[PATCH 5.14 075/849] spi: altera: Change to dynamic allocation of spi id

[Greg Kroah-Hartman]

From: Russ Weight <russell.h.weight@xxxxxxxxx>

[ Upstream commit f09f6dfef8ce7b70a240cf83811e2b1909c3e47b ]

The spi-altera driver has two flavors: platform and dfl. I'm seeing
a case where I have both device types in the same machine, and they
are conflicting on the SPI ID:

... kernel: couldn't get idr
... kernel: WARNING: CPU: 28 PID: 912 at drivers/spi/spi.c:2920 spi_register_controller.cold+0x84/0xc0a

Both the platform and dfl drivers use the parent's driver ID as the SPI
ID. In the error case, the parent devices are dfl_dev.4 and
subdev_spi_altera.4.auto. When the second spi-master is created, the
failure occurs because the SPI ID of 4 has already been allocated.

Change the ID allocation to dynamic (by initializing bus_num to -1) to
avoid duplicate SPI IDs.

Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
Link: https://lore.kernel.org/r/20211019002401.24041-1-russell.h.weight@xxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/spi/spi-altera-dfl.c      | 2 +-
 drivers/spi/spi-altera-platform.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-altera-dfl.c b/drivers/spi/spi-altera-dfl.c
index 39a3e1a032e04..59a5b42c71226 100644
--- a/drivers/spi/spi-altera-dfl.c
+++ b/drivers/spi/spi-altera-dfl.c
@@ -140,7 +140,7 @@ static int dfl_spi_altera_probe(struct dfl_device *dfl_dev)
 	if (!master)
 		return -ENOMEM;
 
-	master->bus_num = dfl_dev->id;
+	master->bus_num = -1;
 
 	hw = spi_master_get_devdata(master);
 
diff --git a/drivers/spi/spi-altera-platform.c b/drivers/spi/spi-altera-platform.c
index f7a7c14e36790..65147aae82a1a 100644
--- a/drivers/spi/spi-altera-platform.c
+++ b/drivers/spi/spi-altera-platform.c
@@ -48,7 +48,7 @@ static int altera_spi_probe(struct platform_device *pdev)
 		return err;
 
 	/* setup the master state. */
-	master->bus_num = pdev->id;
+	master->bus_num = -1;
 
 	if (pdata) {
 		if (pdata->num_chipselect > ALTERA_SPI_MAX_CS) {
-- 
2.33.0