[PATCH 1/3] phy: phy-can-transceiver: default silent GPIO to high during probe

[haibo.chen at oss.nxp.com]

From: Haibo Chen <haibo.chen at nxp.com>

The silent pin of the CAN transceiver is active high, asserting it puts
the transceiver into silent (listen-only) mode where the transmitter is
disabled.

At probe time, and before the PHY is powered on, the transceiver should
default to silent mode. This is the correct and lower-power state: the
transceiver should not actively drive the CAN bus until the PHY is
explicitly powered on. Requesting the silent GPIO as GPIOD_OUT_LOW leaves
the transceiver in normal mode by default, which is both incorrect and
wastes power.

Request the silent GPIO as GPIOD_OUT_HIGH so the transceiver starts in
silent mode, and let the power_on/power_off callbacks manage the mode
afterwards.

Signed-off-by: Haibo Chen <haibo.chen at nxp.com>
---
 drivers/phy/phy-can-transceiver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/phy/phy-can-transceiver.c b/drivers/phy/phy-can-transceiver.c
index 75dc49e75ca0e0e90a1b1b140dcaf8033ec02c50..9aa30662105f063fb6d0e60fd04a95c8d635a515 100644
--- a/drivers/phy/phy-can-transceiver.c
+++ b/drivers/phy/phy-can-transceiver.c
@@ -198,7 +198,7 @@ static int can_transceiver_phy_probe(struct platform_device *pdev)
 
 		if (drvdata->flags & CAN_TRANSCEIVER_SILENT_PRESENT) {
 			silent_gpio = devm_gpiod_get_index_optional(dev, "silent", i,
-								    GPIOD_OUT_LOW);
+								    GPIOD_OUT_HIGH);
 			if (IS_ERR(silent_gpio))
 				return PTR_ERR(silent_gpio);
 			can_transceiver_phy->silent_gpio = silent_gpio;

-- 
2.34.1