// SPDX-License-Identifier: GPL-2.0-only
/*
 * CM3605 Ambient Light and Proximity Sensor
 *
 * Copyright (C) 2016 Linaro Ltd.
 * Author: Linus Walleij <linus.walleij@linaro.org>
 *
 * This hardware was found in the very first Nexus One handset from Google/HTC
 * and an early endavour into mobile light and proximity sensors.
 */

#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include <linux/iio/consumer.h> /* To get our ADC channel */
#include <linux/iio/types.h> /* To deal with our ADC channel */
#include <linux/init.h>
#include <linux/leds.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/math64.h>
#include <linux/pm.h>

#define CM3605_PROX_CHANNEL 0
#define CM3605_ALS_CHANNEL 1
#define CM3605_AOUT_TYP_MAX_MV 1550
/* It should not go above 1.650V according to the data sheet */
#define CM3605_AOUT_MAX_MV 1650

/**
 * struct cm3605 - CM3605 state
 * @dev: pointer to parent device
 * @vdd: regulator controlling VDD
 * @aset: sleep enable GPIO, high = sleep
 * @aout: IIO ADC channel to convert the AOUT signal
 * @als_max: maximum LUX detection (depends on RSET)
 * @dir: proximity direction: start as FALLING
 * @led: trigger for the infrared LED used by the proximity sensor
 */
struct cm3605 {
        struct device *dev;
        struct regulator *vdd;
        struct gpio_desc *aset;
        struct iio_channel *aout;
        s32 als_max;
        enum iio_event_direction dir;
        struct led_trigger *led;
};

static irqreturn_t cm3605_prox_irq(int irq, void *d)
{
        struct iio_dev *indio_dev = d;
        struct cm3605 *cm3605 = iio_priv(indio_dev);
        u64 ev;

        ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, CM3605_PROX_CHANNEL,
                                  IIO_EV_TYPE_THRESH, cm3605->dir);
        iio_push_event(indio_dev, ev, iio_get_time_ns(indio_dev));

        /* Invert the edge for each event */
        if (cm3605->dir == IIO_EV_DIR_RISING)
                cm3605->dir = IIO_EV_DIR_FALLING;
        else
                cm3605->dir = IIO_EV_DIR_RISING;

        return IRQ_HANDLED;
}

static int cm3605_get_lux(struct cm3605 *cm3605)
{
        int ret, res;
        s64 lux;

        ret = iio_read_channel_processed(cm3605->aout, &res);
        if (ret < 0)
                return ret;

        dev_dbg(cm3605->dev, "read %d mV from ADC\n", res);

        /*
         * AOUT has an offset of ~30mV then linear at dark
         * then goes from 2.54 up to 650 LUX yielding 1.55V
         * (1550 mV) so scale the returned value to this interval
         * using simple linear interpolation.
         */
        if (res < 30)
                return 0;
        if (res > CM3605_AOUT_MAX_MV)
                dev_err(cm3605->dev, "device out of range\n");

        /* Remove bias */
        lux = res - 30;

        /* Linear interpolation between 0 and ALS typ max */
        lux *= cm3605->als_max;
        lux = div64_s64(lux, CM3605_AOUT_TYP_MAX_MV);

        return lux;
}

static int cm3605_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan,
                           int *val, int *val2, long mask)
{
        struct cm3605 *cm3605 = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                switch (chan->type) {
                case IIO_LIGHT:
                        ret = cm3605_get_lux(cm3605);
                        if (ret < 0)
                                return ret;
                        *val = ret;
                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }
        default:
                return -EINVAL;
        }
}

static const struct iio_info cm3605_info = {
        .read_raw = cm3605_read_raw,
};

static const struct iio_event_spec cm3605_events[] = {
        {
                .type = IIO_EV_TYPE_THRESH,
                .dir = IIO_EV_DIR_EITHER,
                .mask_separate = BIT(IIO_EV_INFO_ENABLE),
        },
};

static const struct iio_chan_spec cm3605_channels[] = {
        {
                .type = IIO_PROXIMITY,
                .event_spec = cm3605_events,
                .num_event_specs = ARRAY_SIZE(cm3605_events),
        },
        {
                .type = IIO_LIGHT,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
                .channel = CM3605_ALS_CHANNEL,
        },
};

static int cm3605_probe(struct platform_device *pdev)
{
        struct cm3605 *cm3605;
        struct iio_dev *indio_dev;
        struct device *dev = &pdev->dev;
        enum iio_chan_type ch_type;
        u32 rset;
        int irq;
        int ret;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*cm3605));
        if (!indio_dev)
                return -ENOMEM;
        platform_set_drvdata(pdev, indio_dev);

        cm3605 = iio_priv(indio_dev);
        cm3605->dev = dev;
        cm3605->dir = IIO_EV_DIR_FALLING;

