[U-Boot] [PATCH] spi: soft_spi: Fix null ptr when probing soft_spi.

[Horatiu Vultur]

When probing soft_spi the result of dev_get_parent_priv(dev) in probe
function is null ptr because the spi is on the ahb bus which has
per_child_auto_alloc_size set to 0. Therefore it would generate an Ooops
messages when accessing spi_slave structure.

The fix consist of delaying the read of dm_spi_slave_platdata until a
child under the spi is probed, to be able to read SPI mode. Therefore
implement .child_pre_probe in which updates soft_spi_platdata based on
child dm_spi_slave_platdata.

Signed-off-by: Horatiu Vultur <horatiu.vultur at microchip.com>
---
 drivers/spi/soft_spi.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/soft_spi.c b/drivers/spi/soft_spi.c
index b06883f..e28591b 100644
--- a/drivers/spi/soft_spi.c
+++ b/drivers/spi/soft_spi.c
@@ -210,18 +210,13 @@ static int soft_spi_ofdata_to_platdata(struct udevice *dev)
 
 static int soft_spi_probe(struct udevice *dev)
 {
-	struct spi_slave *slave = dev_get_parent_priv(dev);
 	struct soft_spi_platdata *plat = dev->platdata;
-	int cs_flags, clk_flags;
 	int ret;
 
-	cs_flags = (slave->mode & SPI_CS_HIGH) ? 0 : GPIOD_ACTIVE_LOW;
-	clk_flags = (slave->mode & SPI_CPOL) ? GPIOD_ACTIVE_LOW : 0;
-
 	if (gpio_request_by_name(dev, "cs-gpios", 0, &plat->cs,
-				 GPIOD_IS_OUT | cs_flags) ||
+				 GPIOD_IS_OUT) ||
 	    gpio_request_by_name(dev, "gpio-sck", 0, &plat->sclk,
-				 GPIOD_IS_OUT | clk_flags))
+				 GPIOD_IS_OUT))
 		return -EINVAL;
 
 	ret = gpio_request_by_name(dev, "gpio-mosi", 0, &plat->mosi,
@@ -241,6 +236,20 @@ static int soft_spi_probe(struct udevice *dev)
 	return 0;
 }
 
+static int soft_spi_child_pre_probe(struct udevice *dev)
+{
+	struct udevice *bus = dev_get_parent(dev);
+	struct dm_spi_slave_platdata *slave = dev_get_parent_platdata(dev);
+	struct soft_spi_platdata *plat = bus->platdata;
+
+	if (!(slave->mode & SPI_CS_HIGH))
+		plat->cs.flags |= GPIOD_ACTIVE_LOW;
+	if (slave->mode & SPI_CPOL)
+		plat->sclk.flags |= GPIOD_ACTIVE_LOW;
+
+	return 0;
+}
+
 static const struct udevice_id soft_spi_ids[] = {
 	{ .compatible = "spi-gpio" },
 	{ }
@@ -254,5 +263,6 @@ U_BOOT_DRIVER(soft_spi) = {
 	.ofdata_to_platdata = soft_spi_ofdata_to_platdata,
 	.platdata_auto_alloc_size = sizeof(struct soft_spi_platdata),
 	.priv_auto_alloc_size = sizeof(struct soft_spi_priv),
+	.child_pre_probe = soft_spi_child_pre_probe,
 	.probe	= soft_spi_probe,
 };
-- 
2.7.4