// SPDX-License-Identifier: GPL-2.0-only
/*
 * STMicroelectronics sensors buffer library driver
 *
 * Copyright 2012-2013 STMicroelectronics Inc.
 *
 * Denis Ciocca <denis.ciocca@st.com>
 */

#include <linux/kernel.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/interrupt.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/irqreturn.h>
#include <linux/regmap.h>

#include <linux/iio/common/st_sensors.h>


static int st_sensors_get_buffer_element(struct iio_dev *indio_dev, u8 *buf)
{
        struct st_sensor_data *sdata = iio_priv(indio_dev);
        unsigned int num_data_channels = sdata->num_data_channels;
        int i;

        for_each_set_bit(i, indio_dev->active_scan_mask, num_data_channels) {
                const struct iio_chan_spec *channel = &indio_dev->channels[i];
                unsigned int bytes_to_read =
                        DIV_ROUND_UP(channel->scan_type.realbits +
                                     channel->scan_type.shift, 8);
                unsigned int storage_bytes =
                        channel->scan_type.storagebits >> 3;

                buf = PTR_ALIGN(buf, storage_bytes);
                if (regmap_bulk_read(sdata->regmap, channel->address,
                                     buf, bytes_to_read) < 0)
                        return -EIO;

                /* Advance the buffer pointer */
                buf += storage_bytes;
        }

        return 0;
}

irqreturn_t st_sensors_trigger_handler(int irq, void *p)
{
        int len;
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct st_sensor_data *sdata = iio_priv(indio_dev);
        s64 timestamp;

        /*
         * If we do timestamping here, do it before reading the values, because
         * once we've read the values, new interrupts can occur (when using
         * the hardware trigger) and the hw_timestamp may get updated.
         * By storing it in a local variable first, we are safe.
         */
        if (iio_trigger_using_own(indio_dev))
                timestamp = sdata->hw_timestamp;
        else
                timestamp = iio_get_time_ns(indio_dev);

        len = st_sensors_get_buffer_element(indio_dev, sdata->buffer_data);
        if (len < 0)
                goto st_sensors_get_buffer_element_error;

        iio_push_to_buffers_with_timestamp(indio_dev, sdata->buffer_data,
                                           timestamp);

st_sensors_get_buffer_element_error:
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}
EXPORT_SYMBOL_NS(st_sensors_trigger_handler, "IIO_ST_SENSORS");