// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ACPI Ambient Light Sensor Driver
 *
 * Based on ALS driver:
 * Copyright (C) 2009 Zhang Rui <rui.zhang@intel.com>
 *
 * Rework for IIO subsystem:
 * Copyright (C) 2012-2013 Martin Liska <marxin.liska@gmail.com>
 *
 * Final cleanup and debugging:
 * Copyright (C) 2013-2014 Marek Vasut <marex@denx.de>
 * Copyright (C) 2015 Gabriele Mazzotta <gabriele.mzt@gmail.com>
 */

#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/mutex.h>

#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>

#define ACPI_ALS_CLASS                  "als"
#define ACPI_ALS_DEVICE_NAME            "acpi-als"
#define ACPI_ALS_NOTIFY_ILLUMINANCE     0x80

/*
 * So far, there's only one channel in here, but the specification for
 * ACPI0008 says there can be more to what the block can report. Like
 * chromaticity and such. We are ready for incoming additions!
 */
static const struct iio_chan_spec acpi_als_channels[] = {
        {
                .type           = IIO_LIGHT,
                .scan_type      = {
                        .sign           = 's',
                        .realbits       = 32,
                        .storagebits    = 32,
                },
                /* _RAW is here for backward ABI compatibility */
                .info_mask_separate     = BIT(IIO_CHAN_INFO_RAW) |
                                          BIT(IIO_CHAN_INFO_PROCESSED),
        },
        IIO_CHAN_SOFT_TIMESTAMP(1),
};

struct acpi_als {
        struct acpi_device      *device;
        struct mutex            lock;
        struct iio_trigger      *trig;
};

/*
 * All types of properties the ACPI0008 block can report. The ALI, ALC, ALT
 * and ALP can all be handled by acpi_als_read_value() below, while the ALR is
 * special.
 *
 * The _ALR property returns tables that can be used to fine-tune the values
 * reported by the other props based on the particular hardware type and it's
 * location (it contains tables for "rainy", "bright inhouse lighting" etc.).
 *
 * So far, we support only ALI (illuminance).
 */
#define ACPI_ALS_ILLUMINANCE    "_ALI"
#define ACPI_ALS_CHROMATICITY   "_ALC"
#define ACPI_ALS_COLOR_TEMP     "_ALT"
#define ACPI_ALS_POLLING        "_ALP"
#define ACPI_ALS_TABLES         "_ALR"

static int acpi_als_read_value(struct acpi_als *als, char *prop, s32 *val)
{
        unsigned long long temp_val;
        acpi_status status;

        status = acpi_evaluate_integer(als->device->handle, prop, NULL,
                                       &temp_val);

        if (ACPI_FAILURE(status)) {
                acpi_evaluation_failure_warn(als->device->handle, prop, status);
                return -EIO;
        }

        *val = temp_val;

        return 0;
}

static void acpi_als_notify(struct acpi_device *device, u32 event)
{
        struct iio_dev *indio_dev = acpi_driver_data(device);
        struct acpi_als *als = iio_priv(indio_dev);

        if (iio_buffer_enabled(indio_dev) && iio_trigger_using_own(indio_dev)) {
                switch (event) {
                case ACPI_ALS_NOTIFY_ILLUMINANCE:
                        iio_trigger_poll_nested(als->trig);
                        break;
                default:
                        /* Unhandled event */
                        dev_dbg(&device->dev,
                                "Unhandled ACPI ALS event (%08x)!\n",
                                event);
                }
        }
}

static int acpi_als_read_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan, int *val,
                             int *val2, long mask)
{
        struct acpi_als *als = iio_priv(indio_dev);
        s32 temp_val;
        int ret;

        if ((mask != IIO_CHAN_INFO_PROCESSED) && (mask != IIO_CHAN_INFO_RAW))
                return -EINVAL;

        /* we support only illumination (_ALI) so far. */
        if (chan->type != IIO_LIGHT)
                return -EINVAL;

        ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &temp_val);
        if (ret < 0)
                return ret;

        *val = temp_val;

        return IIO_VAL_INT;
}

static const struct iio_info acpi_als_info = {
        .read_raw               = acpi_als_read_raw,
};

static irqreturn_t acpi_als_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct acpi_als *als = iio_priv(indio_dev);
        struct {
                s32 light;
                aligned_s64 ts;
        } scan = { };
        s32 val;
        int ret;

        mutex_lock(&als->lock);

        ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &val);
        if (ret < 0)
                goto out;
        scan.light = val;

        /*
         * When coming from own trigger via polls, set polling function
         * timestamp here. Given ACPI notifier is already in a thread and call
         * function directly, there is no need to set the timestamp in the
         * notify function.
         *
         * If the timestamp was actually 0, the timestamp is set one more time.
         */
        if (!pf->timestamp)
                pf->timestamp = iio_get_time_ns(indio_dev);

        iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan), pf->timestamp);
out:
        mutex_unlock(&als->lock);
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static int acpi_als_add(struct acpi_device *device)
{
        struct device *dev = &device->dev;
        struct iio_dev *indio_dev;
        struct acpi_als *als;
        int ret;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*als));
        if (!indio_dev)
                return -ENOMEM;

        als = iio_priv(indio_dev);

        device->driver_data = indio_dev;
        als->device = device;
        mutex_init(&als->lock);

        indio_dev->name = ACPI_ALS_DEVICE_NAME;
        indio_dev->info = &acpi_als_info;
        indio_dev->channels = acpi_als_channels;
        indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);

        als->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
                                           iio_device_id(indio_dev));
        if (!als->trig)
                return -ENOMEM;

        ret = devm_iio_trigger_register(dev, als->trig);
        if (ret)
                return ret;
        /*
         * Set hardware trigger by default to let events flow when
         * BIOS support notification.
         */
        indio_dev->trig = iio_trigger_get(als->trig);

        ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
                                              iio_pollfunc_store_time,
                                              acpi_als_trigger_handler,
                                              NULL);
        if (ret)
                return ret;

        return devm_iio_device_register(dev, indio_dev);
}

static const struct acpi_device_id acpi_als_device_ids[] = {
        {"ACPI0008", 0},
        { }
};

MODULE_DEVICE_TABLE(acpi, acpi_als_device_ids);

static struct acpi_driver acpi_als_driver = {
        .name   = "acpi_als",
        .class  = ACPI_ALS_CLASS,
        .ids    = acpi_als_device_ids,
        .ops = {
                .add    = acpi_als_add,
                .notify = acpi_als_notify,
        },
};

module_acpi_driver(acpi_als_driver);

MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
MODULE_AUTHOR("Martin Liska <marxin.liska@gmail.com>");
MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
MODULE_LICENSE("GPL");