        ret = device_property_read_u32(dev, "capella,aset-resistance-ohms", &rset);
        if (ret) {
                dev_info(dev, "no RSET specified, assuming 100K\n");
                rset = 100000;
        }
        switch (rset) {
        case 50000:
                cm3605->als_max = 650;
                break;
        case 100000:
                cm3605->als_max = 300;
                break;
        case 300000:
                cm3605->als_max = 100;
                break;
        case 600000:
                cm3605->als_max = 50;
                break;
        default:
                dev_info(dev, "non-standard resistance\n");
                return -EINVAL;
        }

        cm3605->aout = devm_iio_channel_get(dev, "aout");
        if (IS_ERR(cm3605->aout)) {
                ret = PTR_ERR(cm3605->aout);
                ret = (ret == -ENODEV) ? -EPROBE_DEFER : ret;
                return dev_err_probe(dev, ret, "failed to get AOUT ADC channel\n");
        }
        ret = iio_get_channel_type(cm3605->aout, &ch_type);
        if (ret < 0)
                return ret;
        if (ch_type != IIO_VOLTAGE) {
                dev_err(dev, "wrong type of IIO channel specified for AOUT\n");
                return -EINVAL;
        }

        cm3605->vdd = devm_regulator_get(dev, "vdd");
        if (IS_ERR(cm3605->vdd))
                return dev_err_probe(dev, PTR_ERR(cm3605->vdd),
                                     "failed to get VDD regulator\n");

        ret = regulator_enable(cm3605->vdd);
        if (ret) {
                dev_err(dev, "failed to enable VDD regulator\n");
                return ret;
        }

        cm3605->aset = devm_gpiod_get(dev, "aset", GPIOD_OUT_HIGH);
        if (IS_ERR(cm3605->aset)) {
                ret = dev_err_probe(dev, PTR_ERR(cm3605->aset), "no ASET GPIO\n");
                goto out_disable_vdd;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                ret = irq;
                goto out_disable_aset;
        }

        ret = devm_request_threaded_irq(dev, irq, cm3605_prox_irq,
                                        NULL, 0, "cm3605", indio_dev);
        if (ret) {
                dev_err(dev, "unable to request IRQ\n");
                goto out_disable_aset;
        }

        /* Just name the trigger the same as the driver */
        led_trigger_register_simple("cm3605", &cm3605->led);
        led_trigger_event(cm3605->led, LED_FULL);

        indio_dev->info = &cm3605_info;
        indio_dev->name = "cm3605";
        indio_dev->channels = cm3605_channels;
        indio_dev->num_channels = ARRAY_SIZE(cm3605_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = iio_device_register(indio_dev);
        if (ret)
                goto out_remove_trigger;
        dev_info(dev, "Capella Microsystems CM3605 enabled range 0..%d LUX\n",
                 cm3605->als_max);

        return 0;

out_remove_trigger:
        led_trigger_event(cm3605->led, LED_OFF);
        led_trigger_unregister_simple(cm3605->led);
out_disable_aset:
        gpiod_set_value_cansleep(cm3605->aset, 0);
out_disable_vdd:
        regulator_disable(cm3605->vdd);
        return ret;
}

static void cm3605_remove(struct platform_device *pdev)
{
        struct iio_dev *indio_dev = platform_get_drvdata(pdev);
        struct cm3605 *cm3605 = iio_priv(indio_dev);

        led_trigger_event(cm3605->led, LED_OFF);
        led_trigger_unregister_simple(cm3605->led);
        gpiod_set_value_cansleep(cm3605->aset, 0);
        iio_device_unregister(indio_dev);
        regulator_disable(cm3605->vdd);
}

static int cm3605_pm_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct cm3605 *cm3605 = iio_priv(indio_dev);

        led_trigger_event(cm3605->led, LED_OFF);
        regulator_disable(cm3605->vdd);

        return 0;
}

static int cm3605_pm_resume(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct cm3605 *cm3605 = iio_priv(indio_dev);
        int ret;

        ret = regulator_enable(cm3605->vdd);
        if (ret)
                dev_err(dev, "failed to enable regulator in resume path\n");
        led_trigger_event(cm3605->led, LED_FULL);

        return 0;
}
static DEFINE_SIMPLE_DEV_PM_OPS(cm3605_dev_pm_ops, cm3605_pm_suspend,
                                cm3605_pm_resume);

static const struct of_device_id cm3605_of_match[] = {
        {.compatible = "capella,cm3605"},
        { }
};
MODULE_DEVICE_TABLE(of, cm3605_of_match);

static struct platform_driver cm3605_driver = {
        .driver = {
                .name = "cm3605",
                .of_match_table = cm3605_of_match,
                .pm = pm_sleep_ptr(&cm3605_dev_pm_ops),
        },
        .probe = cm3605_probe,
        .remove = cm3605_remove,
};
module_platform_driver(cm3605_driver);

MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
MODULE_DESCRIPTION("CM3605 ambient light and proximity sensor driver");
MODULE_LICENSE("GPL");