[PATCH v3] net: phy: micrel: Fix regression in kszphy_probe

[Niklas Cassel <niklas.cassel@axis.com>]

Don't do clock-mode-select if clk == NULL,
since when building without CONFIG_HAVE_CLK,
clk_get returns NULL and clk_get_rate returns 0.

Doing clock-mode-select in this cause causes kszphy_probe to
return -EINVAL and thus prevents the device from being probed.

The original code (before regression) would return 0
when building without CONFIG_HAVE_CLK.

Cc: stable <stable@vger.kernel.org> # 3.19+
Fixes: 63f44b2bfccd ("net: phy: micrel: add generic clock-mode-select
support")
Signed-off-by: Niklas Cassel <niklass@axis.com>
---
 drivers/net/phy/micrel.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 1190fd8..f6a34e3 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -548,7 +548,11 @@ static int kszphy_probe(struct phy_device *phydev)
 	}
 
 	clk = devm_clk_get(&phydev->dev, "rmii-ref");
-	if (!IS_ERR(clk)) {
+	/* Don't check rate if clk == NULL, since when CONFIG_HAVE_CLK is not
+	 * set, clk_get returns NULL and clk_get_rate returns 0.  Doing so
+	 * would return -EINVAL and prevent the device from being probed.
+	 */
+	if (!IS_ERR_OR_NULL(clk)) {
 		unsigned long rate = clk_get_rate(clk);
 		bool rmii_ref_clk_sel_25_mhz;
 
-- 
2.1.4