diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iio/pressure/mprls0025pa_spi.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/drivers/iio/pressure/mprls0025pa_spi.c b/drivers/iio/pressure/mprls0025pa_spi.c index f4807dac61e0..241ad36f6501 100644 --- a/drivers/iio/pressure/mprls0025pa_spi.c +++ b/drivers/iio/pressure/mprls0025pa_spi.c @@ -8,6 +8,7 @@ * https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/products/sensors/pressure-sensors/board-mount-pressure-sensors/micropressure-mpr-series/documents/sps-siot-mpr-series-datasheet-32332628-ciid-172626.pdf */ +#include <linux/array_size.h> #include <linux/device.h> #include <linux/errno.h> #include <linux/mod_devicetable.h> @@ -40,17 +41,25 @@ static int mpr_spi_xfer(struct mpr_data *data, const u8 cmd, const u8 pkt_len) { struct spi_device *spi = to_spi_device(data->dev); struct mpr_spi_buf *buf = spi_get_drvdata(spi); - struct spi_transfer xfer = { }; + struct spi_transfer xfers[2] = { }; if (pkt_len > MPR_MEASUREMENT_RD_SIZE) return -EOVERFLOW; buf->tx[0] = cmd; - xfer.tx_buf = buf->tx; - xfer.rx_buf = data->buffer; - xfer.len = pkt_len; - return spi_sync_transfer(spi, &xfer, 1); + /* + * Dummy transfer with no data, just cause a 2.5us+ delay between the CS assert + * and the first clock edge as per the datasheet tHDSS timing requirement. + */ + xfers[0].delay.value = 2500; + xfers[0].delay.unit = SPI_DELAY_UNIT_NSECS; + + xfers[1].tx_buf = buf->tx; + xfers[1].rx_buf = data->buffer; + xfers[1].len = pkt_len; + + return spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers)); } static const struct mpr_ops mpr_spi_ops = { |