linux/drivers/iio/light/cm3605.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * CM3605 Ambient Light and Proximity Sensor
   4 *
   5 * Copyright (C) 2016 Linaro Ltd.
   6 * Author: Linus Walleij <linus.walleij@linaro.org>
   7 *
   8 * This hardware was found in the very first Nexus One handset from Google/HTC
   9 * and an early endavour into mobile light and proximity sensors.
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/iio/iio.h>
  14#include <linux/iio/sysfs.h>
  15#include <linux/iio/events.h>
  16#include <linux/iio/consumer.h> /* To get our ADC channel */
  17#include <linux/iio/types.h> /* To deal with our ADC channel */
  18#include <linux/init.h>
  19#include <linux/leds.h>
  20#include <linux/platform_device.h>
  21#include <linux/of.h>
  22#include <linux/regulator/consumer.h>
  23#include <linux/gpio/consumer.h>
  24#include <linux/interrupt.h>
  25#include <linux/math64.h>
  26#include <linux/pm.h>
  27
  28#define CM3605_PROX_CHANNEL 0
  29#define CM3605_ALS_CHANNEL 1
  30#define CM3605_AOUT_TYP_MAX_MV 1550
  31/* It should not go above 1.650V according to the data sheet */
  32#define CM3605_AOUT_MAX_MV 1650
  33
  34/**
  35 * struct cm3605 - CM3605 state
  36 * @dev: pointer to parent device
  37 * @vdd: regulator controlling VDD
  38 * @aset: sleep enable GPIO, high = sleep
  39 * @aout: IIO ADC channel to convert the AOUT signal
  40 * @als_max: maximum LUX detection (depends on RSET)
  41 * @dir: proximity direction: start as FALLING
  42 * @led: trigger for the infrared LED used by the proximity sensor
  43 */
  44struct cm3605 {
  45        struct device *dev;
  46        struct regulator *vdd;
  47        struct gpio_desc *aset;
  48        struct iio_channel *aout;
  49        s32 als_max;
  50        enum iio_event_direction dir;
  51        struct led_trigger *led;
  52};
  53
  54static irqreturn_t cm3605_prox_irq(int irq, void *d)
  55{
  56        struct iio_dev *indio_dev = d;
  57        struct cm3605 *cm3605 = iio_priv(indio_dev);
  58        u64 ev;
  59
  60        ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, CM3605_PROX_CHANNEL,
  61                                  IIO_EV_TYPE_THRESH, cm3605->dir);
  62        iio_push_event(indio_dev, ev, iio_get_time_ns(indio_dev));
  63
  64        /* Invert the edge for each event */
  65        if (cm3605->dir == IIO_EV_DIR_RISING)
  66                cm3605->dir = IIO_EV_DIR_FALLING;
  67        else
  68                cm3605->dir = IIO_EV_DIR_RISING;
  69
  70        return IRQ_HANDLED;
  71}
  72
  73static int cm3605_get_lux(struct cm3605 *cm3605)
  74{
  75        int ret, res;
  76        s64 lux;
  77
  78        ret = iio_read_channel_processed(cm3605->aout, &res);
  79        if (ret < 0)
  80                return ret;
  81
  82        dev_dbg(cm3605->dev, "read %d mV from ADC\n", res);
  83
  84        /*
  85         * AOUT has an offset of ~30mV then linear at dark
  86         * then goes from 2.54 up to 650 LUX yielding 1.55V
  87         * (1550 mV) so scale the returned value to this interval
  88         * using simple linear interpolation.
  89         */
  90        if (res < 30)
  91                return 0;
  92        if (res > CM3605_AOUT_MAX_MV)
  93                dev_err(cm3605->dev, "device out of range\n");
  94
  95        /* Remove bias */
  96        lux = res - 30;
  97
  98        /* Linear interpolation between 0 and ALS typ max */
  99        lux *= cm3605->als_max;
 100        lux = div64_s64(lux, CM3605_AOUT_TYP_MAX_MV);
 101
 102        return lux;
 103}
 104
 105static int cm3605_read_raw(struct iio_dev *indio_dev,
 106                           struct iio_chan_spec const *chan,
 107                           int *val, int *val2, long mask)
 108{
 109        struct cm3605 *cm3605 = iio_priv(indio_dev);
 110        int ret;
 111
 112        switch (mask) {
 113        case IIO_CHAN_INFO_RAW:
 114                switch (chan->type) {
 115                case IIO_LIGHT:
 116                        ret = cm3605_get_lux(cm3605);
 117                        if (ret < 0)
 118                                return ret;
 119                        *val = ret;
 120                        return IIO_VAL_INT;
 121                default:
 122                        return -EINVAL;
 123                }
 124        default:
 125                return -EINVAL;
 126        }
 127}
 128
 129static const struct iio_info cm3605_info = {
 130        .read_raw = cm3605_read_raw,
 131};
 132
 133static const struct iio_event_spec cm3605_events[] = {
 134        {
 135                .type = IIO_EV_TYPE_THRESH,
 136                .dir = IIO_EV_DIR_EITHER,
 137                .mask_separate = BIT(IIO_EV_INFO_ENABLE),
 138        },
 139};
 140
 141static const struct iio_chan_spec cm3605_channels[] = {
 142        {
 143                .type = IIO_PROXIMITY,
