text: // 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;
  	if (adis->data->burst_max_speed_hz)
  		adis->xfer[0].speed_hz = adis->data->burst_max_speed_hz;
  	adis->xfer[1].rx_buf = adis->buffer;
  	adis->xfer[1].bits_per_word = 8;
  	adis->xfer[1].len = burst_length;
  	if (adis->data->burst_max_speed_hz)
  		adis->xfer[1].speed_hz = adis->data->burst_max_speed_hz;
  
  	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->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;
  			ret = spi_write(adis->spi, adis->tx, 2);
  			if (ret) {
  				dev_err(&adis->spi->dev, "Failed to change device page: %d\n", ret);
  				mutex_unlock(&adis->state_lock);
  				goto irq_done;
  			}
  
  			adis->current_page = 0;
  		}
  	}
  
  	ret = spi_sync(adis->spi, &adis->msg);
  	if (adis->data->has_paging)
  		mutex_unlock(&adis->state_lock);
  	if (ret) {
  		dev_err(&adis->spi->dev, "Failed to read data: %d", ret);
  		goto irq_done;
  	}
  
  	iio_push_to_buffers_with_timestamp(indio_dev, adis->buffer,
  		pf->timestamp);
  
  irq_done:
  	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);
  
  