[PATCH] of: spi: Return error from of_spi_register_master on bad "cs-gpios" property

From: Andreas Larsson
Date: Wed Feb 13 2013 - 08:23:39 EST

This makes sure that an error is returned on an incorrectly formed
"cs-gpios" property, but reports success when the "cs-gpios" property is
well formed or missing.

When holes in the cs-gpios property phandle list is used to indicate
that some other form of chipselect is to be used it is important that
failure to read a broken "cs-gpios" property does not silently fail
leading to the spi controller to use an unintended chipselect.

Signed-off-by: Andreas Larsson <andreas@xxxxxxxxxxx>

Can only be applied to devicetree/next as it builds upon the
"of: Add helper for counting phandle refernces" patch series.

drivers/spi/spi.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 21c4748..9b5f024 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1068,8 +1068,11 @@ static int of_spi_register_master(struct spi_master *master)
nb = of_gpio_named_count(np, "cs-gpios");
master->num_chipselect = max(nb, (int)master->num_chipselect);

- if (nb < 1)
+ /* Return error only for an incorrectly formed cs-gpios property */
+ if (nb == 0 || nb == -ENOENT)
return 0;
+ else if (nb < 0)
+ return nb;

cs = devm_kzalloc(&master->dev,
sizeof(int) * master->num_chipselect,

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