spi: rspi: Fix NULL pointer dereference on SH7757

SH7757 doesn't pass platform data, in which case spi-rspi uses default
parameters.

However, commit 5ce0ba88650f2606244a761d92e2b725f4ab3583 ("spi: rcar: add
Renesas QSPI support on RSPI") added a new user of the platform data, but
forgot to check for its validity first, causing a NULL pointer dereference
on SH7757.

Add the missing check to fix this.

Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 58449ad4ad0d..b60862f58534 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -958,8 +958,9 @@ static int rspi_probe(struct platform_device *pdev)
         INIT_WORK(&rspi->ws, rspi_work);
         init_waitqueue_head(&rspi->wait);
 
-        master->num_chipselect = rspi_pd->num_chipselect;
-        if (!master->num_chipselect)
+        if (rspi_pd && rspi_pd->num_chipselect)
+                master->num_chipselect = rspi_pd->num_chipselect;
+        else
                 master->num_chipselect = 2; /* default */
 
         master->bus_num = pdev->id;