spi: orion: fix incorrect handling of cell-index DT property

In commit f814f9ac5a81 ("spi/orion: add device tree binding"), Device
Tree support was added to the spi-orion driver. However, this commit
reads the "cell-index" property, without taking into account the fact
that DT properties are big-endian encoded.

Since most of the platforms using spi-orion with DT have apparently
not used anything but cell-index = <0>, the problem was not
visible. But as soon as one starts using cell-index = <1>, the problem
becomes clearly visible, as the master->bus_num gets a wrong value
(actually it gets the value 0, which conflicts with the first bus that
has cell-index = <0>).

This commit fixes that by using of_property_read_u32() to read the
property value, which does the appropriate endianness conversion when
needed.

Fixes: f814f9ac5a81 ("spi/orion: add device tree binding")
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: <stable@vger.kernel.org> # v3.6+

1 files changed, 4 insertions, 6 deletions

diff --git a/drivers/spi/spi-orion.c b/drivers/spi/spi-orion.c
index d018a4aac3a1..c206a4ad83cd 100644
--- a/drivers/spi/spi-orion.c
+++ b/drivers/spi/spi-orion.c
@@ -346,8 +346,6 @@ static int orion_spi_probe(struct platform_device *pdev)
         struct resource *r;
         unsigned long tclk_hz;
         int status = 0;
-        const u32 *iprop;
-        int size;
 
         master = spi_alloc_master(&pdev->dev, sizeof(*spi));
         if (master == NULL) {
@@ -358,10 +356,10 @@ static int orion_spi_probe(struct platform_device *pdev)
         if (pdev->id != -1)
                 master->bus_num = pdev->id;
         if (pdev->dev.of_node) {
-                iprop = of_get_property(pdev->dev.of_node, "cell-index",
-                                        &size);
-                if (iprop && size == sizeof(*iprop))
-                        master->bus_num = *iprop;
+                u32 cell_index;
+                if (!of_property_read_u32(pdev->dev.of_node, "cell-index",
+                                          &cell_index))
+                        master->bus_num = cell_index;
         }
 
         /* we support only mode 0, and no options */