[PATCH] net: fec: add post PHY reset delay DT property

[Quentin Schulz <quentin.schulz@free-electrons.com>]

Some PHY require to wait for a bit after the reset GPIO has been
toggled. This adds support for the DT property `phy-reset-post-delay`
which gives the delay in milliseconds to wait after reset.

If the DT property is not given, no delay is observed. Post reset delay
greater than 1000ms are invalid and are default to 1ms.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
---
 Documentation/devicetree/bindings/net/fsl-fec.txt |  5 +++++
 drivers/net/ethernet/freescale/fec_main.c         | 17 +++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt b/Documentation/devicetree/bindings/net/fsl-fec.txt
index a1e3693cca16..8795e8ca5793 100644
--- a/Documentation/devicetree/bindings/net/fsl-fec.txt
+++ b/Documentation/devicetree/bindings/net/fsl-fec.txt
@@ -15,6 +15,11 @@ Optional properties:
 - phy-reset-active-high : If present then the reset sequence using the GPIO
   specified in the "phy-reset-gpios" property is reversed (H=reset state,
   L=operation state).
+- phy-reset-post-delay : Post reset delay in milliseconds. If present then
+  a delay of phy-reset-post-delay milliseconds will be observed after the
+  phy-reset-gpios has been toggled. Can be omitted thus no delay is
+  observed. Delay is in range of 1ms to 1000ms. If given delay is higher
+  than 1000ms, 1ms delay is done instead.
 - phy-supply : regulator that powers the Ethernet PHY.
 - phy-handle : phandle to the PHY device connected to this device.
 - fixed-link : Assume a fixed link. See fixed-link.txt in the same directory.
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 56a563f90b0b..00a7fd0bcd59 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -3192,7 +3192,7 @@ static int fec_reset_phy(struct platform_device *pdev)
 {
 	int err, phy_reset;
 	bool active_high = false;
-	int msec = 1;
+	int msec = 1, phy_post_delay = 0;
 	struct device_node *np = pdev->dev.of_node;
 
 	if (!np)
@@ -3210,7 +3210,6 @@ static int fec_reset_phy(struct platform_device *pdev)
 		return 0;
 
 	active_high = of_property_read_bool(np, "phy-reset-active-high");
-
 	err = devm_gpio_request_one(&pdev->dev, phy_reset,
 			active_high ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
 			"phy-reset");
@@ -3219,6 +3218,11 @@ static int fec_reset_phy(struct platform_device *pdev)
 		return err;
 	}
 
+	err = of_property_read_u32(np, "phy-reset-post-delay", &phy_post_delay);
+	/* valid reset duration should be less than 1s */
+	if (!err && phy_post_delay > 1000)
+		phy_post_delay = 1;
+
 	if (msec > 20)
 		msleep(msec);
 	else
@@ -3226,6 +3230,15 @@ static int fec_reset_phy(struct platform_device *pdev)
 
 	gpio_set_value_cansleep(phy_reset, !active_high);
 
+	if (!phy_post_delay)
+		return 0;
+
+	if (phy_post_delay > 20)
+		msleep(phy_post_delay);
+	else
+		usleep_range(phy_post_delay * 1000,
+			     phy_post_delay * 1000 + 1000);
+
 	return 0;
 }
 #else /* CONFIG_OF */
-- 
2.11.0