[PATCH] phy: can-transceiver: Re-instate "mux-states" property presence check

[Geert Uytterhoeven]

On the Renesas Gray Hawk Single development board:

    can-transceiver-phy can-phy0: /can-phy0: failed to get mux-state (0)

"mux-states" is an optional property for CAN transceivers.  However,
mux_get() always prints an error message in case of an error, including
when the property is not present, confusing the user.

Fix this by re-instating the property presence check.

This is bascially a revert of commit d02dfd4ceb2e9f34 ("phy:
can-transceiver: Drop unnecessary "mux-states" property presence
check"), with two changes:
  1. Use the proper API for checking whether a property is present,
  2. Do not print an error message, as the mux core already takes care
     of that.

Fixes: d02dfd4ceb2e9f34 ("phy: can-transceiver: Drop unnecessary "mux-states" property presence check")
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
Alternatively, the multiplexer subsystem needs to gain support for
getting an optional mux...
---
 drivers/phy/phy-can-transceiver.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/phy/phy-can-transceiver.c b/drivers/phy/phy-can-transceiver.c
index 2bec70615449f94d..539b3446b9c33eed 100644
--- a/drivers/phy/phy-can-transceiver.c
+++ b/drivers/phy/phy-can-transceiver.c
@@ -103,7 +103,6 @@ static int can_transceiver_phy_probe(struct platform_device *pdev)
 	struct phy *phy;
 	struct gpio_desc *standby_gpio;
 	struct gpio_desc *enable_gpio;
-	struct mux_state *mux_state;
 	u32 max_bitrate = 0;
 	int err;
 
@@ -114,11 +113,13 @@ static int can_transceiver_phy_probe(struct platform_device *pdev)
 	match = of_match_node(can_transceiver_phy_ids, pdev->dev.of_node);
 	drvdata = match->data;
 
-	mux_state = devm_mux_state_get(dev, NULL);
-	if (IS_ERR(mux_state)) {
-		if (PTR_ERR(mux_state) == -EPROBE_DEFER)
+	if (of_property_present(dev->of_node, "mux-states")) {
+		struct mux_state *mux_state;
+
+		mux_state = devm_mux_state_get(dev, NULL);
+		if (IS_ERR(mux_state))
 			return PTR_ERR(mux_state);
-	} else {
+
 		can_transceiver_phy->mux_state = mux_state;
 	}
 
-- 
2.43.0