releases/3.16.3/spi-orion-fix-incorrect-handling-of-cell-index-dt-property.patch

   1 From e06871cd2c92e5c65d7ca1d32866b4ca5dd4ac30 Mon Sep 17 00:00:00 2001
   2 From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   3 Date: Sun, 27 Jul 2014 23:53:19 +0200
   4 Subject: spi: orion: fix incorrect handling of cell-index DT property
   5
   6 From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   7
   8 commit e06871cd2c92e5c65d7ca1d32866b4ca5dd4ac30 upstream.
   9
  10 In commit f814f9ac5a81 ("spi/orion: add device tree binding"), Device
  11 Tree support was added to the spi-orion driver. However, this commit
  12 reads the "cell-index" property, without taking into account the fact
  13 that DT properties are big-endian encoded.
  14
  15 Since most of the platforms using spi-orion with DT have apparently
  16 not used anything but cell-index = <0>, the problem was not
  17 visible. But as soon as one starts using cell-index = <1>, the problem
  18 becomes clearly visible, as the master->bus_num gets a wrong value
  19 (actually it gets the value 0, which conflicts with the first bus that
  20 has cell-index = <0>).
  21
  22 This commit fixes that by using of_property_read_u32() to read the
  23 property value, which does the appropriate endianness conversion when
  24 needed.
  25
  26 Fixes: f814f9ac5a81 ("spi/orion: add device tree binding")
  27 Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
  28 Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
  29 Signed-off-by: Mark Brown <broonie@linaro.org>
  30 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  31
  32 ---
  33  drivers/spi/spi-orion.c |   10 ++++------
  34  1 file changed, 4 insertions(+), 6 deletions(-)
  35
  36 --- a/drivers/spi/spi-orion.c
  37 +++ b/drivers/spi/spi-orion.c
  38 @@ -346,8 +346,6 @@ static int orion_spi_probe(struct platfo
  39         struct resource *r;
  40         unsigned long tclk_hz;
  41         int status = 0;
  42 -       const u32 *iprop;
  43 -       int size;
  44
  45         master = spi_alloc_master(&pdev->dev, sizeof(*spi));
  46         if (master == NULL) {
  47 @@ -358,10 +356,10 @@ static int orion_spi_probe(struct platfo
  48         if (pdev->id != -1)
  49                 master->bus_num = pdev->id;
  50         if (pdev->dev.of_node) {
  51 -               iprop = of_get_property(pdev->dev.of_node, "cell-index",
  52 -                                       &size);
  53 -               if (iprop && size == sizeof(*iprop))
  54 -                       master->bus_num = *iprop;
  55 +               u32 cell_index;
  56 +               if (!of_property_read_u32(pdev->dev.of_node, "cell-index",
  57 +                                         &cell_index))
  58 +                       master->bus_num = cell_index;
  59         }
  60
  61         /* we support only mode 0, and no options */