dfu: sf: rely on DT for spi speed and mode

Align with cmd_sf, and try to rely on DT for spi speed and mode,
and still fallback on spi_flash_probe() if it fails.

With the current scheme, spi_flash_probe() will be called
with CONFIG_SF_DEFAULT_SPEED and CONFIG_SF_DEFAULT_MODE
with are set to 0 by default on DT platforms using DM_SPI_FLASH.

Like cmd_sf, keep the option to specify the speed and mode
from the dfu_alt_mode string, but rely on DT properties
if not specified.

Using CONFIG_SF_DEFAULT_SPEED and CONFIG_SF_DEFAULT_MODE
makes the SPIFC controller on Amlogic Meson G12B & SM1
hardware fail and is unable to recover until a system reboot.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/20241001-uboot-topic-dfu-sf-dt-v2-2-67f7acfa3ff5@linaro.org
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
diff --git a/drivers/dfu/dfu_sf.c b/drivers/dfu/dfu_sf.c
index 7c1c0f9..8f7296a 100644
--- a/drivers/dfu/dfu_sf.c
+++ b/drivers/dfu/dfu_sf.c
@@ -123,6 +123,7 @@
 	unsigned int mode = CONFIG_SF_DEFAULT_MODE;
 	char *s, *endp;
 	struct spi_flash *dev;
+	bool use_dt = true;
 
 	s = strsep(&devstr, ":");
 	if (!s || !*s || (bus = simple_strtoul(s, &endp, 0), *endp)) {
@@ -143,6 +144,8 @@
 			printf("Invalid SPI speed %s\n", s);
 			return NULL;
 		}
+		if (IS_ENABLED(CONFIG_DM_SPI_FLASH))
+			use_dt = false;
 	}
 
 	s = strsep(&devstr, ":");
@@ -152,9 +155,20 @@
 			printf("Invalid SPI mode %s\n", s);
 			return NULL;
 		}
+		if (IS_ENABLED(CONFIG_DM_SPI_FLASH))
+			use_dt = false;
 	}
 
-	dev = spi_flash_probe(bus, cs, speed, mode);
+	if (IS_ENABLED(CONFIG_DM_SPI_FLASH) && use_dt) {
+		struct udevice *new;
+
+		if (!spi_flash_probe_bus_cs(bus, cs, &new))
+			dev = dev_get_uclass_priv(new);
+		else
+			dev = NULL;
+	} else {
+		dev = spi_flash_probe(bus, cs, speed, mode);
+	}
 	if (!dev) {
 		printf("Failed to create SPI flash at %u:%u:%u:%u\n",
 		       bus, cs, speed, mode);