[PATCH v2] mmc: atmel-sdhci: fix the clk_enable call in case of no ops

[Eugen Hristev <eugen.hristev@microchip.com>]

If the clock driver does not offer a clk_enable ops, then the system will
return -ENOSYS.
The clk_enable works with CCF (common clock framework).
Some clocks in some cases (like the generic clock for some products: sama5d2)
do not have the clk_enable primitive, and in this case probing of the driver
will fail.
This patch changes the behavior to return an error in case there is really
an error, and not a missing primitive.
If the clock driver does not have an enable primitive, most likely clocks
are always enabled or enabled in the set_rate primitives.

Fixes: 81f16438d4 ("mmc: atmel-sdhci: enable the required generic clock")
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
Changes in v2:
- fixed issue with ret being 0, it was going to return ret;, when in fact
there was no error. Have to check for both ret != 0 and ret != -ENOSYS.


 drivers/mmc/atmel_sdhci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/atmel_sdhci.c b/drivers/mmc/atmel_sdhci.c
index f56ae63bc2..ca7a98bf1d 100644
--- a/drivers/mmc/atmel_sdhci.c
+++ b/drivers/mmc/atmel_sdhci.c
@@ -86,7 +86,8 @@ static int atmel_sdhci_probe(struct udevice *dev)
 		return -EINVAL;
 
 	ret = clk_enable(&clk);
-	if (ret)
+	/* return error only if the clock really has a clock enable func */
+	if (ret && ret != -ENOSYS)
 		return ret;
 
 	ret = mmc_of_parse(dev, &plat->cfg);
-- 
2.25.1