[PATCH 3/3] spi: dw: Use the rx-sample-delay-ns value parsed by the core

[Frieder Schrempf <frieder@fris.de>]

From: Frieder Schrempf <frieder.schrempf@kontron.de>

The core now parses the "rx-sample-delay-ns" peripheral property into
spi_device.rx_sample_delay_ns, so drop the private copy of that parsing.

The controller-wide default is deliberately left alone. It is read from
the *controller* node into dws->def_rx_sample_dly_ns, which is a
different node and none of the core's business when it parses properties
of a peripheral.

One corner case changes: the peripheral value is now treated as unset
when it is zero, whereas before an absent property could be told apart
from an explicit "rx-sample-delay-ns = <0>", the latter overriding a
non-zero controller default with no delay at all. There are two users of
the property in the whole tree and neither does this, and zero means the
same as unset for every other user of the new field.

Assisted-by: Claude:claude-opus-5
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
---
 drivers/spi/spi-dw-core.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index 206d3f9dd83d..b86b607cc817 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -1104,12 +1104,13 @@ static int dw_spi_setup(struct spi_device *spi)
 		if (!chip)
 			return -ENOMEM;
 		spi_set_ctldata(spi, chip);
-		/* Get specific / default rx-sample-delay */
-		if (device_property_read_u32(&spi->dev,
-					     "rx-sample-delay-ns",
-					     &rx_sample_dly_ns) != 0)
-			/* Use default controller value */
-			rx_sample_dly_ns = dws->def_rx_sample_dly_ns;
+		/*
+		 * Use the per-device value the core parsed from the peripheral
+		 * node, and fall back to the controller-wide default when the
+		 * device does not ask for a delay of its own.
+		 */
+		rx_sample_dly_ns = spi->rx_sample_delay_ns ?:
+				   dws->def_rx_sample_dly_ns;
 		chip->rx_sample_dly = DIV_ROUND_CLOSEST(rx_sample_dly_ns,
 							NSEC_PER_SEC /
 							dws->max_freq);

-- 
2.55.0