabled range 0..%d LUX\n",
 252                  cm3605->als_max);
 253
 254         return 0;
 255
 256 out_remove_trigger:
 257         led_trigger_event(cm3605->led, LED_OFF);
 258         led_trigger_unregister_simple(cm3605->led);
 259 out_disable_aset:
 260         gpiod_set_value_cansleep(cm3605->aset, 0);
 261 out_disable_vdd:
 262         regulator_disable(cm3605->vdd);
 263         return ret;
 264 }
 265
 266 static int cm3605_remove(struct platform_device *pdev)
 267 {
 268         struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 269         struct cm3605 *cm3605 = iio_priv(indio_dev);
 270
 271         led_trigger_event(cm3605->led, LED_OFF);
 272         led_trigger_unregister_simple(cm3605->led);
 273         gpiod_set_value_cansleep(cm3605->aset, 0);
 274         iio_device_unregister(indio_dev);
 275         regulator_disable(cm3605->vdd);
 276
 277         return 0;
 278 }
 279
 280 static int __maybe_unused cm3605_pm_suspend(struct device *dev)
 281 {
 282         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 283         struct cm3605 *cm3605 = iio_priv(indio_dev);
 284
 285         led_trigger_event(cm3605->led, LED_OFF);
 286         regulator_disable(cm3605->vdd);
 287
 288         return 0;
 289 }
 290
 291 static int __maybe_unused cm3605_pm_resume(struct device *dev)
 292 {
 293         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 294         struct cm3605 *cm3605 = iio_priv(indio_dev);
 295         int ret;
 296
 297         ret = regulator_enable(cm3605->vdd);
 298         if (ret)
 299                 dev_err(dev, "failed to enable regulator in resume path\n");
 300         led_trigger_event(cm3605->led, LED_FULL);
 301
 302         return 0;
 303 }
 304
 305 static const struct dev_pm_ops cm3605_dev_pm_ops = {
 306         SET_SYSTEM_SLEEP_PM_OPS(cm3605_pm_suspend,
 307                                 cm3605_pm_resume)
 308 };
 309
 310 static const struct of_device_id cm3605_of_match[] = {
 311         {.compatible = "capella,cm3605"},
 312         { },
 313 };
 314 MODULE_DEVICE_TABLE(of, cm3605_of_match);
 315
 316 static struct platform_driver cm3605_driver = {
 317         .driver = {
 318                 .name = "cm3605",
 319                 .of_match_table = cm3605_of_match,
 320                 .pm = &cm3605_dev_pm_ops,
 321         },
 322         .probe = cm3605_probe,
 323         .remove = cm3605_remove,
 324 };
 325 module_platform_driver(cm3605_driver);
 326
 327 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 328 MODULE_DESCRIPTION("CM3605 ambient light and proximity sensor driver");
 329 MODULE_LICENSE("GPL");