dm: spi: Change cs_info op to return -EINVAL for invalid cs num

We need distinguish the following two situations in various SPI APIs:

- given chip select num is invalid
- given chip select num is valid, but no device is attached

Currently -ENODEV is returned for both cases.

For the first case, it's more reasonable to return -EINVAL instead of
-ENODEV for invalid chip select numbers.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com> # SoPine
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/doc/driver-model/spi-howto.rst b/doc/driver-model/spi-howto.rst
index 44eab39..9631a50 100644
--- a/doc/driver-model/spi-howto.rst
+++ b/doc/driver-model/spi-howto.rst
@@ -116,7 +116,7 @@ Put this code at the bottom of your existing driver file:
 	static int exynos_cs_info(struct udevice *bus, uint cs,
 				  struct spi_cs_info *info)
 	{
-		return -ENODEV;
+		return -EINVAL;
 	}
 
 	static const struct dm_spi_ops exynos_spi_ops = {
@@ -633,7 +633,7 @@ is not obvious from outside the driver. In this case you can provide a
 method for cs_info() to deal with this. If you don't provide it, then the
 device tree will be used to determine what chip selects are valid.
 
-Return -ENODEV if the supplied chip select is invalid, or 0 if it is valid.
+Return -EINVAL if the supplied chip select is invalid, or 0 if it is valid.
 If you don't provide the cs_info() method, 0 is assumed for all chip selects
 that do not appear in the device tree.