 144                .event_spec = cm3605_events,
 145                .num_event_specs = ARRAY_SIZE(cm3605_events),
 146        },
 147        {
 148                .type = IIO_LIGHT,
 149                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 150                .channel = CM3605_ALS_CHANNEL,
 151        },
 152};
 153
 154static int cm3605_probe(struct platform_device *pdev)
 155{
 156        struct cm3605 *cm3605;
 157        struct iio_dev *indio_dev;
 158        struct device *dev = &pdev->dev;
 159        struct device_node *np = dev->of_node;
 160        enum iio_chan_type ch_type;
 161        u32 rset;
 162        int ret;
 163
 164        indio_dev = devm_iio_device_alloc(dev, sizeof(*cm3605));
 165        if (!indio_dev)
 166                return -ENOMEM;
 167        platform_set_drvdata(pdev, indio_dev);
 168
 169        cm3605 = iio_priv(indio_dev);
 170        cm3605->dev = dev;
 171        cm3605->dir = IIO_EV_DIR_FALLING;
 172
 173        ret = of_property_read_u32(np, "capella,aset-resistance-ohms", &rset);
 174        if (ret) {
 175                dev_info(dev, "no RSET specified, assuming 100K\n");
 176                rset = 100000;
 177        }
 178        switch (rset) {
 179        case 50000:
 180                cm3605->als_max = 650;
 181                break;
 182        case 100000:
 183                cm3605->als_max = 300;
 184                break;
 185        case 300000:
 186                cm3605->als_max = 100;
 187                break;
 188        case 600000:
 189                cm3605->als_max = 50;
 190                break;
 191        default:
 192                dev_info(dev, "non-standard resistance\n");
 193                return -EINVAL;
 194        }
 195
 196        cm3605->aout = devm_iio_channel_get(dev, "aout");
 197        if (IS_ERR(cm3605->aout)) {
 198                if (PTR_ERR(cm3605->aout) == -ENODEV) {
 199                        dev_err(dev, "no ADC, deferring...\n");
 200                        return -EPROBE_DEFER;
 201                }
 202                dev_err(dev, "failed to get AOUT ADC channel\n");
 203                return PTR_ERR(cm3605->aout);
 204        }
 205        ret = iio_get_channel_type(cm3605->aout, &ch_type);
 206        if (ret < 0)
 207                return ret;
 208        if (ch_type != IIO_VOLTAGE) {
 209                dev_err(dev, "wrong type of IIO channel specified for AOUT\n");
 210                return -EINVAL;
 211        }
 212
 213        cm3605->vdd = devm_regulator_get(dev, "vdd");
 214        if (IS_ERR(cm3605->vdd)) {
 215                dev_err(dev, "failed to get VDD regulator\n");
 216                return PTR_ERR(cm3605->vdd);
 217        }
 218        ret = regulator_enable(cm3605->vdd);
 219        if (ret) {
 220                dev_err(dev, "failed to enable VDD regulator\n");
 221                return ret;
 222        }
 223
 224        cm3605->aset = devm_gpiod_get(dev, "aset", GPIOD_OUT_HIGH);
 225        if (IS_ERR(cm3605->aset)) {
 226                dev_err(dev, "no ASET GPIO\n");
 227                ret = PTR_ERR(cm3605->aset);
 228                goto out_disable_vdd;
 229        }
 230
 231        ret = devm_request_threaded_irq(dev, platform_get_irq(pdev, 0),
 232                        cm3605_prox_irq, NULL, 0, "cm3605", indio_dev);
 233        if (ret) {
 234                dev_err(dev, "unable to request IRQ\n");
 235                goto out_disable_aset;
 236        }
 237
 238        /* Just name the trigger the same as the driver */
 239        led_trigger_register_simple("cm3605", &cm3605->led);
 240        led_trigger_event(cm3605->led, LED_FULL);
 241
 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
 256out_remove_trigger:
 257        led_trigger_event(cm3605->led, LED_OFF);
 258        led_trigger_unregister_simple(cm3605->led);
 259out_disable_aset:
 260        gpiod_set_value_cansleep(cm3605->aset, 0);
 261out_disable_vdd:
 262        regulator_disable(cm3605->vdd);
 263        return ret;
 264}
 265
 266static 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
 280static 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
 291static 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
 305static const struct dev_pm_ops cm3605_dev_pm_ops = {
 306        SET_SYSTEM_SLEEP_PM_OPS(cm3605_pm_suspend,
 307                                cm3605_pm_resume)
 308};
 309
 310static const struct of_device_id cm3605_of_match[] = {
 311        {.compatible = "capella,cm3605"},
 312        { },
 313};
 314MODULE_DEVICE_TABLE(of, cm3605_of_match);
 315
 316static 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};
 325module_platform_driver(cm3605_driver);
 326
 327MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 328MODULE_DESCRIPTION("CM3605 ambient light and proximity sensor driver");
 329MODULE_LICENSE("GPL");
 330