[U-Boot] [PATCH v3] dm: spi: Read default speed and mode values from DT

[Patrick Delaunay]

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.

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 at st.com>
---

Changes in v3:
    - complete rework of the patch-set to avoid regression

Changes in v2:
    - use variables to avoid duplicated code

 README                   | 3 +++
 cmd/sf.c                 | 3 +--
 common/spl/spl_spi.c     | 2 ++
 drivers/spi/spi-uclass.c | 4 +++-
 include/spi.h            | 9 +++++----
 5 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/README b/README
index 17d56b8..f7fe74f 100644
--- a/README
+++ b/README
@@ -2184,6 +2184,9 @@ The following options need to be configured:
 		CONFIG_SF_DEFAULT_MODE 		(see include/spi.h)
 		CONFIG_SF_DEFAULT_SPEED		in Hz
 
+		In case of DT boot, SPI don't read default speed and mode
+		from CONFIG_*, but from platdata values computed from available
+		DT node
 
 - TFTP Fixed UDP Port:
 		CONFIG_TFTP_PORT
diff --git a/cmd/sf.c b/cmd/sf.c
index 84bb057..f1811d2 100644
--- a/cmd/sf.c
+++ b/cmd/sf.c
@@ -81,14 +81,13 @@ static int do_spi_flash_probe(int argc, char * const argv[])
 {
 	unsigned int bus = CONFIG_SF_DEFAULT_BUS;
 	unsigned int cs = CONFIG_SF_DEFAULT_CS;
+	/* In DM mode, defaults speed and mode will be taken from DT */
 	unsigned int speed = CONFIG_SF_DEFAULT_SPEED;
 	unsigned int mode = CONFIG_SF_DEFAULT_MODE;
 	char *endp;
 #ifdef CONFIG_DM_SPI_FLASH
 	struct udevice *new, *bus_dev;
 	int ret;
-	/* In DM mode defaults will be taken from DT */
-	speed = 0, mode = 0;
 #else
 	struct spi_flash *new;
 #endif
diff --git a/common/spl/spl_spi.c b/common/spl/spl_spi.c
index 8cd4830..9b74473 100644
--- a/common/spl/spl_spi.c
+++ b/common/spl/spl_spi.c
@@ -77,6 +77,8 @@ static int spl_spi_load_image(struct spl_image_info *spl_image,
 
 	/*
 	 * Load U-Boot image from SPI flash into RAM
+	 * In DM mode: defaults speed and mode will be
+	 * taken from DT when available
 	 */
 
 	flash = spi_flash_probe(CONFIG_SF_DEFAULT_BUS,
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;
 	}
diff --git a/include/spi.h b/include/spi.h
index 92427e5..3785941 100644
--- a/include/spi.h
+++ b/include/spi.h
@@ -496,14 +496,15 @@ int spi_find_bus_and_cs(int busnum, int cs, struct udevice **busp,
  * device and slave device.
  *
  * If no such slave exists, and drv_name is not NULL, then a new slave device
- * is automatically bound on this chip select.
+ * is automatically bound on this chip select with requested speed and mode.
  *
- * Ths new slave device is probed ready for use with the given speed and mode.
+ * Ths new slave device is probed ready for use with the speed and mode
+ * from platdata when available or the requested values.
  *
  * @busnum:	SPI bus number
  * @cs:		Chip select to look for
- * @speed:	SPI speed to use for this slave
- * @mode:	SPI mode to use for this slave
+ * @speed:	SPI speed to use for this slave when not available in platdata
+ * @mode:	SPI mode to use for this slave when not available in platdata
  * @drv_name:	Name of driver to attach to this chip select
  * @dev_name:	Name of the new device thus created
  * @busp:	Returns bus device
-- 
2.7.4