// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Common library for ADIS16XXX devices
 *
 * Copyright 2012 Analog Devices Inc.
 *   Author: Lars-Peter Clausen <lars@metafoo.de>
 */

#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>

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

static int adis_update_scan_mode_burst(struct iio_dev *indio_dev,
        const unsigned long *scan_mask)
{
        struct adis *adis = iio_device_get_drvdata(indio_dev);
        unsigned int burst_length, burst_max_length;
        u8 *tx;

        burst_length = adis->data->burst_len + adis->burst_extra_len;

        if (adis->data->burst_max_len)
                burst_max_length = adis->data->burst_max_len;
        else
                burst_max_length = burst_length;

        adis->xfer = kcalloc(2, sizeof(*adis->xfer), GFP_KERNEL);
        if (!adis->xfer)
                return -ENOMEM;

        adis->buffer = kzalloc(burst_max_length + sizeof(u16), GFP_KERNEL);
        if (!adis->buffer) {
                kfree(adis->xfer);
                adis->xfer = NULL;
                return -ENOMEM;
        }

        tx = adis->buffer + burst_max_length;
        tx[0] = ADIS_READ_REG(adis->data->burst_reg_cmd);
        tx[1] = 0;

        adis->xfer[0].tx_buf = tx;
        adis->xfer[0].bits_per_word = 8;
        adis->xfer[0].len = 2;
        adis->xfer[1].rx_buf = adis->buffer;
        adis->xfer[1].bits_per_word = 8;
        adis->xfer[1].len = burst_length;

        spi_message_init(&adis->msg);
        spi_message_add_tail(&adis->xfer[0], &adis->msg);
        spi_message_add_tail(&adis->xfer[1], &adis->msg);

        return 0;
}

int adis_update_scan_mode(struct iio_dev *indio_dev,
        const unsigned long *scan_mask)
{
        struct adis *adis = iio_device_get_drvdata(indio_dev);
        const struct iio_chan_spec *chan;
        unsigned int scan_count;
        unsigned int i, j;
        __be16 *tx, *rx;

        kfree(adis->xfer);
        kfree(adis->buffer);

        if (adis->data->burst_len)
                return adis_update_scan_mode_burst(indio_dev, scan_mask);

        scan_count = indio_dev->scan_bytes / 2;

        adis->xfer = kcalloc(scan_count + 1, sizeof(*adis->xfer), GFP_KERNEL);
        if (!adis->xfer)
                return -ENOMEM;

        adis->buffer = kcalloc(indio_dev->scan_bytes, 2, GFP_KERNEL);
        if (!adis->buffer) {
                kfree(adis->xfer);
                adis->xfer = NULL;
                return -ENOMEM;
        }

        rx = adis->buffer;
        tx = rx + scan_count;

        spi_message_init(&adis->msg);

        for (j = 0; j <= scan_count; j++) {
                adis->xfer[j].bits_per_word = 8;
                if (j != scan_count)
                        adis->xfer[j].cs_change = 1;
                adis->xfer[j].len = 2;
                adis->xfer[j].delay.value = adis->data->read_delay;
                adis->xfer[j].delay.unit = SPI_DELAY_UNIT_USECS;
                if (j < scan_count)
                        adis->xfer[j].tx_buf = &tx[j];
                if (j >= 1)
                        adis->xfer[j].rx_buf = &rx[j - 1];
                spi_message_add_tail(&adis->xfer[j], &adis->msg);
        }

        chan = indio_dev->channels;
        for (i = 0; i < indio_dev->num_channels; i++, chan++) {
                if (!test_bit(chan->scan_index, scan_mask))
                        continue;
                if (chan->scan_type.storagebits == 32)
                        *tx++ = cpu_to_be16((chan->address + 2) << 8);
                *tx++ = cpu_to_be16(chan->address << 8);
        }

        return 0;
}
EXPORT_SYMBOL_GPL(adis_update_scan_mode);

static irqreturn_t adis_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct adis *adis = iio_device_get_drvdata(indio_dev);
        int ret;

        if (!adis->buffer)
                return -ENOMEM;

        if (adis->data->has_paging) {
                mutex_lock(&adis->state_lock);
                if (adis->current_page != 0) {
                        adis->tx[0] = ADIS_WRITE_REG(ADIS_REG_PAGE_ID);
                        adis->tx[1] = 0;
                        spi_write(adis->spi, adis->tx, 2);
                }
        }

        ret = spi_sync(adis->spi, &adis->msg);
        if (ret)
                dev_err(&adis->spi->dev, "Failed to read data: %d", ret);


        if (adis->data->has_paging) {
                adis->current_page = 0;
                mutex_unlock(&adis->state_lock);
        }

        iio_push_to_buffers_with_timestamp(indio_dev, adis->buffer,
                pf->timestamp);

        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static void adis_buffer_cleanup(void *arg)
{
        struct adis *adis = arg;

        kfree(adis->buffer);
        kfree(adis->xfer);
}

/**
 * devm_adis_setup_buffer_and_trigger() - Sets up buffer and trigger for
 *                                        the managed adis device
 * @adis: The adis device
 * @indio_dev: The IIO device
 * @trigger_handler: Optional trigger handler, may be NULL.
 *
 * Returns 0 on success, a negative error code otherwise.
 *
 * This function sets up the buffer and trigger for a adis devices.  If
 * 'trigger_handler' is NULL the default trigger handler will be used. The
 * default trigger handler will simply read the registers assigned to the
 * currently active channels.
 */
int
devm_adis_setup_buffer_and_trigger(struct adis *adis, struct iio_dev *indio_dev,
                                   irq_handler_t trigger_handler)
{
        int ret;

        if (!trigger_handler)
                trigger_handler = adis_trigger_handler;

        ret = devm_iio_triggered_buffer_setup(&adis->spi->dev, indio_dev,
                                              &iio_pollfunc_store_time,
                                              trigger_handler, NULL);
        if (ret)
                return ret;

        if (adis->spi->irq) {
                ret = devm_adis_probe_trigger(adis, indio_dev);
                if (ret)
                        return ret;
        }

        return devm_add_action_or_reset(&adis->spi->dev, adis_buffer_cleanup,
                                        adis);
}
EXPORT_SYMBOL_GPL(devm_adis_setup_buffer_and_trigger);