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authorDavid Lechner <david@lechnology.com>2018-07-21 14:37:34 -0500
committerJonathan Cameron <Jonathan.Cameron@huawei.com>2018-07-23 19:18:12 +0100
commit8134b613b05dd27fc718fbe3785ccc9c5da10e02 (patch)
tree345aca60298f8c51535cab0832d7f86e2d9104f9 /drivers/iio
parent7d7209f0c467ba8b86229dbd4e1aa2f3d9b0c5bb (diff)
downloadlinux-8134b613b05dd27fc718fbe3785ccc9c5da10e02.tar.bz2
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: David Lechner <david@lechnology.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers/iio')
-rw-r--r--drivers/iio/adc/ti-ads7950.c33
1 files changed, 19 insertions, 14 deletions
diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
index f08c4de2bd10..a5bd5944bc66 100644
--- a/drivers/iio/adc/ti-ads7950.c
+++ b/drivers/iio/adc/ti-ads7950.c
@@ -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 @@ out:
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,