dm: spi: Read default speed and mode values from DT

This patch update the behavior introduced by
commit 96907c0fe50a ("dm: spi: Read default speed and mode values from DT")

In case of DT boot, don't read default speed and mode for SPI from
CONFIG_* but instead read from DT node. This will make sure that boards
with multiple SPI/QSPI controllers can be probed at different
bus frequencies and SPI modes.

Remove also use in boards of the value speed=0 (no more supported)
for ENV in SPI by using CONFIG_ENV_SPI_MAX_HZ=0.

DT values will be always used when available (full DM support of
SPI slave with available DT node) even if speed and mode are requested;
for example in splash screen support (in splash_sf_read_raw)
or in SPL boot (in spl_spi_load_image).
The caller of spi_get_bus_and_cs() no more need to force speed=0.

But the current behavior don't change if the SPI slave is not
present (device with generic driver is created automatically)
or if platdata is used (CONFIG_OF_PLATDATA).

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Acked-by: Jagan Teki <jagan@amarulasolutions.com>

2 files changed, 9 insertions, 1 deletions

diff --git a/drivers/mtd/spi/Kconfig b/drivers/mtd/spi/Kconfig
index 5671bca..d3b007a 100644
--- a/drivers/mtd/spi/Kconfig
+++ b/drivers/mtd/spi/Kconfig
@@ -62,6 +62,9 @@ config SF_DEFAULT_MODE
 	  The default mode may be provided by the platform
 	  to handle the common case when only a single serial
 	  flash is present on the system.
+	  Not used for boot with device tree; the SPI driver reads
+	  speed and mode from platdata values computed from
+	  available node.
 
 config SF_DEFAULT_SPEED
 	int "SPI Flash default speed in Hz"
@@ -71,6 +74,9 @@ config SF_DEFAULT_SPEED
 	  The default speed may be provided by the platform
 	  to handle the common case when only a single serial
 	  flash is present on the system.
+	  Not used for boot with device tree; the SPI driver reads
+	  speed and mode from platdata values computed from
+	  available node.
 
 if SPI_FLASH
 
diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
index 2bc289a..88cb2a1 100644
--- a/drivers/spi/spi-uclass.c
+++ b/drivers/spi/spi-uclass.c
@@ -328,7 +328,9 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int mode,
 	}
 
 	plat = dev_get_parent_platdata(dev);
-	if (!speed) {
+
+	/* get speed and mode from platdata when available */
+	if (plat->max_hz) {
 		speed = plat->max_hz;
 		mode = plat->mode;
 	}