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Commit 8134b613 authored by David Lechner's avatar David Lechner Committed by Jonathan Cameron
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iio: adc: ti-ads7950: allow simultaneous use of buffer and direct mode 



This modifies the TI ADS7950 A/DC driver to allow the simultaneous use
of both the triggered buffer and reading channels directly (via in-
kernel API or sysfs).

The use case for this is on LEGO MINDSTORMS EV3. Two of the voltage
channels are used in-kernel by a power supply driver, which reads the
values using iio_read_channel_processed(). These channels are only read
at a slow rate (<= 1Hz).  However, we want to be able to read 12 other
channels at the same time using the triggered buffer at a high rate (>=
100Hz).

Signed-off-by: default avatarDavid Lechner <david@lechnology.com>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 7d7209f0

drivers/iio/adc/ti-ads7950.c

+19 −14
Original line number Diff line number Diff line
@@ -68,6 +68,9 @@ struct ti_ads7950_state { 
	__be16	rx_buf[TI_ADS7950_MAX_CHAN + TI_ADS7950_TIMESTAMP_SIZE]

							____cacheline_aligned;

	__be16	tx_buf[TI_ADS7950_MAX_CHAN];

	__be16			single_tx;

	__be16			single_rx;



};



struct ti_ads7950_chip_info {
@@ -287,18 +290,26 @@ static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p) 
	return IRQ_HANDLED;

}



static int ti_ads7950_scan_direct(struct ti_ads7950_state *st, unsigned int ch)

static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch)

{

	struct ti_ads7950_state *st = iio_priv(indio_dev);

	int ret, cmd;



	mutex_lock(&indio_dev->mlock);



	cmd = TI_ADS7950_CR_WRITE | TI_ADS7950_CR_CHAN(ch) | st->settings;

	st->tx_buf[0] = cpu_to_be16(cmd);

	st->single_tx = cpu_to_be16(cmd);



	ret = spi_sync(st->spi, &st->scan_single_msg);

	if (ret)

		return ret;

		goto out;



	ret = be16_to_cpu(st->single_rx);



	return be16_to_cpu(st->rx_buf[0]);

out:

	mutex_unlock(&indio_dev->mlock);



	return ret;

}



static int ti_ads7950_get_range(struct ti_ads7950_state *st)
@@ -330,13 +341,7 @@ static int ti_ads7950_read_raw(struct iio_dev *indio_dev, 


	switch (m) {

	case IIO_CHAN_INFO_RAW:



		ret = iio_device_claim_direct_mode(indio_dev);

		if (ret < 0)

			return ret;



		ret = ti_ads7950_scan_direct(st, chan->address);

		iio_device_release_direct_mode(indio_dev);

		ret = ti_ads7950_scan_direct(indio_dev, chan->address);

		if (ret < 0)

			return ret;
@@ -402,13 +407,13 @@ static int ti_ads7950_probe(struct spi_device *spi) 
	 * was read at the end of the first transfer.

	 */



	st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];

	st->scan_single_xfer[0].tx_buf = &st->single_tx;

	st->scan_single_xfer[0].len = 2;

	st->scan_single_xfer[0].cs_change = 1;

	st->scan_single_xfer[1].tx_buf = &st->tx_buf[0];

	st->scan_single_xfer[1].tx_buf = &st->single_tx;

	st->scan_single_xfer[1].len = 2;

	st->scan_single_xfer[1].cs_change = 1;

	st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];

	st->scan_single_xfer[2].rx_buf = &st->single_rx;

	st->scan_single_xfer[2].len = 2;



	spi_message_init_with_transfers(&st->scan_single_msg,