iio: adis16400: do not directly change spi 'max_speed_hz'

With commit 3ba10e37371d ("iio: adis: add burst_max_speed_hz variable"), we
just need to define 'burst_max_speed_hz' and the adis core will take
care of setting up the spi transfers for burst mode. Hence, we fix
a potential race with the spi core where we could be left witn an
invalid 'max_speed_hz'.
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Fixes: 5eda3550 ("staging:iio:adis16400: Preallocate transfer message")
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20210427085454.30616-7-nuno.sa@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/adis16400.c

@@ -641,25 +641,13 @@ static irqreturn_t adis16400_trigger_handler(int irq, void *p)
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct adis16400_state *st = iio_priv(indio_dev);
 	struct adis *adis = &st->adis;
-	u32 old_speed_hz = st->adis.spi->max_speed_hz;
 	void *buffer;
 	int ret;
 
-	if (!(st->variant->flags & ADIS16400_NO_BURST) &&
-		st->adis.spi->max_speed_hz > ADIS16400_SPI_BURST) {
-		st->adis.spi->max_speed_hz = ADIS16400_SPI_BURST;
-		spi_setup(st->adis.spi);
-	}
-
 	ret = spi_sync(adis->spi, &adis->msg);
 	if (ret)
 		dev_err(&adis->spi->dev, "Failed to read data: %d\n", ret);
 
-	if (!(st->variant->flags & ADIS16400_NO_BURST)) {
-		st->adis.spi->max_speed_hz = old_speed_hz;
-		spi_setup(st->adis.spi);
-	}
-
 	if (st->variant->flags & ADIS16400_BURST_DIAG_STAT)
 		buffer = adis->buffer + sizeof(u16);
 	else
@@ -965,7 +953,8 @@ static const char * const adis16400_status_error_msgs[] = {
 		BIT(ADIS16400_DIAG_STAT_POWER_LOW),			\
 	.timeouts = (_timeouts),					\
 	.burst_reg_cmd = ADIS16400_GLOB_CMD,				\
-	.burst_len = (_burst_len)					\
+	.burst_len = (_burst_len),					\
+	.burst_max_speed_hz = ADIS16400_SPI_BURST			\
 }
 
 static const struct adis_timeout adis16300_timeouts = {