spi: Initialize cs_gpio and cs_gpios with -ENOENT

The return value from of_get_named_gpio is -ENOENT when the given index
matches a hole in the "cs-gpios" property phandle list. However, the
default value of cs_gpio in struct spi_device and entries of cs_gpios in
struct spi_master is -EINVAL, which is documented to indicate that a
GPIO line should not be used for the given spi_device.

This sets the default value of cs_gpio in struct spi_device and entries
of cs_gpios in struct spi_master to -ENOENT. Thus, -ENOENT is the only
value used to indicate that no GPIO line should be used.

Signed-off-by: Andreas Larsson <[email protected]>
Signed-off-by: Grant Likely <[email protected]>
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 38c2b92..c395f32 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -57,7 +57,7 @@
  * @modalias: Name of the driver to use with this device, or an alias
  *	for that name.  This appears in the sysfs "modalias" attribute
  *	for driver coldplugging, and in uevents used for hotplugging
- * @cs_gpio: gpio number of the chipselect line (optional, -EINVAL when
+ * @cs_gpio: gpio number of the chipselect line (optional, -ENOENT when
  *	when not using a GPIO line)
  *
  * A @spi_device is used to interchange data between an SPI slave
@@ -261,7 +261,7 @@
  *	queue so the subsystem notifies the driver that it may relax the
  *	hardware by issuing this call
  * @cs_gpios: Array of GPIOs to use as chip select lines; one per CS
- *	number. Any individual value may be -EINVAL for CS lines that
+ *	number. Any individual value may be -ENOENT for CS lines that
  *	are not GPIOs (driven by the SPI controller itself).
  *
  * Each SPI master controller can communicate with one or more @spi_device