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 <andr...@gaisler.com>
---
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,
--
1.7.0.4
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